Observing quantum many-body dynamics in emergent curved spacetime using programmable quantum processors

TL;DR

This paper demonstrates how programmable quantum processors can simulate quantum many-body dynamics in emergent curved spacetime, revealing phenomena like curved light-cone propagation and horizon effects in a spin chain model.

Contribution

It introduces a method to engineer spatially varying couplings in a quantum processor to emulate inhomogeneous curved spacetime for many-body quantum simulations.

Findings

Observation of curved light-cone propagation

Detection of horizon-induced freezing in magnetization

Ballistic quasiparticle propagation despite inhomogeneity

Abstract

We digitally simulate quantum many-body dynamics in emergent curved backgrounds using 80 superconducting qubits on IBM Heron processors. By engineering spatially varying couplings in the spin-$\frac12$ XXZ chain, consistent with the low-energy description of the model in terms of an inhomogeneous Tomonaga-Luttinger liquid, we realize excitations that follow geodesics of an effective metric inherited from the underlying spatial deformation. Following quenches from N\'eel and few-spin-flip states, we observe curved light-cone propagation, horizon-induced freezing in the local magnetization, and position-dependent oscillation frequencies set by the engineered spatial deformation. Despite strong spatial inhomogeneity, unequal-time correlators reveal ballistic quasiparticle propagation in the spin chain. These results establish large-scale digital quantum processors as a flexible platform for detailed and controlled exploration of many-body dynamics in tunable and synthetic curved spacetimes.