Quantum correlator outside a Schwarzschild black hole

Understand

We calculate the quantum correlator in Schwarzschild black hole space-time.

• We perform the calculation for a scalar field in three different quantum states: Boulware, Unruh and Hartle-Hawking, and for points along a timelike circular geodesic.
• The results show that the correlator presents a global fourfold singularity structure, which is state-independent.
• Our results also show the different correlations in the three different quantum states arising in-between the singularities.