Observation of string breaking on a (2 + 1)D Rydberg quantum simulator

Abstract

Lattice gauge theories (LGTs) describe a broad range of phenomena in condensed matter and particle physics. A prominent example is confinement, responsible for bounding quarks inside hadrons such as protons or neutrons¹. When quark-antiquark pairs are separated, the energy stored in the string of gluon fields connecting them grows linearly with their distance, until there is enough energy to create new pairs from the vacuum and break the string. Although these phenomena are ubiquitous in LGTs, simulating the resulting dynamics is a challenging task². Here we report the observation of string breaking in synthetic quantum matter using a programmable quantum simulator based on neutral atom arrays^3-5. We show that a (2 + 1)-dimensional LGT with dynamical matter can be efficiently implemented when the atoms are placed on a Kagome geometry⁶, with a local U(1) symmetry emerging from the Rydberg blockade⁷. Long-range Rydberg interactions naturally give rise to a linear confining potential for a pair of charges, allowing us to tune both their masses and the string tension. We experimentally probe string breaking in equilibrium by adiabatically preparing the ground state of the atom array in the presence of defects, distinguishing regions within the confined phase dominated by fluctuating strings or by broken string configurations. Finally, by harnessing local control over the atomic detuning, we quench string states and observe string-breaking dynamics exhibiting a many-body resonance phenomenon. Our work provides opportunities for exploring phenomena in high-energy physics using programmable quantum simulators.