The Cavendish Laboratory History Current Research and Future

The Cavendish Laboratory History, Current Research and Future Development The Department of Physics 2008

The Role of Physics • Practical Application of Physics Research for the Benefit of Society • The Intellectual Underpinning of Physics and all Cognate Sciences • The Development of Individuals with the Ability to Relate Phenomena to Mathematical Structures in a Non-trivial Way • Physics for Its Own Sake – Insights into the Nature of Our Physical Universe

The Cavendish Laboratory • The policy of the Department is to maintain a very powerful core of fundamental physics in all its diversity supported by theory. • Today, we want to concentrate on two of the major new areas of research – Biological and Soft Systems (BSS), leading to the Physics of Medicine (Po. M), and Atomic, Mesoscopic and Optical Physics (AMOP). • Physics is what Physicists do. • Physics is extensive.

The Founding of the Cavendish Laboratory In 1871, the Chancellor of the University, William Cavendish, Seventh Duke of Devonshire provided £ 6, 300 from his own resources to meet the costs of building and equipping a physics laboratory, on condition that the Colleges provided the funding for a Professorship of Experimental Physics.

James Clerk Maxwell was elected the first Cavendish Professor in 1871. He was somewhat reluctant to accept the position since he had resigned from his post in King’s College London some years earlier to devote his time to his estate in Scotland the writing of his great Treatise on Electricity and Magnetism. Maxwell was responsible for the design of the Laboratory and the equipping of its laboratories.

James Clerk Maxwell Later this year, a splendid statue of Maxwell will be unveiled in George Street Edinburgh, the first such memorial in Scotland. It recognises the fact that Maxwell was the key figure whose discoveries provided the essential link between Newton and Einstein.

James Clerk Maxwell did not live to see his theories of electricity, magnetism and statistical physics fully confirmed by experiment. He designed apparatus to test his theory of the electromagnetic field, which were carried out by his successor, Lord Rayleigh. Maxwell died in 1879 at the early age of 48. Cavendish Laboratory in Free School Lane

John William Strutt, Lord Rayleigh agreed to hold the chair for only five years. His name is associated with many physical phenomena. He discovered the correct expression for the spectrum of a black-body at low frequencies, the Rayleigh-Jeans law. Other phenomena include the Rayleigh criterion in optics, the Raleigh-Taylor instability in fluids, Rayleigh scattering, . . .

John Joseph (JJ) Thomson In 1884, Rayleigh was succeeded by the young J. J. Thomson, who held the Cavendish Chair until 1919. His election was a surprise since he had little experience of experiment and had a reputation for being clumsy with his hands. He was supported by an outstanding group of Laboratory assistants, pride of place going to the chief assistant Ebenezar Everett, who constructed the experiments.

The Cavendish Laboratory 1897 In 1895, the University allowed students from other Universities to come to Cambridge to study for a research degree. The first two students to take advantage of this were Ernest Rutherford from New Zealand John Townsend from Dublin. Thomson’s tenure marked the beginning of the great period of discovery for Cavendish physics.

Changes of direction In 1895, Rontgen announced the discovery of X-rays and in the following year, 1896, Becquerel discovered natural radioactivity. Thomson and Rutherford quickly changed their research directions, Thomson to understand the cathode rays which produced the X-rays and Rutherford to radioactivity. In 1897, Thomson carried out one of the great experiments of physics when he measured the charge to mass ratio of cathodes rays. These had been discovered in experiments with discharge tubes at low pressures. Thomson’s most famous experiment involved passing a beam of cathode rays through crossed electric and magnetic fields.

The Original Thomson Tube In the famous experiment of October 1897, Thomson found the charge to mass ratio of the cathode rays by balancing the electric and magnetic forces acting on the cathode rays. The charge of mass ratio was much less than that of hydrogen Thomson’s original tube. Replica on show in the museum. e/m » 1000 – 1800 (e/m)Hydrogen

Geoffrey Taylor One remarkable experiment was carried out in 1909 by the young G. I Taylor which bears upon the AMOP experiments you will see later. As an undergraduate, Taylor carried out an experiment with low level light which demonstrated that, even at a very low light level, individual photons form a diffraction pattern on a screen. This was the first quantum optics experiment.

