About Theoretical Physics
At present the Theoretical Physics Group includes eleven permanent members of academic staff, three postdoctoral research associates, twelve PhD students and a few visitors. The work of the Group is currently supported by research grants from various agencies, including the Engineering and Physical Sciences Research Council (EPSRC), the European Union (EU) and NATO.
Research within the Theoretical Physics Group is done (mainly) in the following areas
- Condensed matter physics
- Statistical Physics
- Nuclear and subnuclear physics
- Quantum optics and mesoscopics
- Biological physics
- Quantum and Classical Field Theory
- Quantum Many-Body Methods
- Computational Methods
Condensed Matter Physics
We have a particular interest in spin lattice systems. Recently we have demonstrated that our CCM calculations able to describe qualitatively and quantitatively the quantum phase transitions and quantum order exhibited in abundance by such systems. We can now accurately calculate the critical indices describing the phase transitions from a wholly first-principles approach.
We also peform substantial numerical work on quantum fluids and solids in two dimensions, including neutron scattering
Personnel: Gernoth.
Another major interest, which is also a topic of practical importance is phenomenology of high-temperature superconductors. These materials will have large-scale applications only if their critical currents can be increased from their present low values. Our research is focused on understanding the phase transitions in these superconductors.
Personnel: Moore.
Finally we have a keen interest in quantum Hall systems
Personnel: Walet.
Statistical Phyics
The work in this area relies heavily on field-theoretical methods.
This is useful if the systems under investigation have scaling or universal features, as in the well-studied examples of continuous phase transitions and turbulence. The group has particular expertise in evaluating the role played by disorder in phase transitions. We are also interested in systems which are initially far from equilibrium but are relaxing into an equilibrium final state.
Statistical mechanics for such non-equilibrium systems is a large and relatively underdeveloped area. We are interested in the development of new approaches, based on quantum field theory, to describe the general properties of these systems. Scaling phenomena associated with the growth of order have been investigated in physical examples ranging from alloys and ferromagnets to ones from other areas of physics, such as the structure of the background radiation left by the Big Bang. We are also interested in developing new applications of the concepts of non-equilibrium statistical mechanics to other disciplines outside physics and we are collaborating with biologists, economists and others on this.
Personnel: Bray, Moore, McKane.
Quantum optics, mesoscopics and quantum information
We do substantial research in the area of quantum optics, and the closely related area of the repsonse of mesocopic systems to light or phonons. The techniques used range from rather simple master equations to fully fledged many-body methods. This interesting areas has close connections with quantum information processing, much of which is performed on mesoscopics or quantum-optical systems
Personnel; Bishop.
Nuclear and Particle Physics
(For high energy particle physics see this link.)
Our interest range from the dynamics and structure of atomic nuclei at low energies, through problems involving aspects of QCD in nuclear physics, to lattice gauge theories. A few specific examples of our wide interests in this area are:
- We use the Coupled-Cluster Method to describe accurately the structure of atomic nuclei, in collaboration with colleagues in Norway and the USA.
- We are using effective field theories for the interactions of pions and nucleons in order to describe the structure of the nucleon, as probed at modern high-intensity electron accelerators.
-
We are also interested in how the structure of a nucleon inside a nucleus may differ from that of a free nucleon. If the nuclear matter is sufficiently heated or compressed, the nucleons might ``melt'' completely, leading to a new state of matter: a quark--gluon plasma. This might exist in the cores of neutron stars and might be created in high-energy heavy-ion collisions in laboratories like CERN and BNL.
Personnel: Bishop, Birse, McGovern, Walet.
Biological Physics
We work on two areas of biological physics: Application of statistical physics techniques to biological dynamics, and the study of nonlinear dynamics in models of biological molecules.
Personnel: McKane, Galla. Walet.
Much of our work is performed in international collaborations, both with experimenters at major laboratories and with other theory groups, offering opportunities to travel and to interact with a global community.