Measuring the entanglement of analogue Hawking radiation by the density-density correlation function

Understand

We theoretically study the entanglement of Hawking radiation pairs emitted by an analogue black hole.

• We find that this entanglement can be measured by the experimentally accessible density-density correlation function, vastly simplifying the measurement.
• We find that while the Hawking radiation exiting the black hole might be Planck-distributed, the correlations between the Hawking radiation and the partner particles has a distribution which is weaker but broader than Planckian.
• Thus, the high energy tail of the distribution of Hawking radiation should be entangled, whereas the low energy part should not be.