This volume provides an adequate mathematical description of solid state properties. It concentrates on group action methods, generalized statistics and molecular symmetries (unitary and symmetric groups).

This volume continues the series of proceedings of summer schools on theoretical physics which aim at an adequate description of the structure of condensed matter in terms of sophisticated, advanced mathematical tools. This time, the main emphasis is put on the question of whether (and when) the energy bands in solids are continuous. Profs. L Michel, J Zak and others consider the origin, existence and continuity of band structure. Also, some previously discussed problems (magnetic symmetry, flux quantization, statistics, quasicrystals, the Bethe ansatz) are pursued further, and appropriate mathematical tools, rooted in “actions of groups on sets”, are developed.

This volume is the seventh in a series of proceedings on theoretical physics related to various aspects of the structure of condensed matter and to appropriate mathematical methods for adequate description. Three main topics are considered: conformal symmetry, central charge, condensation of flux; rigged string configurations, Yang-Baxter equations and their applications in solid state physics; and energy band structure in solids.

This volume reviews some selected problems in solid state physics with an emphasis on adequate mathematical tools. The three main subjects are magnetic structures and neutron scattering; Berry phases and energy bands in solids (symmetry, analicity, Hofstadter butterfly, van Hove singularities); and quasicrystals, finite systems, and group action on sets (unitary group approach, Schur functions). Software presentations are included as a separate part.

These proceedings review the recent developments in current research connected with an adequate description of condensed matter in statistics of quasiparticles, topological invariants and self-similar structures.

This volume is the seventh in a series of proceedings on theoretical physics related to various aspects of the structure of condensed matter and to appropriate mathematical methods for adequate description. Three main topics are considered: conformal symmetry, central charge, condensation of flux; rigged string configurations, YangOCoBaxter equations and their applications in solid state physics; and energy band structure in solids."

This volume continues the series of proceedings of summer schools on theoretical physics related to various aspects of the structure of condensed matter, and to appropriate mathematical methods for an adequate description. Three main topics are covered: (i) symmetric and unitary groups versus electron correlations in multicentre systems; (ii) conformal symmetries, the Bethe ansatz and quantum groups; (iii) paradoxes of statistics, space-time, and time quantum mechanics. Problems considered in previous schools are merged with some new developments, like statistics with continuous Young diagrams, the existence and structure of energy bands in solids with fullerenes, membranes and some coverings of graphite sheets, or vortex condensates with quantum counterparts of Maxwell lows.

Prof T-Y Wu is not only an eminent physicist with an encyclopedic knowledge, but also a motivational teacher and an influential policy maker in science and technology. The young Wu was inspired by Prof Y-T Yao, whose course on modern physics sparked an interest that burned during a long and productive career. Among Wu's achievements are 14 books and more than 120 papers covering subjects from atomic and molecular physics to plasmas and gases to atmospheric physics to relativity theory. Even at the age of 90 he remains active, publishing papers and lecturing on physics.Prof Wu feels grateful that he had the opportunity to educate a group of extremely talented students and, in particular, to discover T D Lee's remarkable talent. Although creative talent is no doubt a product of nature, it must also be nurtured. Prof Wu has played a crucial role for an entire generation of physicists in China and has won great respect from former students such as C N Yang, T D Lee, K Huang, and countless others. Prof Wu's love of physics and his dedication in teaching and research will always be remembered.

This volume continues the series of proceedings of summer schools on theoretical physics related to various aspects of the structure of condensed matter, and to appropriate mathematical methods for an adequate description. Three main topics are covered: (i) symmetric and unitary groups versus electron correlations in multicentre systems; (ii) conformal symmetries, the Bethe ansatz and quantum groups; (iii) paradoxes of statistics, space-time, and time quantum mechanics. Problems considered in previous schools are merged with some new developments, like statistics with continuous Young diagrams, the existence and structure of energy bands in solids with fullerenes, membranes and some coverings of graphite sheets, or vortex condensates with quantum counterparts of Maxwell lows.

This collection of papers provides a broad view of the development of Lorentz and Poincaré invariance and spacetime symmetry throughout the past 100 years. The issues explored in these papers include: (1) formulations of relativity theories in which the speed of light is not a universal constant but which are consistent with the four-dimensional symmetry of the Lorentz and Poincaré groups and with experimental results, (2) analyses and discussions by Reichenbach concerning the concepts of simultaneity and physical time from a philosophical point of view, and (3) results achieved by the union of the relativity and quantum theories, marking the beginnings of quantum electrodynamics and relativistic quantum mechanics.Ten of the fundamental experiments testing special relativity are also discussed, showing that they actually support a four-dimensional spacetime based on broad Lorentz and Poincaré invariance which is more general than and includes the special theory of relativity. The generalization of the concepts of simultaneity, physical time and the nature of the speed of light within a four-dimensional spacetime framework leads to the conclusion that the symmetries embodied by the special theory of relativity can be realized using only a single postulate — the principle of relativity for physical laws.