The 2003 Nobel Prize in Physics
Transcription
The 2003 Nobel Prize in Physics
2 AAPPS Bulletin Vol. 13, No. 5 Highlight of the Issue The 2003 Nobel Prize in Physics The Royal Swedish Academy of Sciences 1. SUPERFLUIDS AND SUPERCONDUCTORS: QUANTUM MECHANICS ON A MACROSCOPIC SCALE Superfluidity or superconductivity—which is the preferred term if the fluid is made up of charged particles like electrons—is a fascinating phenomenon that allows us to observe a variety of quantum mechanical effects on the macroscopic scale. Besides being of tremendous interest in themselves and vehicles for developing key concepts and methods in theoretical physics, superfluids have found important applications in modern society. For instance, superconducting magnets are able to create strong enough magnetic fields for the magnetic resonance imaging technique (MRI) to be used for diagnostic purposes in medicine, for illuminating the structure of complicated molecules by nuclear magnetic resonance (NMR), and for confining plasmas in the context of fusion-reactor research. Superconducting magnets are also used for bending the paths of charged particles moving at speeds close to the speed of light into closed orbits in particle accelerators like the Large Hadron Collider (LHC) under construction at CERN. The Royal Swedish Academy of Scinces (Kung1 Vetenskapsakademien) Information Department P. O. BOX 50005 SE-104 05 Stockholm, Sweden Phone:+46-8-673-95-00 Fax: +46-8-15-56-70 E-mail: info@kva.se Website: www.kva.se The content of this Highlight on “The 2003 Nobel Prize in Physics” was released originally by the Nobel Foundation on the website Nobel e-Museum. Permission for reprinting in the Bulletin this news release was requested and granted. 1.1. Discovery of Three Model Superfluids Two experimental discoveries of superfluids were made early on. The first was made in 1911 by Heike Kamerlingh Onnes (Nobel Prize in 1913), who discovered that the electrical resistance of mercury completely disappeared at liquid helium temperatures. He coined the name “superconductivity” for this phenomenon. The second discovery—that of superfluid 4 He—was made in 1938 by Pyotr Kapitsa and independently by J. F. Allen and A. D. Misener (Kapitsa received the 1978 Nobel Prize for his inventions and discoveries in low temperature physics). It is believed that the superfluid transition in 4He is a manifestation of Bose-Einstein condensation, i.e. the tendency of particles—like 4He—that obey Bose-Einstein statistics to condense into the lowest-energy single—particle state at low temperatures (the strong interaction between the helium atoms blurs the picture somewhat). Electrons, however, obey Fermi-Dirac statistics and are prevented by the Pauli principle from having more than one particle in each state. This is why it took almost fifty years to discover the mechanism responsible for superconductivity. The key was provided by John Bardeen, Leon Cooper and Robert Schrieffer, whose 1957 “BCS theory” showed that pairs of electrons with opposite momentum and spin projection form “Cooper pairs.” For this work they received the 1972 Nobel Prize in Physics. In their theory the Cooper pairs are structureless objects, i.e. the two partners form a spin-singlet in a relative s-wave orbital state, and can to a good approximation be thought of as composite bosons that undergo Bose-Einstein condensation into a condensate characterised by macroscopic quantum coherence. Since both the Cooper pairs of the original BCS theory and the helium atoms are spherically symmetric objects, they form isotropic superfluids on condensation. The situation is more complex—and therefore more interesting—in a third model superfluid discovered by David Lee, Douglas Osheroff, and Robert Richardson in 1972. Their discovery of superfluidity in 3He was rewarded by a Nobel Prize in 1996. While 4He is a boson, 3He with three rather than four nucleons is a fermion, AAPPS Bulletin October 2003 3 “for pioneering contributions to the theory of superconductors and superfluids” ©Stephen J. Carrera@Associated Press, AP Alexei A. Abrikosov 1/3 of the prize USA and Russia Argonne National Laboratory Argonne, IL, USA b. 1928 ©Alexander Zemlianichenko@Associated Press, AP Vitaly L. Ginzburg 1/3 of the prize Russia P. N. Lebedev Physical Institute Moscow, Russia b. 1916 and superfluid 3He is formed by condensation of Cooper pairs of 3He atoms (or more precisely of “quasiparticles” of atoms each with a surrounding cloud of other atoms) that have internal degrees of freedom. This is because the two partners form a spin-triplet in a relative orbital p-state. Both the net spin of the pair and their relative orbital momentum are therefore different from zero and the superfluid is intrinsically anistropic; roughly speaking, each pair carries two vectors that can point in various directions as will be discussed below. 1.2. Broken Symmetry and the Order Parameter Even before the discovery of superfluid 3He, theoreticians had been interested in anistropic superfluids. In order to appreciate their significance it is useful to recall the importance of the concepts of order parameter and spontaneously broken symmetry in the theory of superfluidity. The concept of an order parameter was introduced by Lev Landau in connection with his 1937 theory of second order phase transitions. The order parameter is a quantity that is zero in the disordered phase above a critical temperature Tc, but has a finite value in the ordered state below Tc. In the theory of ferromagnetism, e.g., spontaneous magnetisation, which is zero in the magnetically disordered paramagnetic state and nonzero in the spin-ordered ferromagnetic state, is chosen to be the order parameter of the ferromagnetic state. Clearly, the existence of a preferred direction of the spins implies that the symmetry of the ferromagnet under spin rotation is reduced (“broken”) when compared to the paramagnet. This is the phenomenon called spontaneously (i.e. not caused by any external field) broken symmetry. It describes the property of a macroscopic system in a state that does not have the full symmetry of the underlying microscopic dynamics. ©Bill Wiegand@University of Illinois Anthony J. Leggett 1/3 of the prize United Kingdom and USA University of Illinois Urbana, IL, USA b. 1938 In the theory of superfluidity the order parameter measures the existence of Bose condensed particles (Cooper pairs) and is given by the probability amplitude of such particles. The interparticle forces between electrons, between 4He and between 3He atoms, are rotationally invariant in spin and orbital space and, of course, conserve particle number. The latter symmetry gives rise to a somewhat abstract symmetry called “gauge symmetry”, which is broken in any superfluid. In the theory of isotropic superfluids like a BCS superconductor or superfluid 4He, the order parameter is a complex number with two components, an amplitude and a phase (“gauge”) . Above Tc the system is invariant under an arbitrary change of the phase ’, i.e. under a gauge transformation. Below Tc a particular value of is spontaneously preferred. 1.3. Multiple Simultaneously Broken Continuous Symmetries In anistropic superfluids, additional symmetries can be spontaneously broken, corresponding to an order parameter with more components. In 3He—the best studied example with a parameter having no fewer than 18 components—the pairs are in a spin-triplet state, meaning that rotational symmetry in spin space is broken, just as in a magnet. At the same time, the anisotropy of the Cooper-pair wave function in orbital space calls for a spontaneous breakdown of orbital rotation symmetry, as in liquid crystals. Including the gauge symmetry, three symmetries are therefore broken in superfluid 3He. The 1972 theoretical discovery that several simultaneously broken symmetries can appear in condensed matter was made by Anthony Leggett, and represented a breakthrough in the theory of anisotropic superfluids. This leads to superfluid phases whose properties cannot be understood by simply adding the properties 4 Vitaly L. Ginzburg, 87, a Russian based at the P. N. Lebedev Physical Institute in Moscow, looks through some notes at his institute, Tuesday, Oct. 7, 2003. Two American citizens and a Russian scientist Ginzburg won the 2003 Nobel Prize in physics Tuesday for theories about how matter can show bizarre behavior at extremely low temperatures. The US$1.3 million prize money will be shared equally among the three winners. (Photo by Aelxander Zemlianichenko, Associated Press) of systems in which each symmetry is broken individually. Such phases may have long range order in combined, rather than individual degrees of freedom, as illustrated in Fig. 1. An example is the so-called A phase of superfluid 3He. Leggett showed, for example, that what he called spontaneously broken spin-orbit symmetry leads to unusual properties that enabled him to identify this phase with a particular microscopic state, the ABM state (see below). The microscopic 1957 BCS theory of superconductivity represents a major breakthrough in the understanding of isotropic charged superfluids (superconductors). The original theory does not, however, address the properties of anisotropic superfluids (like superfluid 3He, high temperature superconductors, and heavy fermion superfluids), which were treated much later with decisive contributions from Leggett and others. Neither is the BCS theory able to describe inhomogeneous superfluids with an order parameter that varies in space as may happen, for example, in the presence of a magnetic field. A particularly important example of such a phenomenon is the type of superconductor used in the powerful superconducting magnets mentioned earlier. Here superconductivity and magnetism coexist. The theoretical description of this very important class of superconductors relies on a phenomenological theory developed in the 1950s by Alexei Abrikosov, building on previous work by Vitaly Ginzburg and Lev Landau (Landau, who received the Nobel Prize in physics in 1962, died in 1968). 1.4. Superconductivity and Magnetism Superconductivity is characterised by electron pairs (or holes) AAPPS Bulletin Vol. 13, No. 5 Nobel Prize winner for physics Alexei Abrikosov, right, talks with fellow researcher Valerii Vinokour, left, in Abrikosov’s office at the Argonne National Laboratory in Argonne III. Tuesday, Oct. 7, 2003. Abrikosov, a Russian, and two American citizens won the 2003 Nobel Prize in physics for their work concerning two phenomena called super conductivity and super fluidity. (Photo by Stephen J. Carrera, Associated Press) that have condensed into a ground state, where they all move coherently. This means not only that the resistance disappears but also that a magnetic field is expelled from the superconductor (the charged superfluid). This is known as the Meissner effect. Many superconductors show a complete Meissner effect, which means that a transition from the superconducting to the normal state occurs discontinuously at a certain critical external magnetic field Hc. Other superconductors, in particular alloys, only show a partial Meissner effect or none at all. Work done in Kharkov by A. Shubnikov and by others elsewhere showed that the magnetisation may change continuously as the external field is increased, starting at a lower critical field, Hc1, while the superconductor continues to show no resistance up to a much higher upper critical field, Hc2. This effect is illustrated in Fig. 2. Between the lower and the upper critical fields the superconducting state coexists with a magnetic field. The theoretical framework for understanding the behavior of superconductors in the presence of such strong magnetic fields was developed in the 1950’s by a group of Soviet physicists. In a groundbreaking paper, published in 1957, Abrikosov discovered the vortices in the order parameter of a superconductor and described their crucial role for the coexistence of a magnetic field and superconductivity in superconductors “of the second group,” or in “type-II superconductors” as we would say today. In the same paper, Abrikosov provided an amazingly detailed prediction—later to be borne out by experiments—of the way in which a stronger magnetic field suppresses superconductivity: vortices, which form a lattice, come closer to each other, and at some field the vortex cores overlap, suppressing the order parameter everywhere in the su- AAPPS Bulletin October 2003 5 (a) (b) (d) ”A phase” (c) (d) ”B phase” Fig. 1: The possible states in a two-dimensional model liquid of particles with two internal degrees of freedom: spin (full-line arrow) and orbital angular momentum (broken-line arrow). (a) Disordered state: isotropic with respect to the orientation of both degrees of freedom. The system is invariant under separate rotations in spin and orbital space and has no long range order (paramagnetic liquid). (b)—(e) States with different types of long range order corresponding to all possible broken symmetries. (b) Broken rotational symmetry in spin space (ferromagnetic liquid). (c) Broken rotational symmetry in orbital space (“liquid crystal”). (d) Rotational symmetries in both spin and orbital space separately broken (as in the A phase of superfluid 3He). (e) Only the symmetry related to the relative orientation of the spin and orbital degrees of freedom is broken (as in the B phase of superfluid 3He). Leggett introduced the term spontaneosuly broken spin-orbit symmetry for the broken symmetry leading to the ordered states in (d) and (e). perconducting material—hence driving it into the normal state. Abrikosov’s results came from an insightful analysis of the Ginzburg-Landau equations, a phenomenological description of superconductivity published in 1950 by Vitaly Ginzburg and Lev Landau. One of the motivations behind their work was the need to develop a theory that would make it possible to describe correctly the destruction of superconductivity by a magnetic field or an electric current. The Ginzburg-Landau equations have proved to be of great importance in physics, not only for describing superconductivity in the presence of a magnetic field. In their 1950 paper Ginzburg and Landau were the first to realize that superconductors can be divided into two classes with regard to their behaviour in a magnetic field. They introduced a quantity , now known as the GinzburgLandau parameter, which enabled them to make a distinction between the two classes. Superconductors with < 1/ do not allow the coexistence of a magnetic field and superconductivity in the same volume. Superconducting materials with do allow for such a coexistence. In modern language is the ratio of the magnetic field penetration length and the coherence length . The superconductors known at the time had <<1, e.g., ≈ 16 for mercury. That is why Ginzburg and Landau did not seriously pursue this parameter region beyond showing that if a material with > 1/ is placed in a magnetic field somewhat larger than the thermodynamic critical value, the normal phase is unstable with respect to formation of a su- perconducting state. However, they introduced the crucial notions of a superconducting order parameter, of negative surface energy of the boundary separating the superconducting from the normal phase in type-II superconductors, and (in modern terminology) of the upper critical magnetic field, where superconductivity vanishes in type-II materials. Even so, it was left to Abrikosov to describe in 1957 the result of this instability and to formulate the complete phenomenological theory of typeII superconductors. At the same time it is clear that the GinzburgLandau equation and the partial understanding achieved by Ginzburg and Landau was a necessary basis for his work. Below we describe the main contributions of Abrikosov, Ginzburg and Leggett, the 2003 Nobel Physics Laureates, in some more detail. We will do this in the chronological order the contributions were made. [Readers who want to skip the next three, somewhat technical sections, can go directly to the last section on the importance of the contributions.] 