Decoherence of quantum superpositions by Reissner-Nordström black holes

Abstract: Recently, it was shown by Danielson-Satishchandran-Wald (DSW) that for the massive or charged body in a quantum spatial separated superposition state, the presence of a black hole can decohere the superposition inevitably towards capturing the radiation of soft photons or gravitons. In this work, we study the DSW decoherence effect for the static charged body in the Reissner-Nordstr\"om black holes. By calculating the decohering rate for this case, it is shown that the superposition is decohered by the low frequency photons that propagate through the black hole horizon. For the extremal Reissner-Nordstr\"om black hole, the decoherence of quantum superposition is completely suppressed due to the black hole Meissner effect.It is also found that the decoherence effect caused by the Reissner-Nordstr\"om black hole is equivalent to that of an ordinary matter system with the same size and charge.