Alice falls into a black hole: Acceleration and quantum entanglement

This upcoming publication by I. Fuentes-Schuller and R. B. Mann will appear in Physical Review Letters.

What would happen to their entanglement if Alice fell into a black hole and Bob stayed safely outside? We can model this situation by considering Alice to be stationary and Rob (formerly Bob) to be uniformly accelerated with respect to Alice. We found that although the entanglement between them is reduced due to Rob's acceleration, it remains nonzero as long as Rob's acceleration is not infinite.

This has important consequences in quantum teleportation between relatively accelerated parties, since entanglement is the main resource in this task.

The 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 non-inertial frames. In the high acceleration limit, our results can be applied to a non-accelerated 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.

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Source: Perimeter Institute for Theoretical Physics