Decoherence due to the Horizon after Inflation

Abstract

The fluctuations in the inflaton field at the end of inflation which seed the density perturbations are prepared in a pure quantum state. It is generally assumed that some physics causes this pure state to decohere so that it should be treated probabilistically. We show that the entanglement entropy between the universe inside our observable horizon and that outside our horizon is sufficient to do this. For the modes which are super-Hubble at the end of inflation, this entanglement entropy grows with volume inside the horizon, rather than with the horizon's area, and is proportional to the number of e-folds since Hubble crossing.

11 pages

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Cited by in corpus (16)

• Quantum Decoherence During Inflation from Gravitational Nonlinearities
• Bell violation in the Sky
• Observational constraints on quantum decoherence during inflation
• Minimal decoherence from inflation
• Non Gaussianities from Quantum Decoherence during Inflation
• Entanglement of Quantum Fluctuations in the Inflationary Universe
• Low Frequency Observations of the Moon with the Murchison Widefield Array
• Decoherence in an Interacting Quantum Field Theory: The Vacuum Case
• Universal signature of quantum entanglement across cosmological distances
• Emergence of classical behavior in the early universe
• In-in formalism for the entropy of quantum fields in curved spacetimes
• Failure of Perturbation Theory Near Horizons: the Rindler Example
• Characterizing Entanglement Entropy Produced by Non-Linear Scalar Interactions During Inflation
• Decoherence in an Interacting Quantum Field Theory: Thermal Case
• Classical branches and entanglement structure in the wavefunction of cosmological fluctuations
• A Search for Classical Subsystems in Quantum Worlds