Quantum non-linear evolution of inflationary tensor perturbations

Abstract

We study the quantum mechanical evolution of the tensor perturbations during inflation with non-linear tensor interactions. We first obtain the Lindblad terms generated by non-linear interactions by tracing out unobservable sub-horizon modes. Then we calculate explicitly the reduced density matrix for the super-horizon modes, and show that the probability of maintaining the unitarity of the squeezed state decreases in time. The decreased probability is transferred to other elements of the reduced density matrix including off-diagonal ones, so the evolution of the reduced density matrix describes the quantum-to-classical transition of the tensor perturbations. This is different from the classicality accomplished by the squeezed state, the suppression of the non-commutative effect, which is originated from the quadratic, linear interaction, and also maintains the unitarity. The quantum-to-classical transition occurs within 5 - 10 e-folds, faster than the curvature perturbation.

(v1) 39 pages, (v2) typos corrected, to be published in Journal of High Energy Physics

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Cited by in corpus (19)

• Entanglement Entropy of Cosmological Perturbations
• Minimal decoherence from inflation
• Quantum corrections to the primordial tensor spectrum: Open EFTs & Markovian decoupling of UV modes
• Cosmic decoherence: primordial power spectra and non-Gaussianities
• The Early Universe as an Open Quantum System: Complexity and Decoherence
• On the Decoherence of Primordial Gravitons
• Saturation of Thermal Complexity of Purification
• Entropy production in inflation from spectator loops
• Instability of de Sitter space under thermal radiation in different vacua
• Cosmological Bell Tests with Decoherence Effects
• Distinguishing cosmological models through quantum signatures of primordial perturbations
• The effect of quantum decoherence on inflationary gravitational waves
• Eternal inflation in light of Wheeler-DeWitt equation
• Quantum nature of Wigner function for inflationary tensor perturbations
• Von Neumann algebra description of inflationary cosmology
• Quantum decoherence of gravitational waves
• Open system dynamics in interacting quantum field theories
• Black hole production, eternal inflation, and information in quasi-de Sitter space
• Testing quantum gravity with primordial gravitational waves