Framework for simulating gauge theories with dipolar spin systems

TL;DR

This paper proposes an analog quantum simulation method for gauge theories using dipolar spin systems, enabling exploration of nonperturbative phenomena like string breaking in near-term experiments.

Contribution

It introduces a novel approach to simulate gauge theories with fixed dipolar molecules, preserving gauge invariance through position and energy tuning, suitable for experimental realization.

Findings

Numerical validation of the scheme for U(1) quantum link models in (1+1)D.

Demonstration of observing string inversion and string breaking phenomena.

Bridging atomic physics, condensed matter, high-energy physics, and quantum information for gauge theory studies.

Abstract

Gauge theories appear broadly in physics, ranging from the standard model of particle physics to long-wavelength descriptions of topological systems in condensed matter. However, systems with sign problems are largely inaccessible to classical computations and also beyond the current limitations of digital quantum hardware. In this work, we develop an analog approach to simulating gauge theories with an experimental setup that employs dipolar spins (molecules or Rydberg atoms). We consider molecules fixed in space and interacting through dipole-dipole interactions, avoiding the need for itinerant degrees of freedom. Each molecule represents either a site or gauge degree of freedom, and Gauss law is preserved by a direct and programmatic tuning of positions and internal state energies. This approach can be regarded as a form of analog systems programming and charts a path forward for near-term quantum simulation. As a first step, we numerically validate this scheme in a small-system study of U(1) quantum link models in (1+1) dimensions with link spin S = 1/2 and S = 1 and illustrate how dynamical phenomena such as string inversion and string breaking could be observed in near-term experiments. Our work brings together methods from atomic and molecular physics, condensed matter physics, high-energy physics, and quantum information science for the study of nonperturbative processes in gauge theories.