Microcanonical fluctuations of the condensate in weakly interacting Bose gases
- 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, Vol. 71, Issue 5; Other Information: DOI: 10.1103/PhysRevA.71.053604; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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