Current Research

Introduction

By Professor Ian Walmsley *

Research in the department involves some of the most rapidly developing areas of physical science, studying novel states of matter at extreme ranges of temperature, laser-produced plasmas under extreme nonequilibrium conditions, highly nonclassical quantum phenomena using atoms and photons, and precise spectroscopy using extremely stable broadband lasers and quantum optics. The work in these areas has broad implications for physics, ranging from new approaches to computation based on quantum mechanics to novel schemes for particle accelerators based on laser plasmas. Indeed, there are consequences for the technology of the future, from improved global positioning systems to completely secure optical communications systems.

        The main research thrusts are focused in the following areas:

High-intensity laser-matter interactions: The extremely high peak intensities associated with modern short-pulse laser systems can produce electric fields greater than those binding valence electrons in atoms. The behaviour of matter under such extreme, yet transient, conditions gives rise to highly nonlinear phenomena, such as the generation of XUV and X-ray radiation. The novel light sources so produced can be used to study the dynamics of a vast range of matter, as well as its structural changes, on unprecedented timescales.

Ultracold matter: The study of mesoscopic quantum states of matter in the regime where the de Broglie wavelength of the atoms is comparable with their spacing, giving rise to quantum phase transitions such as those associated with Bose condensation and superfluidity. The precision with which these phase transitions can be engineered, using stabilized lasers and designer electromagnets, enables the detailed studies of many-body phenomena normally associated with condensed matter, and allows these states to be exploited for applications.

Quantum information processing: The Centre for Quantum Computation concentrates both on harnessing the power of quantum physics for computing and cryptography, and on understanding the implications of information theoretic ideas for quantum mechanics. The enormous potential for increased capacity for information processing requires both complex protocols for combating decoherence, and robust control of individual atoms and ions, as well as their collective excitations. The precise manipulation of trapped atoms and ions, are key technologies that are exploited in building prototypical quantum processors.

Quantum and nonlinear optics: The interaction of light and matter at the quantum level, especially using laser pulses of extreme brevity, with durations in the femto and even atto seconds regime, opens up new ranges of phenomena associated with the timescales of internuclear motion in molecules and electronic motion in atoms and on surfaces. These interactions can be used not only to probe atomic and molecular dynamics, but also to control them. Non-classical optics is also applied to fundamental studies of the structure of quantum mechanics, and its implications for quantum enhanced communications and metrology.

Within these themes there is a range of experimental and theoretical activity, as well as broad overlap between the areas. Many faculty work in more than one area, and there is strong exchange of ideas and of expertise in interactions between groups. In short, we cover the ultracold, ultraintense, ultrafast and ultraweird, using a gamut of cutting edge technologies.

*(Taken from the Atomic & Laser Physics Research Booklet)