Entanglement and Expansion

Abstract

We study the entanglement entropy resulting from tracing out local degrees of freedom of a quantum scalar field in an expanding universe. It is known that when field modes become superhorizon during inflation they evolve to increasingly squeezed states. We argue that this causes the entanglement entropy to grow continuously as successive modes cross the horizon. The resulting entropy is proportional to the total duration of inflation. It is preserved during a subsequent radiation or matter dominated era, and thus it may be relevant for today's universe. We demonstrate explicitly these features in a toy model of a scalar field in 1+1 dimensions.

arXiv comment42 pages, 8 figures. v2: references added

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Cited by in corpus (10)

• Entanglement of Harmonic Systems in Squeezed States
• Real-space quantum-to-classical transition of time dependent background fluctuations
• Entanglement in Cosmology
• Modular Hamiltonian for de Sitter diamonds
• Distinguishing cosmological models through quantum signatures of primordial perturbations
• Evolution of capacity of entanglement and modular entropy in harmonic chains and scalar fields
• Entanglement Entropy of a Scalar Field in a Squeezed State
• Amplifying quantum discord during inflationary magnetogenesis through violation of parity
• Entanglement entropy evolution during gravitational collapse
• The area and volume laws for entanglement of scalar fields in flat and cosmological spacetimes