Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Kinetic Theory of a Spin-1/2 Bose-Condensed Gas



T Nikuni, J E. Williams


We derive a kinetic theory for a spin-1/2 Bose-condensed gas of two-level atoms at finite temperatures. The condensate dynamics is described by a generalized Gross-Pitaevskii equaiton for the two-component spinor order parameter, which includes the interaction with the uncondensed fraction. The noncondensate atoms are described by a quantum kinetic equation, which is a generalization of the spin kinetic equation for spin-polarized quantum gases to include couplings to the condensate degree of freedom. The kinetic equation is used to derive hydrodynamic equations for the noncondensate spin density. The condensate and noncondensate spins are coupled directly through the exchange mean field. Collisions between the condensate and noncondensate atoms give rise to an additional contribution to the spin diffusion relaxation rate. In addition, they give rise to mutual relaxation of the condensate and noncondensate due to lack of local equilibrium between the two components.
Journal of Low Temperature Physics


Bose-Einstein condensation, kinetic theory, quantum coherence, spin waves, spin-1/2 Bose gas


Nikuni, T. and Williams, J. (2021), Kinetic Theory of a Spin-1/2 Bose-Condensed Gas, Journal of Low Temperature Physics (Accessed July 20, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created October 12, 2021