Entanglement and violation of classical inequalities in the Hawking radiation of flowing atom condensates

TL;DR

This paper investigates quantum correlations in Hawking radiation analogs within flowing atom condensates, showing that certain measurable inequalities reveal nonclassical behavior and are experimentally accessible.

Contribution

It unifies previous criteria for nonclassical correlations in Hawking radiation analogs and demonstrates the measurability of quantum effects in realistic detection schemes.

Findings

Violation of quadratic Cauchy-Schwarz inequalities indicates nonclassical correlations.

Numerical results support the feasibility of measuring quantum correlations.

Only specific detection schemes can reliably reveal deep quantum effects.

Abstract

We consider a sonic black-hole scenario where an atom condensate flows through a subsonic-supersonic interface. We discuss several criteria that reveal the existence of nonclassical correlations resulting from the quantum character of the spontaneous Hawking radiation. We unify previous general work as applied to Hawking radiation analogs. We investigate the measurability of the various indicators and conclude that, within a class of detection schemes, only the violation of quadratic Cauchy-Schwarz inequalities can be discerned. We show numerical results that further support the viability of measuring deep quantum correlations in concrete scenarios.