Thermalization by a synthetic horizon

TL;DR

This paper demonstrates how synthetic horizons in quantum systems can lead to thermalization analogous to gravitational horizons, linking condensed matter models with fundamental gravitational phenomena.

Contribution

It introduces a model of horizon formation via a quench in a lattice system, showing thermalization and matching Unruh temperature, bridging quantum matter and gravitational concepts.

Findings

Thermal states emerge after a horizon-forming quench.

The temperature matches the Unruh temperature for long chains.

Conditions are identified for the horizon to act as a thermal source.

Abstract

Synthetic horizons in models for quantum matter provide an alternative route to explore fundamental questions of modern gravitational theory. Here, we apply these concepts to the problem of emergence of thermal quantum states in the presence of a horizon, by studying ground-state thermalization due to instantaneous horizon creation in a gravitational setting and its condensed matter analogue. By a sudden quench to position-dependent hopping amplitudes in a one-dimensional lattice model, we establish the emergence of a thermal state accompanying the formation of a synthetic horizon. The resulting temperature for long chains is shown to be identical to the corresponding Unruh temperature, provided that the post-quench Hamiltonian matches the entanglement Hamiltonian of the pre-quench system. Based on detailed analysis of the outgoing radiation we formulate the conditions required for the synthetic horizon to behave as a purely thermal source, paving a way to explore this interplay of quantum-mechanical and gravitational aspects experimentally.