The Berezinskii–Kosterlitz–Thouless (BKT) phase transition, occurring in two-dimensional Bose gases, is expected to show an extended range of universal scaling behaviour in thermodynamic quantities; however, a clear demonstration of this 'critical' behaviour has remained elusive. Its existence is now confirmed through in situ density and density-fluctuation measurements of two-dimensional caesium Bose gases at different temperatures and interaction strengths.
- Chen-Lung Hung
- Xibo Zhang
- Cheng Chin