Ernest Rutherford with the apparatus with which he demonstrated the disintegration of nuclei by incident a-particles in 1919. The original apparatus is in the Cavendish Museum. These disintegrations were photographed by Blackett with his automated cloud chamber in 1925.

Lawrence Bragg was Cavendish Professor from 1938 -1953. He and his father were awarded the Nobel prize for their discovery the law of diffraction of X-rays from crystals in 1912. They exploited the technique of X-ray diffraction to study the structures of all types of materials and this gave rise to the discipline of Xray crystallography.

Francis Crick and James Watson In the early 1950 s, Frances Crick and James Watson worked in Bragg’s X-ray crystallography group and carried out their studies of the double helix structure of DNA. These discoveries led to the foundation of the Laboratory for Molecular Biology, a separate organisation founded by the Medical Research Council.

Nevill Mott Bragg was succeeded by Nevill Mott as Cavendish Professor in 1953. He was a specialist in solid state physics and won the Nobel prize for his studies of the electric and magnetic properties of non-crystalline materials. During his tenure, new research groups made many notable advances. These included the radio astronomy and physics and chemistry of solids.

Brain Pippard Mott was succeeded by Brian Pippard as Cavendish Professor in 1970. Pippard was a specialist in lowtemperature physics who made the first experimental determinations of the Fermi surface of copper. During his tenure as Cavendish Professor, he organised the move of the Laboratory to West Cambridge and the construction of the present Laboratory.

Sam Edwards Pippard was successed as Cavendish Professor by Sam Edwards who started major initiatives in the area of soft condensed matter physics. This has become one of the major growth areas in the Laboratory and in turn has given rise to the new programmes in the physics of biology and the physics of medicine.

Physics of Medicine • Physics of Medicine is a new initiative led by the Cavendish. • It will create an environment where researchers can freely mix, discuss and share ideas at the interface of the physical sciences, technology, life sciences and clinical research. • A new building is being fitted out at the moment. • Phase One will officially open in Dec 2008. • Priority project is the construction of Phase Two.

The Research Groups

Members of the Laboratory University Officers Of these, Research-Teaching Staff 90 65 Contract Staff - Research Fellows, PDRAs 150 Research Students 250 Emeritus and Visitors 70 Assistant staff 140 Total 700

The Research Groups Research is divided into 12 Groups • Astrophysics • High Energy Physics • Detector Physics • Opto and Microelectronics • Atomic, Mesoscopic and Optical Physics • Surface, Microstructure and Fracture • Biological and Soft Systems • Quantum Matter • Inference • Semiconductor Physics • Nanophotonics • Theory of Condensed Matter

Astrophysics • The research programmes of the Astrophysics group are centred on four major areas, each linked to instrumental programmes at the cutting edge of astronomical technology. • Formation of Stars and Planets • Atacama Large Millimetre Array (ALMA) • James Clerk Maxwell Telescope (JCMT) • Observational Cosmology of the Microwave Background Radiation • Arcminute Microkelvin Imager (AMI) • ESA Plank Surveyor Satellite

Astrophysics • Formation and Evolution of Galaxies • Low Frequency Array (LOFAR) • Square Kilometre Array (SKA) • High resolution imaging of Stellar Systems and Active Galactic Nuclei • Magdalena Ridge Observatory and Interferometer (MROI) • Kavli Institute for Cosmology • In Aug 2006, the establishment of a Kavli Institute for Cosmology was approved. • Funds provided by the Kavli Foundation will support 5 -year senior research fellowships.

