Spatial correlation functions of one-dimensional Bose gases at equilibrium

Journal Article · Wed Nov 15 00:00:00 EST 2006 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.74.053617· OSTI ID:20979333

Proukakis, N P ^[1]

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1. School of Mathematics and Statistics, University of Newcastle, Merz Court, Newcastle NE1 7RU (United Kingdom)

The dependence of the three lowest order spatial correlation functions of a harmonically confined Bose gas on temperature and interaction strength is presented at equilibrium. Our analysis is based on a stochastic Langevin equation for the order parameter of a weakly interacting gas. Comparison of the predicted first order correlation functions to those of appropriate mean field theories demonstrates the potentially crucial role of density fluctuations on the equilibrium coherence length. Furthermore, the change in both coherence length and shape of the correlation function, from Gaussian to exponential, with increasing temperature is quantified. Moreover, the presented results for higher order correlation functions are shown to be in agreement with existing predictions. Experimentalists often define a 'quasi-condensate' via bimodal density fits, and this work reveals how consideration of local density-density correlations provides an alternative determination of this quantity.

• OSTI ID: 20979333
• Journal Information: Physical Review. A, Vol. 74, Issue 5; Other Information: DOI: 10.1103/PhysRevA.74.053617; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOSE-EINSTEIN CONDENSATION
BOSE-EINSTEIN GAS
COHERENCE LENGTH
CORRELATION FUNCTIONS
CORRELATIONS
DENSITY
EQUILIBRIUM
FLUCTUATIONS
FORECASTING
GAUSS FUNCTION
INTERACTIONS
LANGEVIN EQUATION
MEAN-FIELD THEORY
ONE-DIMENSIONAL CALCULATIONS
STOCHASTIC PROCESSES