Microcanonical fluctuations of the condensate in weakly interacting Bose gases

Journal Article · Sun May 15 04:00:00 EDT 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.71.053604· OSTI ID:20717789

Idziaszek, Zbigniew ^[1]

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1. Istituto Nazionale per la Fisica della Materia, BEC-INFM Trento, I-38050 Povo (Italy) and Centrum Fizyki Teoretycznej, Polska Akademia Nauk, 02-668 Warsaw (Poland)

We study fluctuations of the number of Bose condensed atoms in a weakly interacting homogeneous and trapped gases. For a homogeneous system we apply the particle-number-conserving formulation of the Bogoliubov theory and calculate the condensate fluctuations within the canonical and the microcanonical ensembles. We demonstrate that, at least in the low-temperature regime, predictions of the particle-number-conserving and traditional, nonconserving theory are identical, and lead to the anomalous scaling of fluctuations. Furthermore, the microcanonical fluctuations differ from the canonical ones by a quantity which scales normally in the number of particles, thus predictions of both ensembles are equivalent in the thermodynamic limit. We observe a similar behavior for a weakly interacting gas in a harmonic trap. This is in contrast to the trapped, ideal gas, where microcanonical and canonical fluctuations are different in the thermodynamic limit.

• OSTI ID: 20717789
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 5 Vol. 71; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOMS
BOSE-EINSTEIN CONDENSATION
BOSE-EINSTEIN GAS
FLUCTUATIONS
RADIATION PRESSURE
TRAPPING
TRAPS