The critical exponents of the superfluid transition in He4

TL;DR

This paper refines theoretical estimates of critical exponents for the superfluid transition in He4 using advanced Monte Carlo simulations and high-temperature expansions, highlighting a discrepancy with recent experimental results.

Contribution

It provides improved theoretical estimates of critical exponents for the superfluid transition in He4, employing finite-size scaling and high-order series expansions.

Findings

Estimated critical exponents with high precision.

Discrepancy between theoretical and experimental alpha exponent.

Use of large lattice sizes and improved models.

Abstract

We improve the theoretical estimates of the critical exponents for the three-dimensional XY universality class, which apply to the superfluid transition in He4 along the lambda-line of its phase diagram. We obtain the estimates alpha=-0.0151(3), nu=0.6717(1), eta=0.0381(2), gamma=1.3178(2), beta=0.3486(1), and delta=4.780(1). Our results are obtained by finite-size scaling analyses of high-statistics Monte Carlo simulations up to lattice size L=128 and resummations of 22nd-order high-temperature expansions of two improved models with suppressed leading scaling corrections. We note that our result for the specific-heat exponent alpha disagrees with the most recent experimental estimate alpha=-0.0127(3) at the superfluid transition of He4 in microgravity environment.