Quantum vacuum near non-rotating compact objects

Requiring the validity of the Einstein equivalence principle in local quantum field theory in curved spacetime, we define and study a quantum-vacuum state near non-rotating gravitational compact objects. For non-evaporating black holes, we show that this quantum vacuum approximates, to a certain extent, the Hartle–Hawking vacuum in the near-horizon region and the Boulware vacuum in the far-horizon region. (paper)