Observation of thermal Hawking radiation at the Hawking temperature in an analogue black hole

TL;DR

This study experimentally confirms that analogue black holes emit thermal Hawking radiation at the predicted temperature, supporting Hawking's theory and providing insights into black hole thermodynamics and information paradox.

Contribution

First direct measurement of thermal Hawking radiation spectrum in an analogue black hole confirming theoretical predictions.

Findings

Hawking radiation is thermal at the predicted temperature.

Radiation inside the black hole consists of negative-energy partners.

The correlations suggest no analogue firewall exists.

Abstract

We measure the correlation spectrum of the Hawking radiation emitted by an analogue black hole and find it to be thermal at the Hawking temperature implied by the analogue surface gravity. The Hawking radiation is in the regime of linear dispersion, in analogy with a real black hole. Furthermore, the radiation inside of the black hole is seen to be composed of negative-energy partners only. This work confirms the prediction of Hawking's theory regarding the value of the Hawking temperature, as well as the thermality of the spectrum. The thermality of Hawking radiation is the root of the information paradox. The correlations between the Hawking and partner particles imply that the analogue black hole has no analogue firewall.