title: Alice falls into a black hole: entanglement in noninertial frames.
abstract: Two observers determine the entanglement between two free bosonic modes by each detecting one of the modes and observing the correlations between their measurements. We show that a state which is maximally entangled in an inertial frame becomes less entangled if the observers are relatively accelerated. This phenomenon, which is a consequence of the Unruh effect, shows that entanglement is an observer-dependent quantity in noninertial frames. In the high acceleration limit, our results can be applied to a nonaccelerated observer falling into a black hole while the accelerated one barely escapes. If the observer escapes with infinite acceleration, the state's distillable entanglement vanishes.
authors.affiliation: Centre for Quantum Computation, Clarendon Laboratory, University of Oxford, Parks Road OX1 3PU, United Kingdom.
authors.forename: I
authors.initials: I
authors.lastname: Fuentes-Schuller
authors.forename: R B
authors.initials: RB
authors.lastname: Mann