Numerical tests of the large charge expansion

TL;DR

This paper uses Monte-Carlo simulations to test predictions of the large charge superfluid effective field theory in the 3D critical O(2) model, focusing on charged operator correlation functions.

Contribution

It introduces improved algorithms and measurement schemes for accurate large charge measurements in lattice simulations, validating theoretical predictions.

Findings

Results agree with large charge superfluid EFT predictions

Enhanced Monte-Carlo methods reduce finite size and lattice uncertainties

Provides reliable data for high-charge operators in 3D O(2) model

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.