Ultracold quantum matter

Abstract:

We describe in detail our caesium atom interferometer which uses a combination of microwaves and momentum-changing adiabatic transfer pulses. This combination allows us to achieve spatial separation between the arms of the interferometer. We account for the observed visibility of the resulting interference fringes and find that the effects which contribute the most are optical pumping and magnetic fields.

Abstract:

We report on the demonstration of Berry’s phase in an atomic state interacting with a laser field. We draw an analogy between this system and that of a spin interacting with a directionally varying magnetic field. This allows us to identify an effective magnetic quantum number for the atom-light system that governs the maximum Berry phase the atomic state can acquire. We realize two systems that have different effective magnetic quantum numbers, and use a recently developed atom interferometer to make measurements of Berry’s phase. © 1999 The American Physical Society.

Abstract:

We describe the low-energy scattering theory relevant to the description of the Bose-Einstein condensed gases recently produced using evaporative cooling. We examine the validity range of the approximations being used to describe the ultracold interactions in the context of the interaction between caesium atoms at the temperatures produced by evaporation in a magnetic trap. We discuss the prospects for future developments in the field.

Abstract:

We have constructed and characterised a novel source of slow atoms based on a pyramidal magneto optical trap with a small hole at its vertex. Atoms are first captured in the trap and then pushed through the hole by a laser beam. The size and velocity of the resulting pulses of atoms were measured. The flux of cold atoms was 1.1 × 109 atoms/s and the apparatus is readily scaleable to obtain higher fluxes. © 1998 Elsevier Science B.V. All rights reserved.