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Updated: Aug 22, 2026

Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Nonequilibrium field theory description of the Bose-Einstein condensate
D G Barci1, E S Fraga, R O Ramos
1Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080.
Abstract:
We study the detailed out-of-equilibrium time evolution of a homogeneous Bose-Einstein condensate (BEC). We consider a nonrelativistic quantum theory for a self-interacting complex scalar field, immersed in a thermal bath, as an effective microscopic model for the description of the BEC. The interaction between fluctuations proves to be crucial in the mechanism of instability generation. We show the existence of two regimes in k space, with a crossover for k(2)/2m approximately 2 lambda|phi(0)|(2), where lambda is the coupling constant and |phi(0)|(2) is the condensate density. We deduce and solve a set of coupled equations that completely determines the nonequilibrium dynamics of the condensate density.
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