Abstract

The recent spectacular success in the production of Bose-Einstein Condensed gases has been a strong incentive for the development of the theory of trappedBose gases. In this talk I will give an overview of this theory with examples taken from the theory performed by the Georgia Southern University-NIST-Oxfordcollaboration. One of the great joys of this work is to be able to start with aneffectively microscopic input from the measurements made of the scattering lengths and my first task will be to show how this enters the calculations andthe approximations that lie behind it. I will then turn to the principalfeatures of the condensates that have been formed to date. This will include the reasons for us being able to describe them accurately using mean field theory. In the next part of the talk I will turn to the reasons for us being able to think of the condensate as a macroscopic object and link this to the notions of Off-Diagonal Long Range Order as well as Spontaneous Symmetry Breaking. This will lead me naturally to the reasons for thinking of the condensates as superfluids and for looking at the elementary excitationsthat they support. I will be able to present comparisons between our theoryand recent measurements at JILA/NIST of these excitations.

© 1996 Optical Society of America