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Cavendish Research in West Cambridge

Prof. A. Howie

Note: The following extract was accurate at the time of writing. For an overview of the Cavendish's latest research, please go to the Research page.

Within twenty years of the move to West Cambridge, the research effort has grown so prodigiously that much of the generous space so fortunately provided in our new buildings has been filled up and further laboratories have had to be constructed. The most direct index of this expansion is the near doubling of research student and postdoctoral numbers to their current levels of 250 and 160 respectively. We have evidently come a long way from the time when Chadwick could discuss each project with the individuals concerned and report the results to Rutherford every day at 11 a.m! In the struggle to keep open the lines of communication between research groups, the trusted mechanisms of the colloquium, the shared enterprise of undergraduate teaching or examining, the cricket or football team and the canteen are more vital than ever. The government-imposed biennial appraisal of the academic staff and research workers, though certainly one of several considerable extra burdens, also straddles research group boundaries and helps in this process.

Numbers of teaching staff and assistant staff have been by comparison relatively static at 70 and 150 over these years of dramatic expansion in research activity. This contrast correctly reflects the tremendous pressure which now bears over the whole range of the research support operation. It should not however give any impression of stagnation in the guidance of our research, since more than three quarters of our current staff were first appointed after the move to West Cambridge and over twenty of them were appointed in the last five years. These changes in staff have meant that the increased activity has partly gone into new lines of research as well as revitalising old ones.

In condensed matter physics which now accounts for three-quarters of our overall research, two major new ventures are in the related fields of semiconductor physics (Professor Pepper) and in Microelectronics (Professor Ahmed). In both cases, substantial clean room facilities for semiconductor growth, device patterning and characterisation have been required and in 1990 a new building was constructed, mainly with our own funds, but supplemented by valuable donations from Hitachi, Toshiba and Schlumberger, to house the Microelectronics work. The semiconductor physics group employs high magnetic field, low temperature techniques to explore fundamental quantum interference phenomena such as the quantum Hall effect in nanometer-scale structures grown by molecular beam epitaxy methods.

Another major development has been in polymer and colloid physics where Professor Edwards has built up an impressive theoretical and experimental team. Following an old Cavendish tradition, they are now showing us that mud, sludge, treacle and sand are all materials which present the modern physicist with challenging and rewarding problems. An exciting bridge between this work and the semiconductor research programme has been constructed by a team under Dr Friend, which is exploring the electronic and optical properties of conducting polymers with a view to the design of useful molecular electronic devices.

The main UK response to the discovery of high temperature ceramic superconductors was to set up an Interdisciplinary Research Centre (IRC) in Cambridge, involving five departments (Physics, Chemistry, Engineering, Materials Science and Earth Sciences) as partners. The Cavendish provided space for the start-up operation and contributed funds for a new building on our site, which was formally opened a month ago. The director, Professor Liang and one of the co-directors, Dr Waldram, are seconded from our staff, but several other staff are closely involved in studying the ceramic superconductors, not least Professor Mott, who is as eager as ever to conquer a new field.

Some longer established lines of solid state research continue to flourish. In low temperature physics, the properties of granular metals and heavy fermions are studied. In Microstructural Physics (previously Metal Physics) electron scattering and neutron scattering methods are applied to the investigation of amorphous solids, glasses, surfaces and catalysts. The Cavendish tradition in electron microscopy and diffraction which this work carries on, is most evident in Dr Rodenburg's super-resolution project to reconstruct images by processing of the intensity scattered at high angles in a scanning transmission electron microscope. The PCS research group, once the largest in the whole laboratory, spawned the experimental polymer work noted earlier, and still embraces work on surface physics (using ion scattering), ultra-thin magnetic films, explosion and fracture processes studied by high speed photography. A long established effort in the theory of the electronic structure of solids under Professor Heine is energetically exploiting the opportunities of modern computational physics to address important problems which would be very difficult, or even impossible, to tackle experimentally.

Radio Astronomy continues to be our main activity outside solid state physics. Although the telescopes at Lord's Bridge remain in active use, studying for example the anisotropy in the background radiation, activity has now spread outside the radio region. Professor Hills and his team, having played a key role in the design and construction in Hawaii of the James Clerk Maxwell Telescope for millimetre wave astronomy, are prominent producers of the exciting results which are beginning to emerge. Professor Baldwin and his colleagues have constructed an optical interferometry system which applies the techniques of radio astronomy in the optical region, thus countering the problem of atmospheric scintillations and raising the possibility that optical astronomy can once again be an active Cambridge-based subject. The radio astronomy programme has also generated some valuable spin-off work of which two examples are Dr Gull's activity in maximum entropy data analysis and Dr Duffett-Smith's project in precision location of a vehicle using commercial radio stations.

The High Energy Physics Group in the Cavendish continues to play a part in the UK programme at CERN which is out of all proportion to its relatively small size. Their work has concentrated on the OPAL system with a new silicon microvertex detector and they are also prominently engaged in actively developing aspects of the programme proposed for the large hadron collider (LHC). The exciting combination of basic physics, demanding instrumentation and exacting problems of research management which characterise so many research projects in the modern Cavendish are perhaps most dramatically apparent in this field.

The twentieth century has been one of the most tumultuous in physics and the Cavendish laboratory has been fortunate to play a major part in it. If we can preserve the traditions of informality and the nurturing of individual ideas and excellence amidst the increasing pressure for more large-scale centrally planned research, we may hope that this success can roll forward into the next century.