# Quantum quenches, sonic horizons and the Hawking radiation in a class of exactly solvable models

## TL;DR

This paper uses an exactly solvable model to analyze the emergence of Hawking radiation analogues in cold atom systems, revealing conditions for thermal and non-thermal radiation in stationary states.

## Contribution

It provides a detailed microscopic analysis of Hawking radiation in a solvable many-body model, clarifying when thermal behavior occurs in analogue gravity experiments.

## Key findings

- Stationary states can be thermal under specific conditions.
- Most experimental setups produce non-thermal Hawking-like radiation.
- The work offers a microscopic interpretation of the Hawking mechanism in cold atoms.

## Abstract

Taking advantage of the known exact mapping of the one-dimensional Hard Core Bose (HCB) fluid onto a non-interacting spinless fermion gas, we examine in full detail a thought experiment on cold atoms confined in a quasi-one-dimensional trap, in order to investigate the emergence of the analogue Hawking radiation. The dynamics of a gas of interacting bosons impinging on an external potential is exactly tracked up to the reach of a stationary state. Under few strict conditions on the experimental parameters, the stationary state is shown to be described asymptotically by a thermal distribution, precisely at the expected (analogue) Hawking temperature. However, we find that in most experimental conditions the emerging `Hawking-like radiation' is not thermal. This analysis provides a novel many-body microscopic interpretation of the Hawking mechanism, together with useful limits and conditions for the design of future experiments in Bose-Einstein condensates.