Cosmic decoherence: primordial power spectra and non-Gaussianities

Abstract

We study the effect of quantum decoherence on the inflationary cosmological perturbations. This process might imprint specific observational signatures revealing the quantum nature of the inflationary mechanism being related to the longstanding issue of the quantum-to-classical transition of inflationary fluctuations. Several works have investigated the effect of quantum decoherence on the statistical properties of primordial fluctuations. In particular, it has been shown that cosmic decoherence leads to corrections to the curvature power spectrum predicted by standard slow-roll inflation. Equally interesting, a non zero curvature trispectrum has been shown to be purely induced by cosmic decoherence, but surprisingly, decoherence seems not to generate any bispectrum. We further develop such an analysis by adopting a generalized form of the pointer observable, showing that decoherence does induce a non vanishing curvature bispectrum and providing a specific underlying concrete physical process. Present constraints on primordial bispectra allow to put an upper bound on the strength of the environment-system interaction. In full generality, the decoherence-induced bispectrum can be scale dependent provided one imposes the corresponding correction to the power spectrum to be scale independent. Such scale dependence on the largest cosmological scales might represent a distinctive imprint of the quantum decoherence process taking place during inflation. We also provide a criterion that allows to understand when cosmic decoherence induces scale independent corrections, independently of the type of environment considered. As a final result, we study the effect of cosmic decoherence on tensor perturbations and we derive the decoherence corrected tensor-to-scalar perturbation ratio. In specific cases, decoherence induces a blue tilted correction to the standard tensor power spectrum.

56 pages, 6 figures, v2: references added. Matches published version in JCAP

References in corpus (14)

• Primordial Non-Gaussianities from Inflation Models
• Decoherence in Crystals of Quantum Molecular Magnets
• Pointer states for primordial fluctuations in inflationary cosmology
• On the Decoherence of Primordial Fluctuations During Inflation
• Experimental motivation and empirical consistency in minimal no-collapse quantum mechanics
• Minimal decoherence from inflation
• Effective Field Theory out of Equilibrium: Brownian quantum fields
• Benchmarking the cosmological master equations
• Breaking quantum linearity: constraints from human perception and cosmological implications
• Cosmological Consequences of Initial State Entanglement
• Quantum non-linear evolution of inflationary tensor perturbations
• Enhanced power on small scales and evolution of quantum state of perturbations in single and two field inflationary models
• Cosmic Decoherence: Massive Fields
• Non-Gaussianity from Entanglement During Inflation

Cited by in corpus (14)

• Minimal decoherence from inflation
• The Open Effective Field Theory of Inflation
• Cosmic Purity Lost: Perturbative and Resummed Late-Time Inflationary Decoherence
• Decoherence out of fire: Purity loss in expanding and contracting universes
• On the Decoherence of Primordial Gravitons
• In-in formalism for the entropy of quantum fields in curved spacetimes
• An Open Effective Field Theory for light in a medium
• Open Quantum System Approach to the Gravitational Decoherence of Spin-1/2 Particles
• The effect of quantum decoherence on inflationary gravitational waves
• Resummation of local and non-local scalar self energies via the Schwinger-Dyson equation in de Sitter spacetime
• Open system dynamics in interacting quantum field theories
• Amplifying quantum discord during inflationary magnetogenesis through violation of parity
• Anharmonic Effects on the Squeezing of Axion Perturbations
• Introdução à Cosmologia Quântica