Professor Christopher Foot

Abstract:

We demonstrate a novel experimental arrangement which can rotate a 2D optical lattice at frequencies up to several kilohertz. Ultracold atoms in such a rotating lattice can be used for the direct quantum simulation of strongly correlated systems under large effective magnetic fields, allowing investigation of phenomena such as the fractional quantum Hall effect. Our arrangement also allows the periodicity of a 2D optical lattice to be varied dynamically, producing a 2D accordion lattice.

Abstract:

We combine an RF-dressed magnetic trap with an optical potential to produce a toroidal trapping potential for ultracold 87Rb atoms. We load atoms into this ring trap from a conventional magnetic trap and compare the measured oscillation frequencies with theoretical predictions. This method of making a toroidal trap gives a high degree of flexibility such as a tuneable radius and variable transverse oscillation frequency. The ring trap is ideal for the creation of a multiply connected Bose-Einstein condensate (BEC) and the study of persistent flow and we propose a scheme for introducing a flow of the atoms around the ring. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Abstract:

We present a method of transferring a cold atom between spatially separated microtraps by means of a Raman transition between the ground motional states of the two traps. The intermediate states for the Raman transition are the vibrational levels of a third microtrap, and we determine the experimental conditions for which the overlap of the wavefunctions leads to an efficient transfer. There is a close analogy with the Franck-Condon principle in the spectroscopy of molecules. The spin-dependent manipulation of neutral atoms in microtraps has important applications in quantum information processing. We also show that, starting with several atoms, precisely one atom can be transferred to the final potential well hence giving deterministic preparation of single atoms. © 2007 IOP Publishing Ltd.