Evaporation of black holes in flat space entangled with an auxiliary universe

Abstract We study a thermofield double type entangled state on two disjoint universes A and B, where one of the is asymptotically flat containing black hole. As we increase entanglement temperature, this hole receives back-reaction from stress–energy tensor state. This results in lengthening wormhole region interior, decreasing its horizon area, both which are key features an evaporating then compute entropy universe through island formula, argue that it naturally follows Page curve space. also effects local operations gravitating with find they accelerate evaporation hole, thereby disrupting between universes. Furthermore, observe that, depending whether operation can be regarded as classical communication or not, behavior changes. In particular, when made neither wedge radiation system nor transition phase no-island happen multiple times.