2. GINZBURG-LANDAU THEORY When Ginzburg and Landau formulated their phenomenological theory of superconductivity in 1950, almost 50 years had passed since Kamerlingh Onnes discovered the superfluid electron liquid in mercury. This was well before the BCS theory but a certain level of understanding had been reached using phenomenological methods. Early on, Gorter and Casimir introduced the two-fluid model (a similar model was developed for superfluid helium). They divided the conduction electrons into two groups, a superconducting condensate and normal elec- 6 trons excited from the condensate. Later, in 1935, the brothers Fritz and Heinz London presented a phenomenological theory that could explain why a magnetic field does not penetrate further into a metal than the London penetration depth , , a concept we have already alluded to. However, the London theory could not describe correctly the destruction of superconductivity by a magnetic field or current. Nor did it allow a determination of the surface tension between the superconducting and normal phases in the same material. [Landau had in 1937 assumed the surface tension to be positive in his theory of the so called intermediate state.] Neither could the London theory explain why the critical magnetic fields needed to destroy superconductivty in thin films are different from the critical fields for bulk superconductors of the same material. These deficiencies provided the motivation for Ginzburg and Landau. Their phenomenological Ginzburg-Landau theory of superconductivity was indeed able to solve these problems. The Ginzburg-Landau (GL) theory is based on Landau’s theory of second order phase transitions from 1937. This was a natural starting point, since in the absence of a magnetic field the transition into the superconducting state at a critical temperature Tc is a second-order phase transition. Landau’s theory describes the transition from a disordered to an ordered state in terms of an “order parameter,” which is zero in the disordered phase and nonzero in the ordered phase. In the theory of ferromagnetism, for example, the order parameter is the spontaneous magnetisation. In order to describe the transition to a superconducting state, GL took the order parameter AAPPS Bulletin Vol. 13, No. 5 to be a certain complex function ( ), which they interpreted as the “effective” wave function of the “superconducting electrons,” whose density ns is given by | |2; today we would say that ( ) is the macroscopic wave function of the superconducting condensate. In accordance with Landau’s general theory of second-order phase transitions, the free energy of the superconductor depends only on | |2 and may be expanded in a power series close to Tc. Assuming first that ( ) does not vary in space, the free energy density becomes where the subscripts n and s refer to the contributions from the normal and the superconducting state respectively. A stable superconducting state is obtained if is a positive constant and (T-Tc ). 0 Since the purpose of Ginzburg and Landau was to describe the superconductor in the presence of a magnetic field, H, when the order parameter may vary in space, gradient terms had to be added to the expansion. The lowest order gradient term looks like a kinetic energy term in quantum mechanics, which is why GL wrote it—adding a term for the magnetic field energy—as Here the magnetic field is described by its vector potential, A (r), which enters the kinetic energy term as Fig. 2: (Colour) Magnetisation M (blue) and induced field B (red) as a function of external magnetic field H for superconductors with complete (dashed lines) and partial (full lines) Meissner effect (see text). AAPPS Bulletin October 2003 7 Fig. 3: Sketch of the border region between a normal and a superconducting phase, illustrating the concepts of penetration length and coherence length . If the magnetic field is Hc in the normal phase, it decays to zero in the superconducting phase over a length . At the same time the superconducting order increases from zero at the interface to its full value inside the superconducting phase over a distance . required by gauge-invariance. The total free energy Fs is obtained by integrating the free energy density fs over volume. By minimising the free energy Fs with respect to the GL equations are obtained. They are * and A, plus a boundary condition. The second equation has the same form as the usual expression for the current density in quantum mechanics, while the first—except for a term nonlinear in , which acts like a repulsive potential—resembles the Schrödinger equation for a particle of mass m*, charge e* with energy eigenvalue - . In their paper Ginzburg and Landau wrote that “e* is the charge, which there is no reason to consider as different from the electronic charge.” As soon as they learned about the BCS theory and Cooper pairs, however, they realized that e*=2e and m*=2m. The GL equations are capable of describing many phenomena. An analysis shows, for example, that a magnetic field penetrating into a superconductor decays with its distance from the border to a normal phase region over a characteristic length , 2 * *2 where m /( | | e ). This is the London penetration length. Furthermore, it is found that a disturbance from an equilibrium value of the order parameter, decays over a characteristic length , where Therefore, the penetration length and the coherence length are two characteristic lengths in the GL theory. [Although the physics was clear to them, Ginzburg and Landau used neither this notation nor this terminology; the concept of a coherence length was only introduced three years later by B. Pippard]. The two lengths have the same temperature dependence close to Tc, where In 1950 Ginzburg and Landau made a number of predictions for the critical magnetic field and critical current density for thin superconducting films and the surface energy between superconducting and normal phases of the same material. These predictions could soon be tested experimentally with positive results. At this point a short digression about the surface energy between superconducting and normal phases of the same material is called for. It follows from the GL equations that this quantity depends on the two characteristic lengths and in a way that can be understood from Fig. 3. The penetration of the magnetic field, a distance of the order , into the superconductor corresponds to a gain in energy, which is proportional to and due to the decreased distortion of the field. On the other hand, the fact that the superconducting state vanishes over a distance of the order close to the border decreases the gain in condensation energy, and hence gives an energy increase proportional to . The net surface energy is the sum of the two contributions and can be expressed as In terms of the Ginzburg-Landau parameter k = / we see that the surface energy is positive if k > 1/ and negative if k > 1/ . Ginzburg and Landau were mainly interested in clean metals for which is much smaller than unity. Nevertheless, they did note this fact and pointed out 8 that there is a “peculiar” instability of the normal phase of the metal if k > 1/ , which is associated with this negative surface energy. 3. THEORY OF TYPE-II SUPERCONDUCTORS One of the physicists who soon began to test the predictions of the GL theory was the young N. V. Zavaritzkii. Working at the Kapitsa Institute for Physical Problems in Moscow, he was able to verify the theoretical predictions about the dependence on film thickness and temperature of the critical magnetic field of superconducting films. However, when he tried to make better samples by a new technique (vapour deposition on glass substrates at low temperatures) he discovered that the critical fields no longer agreed with the GL theory. He brought this to the attention of his room mate at the university, Alexei Abrikosov. Abrikosov looked for a solution to this mystery within the GL theory and started to think about the true nature of the superconducting state for k > 1/ . In contrast to the superconductors that were the focus of Ginzburg’s and Landau’s interest in 1950, the new materials had values in this parameter regime. In 1952 Abrikosov was able to calculate the critical magnetic fields for this parameter regime and found agreement with Zavaritzkii’s measurements. Abrikosov continued to think about strongly “type-II superconductors” with large values of k. It was clear that superconductivity could not exist in magnetic fields of a certain strength. But Abrikosov was able to show that when the field is diminished again, small superconducting regions start to nucleate at a magnetic field Hc2 Hc / , which for k > is larger than the Fig. 4: Abrikosov lattice of magnetic flux lines (vortices) in NbSe2 — a type-II superconductor - visualised by magneto-optical imaging. The first pictures of such a vortex lattice were taken in 1967 by U. Essmann and H. Träuble, who sprinkled their sample surfaces with aferromagnetic powder that arranges itselfin a pattern reflecting the magnetic flux line structure. AAPPS Bulletin Vol. 13, No. 5 thermodynamic critical field Hc. The latter is the critical field that is relevant for normal, or “type-I” superconductors. We now call Hc2 the upper critical magnetic field. However, the material is not completely superconducting in the sense that the magetic field vanishes everywhere in the material. Abrikosov found that a periodic distribution of the magnetic field, as a lattice, minimised the total energy. An experimentally observed Abrikosov lattice of this type is shown in Fig. 4. The approach that worked for magnetic fields just below the upper critical field, where the order parameter is small and the nonlinear term in the first GL equation can be neglected, does not work for much weaker fields. However, by studying the nature of the solutions for fields just below Hc2, Abrikosov realised that they correspond to vortices in the order parameter and that this type of solution must be valid for weaker fields as well. The point is that because we require the theory to be gauge invariant, the vector potential A and the phase of the order parameter = exp (i ) appear in the combination in the first GL equation. Now, for the magnetic field to be constant inside the superconductor A has to grow. If, for example, we choose a gauge where the y component of A grows linearly in the x direction, so that Hz = ∂Ay /∂x with Ay = Hzx , the magnetic field points in the z direction. If the free energy is not to grow without limit, the growth in the vector potential has to be compensated by jumps in the phase. It turns out that this corresponds to vortex solutions in which the order parameter vanishes at the points of a regular (triangular or hexagonal) lattice and the phase of the order parameter changes by 2 on a closed contour around these lattice points. Abrikosov discovered these solutions in 1953, but they were unexpected and he did not publish them until 1957. The suggestion by R. P. Feynman in 1955 that vortex filaments are formed in superfluid 4He had then reached the Soviet Union. The level of scientific contact between East and West was very low during the Cold War and the work of Soviet scientists did not, in general, get much attention from researchers in the West. The work of Ginzburg-Landau was received with scepticism until L. P. Gorkov showed in 1959 that the GL equations could be derived from the microscopic BCS theory in the appropriate limit. Later, P. C. Hohenburg showed that the GL equations are valid not only close to the transition point in temperature or magnetic field but also at temperatures and in magnetic fields where the superconducting order is not small. The work of Abrikosov was not fully appreciated in the West until the 1960s, when superconductors with very high critical fields had been discovered. 4. SUPERFLUID 3He—A MODEL ANISOTROPIC SUPERFLUID AAPPS Bulletin October 2003 We have already remarked that 3He with its two electrons and three nucleons is a fermion. A large class of interacting fermion systems, like the normal electron liquid in many metals, can be described by Landau’s fermi liquid theory developed during the 1950’s. At the time of the BCS theory experimentalists had started to investigate the properties of liquid 3He to see if it could be described by the Landau theory. J.C. Wheatly played a decisive role here by showing that liquid 3He could indeed be very well described by Landau’s fermi liquid theory below 100 mK. This is a much higher temperature than 2.7 mK, which later proved to be the critical temperature for a transition to the superfluid state. For a quantitative understanding of the liquid this result was important, since the atoms in liquid 3He interacts strongly with each other. Landau’s theory is phenomenological and describes a system of interacting fermi particles in terms of “quasiparticles,” a term he introduced. A quasiparticle can be viewed as a “bare” particle interacting with a cloud of surrounding particles. The theory has one parameter, the effective mass m*, which describes the single-quasiparticle excitation spectrum, and a number of parameters that describe the effects of external fields. Often it is sufficient to have a few of these parameters, which can be determined from experiments. Landau’s theory applies at “low enough” temperatures—a criterion that for liquid 3He is very well satisfied at the transition temperature to superfluidity. In the mid 1960s Leggett was able to extend the Landau theory to the superfluid phases and calculate the (large) renormalisation of the nuclear spin susceptibility by interaction effects. His prediction agreed very well with later NMR measurements (see below). Liquid 3He was, as we have seen, of considerable experimental interest from the mid 1950s on. Only a few years after the publication of the BCS theory several authors—among them Pitaevskii; Brueckner, Soda, Anderson, and Morel; and Emery and Sessler—suggested that a BCS-like pair condensation into a superfluid state might occur in liquid 3He. It was immediately clear that the strong repulsive interaction between the atoms would favour a relative orbital momentum state corresponding to p- or d-wave pairing in which the pair particles would be kept at some distance from each other. The superfluid would then be anisotropic, as we have discussed earlier in this text. We now know that the condensed pairs of 3He atoms are in a relative p-state (L=1), which means that the total wave function is antisymmetric with respect to an exchange of the spatial coordinates of two particles. Since the total wave function has to be antisymmetric (the Pauli principle) it follows that the wave function must be even with respect to an exchange of the spin coordinates of the two particles. The total spin of the pair must therefore be in a spin triplet state (S=1) with three possible values of the spin projection (Sz = +1, 0, -1) 9 and ( ) corresponding to the spin states ( ), ( + )/ . Some properties of anistropic superfluids that can form under these circumstances were calculated theoretically. In 1961 