Vacuum Expectation Values from a variational approach

TL;DR

This paper introduces an extension of the Truncated Conformal Space approach to numerically compute vacuum expectation values in perturbed conformal field theories, demonstrated on Ising and Tricritical Ising models.

Contribution

It presents a novel application of the Truncated Conformal Space method to calculate VEVs in perturbed CFTs, providing a new computational tool.

Findings

Accurately estimated VEVs for primary operators in Ising and Tricritical Ising models.

Validated results against independent predictions.

Demonstrated the method's effectiveness for various relevant perturbations.

Abstract

In this letter we propose to use an extension of the variational approach known as Truncated Conformal Space to compute numerically the Vacuum Expectation Values of the operators of a conformal field theory perturbed by a relevant operator. As an example we estimate the VEV's of all (UV regular) primary operators of the Ising model and of some of the Tricritical Ising Model conformal field theories when perturbed by any choice of the relevant primary operators. We compare our results with some other independent predictions.