Chiral Spin-Chain Interfaces Exhibiting Event-Horizon Physics

TL;DR

This paper explores the interface between chiral spin chains, revealing a surprising analogy to black hole horizons where quantum phase boundaries mimic event horizons, leading to thermalization phenomena akin to Hawking radiation.

Contribution

It introduces a novel connection between chiral spin-chain interfaces and event-horizon physics, combining analytical bosonisation and numerical MPS methods to demonstrate this analogy.

Findings

Boundary acts as a black hole horizon in the model

Quenches induce thermalization at Hawking temperature

Analytical and numerical methods confirm the horizon analogy

Abstract

The interface between different quantum phases of matter can give rise to novel physics, such as exotic topological phases or non-unitary conformal field theories. Here we investigate the interface between two spin chains in different chiral phases. Surprisingly, the mean-field theory description of this interacting composite system is given in terms of Dirac fermions in a curved space-time geometry. In particular, the boundary between the two phases represents a black hole horizon. We demonstrate that this representation is faithful both analytically, by employing bosonisation to obtain a Luttinger liquid model, and numerically, by employing Matrix Product State methods. A striking prediction from the black hole equivalence emerges when a quench, at one side of the interface between two opposite chiralities, causes the other side to thermalise with the Hawking temperature for a wide range of parameters and initial conditions.