Detector Physics • The Detector Physics Group runs a major facility for designing, manufacturing and testing a new generation of superconducting detectors for astrophysics and the applied sciences. • The Detector Technology • The group is involved in the development of a range of detector technologies. • The Facilities • Better than Class 100 lithography room. • Full cryogenics and RF test facility

Atomic, Mesoscopic and Optical Physics • The Atomic, Mesoscopic and Optical Physics group studies quantum aspects of condensed matter; from Bose-Einstein condensates to semiconductor quantum dots. • Quantum gases and collective phenomena • Areas of interest: superfluidity, quantum magnetism, nonequilibrium phenomena. • Quantum optics and cold atoms • Correlation phenomena of bosonic and fermionic atoms. • Quantum Optoelectronics • Dynamics of spins in lowdimensional semiconductors. • Quantum optics and mesoscopic systems • Optical control and manipulation of multiple spins in quantum confines systems

Biological and Soft Systems • The 21 st Century promises a major expansion at the interface of physics with the life sciences. The Biological and Soft Systems group is pursuing this kind of multidisciplinary research. • Soft Matter • Colloids • Polymers and Composites • Thin Films and Interfaces • Imaging • Environmental Scanning Electron microscope (ESEM) • Medical imaging • Micromechanics and Optical Manipulation

Biological and Soft Systems • Physical properties of biological systems • Cell Biophysics • Molecular Biophysics • Physics of Medicine • Many of the activities are expected to move into the new facility.

Inference • The Inference Group is involved in a wide range of projects in the general area of machine learning and information theory. From the optimisation of errorcorrecting codes to automated strategies for Go. • The Dasher project • Neural Networks • A text-entry interface driven • Used to understand how by natural continuous the brain works. pointing gestures. • Energy research • Informing the public and government of ways energy can be harnessed efficiently and sustainably.

Nanophotonics • In Nanophotonics, new materials are constructed in which atoms are arranged in sophisticated ways on the nanometre scale. These metamaterials often display new properties not observed in the constituents. • Nanoplasmonics • Semiconductor microcavities • Nanoscale self-assembly results • Microcavities represent a new in nanostructured surfaces with interface for light and matter to specific optical properties. meet. • Polymer photonic crystals • Flexible polymer-based photonic crystals change colour under strain.

High Energy Physics • The High Energy Physics group’s research is based on experiments a high energy particle accelerators, with group members making up part of several international collaborations. • ATLAS • A particle physics experiment based at the CERN LHC. • Large Hadron Collider beauty experiment (LHCb) • A special purpose experiment at the LHC used to investigate “Bparticles”

High Energy Physics • Main Injector Neutrino Oscillation Search (MINOS) • The main goal is to study the phenomenon of neutrino oscillation. • Research and Development • The group works on an R&D programme to solve the challenges of next-gen detectors. • Cavendish HEP Theory work • The groups works on Quantum Chromodynamics and beyond. Standard Model phenomenology.

Opto and Microelectronics • The Optoelectronics group carries out fundamental physics studies in different aspects of organic semiconductor materials; long-chain molecules made from conjugated units such as benzene. • Light Emitting Polymers • The group pioneered the physics of semiconducting polymers as LEDs • Solar Cells • Understanding the formation of electronic states is important to optimise efficiency.

Opto and Microelectronics • Transistors • Research is focussed on the charge transport of organic semiconductors • Microelectronics Research Centre • The MRC works closely with the Hitachi Cambridge laboratory on novel electronic quantum devices.

Quantum Matter • The Shoenberg Laboratory for Quantum Matter studies matter under extreme conditions using advanced experimental techniques and very low temperatures, high magnetic fields and high pressures. • Anisotropic Superconductivity • Exploring theory for p-wave and d-wave superconductivity • Correlated Electron Materials • Studying manifestations of electron-electron correlation • Exotic States of Matter • Non-Fermi liquid behaviour

Quantum Matter • High-Tc Materials • Continuing investigation • High Pressure • A new quantum parameter • Novel Superconductors • Superconduction from new material combinations • Quantum Ferroelectrics • New quantum critical point • New Cryogenics • Simplifying equipment

Semiconductor Physics • The Semiconductor Physics group explores and develops new physics using state-of-the-art semiconductor device fabrication technology, particularly in new types of nanostructures. • One-dimensional Electron transport • Mesoscopic 2 D Electron transport • Examining behaviour in low dimensional systems. • Electron transport in Quantum dots • Possible future as a new computing architecture.