P. W. Anderson and P. Morel proposed a superfluid condensate of pairs forming spin triplets with circular polarization (Sz= 1), where only the states ( ) and ( ) are involved (the ABM state). Two years later, however, R. Balian and N. R. Wertheimer and independently Y. A. Vdovin showed that lower energy is achieved with a pair state that also involves the spin state ( )/ (the BW state). The experimental discovery of the superfluid A, B and A1 phases in 3He was made in 1972 by David Lee, Douglas Osheroff and Robert Richardson. Investigations, together with W. J. Gully, of the collective magnetic (i.e. spin-dependent) properties of the superfluid phases by nuclear magnetic resonance (NMR) were particularly useful in identifying the order parameter structure of these phases. In ordinary NMR experiments the system under study is subjected to a strong magnetic field Ho in the z direction, which forces the spin S to precess around Ho. By applying a weak magnetic field Hrf of high frequency perpendicular to Ho, it is possible to induce transitions in Sz, the component along Ho, of magnitude . This effect is observed as energy absorption from the magnetic field. If the spins do not interact, these transitions occur exactly when equals the Larmor frequency Ho, where is the gyromagnetic ratio of the nucleus. In fact, as long as the interactions in the system conserve spin it had been shown that the resonance remains at the Larmor frequency. On the other hand, for interactions that do not conserve spin, such as the spin-orbit interaction caused by the dipole coupling of the nuclear spins, a shift may occur. Normally this is expected to be very small, of the order of the line width. The NMR data published in connection with the experimental discovery of the superfluid phases was therefore a major surprise since it was found that although the resonance was still very sharp, it occurred at frequencies substantially higher than L. The solution to this puzzling fact was immediately found by Leggett, who showed that the NMR shifts are a consequence of the “spontaneously broken spin-orbit symmetry” of the spin-triplet p-wave state. As explained earlier, the meaning of this concept is that the preferred directions in spin and orbital space are longrange ordered, as illustrated for a simpler model in Fig. 1d and 1e. The tiny dipole interaction may take advantage of this situation; the macroscopic quantum coherence of the condensate raises the dipole coupling to macroscopic importance the dipoles are aligned in the same direction and their moments add up coherently. In this way Leggett was first able to calculate the general NMR response of a spin-triplet p-wave condensate. In particular in the A-phase the transverse NMR frequency t is given by 2 t = 2 L + 2 A (T) 10 AAPPS Bulletin Vol. 13, No. 5 describe this state the ABM state). This only happens at somewhat elevated pressures, when the spin fluctuations become more pronounced. This left room for the B phase to be identified with the BW state, which was soon done. Finally, V. Ambegaokar and N. D. Mermin identified the A1 phase, which appears at higher magnetic fields, with a state where only one of the spin states ( ) and ( ) is involved. 5. IMPORTANCE Fig. 5: Vortex lines in a superfluid are analogous to the flux lines that occur in a type-II superconductor when it is placed in a magnetic field (Cf. Fig. 4). The picture illlustrates vortex lines in rotating superfluid 3He, where the vortex structure is particularily rich. The vortex lines are shown in yellow, and the circulating flow around them is indicated by arrows. where A2 (T) is proportional to the dipole coupling constant and depends on temperature but not on H o. Later, Leggett worked out the complete theory of the spin dynamics, whose predictions were experimentally confirmed in every detail. One of the predictions that were confirmed concerned “longitudinal” resonant NMR absorption in both the A and the B phase of energy from a high-frequency field oriented parallel with rather than perpendicular to the static field. In the A phase the resonant frequency of this longitudinal oscillation occurs at A (T) where A(T) is the same frequency that appears in the expression for the transverse frequency. Leggett identified the ABM state as a candidate to describe the A phase of superfluid 3He, but noted that the BW state had been shown to have the lower energy. This, however, had only been proven within “weak-coupling” theory. After Leggett’s prediction it became necessary to consider “strong-coupling” effects. The attractive interaction that is responsible for the pair formation in liquid helium is due to to the liquid itself, unlike (conventional) superconductors, where the pairing interaction between electrons is mediated by the lattice. P. W. Anderson and W. Brinkman showed that there is a conceptually simple effect that can explain the stabilisation of the ABM state over the BW state. It is based on a feedback mechanism: the pair correlations in the condensed state change the pairing interaction between the 3He quasiparticles in a manner that depends on the state itself. As a specific interaction mechanism, Anderson and Brinkman considered spin fluctuations and found that a stabilisation of the state first proposed by Anderson and Morel is possible (hence the initials of all three authors are used to The Ginzburg-Landau (GL) theory has been important in many fields of physics, including particle physics, where it is used in string theory. Today, the GL theory is extensively used to describe superconductive properties that are important in practical applications. This theory is able to describe, for example, spatially varying superconducting order, superconductivity in strong magnetic fields and fluctuating time-dependent superconducting order. Abrikosov’s theory of superconductors in a magnetic field created a new field of physics the study of type-II superconductors. After the discovery in 1986 of the ceramic “high-temperature” superconductors, which are extreme typeII superconductors, by Gerd Bednorz and Alex Müller (Nobel Prize 1987) research to understand and use these new materials has become a very large activity. The vortex/flux lines discovered by Abrikosov are very important for the properties of these materials the term “vortex matter” is used. The work of Leggett was crucial for understanding the order parameter structure in the superfluid phases of 3He. His discovery that several simultaneously broken symmetries can appear in condensed matter is, however, of more general importance for understanding complex phase transitions in other fields as well, like liquid crystal physics, particle physics, and cosmology. 6. REFERENCES [1] A. A. Abrikosov: Die Entdeckung der Typ-II-Supraleitung, Physikalisches Blätter, 57, 61 (2001). [2] G. W. Crabtree and D. R. Nelson: Vortex physics in high temperature superconductors, Physics Today, April 1997. [3] A. J. Leggett: A theoretical description of the new phases of liquid 3He, Rev. Mod. Phys. 47, 331 (1975). [4] P. W. Anderson and W. F. Brinkman: Theory of anisotropic superfluidity in 3 He, in “The Helium Liquids” (Proceedings of the 15th Scottish Universities Summer School, 1974), ed. J. G.M. Armitage and I. E. Farquhar (Academic Press, London). [5] D. Vollhardt and P. Wölfle: The superfluid phases of helium 3, (Taylor&Francis, London, 1990). [6] O. V. Lounasmaa and G. R. Pickett: The 3He superfluids, Scientific American, June 1990. AAPPS Bulletin October 2003 11 Institution Reports Research Centre for High Energy Physics at University of Melbourne Raymond R. Volkas 1. INTRODUCTION The Research Centre for High Energy Physics (RCHEP), located within the School of Physics at the University of Melbourne, was established by the Council of the University in December 1988. Its main aims were to consolidate the research efforts in high energy physics (HEP) at the University, and in particular to establish a large scale programme in experimental HEP based in Australia but using overseas accelerator laboratories. Fifteen years on, we can confidently say that HEP research is healthier than ever at the University of Melbourne, with the original mission of RCHEP having been fulfilled. RCHEP is host to the Theoretical Particle Physics and Experimental Particle Physics research groups within the School of Physics. Both of these groups are very active in research, receive substantial research funding, and are in high demand by graduate students. The Experimental Particle Physics group has developed impressively since RCHEP’s inception, having made a major contribution to the neutrino oscillation experiment NOMAD at CERN during the 1990’s, and at present being heavily involved with the ATLAS collaboration at the Large Hadron Collider (LHC), and the Belle experiment at KEK in Japan. Prof. Raymond R. Volkas Director & Deputy Head Research Centre for High Energy Physics School of Physics The University of Melbourne Victoria 3010, Australia Email: r.volkas@physics.unimelb.edu.au RCHEP is an important member of the Australian Institute for High Energy Physics (AUSHEP), an umbrella organization whose purpose is to coordinate Australia’s experimental HEP activities at the national level. Through AUSHEP, RCHEP enjoys close and fruitful links with the Department of Physics and the Special Research Centre for the Subatomic Structure of Matter at the University of Adelaide, the School of Physics at the University of Sydney, the Physics Department at the University of Wollongong, and the Australian Nuclear Science & Technology Organization (ANSTO). The University of New South Wales and the Australian National University, through Associate Membership, round out the AUSHEP grouping. Having successfully met its initial challenges, an external review was undertaken in 1999 to update its mission statement. The revised aims emphasize that the coordination through AUSHEP of the national HEP research effort remains a priority. It is seen as a critical player in promoting the health of particle physics in Australia, a focal point for the nation’s ambitions in fundamental science. Internally, a need to strengthen the links between the Experimental and Theoretical Particle Physics groups was recognised, and it was encouraged to continue public outreach activities. 2. HISTORY, CONTEXT, AND LINKAGES Before discussing RCHEP’s scientific research in more depth, let us take the opportunity to place this relatively new organization in the context of its overall academic and research environment. The University of Melbourne is celebrating its 150th anni- 12 versary this year. It was formed in the mid-19th century at the beginning of a long economic boom driven by the discovery of gold in what is now the State of Victoria. This good fortune very quickly created an affluent and sophisticated metropolis —Melbourne—from a small settlement established earlier in that century. The cultural legacies from this auspicious birth are still very much in evidence today, from the elegant and sometimes ostentatious Victorian architecture of the inner city through to the intellectual and cultural enthusiasms of its residents. The University of Melbourne, located just north of the downtown area, has grown from an enrollment of 16 students in 1855 to just under 40,000 today. [The population of the Melbourne metropolitan area has grown from about 30,000 in 1851 to 3.6 million in 2003.] The School of Physics, part of the century-old Faculty of Science, grew out of the School of Natural Philosophy, a pioneering academic department that drew considerable inspiration from the University of Cambridge in the United Kingdom through the conduit of the famous antipodean Ernest Rutherford, discoverer of the atomic nucleus. It began to mature in the middle of the 20th century, through the advent of a doctoral research programme and an increasingly cosmopolitan outlook. Historically strong in nuclear physics, it was also involved in cosmic ray studies in the 1950’s. These strands, contributing a culture of accelerator-based science and a concern with high-energy collisions, can be viewed as precursors to the later development of HEP per se. In the late 1960’s and early 1970’s, both theoretical and experimental particle physics research at Melbourne received a significant boost under the leadership of Professor David Caro, Head of the School of Physics, who subsequently embarked on a distinguished career in higher university administration through Vice-Chancellorships at the University of Tasmania, and then again at Melbourne. The experimental programme in the early 1970’s undertaken by Caro, G. I. Opat, A. G. Klein and J. W. G. Wignall focused on bubble chamber work at Brookhaven. Theoretical HEP research was inaugurated by Bruce H. J. McKellar, the new Professor of Theoretical Physics, together with G. C. Joshi and S.-Y. Lo. When Caro moved into higher administrative office, Stuart N. Tovey was hired from CERN as his replacement. He established the strong links that RCHEP enjoys today with CERN, having led Melbourne’s contributions to the UA2 experiment and hyperon work during the late70’s through to the mid-80’s. RCHEP was created after the UA2 efforts had wound down, and generational change started to occur within the School of Physics. RCHEP was also fortunate to have the services of Professor Colin A. Ramm toward the end of his career. Ramm was a pioneer at CERN of bubblechamber neutrino experiments, returning to his native Australia in the 70’s to become Dean of Science at Melbourne. RCHEP today consists of seven permanent faculty staff, AAPPS Bulletin Vol.13, No. 5 which will increase to eight in the near future, several postdoctoral fellows, about two dozen graduate students and one electronic engineer. It is about one-third of the School of Physics, and is the only Australian organization that has both theoretical particle physicists and accelerator-based particle physicists located in the same institute. Aside from the national administrative and policy role through AUSHEP mentioned above, RCHEP also engages at the national level in very active collaborative research programmes. Over the last decade, on the experimental side, a very close relationship has developed with the Falkiner High Energy Physics Department in the School of Physics at the University of Sydney. RCHEP also has a strong involvement through instrumentation for medical research, especially the imaging of brain activity, with the University of Wollongong and the Howard Florey Institute of Experimental Physiology and Medicine at the University of Melbourne. RCHEP is thus an outward-looking organization, open to cross-disciplinary opportunities, but with its intellectual bedrock being a passionate commitment to fundamental particle physics research for its own sake. On the theoretical side, links to the Special Research Centre for the Subatomic Structure of Matter at Adelaide, especially through lattice gauge theory and computational physics, are also very strong. An important cross-disciplinary link involving theory is through Dr. L. C. L. Hollenberg to the Centre of Excellence—Centre for Quantum Computer Technology, a multi-university collaboration with eight nodes including Melbourne. In addition to the formal institution-level links to CERN and KEK, RCHEP has numerous less formal but extremely important and active international research connections, including several in the Asia-Pacific area. In the last two years alone, RCHEP theoreticians have published papers with physicists at Arizona U, Ben-Gurion U, Brown U, Delaware U, Delhi U, Fermilab, Harish-Chandra Research Institute, KIAS, Los