Observation of scale invariance and universality in two-dimensional Bose gases

Understand

The collective behavior of a many-body system near a continuous phase transition is insensitive to the details of its microscopic physics[1].

• Characteristic features near the phase transition are that the thermodynamic observables follow generalized scaling laws[1].
• The Berezinskii-Kosterlitz-Thouless (BKT) phase transition[2,3] in two-dimensional (2D) Bose gases presents a particularly interesting case because the marginal dimensionality and intrinsic scaling symmetry[4] result in a broad fluctuation regime which manifests itself in an extended range of universal scaling behavior.
• Studies on BKT transition in cold atoms have stimulated great interest in recent years[5-10], clear demonstration of a critical behavior near the phase transition, however, has remained an elusive goal.