Nonequilibrium Dynamics of Atomic Gases in Optical Lattices

Started: 1st October 2012
Ended: 1st October 2015
Research Team: Sophie Marika Reed

Overview

Quantum statistics have interesting implications with respect to the behaviour of certain gases when cooled to temperatures close to absolute zero, creating a Bose-Einstein Condensate (BEC) or a superfluid. BECs (whose behaviour can only be understood by quantum-mechanical theory and not classical physics) of ultra-cold metal atoms have been studied experimentally with a high degree of control since the advent of new cooling techniques in the 1990’s.

BECs can be confined in a cavity by the potential of a standing wave of light. Such a system has been used to probe the boundaries between classical and quantum mechanical systems (Braginsky, Vorontsov and Thorne, 1980). Past experiments in this area had light playing a passive role in BEC dynamics, however the recent experimental possibility of coupling the BEC and light dynamics allows for new and emergent physics to be explored.

In 2008 experimentalists found that an atomic alkali metal gas can be coupled to a light field at the single photon level (Brenneck, Ritter, Donner and Esslinger, 2008), where one quantum event can determine which macroscopic density profile the gas will consequently exhibit. Simulations of such experiments will be carried out in the PhD. Atomic gases in optical lattice potentials are a clean many-particle system that has unprecedented quantum control, opening up possibilities for promising applications, e.g. in using such systems to simulate strong interactions in order to improve the understanding of some outstanding problems in physics, such as high-Tc superconductivity.

‘Developing quantum technologies’ was highlighted by the US National Academy of Sciences (USNAS) recently as one of the six 'grand challenges ' in physics (USNAS, 2001). NAS predict that as our ability to understand and manipulate the quantum world increases we may be able to develop new materials, analyse the human genome, create measurement instruments of extraordinary sensitivity and physically realise quantum computation, quantum cryptography, and quantum-controlled chemistry. Another of the six grand challenges considered by USNAS is ‘understanding complex systems’ and specifically mentions quantum many-body challenges in condensed-matter physics (USNAS, 2001), where the interaction between a pair of constituents is not necessarily a sufficient guide to predict emergent many-particle dynamics. With huge advances in computing power as well as theory, our ability to model and predict complex and non-linear behaviour has improved notably, and has the potential to improve further. Understanding complex systems should hopefully provide us with new levels of description of systems.

Focus

The non-equilibrium quantum dynamics of BECs in optical lattice potentials interacting with the cavity field will be investigated. The spontaneous self-organisation of the BEC will be studied.

Style

Papers produced throughout this PhD are expected to be appropriate at conferences in condensed matter physics, quantum optics and quantum information.

Computational Modelling Group

Nonequilibrium Dynamics of Atomic Gases in Optical Lattices

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