Alamos, National Taiwan University, New Mexico U, SUNY Stony Brook, Syracuse U, and UCSB. 3. RESEARCH HIGHLIGHTS 1988-2003 3.1. Experiment In 1987, the Melbourne experimental particle physics group became an institutional member of the UA2 experiment. [Previously Stuart Tovey and his student Gary Egan had worked on UA2, but as visitors within the CERN group.] The Melbourne contingent worked on the silicon detectors at the core of the UA2 upgrade, and gained some basic experience with that technique. On the basis of their contributionts to UA2, the Melbourne experimentalists, by now part of the newly created RCHEP, were invited to join three experiments: AAPPS Bulletin October 2003 oscillation search at CERN that ran • NOMAD, a to from 1993 to 1999. • RD2, a generic ‘research and development’ experiment testing the radiation hardness of silicon detectors. • EAGLE, a proposal for an experiment at the planned LHC. 13 • Leanne Guy investigated the sensitivity of ATLAS to Bs mixing. • Sandor Kazi is studying the sensitivity of ATLAS to new exotics. • Gaby Bright is studying the sensitivity of ATLAS to B + ll . It is interesting to note that all three experiments were led by UA2 physicists, so these later invitations demonstrated the good standing the Melbourne/RCHEP physicists gained within UA2. In 1987, Geoffrey N. Taylor was lured back to Australia, where he is now both the leader of the Melbourne experimental particle physics group and the current Head of the School of Physics. At the time of his recruitment, Geoff Taylor was involved in a number of deep-inelastic scattering experiments involving neutrinos and muons at Fermilab and CERN. He subsequently became a key member of the Radiative Muon Decay experiment at TRIUMF, Vancouver while maintaining involvement with the European and New Muon Collaborations at CERN. Fig. 2: A graphic of the assembled ATLAS detector. In 1995, EAGLE merged with another proposed LHC experiment and was renamed ATLAS. Under Taylor’s leadership, the RCHEP group is constructing semiconductor tracker (SCT) modules for the inner part of the ATLAS detector. The expertise gained with silicon at UA2 continues to strongly influence the activities of the group. GRID computing is another strong component of our ATLAS programme. As well as contributing to hardware and GRID development, RCHEP staff and graduate students are also very involved with simulations of the new physics ATLAS will explore when the LHC starts in 2006. In particular: • Fawzi Fares investigated the sensitivity of ATLAS for searches for the Higgs particle via H Z0Z* decays. • Brendan Dick investigated the sensitivity of ATLAS for — searches for the Higgs particle via H bb decays. Fig. 3: A graphic of the inner part of the ATLAS detector, showing the location of the semiconductor tracker (SCT) modules. Fig. 1: Aerial view of the LHC accelerator ring at CERN near Geneva, Switzerland. Fig. 4: The assembly station in Melbourne for assembling the semiconductor tracker (SCT) modules for the ATLAS experiment. 14 Fig. 5: The precision metrology station in Melbourne for surveying and verification of assembled SCT modules produced in Melbourne. AAPPS Bulletin Vol.13, No. 5 Fig. 8: Example of the many circuit boards being produced in Melbourne for the SCT. tector at TRIUMF, being the spokesperson for experiments on pion-induced pion production and dibaryon searches. Fig. 6: An assembled prototype SCT detector module. In about 1996 it became clear that RCHEP needed an experiment to bridge the gap in time between the end of NOMAD and the start of ATLAS. A perennial challenge for university groups is to have a balanced suite of collaborative commitments, so that graduate students always have actual data to analyse in addition to whatever hardware-development and simulation efforts are required. A short-list of four experiments was drawn up. After considerable discussions, RCHEP accepted an invitation to join the Belle collaboration at the KEK B-factory. Once again, RCHEP’s silicon expertise was at the fore: on the hardware side, our group is a major source for the silicon vertex detector (SVD) modules sited at the centre of the detector. The precise location of decay vertices is a key requirement of the CP violation physics at the heart of the Belle programme. Fig. 7: Screen capture of the visual alignment software for precision assembly of SCT detector modules. In 1993, Tovey and Taylor were joined by Dr Martin Sevior, who had been working for several years on the CHAOS de- RCHEP staff and graduate students have made major contributions to analysis within Belle. The following provides brief descriptions of these projects, with the name of the principal graduate student appended: • Measurement of branching ratio for B X s (Leon Moffitt). • Measurement mB and limits on CPT violation (Nick Hastings). • Measurement of branching ratio for B (Ascelin Gordon). • Measurement of branching ratio of B mesons to doubly charmed final states (Eric Heenan). • Upper limits for (Craig Everton). • Measurement of branching ratios for B0 and B0 (Jasna Dragic). AAPPS Bulletin October 2003 15 Fig. 9: Aerial view of the KEKB accelerator in Tsukuba, Japan. • Measurement of Vub via B Xu l (Antonio Limosani). 0 0 • Ongoing studies of B and B K* 0 (Rohan Dowd). • Ongoing studies of B0 D*D*Ks (Jeremy Dalseno). RCHEP and the School of Physics was delighted to recently recruit Dr. Elisabetta Barberio, who will join the experimental wing in October 2003 after considerable experience at CERN on electron-positron collider experiments (LEP/LEPII). We have been very fortunate for a number of years to have the services of two superb research-only post-doctoral associates, Dr. Gareth Moorhead and Dr. Glenn Moloney, as well as an electronic engineer, Mr. Steve Gregory. It would be impossible to run the group without them. C. L. Hollenberg, Dr. Girish C. Joshi and Professor Raymond R. Volkas. Senior research-only personnel include Dr. Robert Foot, Dr. A. Yu. (Sasha) Ignatiev, Dr. John McIntosh and Dr. Cameron Wellard (qc). (Personnel devoted to entirely to quantum computation research are flagged by “qc.”) The theoretical group has always been blessed with a talented pool of graduate students. The current group consists of Joo-Chew Ang (qc), Ben Carson, Vince Conrad (qc), Jared Cole (qc), Andrew Dusza, Austin Fowler (qc), Catherine Low, James McCaw, Kristian McDonald, Ivona Okuniewicz, Matthew Testolin (qc) and Tim Starling (qc). As ever, the army of graduate students is the heart-and-soul of the experimental group. The present-day contingent is Tom Atkinson, Gaby Bright, Joanne Culpepper, Jeremy Dalseno, Rohan Dowd, Jasna Dragic, Craig Everton, Ascelin Gordon, Sandor Kazi, Toni Limosani, Caitlinn Loftus, and Leon Moffitt. 3.2. Theory The theoretical physics group within RCHEP has active interests in a diverse research portfolio from mathematical physics through lattice gauge theory, extensions of the standard model, particle cosmology and astrophysics to cross-disciplinary studies in condensed matter physics, quantum computation and environmental decoherence. The present-day permanent faculty members are Bruce H. J. McKellar (the Professor of Theoretical Physics), Dr. Lloyd Fig. 10: A wire bonding machine is used to assemble silicon vertex detector (SVD) modules for the Belle detector at the KEK B-factory. 16 While the diverse nature of the group’s research interests make it difficult to provide a comprehensive summary, it is worthwhile to highlight some of the main themes. There has been a real preoccupation with extensions of the standard model, both from the model-building and phenomenological perspectives. McKellar has a long-standing interest in CP violation in the standard model and beyond. Both Volkas and McKellar have worked extensively in all aspects of neutrino theory, including early universe cosmology, neutrino mass models, the interpretation of tritium end-point measurements, and solar and atmospheric neutrino phenomenology. Of particular note is the seminal work performed around 1990 on neutrino quantum kinetic theory by McKellar and his then student Mark J. Thomson, which was later taken up for independent reasons by Foot and Volkas and his students, especially Nicole F. Bell and Yvonne Y. Y. Wong. This research continues to strongly influence studies of the effect of neutrino oscillations on primordial or big bang nucleosynthesis. Around 1990, Foot, Joshi, Volkas and their former colleague Dr. Henry Lew discovered a way to understand electric charge quantization using classical and quantal (anomaly cancellation) constraints, without the necessity of grand unification. Also around that time, Foot, Lew and Volkas developed an explicit gauge theoretic description of mirror matter, a hypothetical set of particles whose properties exactly parallel those of ordinary particles that had been speculated about from the time of Lee and Yang in the late 1950’s. This simple extension of the standard model continues to have interesting implications for neutrino physics and the dark matter problem. Recently, Ignatiev, Joshi and McKellar have been exploring B-physics phenomenology, nicely complementing the experimental side of RCHEP’s activities. They also have a strong interest in the phenomenology of theories with large extra dimensions. Joshi has had a long-standing interest in the use of novel mathematical structures in physics, especially quaternions, octonions and Jordan algebras. He and his students have explored their possible utility in a wide variety of contexts, from fundamental quantum mechanics through to string theory and even in deterministic chaos. Our interest in the phenomenology of hadronic weak interactions led us to work on non-perturbative field theory. Hollenberg and McKellar have worked on the development and application of new methodologies to strong coupling gauge theories. Their 1991 computation of light-cone mesonic states, using Discretized Light Cone Quantisation (DLCQ), was one AAPPS Bulletin Vol.13, No. 5 of the first applications of DLCQ to 3+1 dimensional field theory. Hollenberg then worked on the analytic application of Lanczos diagonalisation to the general many body problem and derived and applied the “plaquette expansion”—a way of computing properties of low lying states of a system from an analytic asymptotic form for the Hamiltonian in a tridiagonal basis. The plaquette expansion method was applied to the Hamiltonian formalism of lattice field theory, which had previously lain relatively dormant compared to the Lagrangian version. Hollenberg carried out a first order analytic diagonalisation of the full lattice QCD theory with staggered fermions and found exressions for the ratio of rho mass to nucleon mass as function of coupling strength, giving a ratio close to the experimental one in the continuum limit. McIntosh and Hollenberg found scaling behaviour for the mass gap of 2+1D U(1) lattice gauge theory to high precision using sophisticated trial states. Carlsson and McKellar have shown how to obtain improved Hamiltonians for lattice gauge theory, and have obtained analytic results for the integrals used in variational calculations for SU(N) gauge theories in 2+1 dimensions. This enables estimates of the mass gap for large N, which suggest the infinite N limit behaves as a 2 dimensional harmonic oscillator. Since 1999 Hollenberg has worked on quantum information processing and the physical implementations of quantum computing. 4. THE FUTURE RCHEP will continue to redefine itself as will the frontiers of particle physics research also. Clearly, though, the experimental programme will maintain its commitment to the ATLAS collaboration, and we very much look forward to advent of the LHC, which will operate for about a decade. The Higgs boson is the missing link in the experimental verification of the standard model, and its discovery (or otherwise!) is eagerly awaited by both the experimental and theoretical halves of RCHEP. GRID computing will become increasingly important. Belle will wind down on a shorter time scale, so an important decision on its replacement will need to be made. Interesting opportunities will always be seriously considered, and the cross-disciplinary efforts in medical imaging and quantum computation will continue to evolve. On the theoretical side, we anticipate that the increasing interdependence of particle physics, astrophysics, and cosmology will loom large in our planning. An imminent challenge is to manage the generational change that will come with the retirements of McKellar and Joshi. The School of Physics will continue to support research at the theoretical frontiers, and the present Director looks forward to welcoming two new theoretical colleagues in the relatively near future. AAPPS Bulletin October 2003 17 Institution Reports Department of Physics at Tsinghua University, Beijing Bang-Fen Zhu 1. HISTORY Since its foundation in 1926 the Department of Physics at Tsinghua University has earned a reputation as one of best Physics Departments in China. Led by Professor Qi-sun Ye (Ch’i-Sun Yeh), the first department head, this Department recruited several most distinguished physicists in China, including You-xun Wu (Y. H. Woo), Pen-Tung Sah, Pei-yuan Zhou (Pei-yuan Chou), and Zhong-yao Zhao (Chung-Yao Chao), and cultivated a large number of outstanding physicists, such as Gan-chang Wang (K. C. Wang), Wei-chang Qian (Wei-zang Chien), San-qiang Qian (San-Tsiang Chien), Chia Chiao Lin, Huan-wu Peng, Da-heng Wang (Ta Heng Wang), and Zhu-xi Wang (C. C. Wang) et al., in early 1930s. In 1937, because of the Japanese Invasion, Tsinghua was forced to move from Beijing to Changsha, Hunan Province, and was merged into the “National Changsha Temporary University” with Peking University and Nankai University. In 1938 it had to move to Kunming, Yunnan Province, again and with its name changed to the “National Southwest Associate University.” In the World War II a great amount of outstanding scholars was educated in the Department of Physics, such as C. N. Yang (Nobel Laureate), T. D. Lee (Nobel Laureate), Kun Huang, Jia-xian Deng, Guang-ya Zhu, et al., which was one of the most magnificent achievements in the history of Chinese modern education. Professor Bang-Fen Zhu Center for Advanced Study and Chairman, Department of Physics Tsinghua University Beijing 100084 Email: bfzhu@castu.tsinghua.edu.cn In 1952 this Department dissolved and most of its faculty members and students joined Peking University, because during that time the China’s education system followed the former Soviet Union, and Tsinghua University was designed to be a polytechnic university. Thus the remained and later-recruited faculty members were concentrated on the university-physics teaching for undergraduate students. In 1956 the Department of Engineering Physics aiming at nuclear technology was set up, in which two groups on nuclear physics and theoretical physics were growing. The Department of Physics at Tsinghua was reestablished in 1982 responding to the demand of modernization and internationalization, and Guang-zhao Zhou (Kuang-Chao Chou), a Physics alumnus and the then President of Chinese Academy of Sciences, assumed the department head. Two years later, the department was entitled “Department of Modern Applied Physics,” and renamed as “Department of Physics” in 1999. After great efforts have been made for more than twenty years, now the Department of Physics has become one of the most important research centers and physicist cultivating bases in China. 