Quantum optics approach to black hole thermodynamics via conformal quantum mechanics

Conformal symmetry of fields near the event horizon of the black hole plays a significant role in determining the temperature of the black hole radiation. In this talk, we show how the near-horizon (NH) conformal symmetry provides a microscopic theory for the area-entropy relation for any static or stationary black hole. To do that, we map the NH behavior of the field modes to the scale-invariant Hamiltonian of conformal quantum mechanics (CQM). We further construct a setup where two-state atoms in their ground state are injected randomly in the Boulware vacuum of the field, and they fall freely towards the black hole. We show that the atoms emit and absorb radiation during the free fall, changing the entropy of the scalar field. The radiation is thermal in nature with the temperature being equal to the Hawking temperature. Due to the NH scale-invariant CQM behavior of the fields and the random injection of atoms, we show that the change of entropy of the fields due to the radiation is proportional to the change in the area of the black hole. Also, the proportionality constant in this case is the same as in the Bekenstein-Hawking entropy. The NH conformal symmetry allows us to extend the results to any non-extremal static or stationary black hole. The universality of the results in this quantum optics approach provides a novel probe for the thermal atmosphere associated with a black hole.