Universal correlations and coherence in quasitwodimensional trapped Bose gases
Abstract
We study the quasitwodimensional Bose gas in harmonic traps at temperatures above the KosterlitzThouless transition, where the gas is in the normal phase. We show that meanfield theory takes into account the dominant interaction effects for experimentally relevant trap geometries. Comparing with quantum Monte Carlo calculations, we quantify the onset of the fluctuation regime, where correlations beyond meanfield become important. Although the density profile depends on the microscopic parameters of the system, we show that the correlation density (the difference between the exact and the meanfield density) is accurately described by a universal expression, obtained from classicalfield calculations of the homogeneous strictly twodimensional gas. Deviations from universality, due to the finite value of the interaction or to the trap geometry, are shown to be small for current experiments. We further study coherence and pair correlations on a microscopic scale. Finitesize effects in the offdiagonal density matrix allow us to characterize the crossover from KosterlitzThouless to BoseEinstein behavior for small particle numbers. BoseEinstein condensation occurs below a characteristic number of particles which rapidly diverges with vanishing interactions.
 Authors:

 LPTMC, Universite Pierre et Marie Curie, 4 Place Jussieu, F75005 Paris (France) and LPMMC, CNRSUJF, BP 166, 38042 Grenoble (France)
 CNRSLaboratoire de Physique Statistique, UPMC, Ecole Normale Superieure, 24 rue Lhomond, F75231 Paris Cedex 05 (France)
 Publication Date:
 OSTI Identifier:
 21408680
 Resource Type:
 Journal Article
 Journal Name:
 Physical Review. A
 Additional Journal Information:
 Journal Volume: 81; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevA.81.043622; (c) 2010 The American Physical Society; Journal ID: ISSN 10502947
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BOSEEINSTEIN CONDENSATION; BOSEEINSTEIN GAS; CORRELATIONS; DENSITY MATRIX; FLUCTUATIONS; GEOMETRY; INTERACTIONS; MEANFIELD THEORY; MONTE CARLO METHOD; TRAPPING; TRAPS; TWODIMENSIONAL CALCULATIONS; CALCULATION METHODS; MATHEMATICS; MATRICES; VARIATIONS
Citation Formats
Holzmann, Markus, Chevallier, Maguelonne, and Krauth, Werner. Universal correlations and coherence in quasitwodimensional trapped Bose gases. United States: N. p., 2010.
Web. doi:10.1103/PHYSREVA.81.043622.
Holzmann, Markus, Chevallier, Maguelonne, & Krauth, Werner. Universal correlations and coherence in quasitwodimensional trapped Bose gases. United States. https://doi.org/10.1103/PHYSREVA.81.043622
Holzmann, Markus, Chevallier, Maguelonne, and Krauth, Werner. Thu .
"Universal correlations and coherence in quasitwodimensional trapped Bose gases". United States. https://doi.org/10.1103/PHYSREVA.81.043622.
@article{osti_21408680,
title = {Universal correlations and coherence in quasitwodimensional trapped Bose gases},
author = {Holzmann, Markus and Chevallier, Maguelonne and Krauth, Werner},
abstractNote = {We study the quasitwodimensional Bose gas in harmonic traps at temperatures above the KosterlitzThouless transition, where the gas is in the normal phase. We show that meanfield theory takes into account the dominant interaction effects for experimentally relevant trap geometries. Comparing with quantum Monte Carlo calculations, we quantify the onset of the fluctuation regime, where correlations beyond meanfield become important. Although the density profile depends on the microscopic parameters of the system, we show that the correlation density (the difference between the exact and the meanfield density) is accurately described by a universal expression, obtained from classicalfield calculations of the homogeneous strictly twodimensional gas. Deviations from universality, due to the finite value of the interaction or to the trap geometry, are shown to be small for current experiments. We further study coherence and pair correlations on a microscopic scale. Finitesize effects in the offdiagonal density matrix allow us to characterize the crossover from KosterlitzThouless to BoseEinstein behavior for small particle numbers. BoseEinstein condensation occurs below a characteristic number of particles which rapidly diverges with vanishing interactions.},
doi = {10.1103/PHYSREVA.81.043622},
url = {https://www.osti.gov/biblio/21408680},
journal = {Physical Review. A},
issn = {10502947},
number = 4,
volume = 81,
place = {United States},
year = {2010},
month = {4}
}