2. STATUS Situated in the northwest of Tsinghua campus, which is surrounded by a few historical sites in northwest Beijing, is the Science Building of the Physics Department. Together with the nearby Department of Chemistry, Department of Biology, and Department of Math, the Department of Physics constitutes the Science School of Tsinghua University. Among the Department’s most significant resources is its highly respected faculty, including 46 full professors and 31 18 AAPPS Bulletin Vol.13, No. 5 Department of Physics at Tsinghua University, Beijing associate professors. 5 professors have been elected as the Members of Chinese Academy of Science. Many faculty members have received various international and national awards for their research achievements, including the National Award in Natural Sciences, China’s Prestigious Chang-Jiang Scholar Award, Chang-Jiang Chair Professorship, Outstanding Youth Scholar Prize from Hong Kong Qiushi Foundation, Alexander von Humboldt research fellow, etc. Three professors are the winners of National Science Fund for Distinguished Young Scholars. Most noticeably, Nobel Laureate C. N. Yang is a full professor as well as a member of the Advisory Committee of this Department. Authorized by the Ministry of Education in 1999, this Department can confer doctoral degree in all sub-fields in physics, including Condensed Matter Physics, Atomic and Molecular Physics, High Energy and Nuclear Physics, Optics, Theoretical Physics, Acoustics, and Plasma Physics. In addition, it is also allowed for this Department to confer the Ph. D. degree in Astrophysics. The guideline of the curriculum is to cultivate first-rate physical specialists who have both plenty of fundamental theory and experiment skills. It is emphasized that the students should be able to catch up with the fast advancing modern physics and related technology, and apply them in different fields. In addition, students who are interested in fundamental physics are specially trained aiming for promotion of corresponding fundamental subjects. About 211 graduate students and 475 undergraduate students, including several National and International Physics Olympiad winners, are currently enrolled in this Department. Since 1984, 1354 students have been conferred bachelor degree, 419 students have been conferred master degree, and 62 students have been conferred doctor degree. Our graduates at all levels have distinguished themselves in academic, industrial, and governmental careers. The Department of Physics has attracted more than tends million Chinese Yuan each year in State and private grants, most from the National Natural Science Foundation, National Key Program of Basic Research Development, National High Technology Research and Development Program, and so on. In recent years, more than 300 research papers are published each year in refereed international and domestic journals and proceedings of international conferences. There exist broad collaborations between this Department and its counterparts abroad. Every year, a large number of faculty members visit foreign Institutions and participate in international conferences; meanwhile many outstanding scholars from abroad are invited to work or lecture in the Department. Research institutions and their interest: Institute of Condensed Matter Physics Computational condensed matter physics and new materials design Theoretical and experimental studies in condensed matter physics, in particular for nano- and low-dimension structures New novel materials growth and characterization Acoustic and ultrasonic applications Institute of High Energy Physics and Nuclear Physics Theoretical and experimental particle physics High energy astrophysics Theoretical and experimental studies of nuclei under extreme conditions AAPPS Bulletin October 2003 Nuclear technology and its applications Institute of Atomic, Molecular and Optic Physics Detecting, identifying and manipulating single atom and molecule Atomic and molecular structures and dynamical processes Near-field Optics and Micro-spectroscopy Laser cooling and ultra-cold atomic physics Nonlinear optics Quantum optics Interdisciplinary research centers: Center of Atomic, Molecular and Nano Science Structure of atoms, molecules and nano systems Fundamental research of detecting, identifying and manipulating single atom and molecule Synthesis, characterization, and Application of Quasi onedimensional material Center for Astrophysics Observation and Investigation of High Energy Radiation from the Space Constructing high energy astrophysics database and data analysis system Applied Superconductivity Research Center PIT BSCCO wires Coated Conductors Characterization of superconducting materials Superconductor devices New materials, new process methods Key laboratories Atomic and Molecular Nanosciences Laboratory (Ministry of Education of China) New technique and method in detecting and manipulating atoms and molecules Properties of material in nano scale Application of molecular nano-science in biomedicine, zoology, and resource exploration Virtual Laboratory for Material Design (Ministry of Science and Technology of China) Simulate new materials Develop software for materials calculation and database Predict novel properties of new materials Quantum Information and Measurements Laboratory (Ministry of Education of China) Quantum correlation and entanglement Quantum cryptography and teleportation Quantum computation 19 3. OUTLOOK With strong support from the University, relying on the mighty engineering background of Tsinghua University and the advantage of its talented student resource, the Department of Physics is forming its own characteristic. The department focuses on enhancing experimental physics, and creating interdisciplinary research programs such as biophysics, cosmography, and quantum information science on the basis of consolidating the traditional subjects. Facing unprecedented opportunities and challenges, this department is reforming its system and aspires to become a first rank department in the world in the near future. 20 AAPPS Bulletin Vol.13, No. 5 Institution Reports Department of Physics at Tsinghua University, Hsin-Chu Hsiu-Hau Lin 1. TSINGHUA IN TAIWAN The story of Tsing-Hua reflects a piece of modern history in Asia. The university was established in 1911, the year before the birth of the first democratic government in Asia. Later, after the civil war in China, it was re-established in 1956, located at Hsinchu city in Taiwan. Since then, National TsingHua University (NTHU) in Taiwan took off and grew rapidly. Now it has become one of the top universities in Taiwan. In fact, the favorite graduates, embraced by industrial recruitments, are nicknamed “Tai-Tsing-Chao.” The name comes from the names of three top universities in Taiwan and ‘Tsing’ stands for National Tsing-Hua University. Hsinchu, where the university is located, is famous as the Silicon Valley in Taiwan. With Science-Based Industrial Park nearby, the development of NTHU has a good balance between creative academic atmosphere and solid scientific trainings for practical operations. Furthermore, being exposed to the open and democratic developments in recent decades in Taiwan, the campus provides an excellent environment of her faculty members and students to excite and exchange novel ideas and thoughts, to advance explorations in research frontiers and to cultivate the essential ingredients of modern citizens with a heart of humanity. 2. PHYSICS DEPARTMENT Shortly after NTHU was established in Taiwan, the importance of natural science came to vision and the physics department was set up in 1965. The original scope of the department concentrated on undergraduate programs. A year later, the graduate program for Master degrees kicked off and eventually evolved into the current scope with full undergraduate, Master and Ph.D. programs. Due to the growing importance and local research strength in astronomy and cosmology, the institute of astronomy for graduate programs was established in 2001. Currently, there are about 250 undergraduates and 150 graduate students (about 100 in master program and 50 in Ph.D.) at the physics department. The department locates at a seven-floor high building, with total area over 12,562 square meters. Currently, there are 33 faculty members plus about 10 adjunct professors, working in various research areas including cosmology and astronomy, particles and fields, experimental and theoretical condensed matter physics, atomic and molecular physics, optical physics, microwave and plasma physics, and some other areas in applied physics. While being a relatively young department, the physics department is among one of the best and competitive institutes in Taiwan. In fact, the department was evaluated as the best physics department in a poll hold by a well-known Taiwanese magazine in 1998. A year later, it was again selected to be the best research department in physics by another poll conducted by another magazine in Taiwan. It is of no doubt that the physics department at NTHU has the best reputation in either research activities or educational trainings. The keen competition among the physics departments in NTHU and National Taiwan University and the institute of Physics at Academia Sinica has played a crucial role in pushing the research standard forward in the past decades. The excellence of our faculty members can be seen by the international and domestic recognitions through many honors and awards. We are the only physics department in Taiwan with three distinguished Fellows of Academy of Science: Prof. Kwo-Ray Chu, Prof. Frank Shu and Prof. Mow-Kuen Wu. AAPPS Bulletin October 2003 21 Fig. 1: Physics Building at NTHU. After joining the Physics Department of NTHU in 1983, Prof. Chu set up a laboratory where, with L. R. Barnett and a team of graduate students, he embarked on experimental research addressing the key physics issues of the electron cyclotron maser (ECM). The culmination of the NTHU group’s research has been the award winning work on the fundamental properties of the ECM, as was reported in six Physical Review Letters from 1989 to 1998. Professor Chu’s most recent research, with S. H. Chen and T. H. Chang, has focused on the theory of, and experimentation with, electron cyclotron maser interaction involving backward waves. This work has revealed the unique feature of nonlinear field contraction in the saturated stage, which has opened up a new horizon for nonlinear science research. Professor Chu was the recipient of the 2001 K. J. Button Medal and Prize of the British Institute of Physics, which cited him for “pioneering contributions to the theoretical formulation and fundamental understanding of electron cyclotron maser interactions and the technology development of novel coherent radiation sources with unprecedented capabilities.” Also in 2001, he received the Plasma Science and Application Award of the IEEE Nuclear and Plasma Sciences Society for “seminal plasma physics investigations yielding fundamental insight into coherent radiation processes, thereby significantly advancing the state of the art of relativistic electron beam driven gyro devices.” In recognition of his contributions to, and leadership in, ECM research, Prof. Chu was recently invited by the Reviews of Modern Physics to author an extensive review article on the physics, history, and technological advances in this field of research. Prof. Shu is the President of NTHU now. He is regarded as one of the world’s top theoretical astrophysicists and the leading theorist in star formation. He is former president of the American Astronomical Society and a member of the National Academy of Sciences. In addition he is known as an excellent teacher. His notes from an introductory astronomy class were turned into an undergraduate text, “The Physics Universe,” which has been described as the “Feynman Lectures” of astrophysics. Among Prof. Shu’s contributions have been major innovations in our understanding of spiral structure in galaxies and in Saturn’s rings, the transfer of mass in binary star systems, the formation of stars and the origin of the solar system. In recent years he has looked at the geochemical composition of meteorites, in search of clues to the early history of the solar system. Prof. Shu received numerous awards in recognition of his groundbreaking research including Warner Prize, Brouwer Award and Heineman Prize from American Astronomical 22 AAPPS Bulletin Vol.13, No. 5 Fig. 2: Front entrance of the Physics Building. Society. He is also Fellow of National Academy of Sciences in United States and in Taiwan, Fellow of America Philosophical Society and American Academy of Arts and Sciences. In 1999, he was elected to be University Professor of the nine Universities of California. This honorable position is attribute to his outstanding performance in research, teaching and services. Later, Prof. Shu decided to come back to Taiwan and become the President of NTHU since 2002, devoting his talents and experiences to lead the university. Prof. Wu is a worldwide known physicist on high-temperature superconductivity. Together with Prof. C. W. Chu, Prof. Wu is the discoverer of YBCO superconducting cuprate oxides with critical temperature above the boiling point of liquid nitrogen. Their original paper in Physical Review Letters has become the classic in field of high-temperature superconductivity. In 1990, Prof. Wu returned to Taiwan to organize a research team working on high Tc superconductors and other oxide compounds that exhibit strong electron-correlated effect at NTHU. He has set up a world-class laboratory at the department and remains influential in the international community. In addition to the great academic achievements, Prof. Wu also devotes his time to promote the research environment in Taiwan. He has served as the director of Material Science Center and the chairman of Research and Development at NTHU. During the period of 2000-2002, Prof. Wu becomes the vice-chairman of National Science Council in Taiwan. He has initiated the Wu Ta-You Research Awards for junior sci- entists and helps to establish the study abroad programs for post- and pre-doctoral fellows. Moreover, he also initiated the modification of the NSC Research Awards program and a new interdisciplinary research program, which involves all the NSC academic divisions. After his service at National Science Council, he took the directorship of Institute of Physics at Academia Sinica (March 2002-present). It is worth mentioning that over 1/3 of the faculty members at the department are recognized by the outstanding awards (1-2 awards in physics every year and each award lasts three years) of National Science Council. In particular, Prof. Darwin Chang, Prof. Huan-Chiu Ku, Prof. Juh-Tzeng Lue, Prof. Shih-Lin Chang received the outstanding awards more than three times and become the distinguished Invited Principal Investigator of NSC research projects. Prof. Chang is the world-class expert in CP violation since his Ph.D. thesis. With more than 100 publications, his recent work on “New two-loop contribution to electric dipole moment in supersymmetric theories” [Phys. Rev. Lett. 82, 900 (1999); ibid. 83, 3972 (1999)] has been the must-cite paper in this area. He continues his efforts in formulating interesting CP models and applies them to important systems [Phys. Rev. Lett. 87, 211601 (2001) and Phys. Rev. D 67, 075013 (2003)]. Prof. Ku is a well-known expert on high-temperature superconductor [Appl. Phys. Lett. 76, 3795 (2000)] and strongly correlated electron systems [Phys. Rev. B 51, 420 (1995) and Phys. Rev. B 50, 351 (1994)]. He has set up a top-class laboratory in AAPPS Bulletin