Physics

Research on elementary particles is carried out by large international teams, operating over periods of years, at the world's biggest accelerator facilities at CERN and DESY. Institute physicists are working on five such experiments, their main concern being with studies of electron-positron interactions at energies up to 190 GeV and studies of discrete symmetries in neutral kaon and Bmeson systems. The more recent and exciting highlights have been the first and spectacular observation of pair formation between two weak vector bosons, W' and W-, the discovery of the transformation of a B-meson into its anti-particle, and direct observation of time-reversal violation. Quantum gravity, unification of matter and forces, and heavy meson decay phenomenology are among the topics studied by the theoretical physicists. Other projects are designed to complement experimental findings in areas such as nuclear physics, ferromagnetism, and noble metal and sapphire surfaces. These numerically intensive applications are supported by one of the largest computers in the country. Nuclear physicists are concerned with measurements of nuclear and sub-nuclear degrees of freedom in electron-nucleus scattering, while atomic physicists are studying multi-particle excitations, provoked by X-rays or synchrotron radiation as well as with electron or ion bombardment. A 2 MV TANDETRON electrostatic accelerator was installed in the Institute in 1997, providing ions suitable for interdisciplinary research on materials and their surfaces, as well as being open to international collaboration.

The Institute houses a rich variety of instrumentation which provides the basis for much of the cross-specialty research, both basic and applied. Spectroscopic tools, for example, range from acoustic methods to microwaves, ultraviolet and visible light, and including fluorescence, Raman and circular dichroism spectroscopies. The electron microscope, tunnelling microscope and atomic force microscope at the Institute are used as powerful tools for surface research. Nuclear magnetic resonance is central to many of the projects in solid state physics, and an important part of the research programme is the development of new measuring methods in the fields of magnetic resonance, magnetic resonance imaging, and optical time resolved spectroscopy.

The physics of condensed matter, both theoretical and experimental, has traditionally involved studies of phase transitions in crystals, but recently interest has shifted towards the study of lessordered systems like quasi-crystals, incommensurable systems and glasses, as well as soft matter, including liquid crystals, gels and polymers. These systems show a variety of properties not found in crystals, and have the potential for a number of applications. In this area, special emphasis is given to new materials, particularly high-temperature superconductors, fullerenes and magnetic nano-clusters. The observation of ferromagnetism in fullerenes and the discovery of an important contribution to pair formation in high-temperature superconductors, together with a theoretical model of strongly correlated electrons, are the most important achievements. Quantum dots and quantum wires, both being studied theoretically, are important for their potential as nanoscale devices such as single electron transistors.