Numerical tests of the large charge expansion

Abstract

We perform Monte-Carlo measurements of two and three point functions of charged operators in the critical O(2) model in 3 dimensions. Our results are compatible with the predictions of the large charge superfluid effective field theory. To obtain reliable measurements for large values of the charge, we improved the Worm algorithm and devised a measurement scheme which mitigates the uncertainties due to lattice and finite size effects.

Comments: 16 pages, 12 figures. v2: Improved finite size scaling. v3: Added comparison between Monte Carlo updates