October 2003 23 Taiwan and pioneered in many interesting experiments in magnetic properties in high-temperature superconducting materials. Prof. Lue works on solid-state electronics and recently develops interests in nanoclusters. His recent works on the quantum size effects in nanoparticles [Phys. Rev. B 49, 17279 (1994), Phys. Rev. B 51, 2467 (1995) and J. Phys. Chem. Solids 62, 1599 (2001)] attract lots of attentions and demonstrate novel quantum effects in nanometer scales. Prof. Lin is a world-known leader in X-ray diffraction and its application to other physical systems. In a series of important papers [Appl. Phys. Lett. 65, 1720 (1994), Phys. Rev. Lett. 80, 301 (1998) and Phys. Rev. Lett. 86, 2026 (2001)], Prof. Lin developed a groundbreaking method to measure the triplet phase directly, which can be used to extract useful information about atomic/molecular configurations in the system. He is now applying this novel technique to probe several interesting/proposed phases in high-temperature superconducting materials. Recently, Prof. Ray-Nien Kwo, NTHU/TSMC distinguished chair professor, joined the department in the fall of 2003. She discovered the modulated magnetic properties [Phys. Rev. Lett. 55, 1402 (1985)] and observation of long-ranged magnetic order in synthetic magnetic superlattices, which led to the subsequent discovery of the giant magnetoresistance effect, and revolutionalized the entire magnetic read/storage industry. Her series of works on high-temperature superconductors are influential [Phys. Rev. Lett. 69, 2975 (1992) and Phys. Rev. Lett. 72, 2636 (1994)]. Recently, with Prof. Hong, she initiated the dielectrics as alternative gate oxide replacthrust on high ing silicon dioxide for nano CMOS [Science 283, 1897 (1999)]. Not only our senior faculty members are well recognized, the junior members at the department are also developing their own reputations. Our junior faculty, Prof. Shangjr (Felix) Gwo pioneered several breakthroughs in scanning-probe based nanofabrication [Appl. Phys. Lett. 75, 2429 (1999)], self-assembly phenomena of quantum dots and nanocrystals [Phys. Rev. Lett. 90, 249901 (2003) and Phys. Rev. Lett. 90, 185506 (2003)], nitride-based optoelectronic materials [Appl. Phys. Lett. 74, 1090 (1999) and Appl. Phys. Lett. 76, 360 (2000)]. Starting from 2003, he is the principal investigator of National Research Program for Nanoscience and Technology, “Nano Sensing and Manipulations.” Besides, our junior faculty members, Prof. Chung-Sun Chu, received Wu Ta-Yu Award from NSC in 2003 and Prof. Lo received Outstanding Junior Award of Academia Sinica in 2001. Since the spring in 2003, Prof. Hsiu-Hau Lin became Wu TY Fellow at the National Center for Theoretical Sciences, which is a prestigious three-year position for junior researchers. 3. FEATURES 3.1. Curriculum While being identified as one of the major research institutes in Taiwan, the department also has an excellent tradition and reputation for scientific education. As the modern sciences and Fig. 3: Physics camp organized by students. 24 technology grow, the department also adjusts its trainings of course work and experimental operations to prepare students for the fast-pace changing world. The curriculum is flexible in the spirit that the students can adjust their directions or/and put more attentions on the interested subfields after receiving solid and basic training in physics. For instance, in addition to the basic courses, the department provides introductory course on nanoscience, computational physics, biophysics and so on, to bring the students to the research frontiers. We put special emphasis to enlarge students’ scopes, meanwhile, keeping their heads and hands down to earth and being familiar with basic background knowledge and techniques. 3.2. Mentor System A unique tradition at the department is that every newly enrolled student is assigned to a ‘family’ of elder students acting as their mentors. The typical size of each family is four or five students and sometimes larger if two families decide to merge. The mentor system not only helps the fresh students to get on track for course work in a short time. It also serves as a social stage for students with different backgrounds, talents and personalities to interact and work together. The members of the ‘family’ usually keep their close friendship even after they graduate from Tsing-Hua. With this unique tradition, not only being familiar with their classmates (horizontal relations), the students also develop interactions between different classes (vertical relations). This has been the major bridge, holding all students at the department together coherently. 3.3. Physics Research Promotion Center At the developing stage of the department, the National Science Council decided to set up the Physics Research Promotion Center (PRPC) at NTHU, in the goal to build a competitive research environment efficiently. The Physics Center has helped the department to develop dramatically from its sketchy period in many aspects. One of the most important impacts is that the library at the physics department is abundantly funded Fig. 4: A corner in the library. AAPPS Bulletin Vol.13, No. 5 and carefully managed through all these years. So far, the library holds more than 45 thousand of books and over 500 journals in paper or/and electronic formats. It is the best physics library in Taiwan without doubt. In addition, the library also provides precious services to other universities and institutes for interlibrary loans, data/references search, electronic journal service and so on. 3.4. National Center for Theoretical Sciences In 1997, the National Center for Theoretical Sciences was established at NTHU and NCTU (another top national university neighboring to Tsing-Hua), after keen domestic competitions and numerous international refereeing/reviewing processes. The center has two divisions devoted to physics and mathematics. The physics building is the host for the Physics Division since 2001. Being modeled after the successful Institute for Theoretical Physics at Santa Barbara, NCTS has provided a vivid research environment for both theorists and experimentalists to present fresh research results, exchange and discuss ideas, and eventually creates mutual collaborations. Not only being a spotlight stage for domestic interactions, the center increases its international visibility through workshops and conferences in the past years. 4. RESEARCH HIGHLIGHTS 4.1. Astronomy The group currently contains three faculty members: HsiangKuang Chang, Dean-Yi Chou and Frank Shu. As mentioned previously that President Shu is regarded as one of the world’s top theoretical astrophysicists and the leading theorist in star formation. Besides, Prof. Chang and Prof. Chou have cooperated to develop a remarkable method to construct the threedimensional image of a region of the solar interior [Nature 389, 825 (1997)]. This influential breakthrough in the wellknown project of Taiwan Oscillation Network (TON) is included in the Encyclopedia of Astronomy and Astrophysics. In fact, in a recent review of the physics department, the astronomy group is evaluated as “the leading group in Taiwan and also being competitive international wise.” After the setup of Institute of Astronomy, we expect the group would grow in size and certainly in the depth and scope of frontier research. 4.2. Condensed Matter Experiments Experimental condensed matter physics is a traditionally strong research field at the department. So far, this research branch has the largest number of faculty members, graduate students and funding resources. Also, the research performance has been renowned for many years. At present, there are five major research areas: (1) Superconductivity and strongly correlated electron systems by Prof. Cheng-Chung Chi, and Prof. HuanChiu Ku; (2) Surface physics and scanning probe of microscopy by Prof. Tom Chen, Prof. Ya-Chang Chou, Prof. Shangjr AAPPS Bulletin October 2003 25 Gwo, Prof. Rong-Li Lo; (3) Solid-state electronics by Prof. Lue; (4) X-ray diffraction and its application in biophysics by Prof. Shih-Lin Chang and Prof. Tian-Huey Lu; (5) Interdisciplinary research in nanomaterials and thin films by most of the members in this group. From 2000-2003, a major four-year research project is supported through the program for Promoting Academic Excellency of Universities, supported by Ministry of Education. One of the main emphases of the project is concentrated on the field of nanomaterials and thin films that combine expertise of members in the group. [Note that there are only TWO projects in Taiwan focusing on condensed matter experiments.] Starting from 2003, Prof. Gwo, with other faculty members at the department, would kick off a brand new research investigated, known as part of the National Project on Nanoscience and Technology in Taiwan. It is expected that the physics department at NTHU would play a major role in this national wise project. 4.3. Condensed Matter Theory The condensed matter theory group has been one of the fields that made the department play an influential role in Taiwan. This reflects in the fact that, constantly in the past, there was at least one representative from the group in the review committee for physics in National Science Council. Currently there are 7 faculty members: Hsin-Hsiung Chen, Felix J. Lee and Keh-Ying Lin, working in statistical physics and Tzay-Ming Hong, Hsiu-Hau Lin, Chung-Yu Mou and WenKai Shung working on the so-called hard condensed matter theory. These two categories also mark the two age groups. Members working in statistical physics are more senior and quite established in Taiwan. With the relatively long history, this field is now merged into the soft condensed matter physics, including the fast-developing biophysics. On the other hand, the hard condensed matter physics group is relative young with research emphasis on the strongly correlated electron systems, including high-temperature superconductivity, low-dimensional correlated systems, magnetism and nanoscale physics. Even though this is a young group, nevertheless, it is quite strong combining with the local experimental group and already obtained firm reputation in domestic society. The hosted NCTS also helps to improve the international visibility and creates international collaborations in the past years. 4.4. Particles and Fields Currently there are six faculty members working in this field: Darwin Chang, Kingman Cheung, Chong-Sun Chu and ChaoQiang Geng, working on high-energy theory, Shiu-Chin Wu on nuclear experiment and Shew-Ching Yeh on particle experiment. Prof. Wu operates a 95DH Tandem Accelerator on campus. Beside service to surface physics in Taiwan, the Fig. 5: National Center for Theoretical Sciences (Physics Division). machine is also used to search for new analyzing methods in material sciences. Prof. Wu also works on nuclear structure data evaluation, in close collaboration with Lawrence Berkeley National Lab in the United States. Prof. Yeh was a member of L3 group at LEP of CERN, led by Nobel Laureate Prof. Samuel C. C. Ting. She is also the pioneer of developing silicon vertex detectors in Taiwan. Prof. Chang is the world-class expert in CP violation as described in the preceding paragraph and has been switching toward condensed matter and computation physics. In the past few years, he has collaborated with condensed matter theory group at the department and carried out several exciting results in low-dimensional correlated electron systems. Meanwhile, he continues his efforts in formulating interesting CP models and in applying to important systems. Prof. Cheung just recently joined the department. He is known to be the best collider physics phenomenologist in his generation. In the past few years, he has finished a series of highly cited papers on constraints on contact interactions, experimental probes of large extra dimensions, as well as some supersymmetry papers. Prof. Chu, although being young, is well known in the community 26 of string theorists. His most famous work in non-commutative string theory is highly cited and receives a lot of respect, with citations over 300 times. Prof. Geng is an expert in Kaon and B meson physics, in particular the T and CP violations. His works in T violation have received lots of attentions internationally. 4.5. Plasma Physics The plasma group consists of three faculty members: KwoRay Chu, Tsun-Hsu Chang and Chwung-Shan Kou. In the past decides, Prof. Chu has established a world-class laboratory with Prof. Chang. His researches on gyrotron device are pioneering and top-notched in this field worldwide. In addition to fundamental plasma physics studies, Prof. Chu has applied his expertise to some important applications, such as developing millimeter wave source for space project in Taiwan and the high-power source for national defense projects. Prof. Kou’s research focuses on the interaction between electromagnetic wave and plasma so as to device new plasma sources. He has invented a large area planar microwave plasma source and a plasma metallic ion source. 4.6. Atomic/Molecular and Optical Physics There are four members in this area: Chen-Shiung Hsue, YiWei Liu, Jow-Tsong Shy and Ite Yu. Prof. Hsue is one of the founders of Synchrotron Radiation Center in Taiwan and an expert in B-spline calculation. In recent years, he has devoted to the ab initio calculations and computational physics. Prof. Liu is a talented and skillful experimentalist. His ambitious plan is to search for permanent electric moment (PEDM) in atoms, an experiment with difficulty at the Nobel-prize level. Prof. Shy has been the leader of the group and is now serving as the department Chairman. Precision measurement of frequency in Prof. Shy’s group has achieved 1 part in 10 billions, which can compete with other group worldwide. In addition to the academic achievements, he has severed in committees of National Science Council, National Center for Theoretical Sciences and was the director of Physics Center. Prof. Yu is the pioneer of the cold-atom study in Taiwan. He succeeds the first magneto-optical trap, producing laser-cooled atoms and certainly plays a crucial role of BEC community in Taiwan. 5. SUMMARY The physics department at NTHU is a place full of enthusiastic and joyful physicists. Not only enthusiastic about explorations in physics wonderland, we also pass on the mission and training to the next generation, with flexibility for them to adjust the brand new world and lots of room to cultivate their creativity. Open and vivid discussions with passions are the common scenes you would constantly run into at our department. For more and updated information, please visit our website http://www.phys.nthu.edu.tw. AAPPS Bulletin Vol.13, No. 5 AAPPS Bulletin October 2003 27 Departments Special Reports Report on the 34th International Physics Olympiad in 2003 Ming-Juey Lin 1. 