Boson Gases

H. A. Buchdahl

Nick Verhelst, Jacques Tempere

In this chapter a basic introduction to the theory of vortices in ultra-cold (superfluid) atomic gases is given. The main focus will be on bosonic atomic gases, since these contain the same basic physics, but with simpler formulas. Towards the end of the chapter, the difference between bosonic and fermionic atomic gases is discussed. This discussion will allow the reader to make the conceptual step from bosonic to fermionic gases, while pinpointing the main differences and difficulties when working with fermionic gases rather than bosonic gases. The goal of this chapter is to provide a good and general starting point for researchers, or other interested parties, who wish to start exploring the physics of ultra-cold gases.

Keith S. Stowe

Stephen J. Blundell, Katherine M. Blundell

Abstract Exchange symmetry affects the occupation of allowed states in quantum gases. If the density of the gas is very low, we can ignore this and forget about exchange symmetry; this is what we do for gases at room temperature. But if the density is high, the effects of exchange symmetry become very important and it really starts to matter whether the particles you are considering are fermions or bosons. This chapter considers quantum gases in detail. It considers non-interacting fermion and boson gases, and discusses Bose-Einstein condensation.