Scalable Quantum Algorithm for Meson Scattering in a Lattice Gauge Theory

TL;DR

This paper presents a scalable quantum algorithm for simulating meson scattering in a lattice gauge theory, introducing a quantum subspace expansion technique and efficient circuit design for near-term quantum devices.

Contribution

It develops a non-variational, scalable quantum simulation framework for meson scattering, including a new operator construction and circuit optimization for lattice gauge theories.

Findings

Successfully simulated elastic and inelastic scattering processes

Analyzed energy transfer, entanglement, and particle production

Reduced quantum circuit depth for wave packet preparation

Abstract

Scattering processes are fundamental for understanding the structure of matter, yet simulating their real-time dynamics remains challenging for classical computers. Quantum computing and quantum-inspired methods offer a promising avenue for efficiently simulating such phenomena. In this work, we investigate meson scattering in a (1+1)-dimensional Z2 lattice gauge theory with staggered fermions. We develop a quantum subspace expansion technique to construct high-fidelity meson creation operators across a broad range of masses and momenta. Using Tensor Networks simulations, we study both elastic and inelastic scattering and provide a detailed analysis of energy transfer, entanglement entropy, and new particle production during the dynamics. In addition, we design an efficient quantum circuit for meson wave packet preparation using Givens rotations, significantly reducing the circuit depth compared to existing methods. Our work provides a non-variational and scalable framework for simulating meson scattering on near-term quantum devices, and provides a concrete strategy for quantum simulation to analyze non-perturbative dynamical processes in confining gauge theories.