Finite size corrections in massive Thirring model

TL;DR

This paper numerically computes finite size corrections in the massive Thirring model, revealing a coupling-dependent central charge that differs from sine-Gordon predictions, highlighting new insights into its boundary effects.

Contribution

First numerical calculation of finite size corrections in the massive Thirring model using Bethe ansatz boundary conditions.

Findings

Central charge around 0.4 at g_0 = -π/4

Central charge decreases to zero at g_0 = -π/3

Results differ from sine-Gordon model predictions

Abstract

We calculate for the first time the finite size corrections in the massive Thirring model. This is done by numerically solving the equations of periodic boundary conditions of the Bethe ansatz solution. It is found that the corresponding central charge extracted from the $1/L$ term is around 0.4 for the coupling constant of ${g_0}=-{\pi\over 4} $ and decreases down to zero when ${g_0}=-{\pi\over{3}}$. This is quite different from the predicted central charge of the sine-Gordon model.