Phase order in superfluid helium films

作者：Bramwell Steven T; Faulkner Michael F; Holdsworth Peter C W; Taroni Andrea

来源：EPL, 2015, 112(5): 56003.

DOI：10.1209/0295-5075/112/56003

Classic experimental data on helium films are transformed to estimate a finite-size phase order parameter that measures the thermal degradation of the condensate fraction in the two-dimensional superfluid. The order parameter is found to evolve thermally with the exponent beta = 3 pi(2)/128, a characteristic, in analogous magnetic systems, of the Berezinskii-Kosterlitz-Thouless (BKT) phase transition. Universal scaling near the BKT fixed point generates a collapse of experimental data on helium and ferromagnetic films, and implies new experiments and theoretical protocols to explore the phase order. These results give a striking example of experimental finite-size scaling in a critical system that is broadly relevant to two-dimensional Bose fluids.
This paper is dedicated to the memory of our friend and colleague Maxime Clusel, with whom we enjoyed many stimulating discussions on related topics.

• 出版日期2015-12