String Breaking and Glueball Dynamics in $2+1$D Quantum Link Electrodynamics

TL;DR

This paper uses tensor network simulations to study flux string breaking and glueball formation in a 2+1D quantum electrodynamics model with a spin-1 gauge field, revealing new microscopic mechanisms and dynamics.

Contribution

It introduces a detailed tensor network analysis of flux string behavior in a spin-1 quantum link model, uncovering novel string breaking processes and real-time dynamics not seen in simpler models.

Findings

Identified a two-stage string breaking mechanism in the spin-1 model.

Demonstrated real-time string breaking and glueball formation in 2+1D.

Provided quantum circuit proposals for experimental simulation.

Abstract

At the heart of quark confinement and hadronization, the physics of flux strings has recently become a focal point in the field of quantum simulation of high-energy physics (HEP). Despite considerable progress, a detailed understanding of the behavior of flux strings in quantum simulation-relevant lattice formulations of gauge theories has remained limited to the lowest truncations of the gauge field, which are severely limited in their ability to draw conclusions about the quantum field theory limit. Here, we employ tensor network simulations to investigate the behavior of flux strings in a quantum link formulation of $2+1$D quantum electrodynamics (QED) with a spin-$1$ representation of the gauge field. We first map out the ground-state phase diagram of this model in the presence of two spatially separated static charges, revealing distinct microscopic processes responsible for string breaking, including a two-stage breaking mechanism not possible in the spin-$\frac{1}{2}$ formulation. Starting in different initial product state string configurations, we then explore far-from-equilibrium quench dynamics across various parameter regimes, demonstrating genuine $2+1$D real-time string breaking and glueball-like bound state formation, with the latter not possible in the spin-$\frac{1}{2}$ formulation. In and out of equilibrium, we consider different values and placements of the static charges. Finally, we provide efficient qudit circuits for a quantum simulation experiment in which our results can be observed in state-of-the-art ion-trap setups. Our findings lay the groundwork for quantum simulations of flux strings towards the quantum field theory limit.