Monte Carlo calculations of the finite density Thirring model

TL;DR

This paper demonstrates a novel numerical simulation of the two-dimensional Thirring model at finite density and temperature, successfully addressing the fermionic sign problem using the holomorphic gradient flow approach, a first in quantum field theory.

Contribution

It introduces the holomorphic gradient flow method to solve the fermionic sign problem in quantum field theory simulations.

Findings

First successful application of holomorphic gradient flow to fermionic sign problem

Demonstrates feasibility of simulating finite density Thirring model

Provides a new computational approach for quantum field theories with sign problems

Abstract

We present results of the numerical simulation of the two-dimensional Thirring model at finite density and temperature. The severe sign problem is dealt with by deforming the domain of integration into complex field space. This is the first example where a fermionic sign problem is solved in a quantum field theory by using the holomorphic gradient flow approach, a generalization of the Lefschetz thimble method.