Communication through quantum fields near a black hole

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We study the quantum channel between two localized first-quantized systems that communicate in 3+1 dimensional Schwarzschild spacetime via a quantum field.

• We analyze the information carrying capacity of direct and black hole-orbiting null geodesics as well as of the timelike contributions that arise because the strong Huygens principle does not hold on the Schwarzschild background.
• We find, in particular, that the non-direct-null and timelike contributions, which do not possess an analog on Minkowski spacetime, can dominate over the direct null contributions.
• We cover the cases of both geodesic and accelerated emitters.