Entanglement in an expanding spacetime

Ball, Jonathan L., Fuentes-Schuller, Ivette and Schuller, Frederic P. (2006) Entanglement in an expanding spacetime. Physics Letters, Section A: General, Atomic and Solid State Physics, 359 (6), 550-554. (doi:10.1016/j.physleta.2006.07.028).

Record type: Article

Abstract

We show that a dynamical spacetime generates entanglement between modes of a quantum field. Conversely, the entanglement encodes information concerning the underlying spacetime structure, which hints at the prospect of applications of this observation to cosmology. Here we illustrate this point by way of an analytically exactly soluble example, that of a scalar quantum field on a two-dimensional asymptotically flat Robertson-Walker expanding spacetime. We explicitly calculate the entanglement in the far future, for a quantum field residing in the vacuum state in the distant past. In this toy universe, it is possible to fully reconstruct the parameters of the cosmic history from the entanglement entropy.

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Published date: 11 December 2006

Additional Information: Funding Information: The authors would like to thank Stefan Hofmann for useful discussions. J.L.B. acknowledges financial support from Keble College in Oxford and EPSRC, and thanks Perimeter Institute for its generous hospitality.