Variational study of U(1) and SU(2) lattice gauge theories with Gaussian states in 1+1 dimensions

TL;DR

This paper presents a Gaussian variational approach to study static and dynamic properties of U(1) and SU(2) lattice gauge theories in 1+1 dimensions, showing accurate results with fewer parameters than tensor networks.

Contribution

It introduces a novel Gaussian variational method with transformations to analyze Abelian and non-Abelian gauge models efficiently.

Findings

Accurate static and dynamic results for string breaking

Excellent agreement with tensor network benchmarks

Fewer variational parameters needed

Abstract

We introduce a method to investigate the static and dynamic properties of both Abelian and non-Abelian lattice gauge models in 1+1 dimensions. Specifically, we identify a set of transformations that disentangle different degrees of freedom, and apply a simple Gaussian variational ansatz to the resulting Hamiltonian. To demonstrate the suitability of the method, we analyze both static and dynamic aspects of string breaking for the U(1) and SU(2) gauge models. We benchmark our results against tensor network simulations and observe excellent agreement, although the number of variational parameters in the Gaussian ansatz is much smaller.