Entanglement and decoherence in cosmology and in analogue gravity experiments

TL;DR

This thesis investigates how quantum entanglement and decoherence evolve during inflationary cosmology and analogue preheating experiments, shedding light on quantum processes in the early universe and laboratory analogues.

Contribution

It provides a detailed analysis of quantum correlations in inflation and preheating, highlighting the role of classical fields in generating entanglement in cosmological and analogue settings.

Findings

Quantum entanglement is generated during inflation and preheating.

Decoherence affects the evolution of quantum correlations in these processes.

Analogue experiments can simulate aspects of early universe quantum phenomena.

Abstract

This thesis is dedicated to analysing the generation and destruction of quantum correlations in the context of inflationary cosmology and an experiment of 'analogue' preheating. Inflation is a phase of accelerated expansion of the Universe, preceding the so-called Standard Model of Big Bang cosmology, introduced to solve some shortcomings of this model. It also provides a mechanism for the emergence of primordial inhomogeneities by amplification of initial quantum fluctuations. Inflation is followed by a 'reheating' period, in which most particles are expected to be generated and reach thermal equilibrium, setting the stage for the standard Big Bang of cosmology. During a 'preheating' period, this creation proceeds partly by parametric excitation of resonant modes of the matter fields initially in their vacuum, a genuine quantum process. The physics of both situations, inflation and preheating, is that of a strong classical field acting on a quantum field to produce entangled (quasi-)particles. When the classical source is the space-time metric itself, as in inflation, we are in the framework of Quantum Field Theory in Curved Space-time (QFTCS). The evolution of the generated quantum correlations is the topic of this PhD.