Effective Lagrangian approach to the trapped Bose gases at low temperatures

Journal Article · Wed Jun 15 04:00:00 EDT 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.71.063604· OSTI ID:20717946

Xiang, Xia; Silbey, Robert J ^[1]

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1. Theoretical Chemical Physics Group, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

We adopt an effective-field-theory view to describe the low-energy excitations of trapped Bose gases, which allows a direct and systematic way to investigate the consequences of spontaneous symmetry breaking. The derivation of the effective Lagrangian can incorporate various approximations and can reproduce the results obtained by the standard hydrodynamic approach. Based on the effective Lagrangian, we calculate the energy spectrum and Matsubara Green's function of trapped one-dimensional Bose gases with {delta}-function repulsive interaction allowing the comparison of various results obtained by different approaches. We also analytically calculate the finite-temperature correlation function of trapped two-dimensional (2D) Bose gases. The calculation scheme can be easily extended to higher dimensions. We find that particle interactions will always decrease the coherence length of the condensate in 2D, confirming recent numerical results. The validation of various asymptotic expressions are given.

• OSTI ID: 20717946
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 6 Vol. 71; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
BOSE-EINSTEIN GAS
BOSONS
COHERENCE LENGTH
COMPARATIVE EVALUATIONS
CORRELATION FUNCTIONS
DELTA FUNCTION
ENERGY SPECTRA
EXCITATION
FUNCTIONAL ANALYSIS
GREEN FUNCTION
LAGRANGIAN FUNCTION
ONE-DIMENSIONAL CALCULATIONS
PARTICLE INTERACTIONS
QUANTUM FIELD THEORY
SYMMETRY BREAKING
TRAPPING
TWO-DIMENSIONAL CALCULATIONS