Work

Bose-Einstein condensation, fluctuations, and spontaneous symmetry breaking

Year: 2026

Type: article

Abstract: The realisation of Bose-Einstein condensation under grand-canonical conditions has provided the experimental evidence for the simultaneous occurrence of macroscopic fluctuations and phase coherence of the condensate. The observation of these two features, against a consolidated tradition which wants the fluctuations to be pathological (grand-canonical catastrophe) and incompatible with spontaneous symmetry braking, calls for a comprehensive rethinking of the approach to the problem. In this paper we consider the uniform ideal gas in a box and we present an alternative conceptual framework. We show that the usually-employed Bogoliubov quasi-average construction fails to reproduce the broken-symmetry state. The observed features are accounted for by a different pattern of spontaneous symmetry breaking, characterised by condensation of fluctuations and long-range correlations of the order parameter.

Source: Physical Review A

DOI: 10.1103/snjg-9k9w

Authors: A. Crisanti, A. Sarracino, M. Zannetti

Institutions: Institute for Complex Systems, Sapienza University of Rome, University of Campania "Luigi Vanvitelli", University of Salerno

Language: English

Topic: Cold Atom Physics and Bose-Einstein Condensates

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funder: Ministero dell'Università e della Ricerca

Awards: G1058477007, G8736391389