54 COUNTRIES PARTICIPATED IN THE 34TH IPhO The Thirty Fourth International Physics Olympiad (IPhO) was held from August 2 to 11 in 2003 in Taipei, Taiwan. It was cohosted by the Ministry of Education and National Science Council and organized by National Taiwan Normal University. A total of 379 participants, including 238 contestants and 141 leaders, observers and visitors, from 54 countries attended the annual global competition. The competition was originally scheduled to be held in the mid-July, but postponed two weeks to the beginning of August owing to the unexpected outbreak of SARS (Severe Acute Respiratory Syndrome) in April, which affected some parts of Asia and lasted for about three months. Despite of the adverse impact and difficult situation caused by SARS, the Organizing Committee was able to make the Physics Olympiad a great success as praised by all of the delegates. The following is the list of the participating countries: Armenia Australia Azerbaijan Belarus Belgium Bolivia Bosnia & Herzegovina Bulgaria Canada Colombia Brazil Croatia Cuba Denmark Czech Germany Estonia Finland Georgia Iceland Indonesia Hungary India Italy Iran Ireland Israel Kazakhstan Kuwaut Kyrgyzstan Latvia Netherlands Liechtenstein Moldova Mongolia Pakistan Norway Philippines Poland Serbia & Montenegro Portugal Romania Russia Singapore Slovakia South Korea Spain Thailand Switzerland Taiwan(ROC) Turkey Ukraine Vietnam USA 2. BRIEF INTRODUCTION TO IPhO The International Physics Olympiad was originated in east EuProfessor Ming-Juey Lin Department of Physics National Taiwan Normal University Taipei, Taiwan Email: mjlin@phy03.phy.ntnu.edu.tw rope in 1967. It aims to enhance the development of international contacts in the field of school education in physics and promote the quality of physics education for science-talented students. The contestants must be in their high school and can not be older than twenty years on June 30th of the year of the competition. Each participant country can send a team of five students and two accompanying leaders at most. The host country is responsible for the cost of organization of IPhO, food, accommodation, and transportation associated with the Olympiad. However, the medical costs and travel expenses of the delegations are the responsibility of the participating country. The official language of the Olympiad is English. The competition tasks including theoretical and experimental problems are prepared by the host country and have to be discussed and accepted by the international board. The leaders are responsible for translating the problems into their mother tongues. It is emphasized in the Statutes that the competition is among individuals. 3. THE PRESIDENT ATTENDED THE OPENING CEREMONY The opening ceremony of the 34th IPhO was held on Sunday, Aug. 3 and was highlighted by the address of the President of Republic of China, Mr. Chen Shui-Bian. He warmly welcomed every delegate from the world by quoting a Taiwanese old saying, “Fate has brought us together.” He declared that Taiwan would continue her enthusiastic support for the search of scientific truth and the promotion of international exchanges. The logo of the 34th IPhO features the portraits of Newton and Einstein and the number three, which symbolizes both of the year of the competition and the hope that the third giant in physics will be coming soon. Based upon the significance of the logo, the President of the Taiwan Physical Society, Dr. Lee ShihChang, encouraged all the competitors to pursue careers in physics in hope that one of them would become this third great physics giant. He asked: “If you have the ability to become a Newton or an Einstein, why become a doctor or an engineer?” The Vice Chairman of National Science Council, Dr. Liao ChunChen and the Minister of Education, Dr. Huang Jong-Tsun, also delivered their welcome speeches. Minister Huang reminded the students that friendship is even more important than competition, 28 AAPPS Bulletin Vol.13, No. 5 Fig. 1: A group photo of all of the participating students and their guides in the 34th IPhO in front of Taipei Grand Hotel. and that there is a link between physics and Formosa (beauty). Finally, he declared the official opening of the 34th IPhO. The speeches were interspersed with cultural performances: Chinese Classical Music by Taipei Youth Chinese Orchestra, Taiwanese Folk Dancing by the Department of Dance of National Taiwan College of Physical Education, and Traditional Lion Dancing by a local professional group, Ching-Ho. After the Opening Ceremony, the Mayor of Taipei, Dr. Ma YingJeou welcomed all of the delegates with a luncheon party. 4. THEORETICAL AND EXPERIMENTAL COMPETITIONS problem, a large mass was placed on the other end, and the bob and the mass were allowed to move freely. The second problem dealt with both of the mechanical and electrical properties of a piezoelectric quartz crystal. They were asked to describe the charge distribution when a voltage is applied to electrodes attached to the crystal. The third problem consists of two separate parts. The students were required to analyze neutron decay if the anti-neutrino has a small mass and then to find the laser power needed to levitate a small glass hemisphere. It is generally commented that the difficulty of the theoretical problems is close to the level of Ph. D. qualifying examination in physics. The students took the five-hour theoretical examination on Monday, August 4. The first problem requires students to do a dynamical analysis of a swing with a falling weight. Initially, the string was held horizontal with one end attached to a pendulum bob and the other end to a cylinder. In a latter part of the The experimental competition, consisting of three parts, was held on Wednesday, August 6. Students were first required to determine the appropriate operating range of a laser by measuring laser light intensity using a photodetector. They were asked to determine how this intensity varied with the current supplied to the laser. In the second part, students analyzed the electro- Fig. 2: In the logo of the 34th IPhO, the number “3” symbolizes the hope that the third physics giant will be coming soon! Fig. 3: The President of Republic of China, Mr. Chen ShuiBien addressed in the Opening Ceremony. AAPPS Bulletin October 2003 29 Fig. 4: The Mayor of Taipei City, Dr. Ma Ying-Jeou welcomed all of the delegates with a luncheon party. Fig. 6: A scene of the experimental examination held at the auditorium of the Science College of National Taiwan Normal University. optical switching characteristics of a 90-degree Twisted Nematic Liquid Crystal cell, a device that rotates the polarization of light by 90 degrees. The students placed the cell between two parallel polarizers and applied an electric field to the cell. A significant electric field causes the molecules to align with the field which diminishes the cell’s polarizing guiding effect. The students had to measure the light intensity as a function of applied voltage. Finally, they analyzed a homogeneous parallelaligned Liquid Crystal cell which has different indices of refraction for rays with their polarizations parallel and perpendicular to its molecular orientation. Students needed to investigate the birefringence of the cell and determine the voltage which causes a phase retardation of 180 degrees. sity of Science and Technology), gave very interesting talks. Aside from the examinations and international board meetings, students and leaders toured museums, scenic areas, and recreation parks. Professor Ting addressed the audience on “My Experience as a Physicist.” He presented four life lessons: (1) Do not always follow the opinions of experts. (2) Always keep faith in yourself. Do what you think is right. (3) Be prepared for surprises. (4) More importantly, be curious. Enjoy what you are doing and try to work hard to achieve your goal. Professor Chu described the development history of superconductivity entitled “An Odyssey in the World of Nothingness.” His group has found stable superconductor at a record high temperature. 6. CLOSING CEREMONY AND FAREWELL BANQUET A special science colloquium was arranged on Friday, August 8, in which all students and leader were present. Two speakers, Professor Samuel Chao-Chung Ting (the 1976 Nobel Laureate in physics) and Professor Paul Ching-Wu Chu (the President of Hong Kong Univer- The closing ceremony, held on Sunday, August 10, featured cultural performances by the symphony orchestra of National Taiwan Normal University, by Taipei Chamber Singers, and by the Department of Dancing of Taipei National University of Arts. The highlight was the presentation of medals and special prizes. According to the Statutes of IPhO, the awarding of Gold, Silver, Bronze Medals and Honorable Mention are stipulated as follows: (a) The minimum suggested by the organizers for the Gold Medal should ensure that the Gold Medal would be ob- Fig. 5: A scene of the theoretical examination held at the gymnasium of National Taiwan Normal University. Fig. 7: Students toured Yeliu, a scenic spot in the north coast of Taiwan. 5. TWO GREAT PHYSICISTS GAVE TALKS IN SCIENCE COLLOQUIUM 30 AAPPS Bulletin Vol.13, No. 5 Fig. 8: Professor Samuel C. C. Ting answered questions from the audience in the science colloquium of 2003 IPhO. Fig. 10: A group photo of all the twenty gold medalists of 2003 IPhO. tained by 6% of the contestants. (b) The minimum suggested by the organizers for the Silver Medal should ensure that the Gold or Silver Medals would be obtained by 18% of the contestants. (c) The minimum suggested by the organizers for the Bronze Medal should ensure that the Gold, Silver or Bronze Medals would be obtained by 36% of the contestants. (d) The minimum suggested by the organizers for the Honorable Mention should ensure that an Olympic Medal or Honorable Mention would be obtained by 60% of the contestants. gratulated the organizers for the great success of the Olympiad. The next host country, South Korea, presented an exciting audio-video preview of the 35th IPhO that will be held in Pohang next year. At last, Dr. Y. T. Lee declared that the 34th IPhO was officially closed. The farewell banquet was held in the evening at Chung-Shan Hall, a historical building in suburban Taipei. A twelve-course Chinese cuisine was served. The banquet was conducted in a delightful and enjoyable atmosphere. In addition to a variety of musical entertainment, students were invited to perform on the stage. It came to the end of 10-day exciting and memorable physics Olympiad amid the students’ exchange of e-mail address and saying goodbye to their new friends. Gold medals were awarded to twenty students from twelve countries. Both of the teams of USA and South Korea won three gold and two silver medals. The host team of Taiwan won three gold, one silver, and one bronze. The first prize was presented to Mr. Pavel Batrachenko from USA by Dr. YuanTseh Lee, the President of Academia Sinica in Taiwan and the 1986 Nobel Laureate in Chemistry. Dr. Lee gave the keynote address. He paraphrased Dr. Linus Pauling’s exhortation that science makes progress when young students tell older professors, “You are wrong.” He also encouraged students that “the more mistakes you make, the more you learn.” At the end, the President of IPhO, Dr. Waldemar Gorzkowski, thanked the support and cooperation of all the delegations and con- Among the many compliments sent by leaders after they returned home, the Finnish Secretary of IPhO, Professor Maija Ahtee said: “ I want to thank you again about all the work you have done to organize the 34th International Physics Olympiad. And I also want to congratulate you as you succeed so well. I can say from my very long experience that this Olympiad was the best organized so far. And all this despite the worries of SARS and that you had to change the time. I want also to thank you very specially on my own behalf as the Secretary of IPhO.” Fig. 9: Professor Paul C. W. Chu gave a talk on development of superconductivity in the science colloquium of 2003 IPhO. Fig. 11: Taiwan team won three gold medals, one silver , and one bronze. AAPPS Bulletin October 2003 31 Special Reports The Twelfth International Competition First Step to Nobel Prize in Physics Institute of Physics at Polish Academy of Sciences 1. FIRST STEP TO NOBEL PRIZE IN PHYSICS This is an International Competition in Physics Research Projects for High School (Lyceum) Students. The competition targets high school (lyceum) students who are interested in physics and are willing to perform their own research works in physics. At times, their results are very interesting and valuable. The Institute of Physics (in the Polish Academy of Sciences) organises the twelfth competition in the 2003/2004 academic year, and invites the participation of students based on the rules given below. The title of the competition expresses dreams of all the physicists, especially of young physicists. We, however, feel necessary to underline that the FIRST STEP is a quite independent competition, without any links to any Nobel institution. 1.1. General Rules (1) All the high school (lyceum) students regardless of the country, type of the school etc. are eligible for the competition. The only conditions are that the school cannot be considered as a university college and the age of the participant should not exceed 20 years on March 31, 2004. (2) There are no restrictions concerning the subject matter of the papers, their level, methods applied etc. All these are left to the participants’ choice. The papers, however, have to have a research character and deal with physics topics or topics directly related to physics. (3) Every participant can submit one or more papers but each paper should have only one author. The total volume (i.e. text + figures + captions + tables + references) of each paper should not exceed 25 normal typed pages (about 50,000 characters). (4) The papers will be refereed by the Organising Committee and the best will be awarded. The number of awarded papers is not limited. All the awards will be considered equivalent. The Authors of the awarded papers will be invited to the Institute of Physics (or to institutions cooperating with the Institute of Physics) for one month’s research stay (the stays are scheduled for November 2004). The necessary stay expenses (without expenses for travel) will be paid by the organisers. Unfortunately, the travel expenses to and from Poland cannot be paid by the organisers and the winners will have to find some sponsors. (5) In addition to the regular awards the Organising Committee may establish a number of honourable mentions. The participants who won the honourable mention receive diplomas, but they are not invited to the research stay. (6) The participants should send their papers in two copies in English only by March 31, 2004 to: Mrs. Maria Ewa Gorzkowska, M. A. Secretary of the FIRST STEP Institute of Physics, Polish Academy of Sciences al. Lotnikow 32/46, (PL) 02-668 Warszawa (7) Each paper should contain the name, birth date and home address of the Author and the name and address of his/her school. (8) IMPORTANT: The papers that do not conform to the above mentioned formal conditions are not evaluated. In particular that refers to the following papers: • written in language different than English or written by hand, • received after the deadline (the participants should have sent the papers out to the organisers early enough), • submitted without copy or without required data about the author, • in which physics does not play a basic role, • which do not have a research character (descriptive papers, essays, papers without any own results received by the Authors etc. are rejected in the first pass of evaluation). 