Semiconductor Physics • Surface Acoustic Waves • Quantum Light sources and detectors • Collaborative efforts with Toshiba Research Europe. • Low Temperature scanning probes • Novel scanning system enable study of conduction in devices. • Terahertz science and technology • Many applications due to noninvasive and non-destructive nature. • Thin Film Magnetism • Novel magnetic properties.

Surface, Microstructure and Fracture • The Surface, Microstructure and Fracture group studies surface physics, microstructure, fracture and microscopy, as well as dynamical material testing and high-speed photography. • Fracture physics • High precision experiments to develop theoretical knowledge. • Surface physics • New technique: He-3 Spin-echo. • Structure and dynamics • Understanding how structures behave by external effects.

Theory of Condensed Matter • Theory of Condensed Matter group constantly evolves to address new theoretical challenges, some of which arise from novel experiments performed in the Cavendish and elsewhere. • Collective Quantum Phenomena • Using theoretical methods to address physical problems • Quantum mechanical methods • Developing new methods with greater accuracy. • Soft condensed matter • Investigating liquid crystal behaviour.

The Department

Teaching • Training future generations of physical scientists continues to be a central pillar of the Cavendish’s programme. • The Laboratory attracts large numbers of the brightest young scientists from the UK and overseas at both undergraduate and graduate levels.

Teaching • Undergraduate Teaching • Physics students are able to develop their enthusiasm and ingenuity through the challenges provided by the course. • Graduate Teaching • The Laboratory offers graduates from around the world the opportunity to work with worldclass researchers across the complete spectrum of physics.

Undergraduate Teaching Student numbers 1 st year Part IA 400 2 nd year Part IB (single) 170 Part IB (double) 150 3 rd year Part II 120 4 th year Part III 100 In the 1 st year students studying Natural Sciences are required to take three experimental subjects and mathematics. Students in 3 rd and 4 th year spend most of their time on the West Cambridge site. Students in the first two years have lectures in the centre and practical classes in the Laboratory.

Undergraduate Numbers

Development • Physics is a living and dynamic discipline, which continues to expand in intellectual depth and breadth. • Particularly significant are the many cross-linkages with other departments, notably the physics of biology, medicine and the life sciences. • These ground-breaking developments require new investment in infrastructure.

Development • The University has recognised that it is essential to rebuild the Laboratory to match the new requirements of the research and teaching programmes. Specifically: • The present buildings, constructed in 1974, are no longer appropriate for the current programme or, in light of new interdisciplinary collaborations and new investigative techniques, for the future direction of research at the Cavendish. • The provision of state-of-the-art laboratories, offices and supporting infrastructure, including scientific computing, with all the advantages of modern design, will enable the Cavendish to maintain and enhance its contribution to physics at the international level. • The reconstruction of the Laboratory will complement the University's ambitious plans for a major contemporary science complex on the West Cambridge site.

Outreach • Educational Outreach to the broader community, particularly young people, is an essential part of the work of the Laboratory. • The Educational Outreach Office has the prime objective of stimulating interest in physics amongst 11 -19 year-olds. • Physics at Work • The flagship event organised by the Cavendish is the Physics at Work exhibition. • Over 2000 young people visit the Laboratory over a three-day period.

Outreach • Working with Schools • Educating the next generation of physicists is regarded as an important responsibility. • Senior Physics Challenge • A major "schools physics development programme” and "university access initiative". • Cavendish Physics Centre • Envisioned well-equipped facilities to demonstrate the scope of physics.

Contacts The Cavendish Laboratory Head of Department JJ Thomson Avenue Prof. Peter Littlewood Cambridge Tel: +44 (0) 1223 337 429 CB 3 0 HE, UK Email: hod@phy. cam. ac. uk Tel: +44 (0) 1223 337 200 Director of Development Fax: +44 (0) 1223 363 263 Prof. Malcolm Longair Email: hod@phy. cam. ac. uk Tel: +44 (0) 1223 765 953 Web: www. phy. cam. ac. uk Email: msl 1000@cam. ac. uk Development website: http: //www. phy. cam. ac. uk/cavendish/development/