Nonequilibrium Field Theory Description of the Bose-Einstein Condensate

Journal Article · Mon Jul 17 04:00:00 EDT 2000 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.85.479· OSTI ID:20217136

Barci, Daniel G ^[1]; Fraga, E S ^[2]; Ramos, Rudnei O ^[3]

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1. Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080 (United States)
2. Physics Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
3. Universidade do Estado do Rio de Janeiro, Instituto de Fisica, Departamento de Fisica Teorica, 20550-013 Rio de Janeiro, Rio de Janeiro, (Brazil)

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{sup 2}/2m{approx}2{lambda}|{phi}{sub 0} |{sup 2} , where {lambda} is the coupling constant and |{phi}{sub 0}|{sup 2} is the condensate density. We deduce and solve a set of coupled equations that completely determines the nonequilibrium dynamics of the condensate density. (c) 2000 The American Physical Society.

• OSTI ID: 20217136
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 3 Vol. 85; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BOSE-EINSTEIN CONDENSATION
FLUCTUATIONS
QUANTUM FIELD THEORY
THEORETICAL DATA