32 We hope that our competition will provide the pupils with an opportunity to compare their own achievements with the achievements of their colleagues from other countries. Also we hope that the stay of young scientists in our Institute will result in friendly relationship among them, what seems especially valuable for the future. On behalf of the Organising Committee: Dr. Yohanes Surya, Vice-President of the Organising Committee (Jakarta, Indonesia) Dr. Waldemar Gorzkowski, President of the Organising Committee (Warsaw, Poland) Additional information on the competition and on the proceedings of the past competitions can be obtained from Dr. Waldemar Gorzkowski phone: (48)22-8435212; fax: (48)22-8430926; e-mail: gorzk@ifpan.edu.pl or from Dr. Yohanes Surya e-mail: yohaness@centrin.net.id or from any of the following Members of the International Advisory Committee (IAC): Mr. Can Altineller, altine@ee.fit.edu (also Turkish) Dr. Marta Brajczewska, marta@teor.fis.uc.pt (also Portuguese) Prof. Dr. Hiroshi Ezawa, hiroshi.ezawa@gakushuin.ac.jp (also Japanese) Dr. Zbigniew Gortel, gortel@phys.ualberta.ca Prof. Dr. Ibrahim Gunal, gunal@metu.edu.tr (also Turkish) Dr. Avi I. Hauser, avihauser@yahoo.com Prof. Dr. Si-zhao Jin, jinsz@ustc.edu.cn (also Chinese) Dr. Hans Jordens, h.jordens@phys.rug.nl (also Dutch) Prof. Dr. Stanislav Kozel, sob@scphys.msk.ru (also Russian) Dr. Juan Leon, leon@imaff.cfmac.csic.es (also Spanish) Prof. Dr. Ming-Juey Lin, mjlin@phy.ntnu.edu.tw (also Chinese) Prof. Dr. Leonid Markovich, markovich@bsu.by (also Belorussian) Prof. Helmuth Mayr, helmuthmayr@hotmail.com (also German) Mr. Markus Mueller, muller@ipno.in2p3.fr (also German and French) Prof. Dr. Shigetoshi Nara, nara@elec.okayama-u.ac.jp (also Japanese) Dr. T. S. Natarajan, tsn@acer.iitm.ernet.in Dr. Dwight E. Neuenschwander, dneuensc@snu.edu, dneuensc@aip.org Prof. Dr. Seong-Ik Park, seongik@plaza.snu.ac.kr (also Korean) Prof. Dr. Igor Pinkevych, pink@phys.univ.kiev.ua (also Ukrainian) Dr. Ammar Sarem, samers@scs-net.org (also Arabic) Prof. Dr. Viktor Urumov, urumov@iunona.pmf.ukim.edu.mk (also Macedonian) Mr. Srdan Verbic, verbic@octopus.phy.bg.ac.yu (also Serbian) Prof. Dr. Paolo Violino, p.violino@tiscalinet.it (also Italian) Prof. Dr. Ivo Volf, ivo.volf@uhk.cz (also Czech) Prof. Dr. Arthur K. West, awest@ctc.edu Mr. Zhong-da Zhang, zhangfmxh@yahoo.com (also Chinese) AAPPS Bulletin Vol.13, No. 5 Prof. Dr. Dong-pei Zhu, zhdp@ustc.edu.cn (also Chinese) The competition papers MUST be written in English, but to get an information about the competition the participants may contact the Members of the IAC also in other languages as shown in parentheses. Please remember that the Members of the IAC are not supervisors and they do not help in any concrete participants’ research. Complete information on the First Step can be found on our home page http://www.ifpan.edu.pl/firststep (you may see also the mirror page maintained by Mr. Johnny Hadryanto: http://tofi.or.id/firststep). 1.2. Description of First Step to Nobel Prize in Physics First Step to Nobel Prize in Physics is an annual international competition in research projects in physics. All the secondary (high) school students regardless of the country, type of the school, sex, nationality etc. are eligible for the competition. The only conditions are that the school cannot be considered as a university college and the age of the participants should not exceed 20 years on March 31 (every year March 31 is the deadline for submitting the competition papers). There are no restrictions concerning the subject matter of the papers, their level, methods applied etc. All these are left to the participants’ choice. The papers, however, have to have a research character and deal with physics topics or topics directly related to physics. The project belongs to the out-of-school education. Participation in the competition does not need any agreement from the school or educational authorities. The pupils conduct their research in the way and conditions which are the most convenient to them. 2. HISTORY OF THE FIRST STEP TO NOBEL PRIZE IN PHYSICS 2.1. Introduction About 15 years ago the Institute of Physics, Polish Academy of Sciences, in co-operation with the Polish Children’s Fund started to organise the so-called Research Workshop on Physics. During the Workshop pupils selected by the Fund partook in various “adult” research projects being carried out at the Institute. Some results obtained by the Workshop participants were extremely valuable and were later published [e.g.: K. Giaro, et al., A Correct Description of the Interaction between a Magnetic Moment and Its Image, Physica C, 168 (1990) 479 - 481; M. Braun, et al., Vibration Frequency and Height of a Magnet Levitating over a Type-II Superconductor, Physica C, 171 (1990) 537 - 542]. 2.2. National Competition Many scientists employed in the Institute of Physics are involved in both national and international Physics Olympiads since their beginnings and are in permanent touch with pupils AAPPS Bulletin October 2003 33 and teachers. During our time with the pupils at both the Workshop and the Physics Olympiads we discovered that some of the high school pupils tried to carry out physical research by themselves—at schools, in some laboratories and even at home. It was then—under permission of the Authorities of the Institute of Physics—that I decided to organise the National Competition in Research Projects on Physics for High School Students. The aims of the competition were obvious. We wanted to recognise pupils’ efforts and provide them with an opportunity to compare their own achievements with those of their colleagues. The first competition of this type started in 1991/2. The number of papers submitted was 59 with many of them being of a surprisingly high level. In this first competition 7 papers won prizes and 19 received honourable mentions. Given the difficulty in comparing papers on, for example, chaotic behaviour with the papers on theory of networks, all prizes were deemed to be of equivalent value. The honourable mentions were divided into two categories: research papers and contributions. Similarly, inside each category the honourable mentions were considered equivalent as well. The prizes in our competition were not typical. Instead of buying items for our winners, such as cameras, computers, sport equipment, etc., we decided to invite them to our Institute for a two-week long research stay. It was felt that in the case of those whose main hobby is physics such a prize is more valuable and more instructive than anything else. Since the first competition was a success we decided to repeat the national competition every year. The second competition was organised in 1992/3. Its level was also very high, perhaps even higher than the previous year. The number of participants and winners increased also: 81 papers, 8 winners, 21 honourable mentions in two categories. Table 1 presents a statistics of the first six national competitions. National Competition No. Statistics Number of Honourable mentions No. of Awards Research papers Contributions Didactic papers aids I 59 (66) 7 (7) II 81 (94) 8 (10) III 88 (106) 10 (14) IV 86 (108) 10 (11) V 98 (113) 8 (9) VI 141 (168) 6 (9) Total 553 (655) 49 (60) 8 (8) 8 (9) 5 (6) 6 (8) 8 (9) 16 (18) 51 (58) 11 (13) 13 (16) 9 (14) 24 (28) 24 (25) 21 (26) 102 (122) (*) (*) (*) (*) (*) 6 (11) 6 (11) Table 1: Without brackets: numbers of papers; in brackets: numbers of authors (in the national competition the papers may be prepared by several authors). (*) honourable mentions in category “Didactic aids” were introduced at the VI competition. Every year the information on the national competition is published in the brochure with the problems of the Polish Physics Olympiads. The brochure is disseminated to all the high schools in Poland. Additionally, the information on the competition is disseminated by the Polish Children’s Fund and published in three very popular journals: Fizyka w Szkole, . Wiedza i Zycie and S’ wiat Nauki. Due to these actions high school students know about the competition. On behalf of the Organising Committee I would like to express our deep thanks to all the institutions and people who help us in distributing information about the competition. Without this help any efficient work would certainly be impossible. It is, however, quite obvious that only a small part of the total number of high school students is interested in conducting their own research and has appropriate conditions for that. It is proper to mention here that conducting research needs a special kind of talent, different than talent to solve well formulated by other people Olympic problems with known solutions. In the national competition in research projects the participants have to formulate the topic of investigation by themselves, they have to create appropriate research workshop, choose methods, collect literature etc. The participants work for a long time but without any time limit, characteristic for the Olympiads. Due to that the work does not cause as big stress as participation in the Olympiads. For these differences the national competition in research papers and the Olympiads are not rivals. They are complementary to each other as they involve different kinds of talents. What are criteria applied when evaluating the papers? First of all we look for new, original and own achievements of the participants. The papers without any new elements have no chance to be awarded. In the first turn essays, philosophical dissertations on different aspects of physics, descriptive papers, papers popularising physics etc. are rejected. The competition is in research and it is quite natural that we look for new results. The papers may be of theoretical or experimental character. Also papers devoted to constructing some new interesting and original devices are recognised. All the achievements of the authors should be presented in an appropriate way characteristic for research papers (including literature). We do not apply any discount for young age of the authors. 2.3. International Competition: First Step to Nobel Prize in Physics Analysis of the papers submitted to the first national competition stimulated me to organise a similar competition in an international scale. Taking into account that the projects should be real research papers we named it First Step to Nobel Prize in Physics. Due to kindness and assistance of the Director of the Institute of Physics and the Scientific Council of the Institute of Physics the international competition has started in 1992/1993. Like the national competition the international one is growing up very quickly and becomes to be more and more popular. 34 The First Step, like the national competition, belongs to the out-of-school education. Participation in the competition does not need any agreement from the school or educational authorities. The pupils conduct their research in the way and conditions, which are the most convenient to them. 2.3.1. Characteristic Features of the First Step (1) The criteria used when evaluating the papers are quite adult we do not apply any discounts for the young age of the participants. (2) There are no prizes such as cameras, video, etc. Also there are no financial prizes. Instead the winners are invited to our Institute for one month for research stays (usually in November). During the stays they are involved into real research works going on in the Institute. (3) Every year the proceedings with all the awarded papers are published. The competition is guided by the Organising Committee and consists of all the members of the Scientific Council of the Institute. The papers are evaluated by the Evaluating Committee, which is nominated by the Organising Committee. In the first two competitions only Polish physicists participated in the Evaluation Committee. In the third competition one foreigner took part in evaluation of the papers. In the fourth competition the number of physicists from foreign countries was 10. In the fifth competition number of foreigners in the Evaluating Committee was 14, etc. In the future we are still going to enlarge the number of foreign physicists in the Evaluation Committee. Two years ago an International Advisory Committee (IAC) has been established. At present if consists of 25 physicists from different countries. The materials on the competition are disseminated to all the countries via diplomatic channels. The competition is also AAPPS Bulletin Vol.13, No. 5 advertised in different physics magazines for pupils and teachers. (Every year about 30 articles on the First Step are published in different countries). Also different private channels are used. In the first eight competitions the pupils from 67 countries participated. The First Step (as far as we know) is the only competition that publishes proceedings with practically all the awarded papers. Due to that all our most important decisions may be verified. 2.3.2 The Main Aims of the Competition (1) Promotion of scientific interests among young pupils; (2) Selection of outstanding pupils (this point is especially important in case of pupils from countries or regions in which access to science is difficult) and their promotion (very often our winners enter better universities and receive appropriate financial help from the local authorities); (3) Enhancing motivation of pupils to scientific work; (4)Stimulation of the schools, parents, local educational centres, etc. for greater activity in work with pupils interested in research (we know that in some countries, some regions and even in some schools a preliminary local selection in organised, sometime such selections involve great numbers of participants); (5) Establishing friendly relations between young physicists (recently all the winners are invited to the institute in the same time, they are accommodated in the same place, they cooperate with each other, etc.). Waldemar Gorzkowski President of the Organizing committee gorzk@ifpan.edu.pl APPENDIX: This is a typical form filled by the judges. Usually several judges judge the competition papers. We include this form to our page to present you the criteria used when evaluating the papers. General criteria for evaluating the competition papers: Award: Papers should be of regular research character in physics (physics should dominate in the papers—that refers to all the recognised competition papers, not to the awarded papers only). They should contain new, original and interesting results obtained by the Author either in theory or in experiment or in constructing devices (or instruments), the results should be presented in an appropriate way, characteristic for research papers. The papers should be ready for publication without any changes or after minor changes of editorial character only. Honourable Mentions: Category: Research papers The same as above, but the paper is not ready for publication without more or less important changes that exceed editorial character only. AAPPS Bulletin October 2003 35 Category: Contributions Interesting contributions or interesting descriptive papers or interesting papers aiming to popularise some topics (the papers in this category should contain at least a new approach to the topic of the paper). The papers should be correct with regards to physics contents and written in good English. (Good English is required from all the recognised papers, but its role in this category is somewhat greater.) Category: Instruments Interesting devices, instruments and other constructions that—at least in principle—are not absolutely new. They, however, should contain some interesting solutions or other interesting details. (The new constructions may be awarded.) First Step to Nobel Prize in Physics No. of the paper: _____________ Country: ______________________ Author of the paper: ___________________________________________ Title of the paper: Suggested result: Award Honourable mention in category: Research paper Contribution Instruments Nothing Short description of the paper should be written on the opposite side (please underline own achievements of the Author). Date: __________________; Signature: _________________________