Quantum optimization within lattice gauge theory model on a quantum simulator

TL;DR

This paper introduces a sweeping quantum annealing protocol for efficiently finding ground states in lattice gauge theories with topological sectors, demonstrating its potential on quantum simulators like Rydberg arrays.

Contribution

The paper proposes a novel sweeping quantum annealing method to overcome topological barriers in lattice gauge theory simulations on quantum devices.

Findings

SQA has linear time complexity in system size.

The protocol is applicable to Rydberg arrays and D-wave annealers.

It effectively finds ground states in topologically constrained systems.

Abstract

Simulating lattice gauge theory (LGT) Hamiltonian and its nontrivial states by programmable quantum devices has attracted numerous attention in recent years. Rydberg atom arrays constitute one of the most rapidly developing arenas for quantum simulation and quantum computing. The $\mathbb{Z}_2$ LGT and topological order has been realized in experiments while the $U(1)$ LGT is being worked hard on the way. States of LGT have local constraint and are fragmented into several winding sectors with topological protection. It is therefore difficult to reach the ground state in target sector for experiments, and it is also an important task for quantum topological memory. Here, we propose a protocol of sweeping quantum annealing (SQA) for searching the ground state among topological sectors. With the quantum Monte Carlo method, we show that this SQA has linear time complexity of size with applications to the antiferromagnetic transverse field Ising model, which has emergent $U(1)$ gauge fields. This SQA protocol can be realized easily on quantum simulation platforms such as Rydberg array and D-wave annealer. We expect this approach would provide an efficient recipe for resolving the topological hindrances in quantum optimization and the preparation of quantum topological state.