Quantum fluctuations and semiclassicality in an inflaton-driven evolution

Abstract

A semiclassical description of quantum systems is applied to probe the dynamics of the cosmological model of an inflationary universe with quadratic inflaton potential, described in a quantum framework of geometrodynamics. The systematic analysis, focusing in particular on the inflationary and post-inflationary epochs, revealed several surprising and counterintuitive features: $(i)$ during inflation the universe rapidly spreads out in volume which leads to significant relative variance by the end of inflation; $(ii)$ despite that, the quantum evolution can still be described to high accuracy by semiclassical methods; $(iii)$ moreover, in the post-inflationary epoch, as the order of included quantum corrections increases, the quantum trajectory approaches the classical one and the description involving second-order corrections only is actually the least accurate there. The consequence of the latter is that the effects of the quantum variances are washed out by the higher-order quantum corrections.

Expanded version of the paper accepted for publication in JCAP. We have included a more detailed derivation of the model, some clarifications on the presentation of the results, and several new references

References in corpus (11)

• Dynamics of dark energy
• Pointer states for primordial fluctuations in inflationary cosmology
• Quantum Cosmology: Effective Theory
• Statistical moments for classical and quantum dynamics: formalism and generalized uncertainty relations
• Cosmological Constant from Decoherence
• Classical Inflationary and Ekpyrotic Universes in the No-Boundary Wavefunction
• Classical and quantum behavior of the harmonic and the quartic oscillators
• Canonical description of cosmological backreaction
• Classical versus quantum evolution for a universe with a positive cosmological constant
• Quantum Kasner transition in a locally rotationally symmetric Bianchi II universe
• Semiclassical study of the Mixmaster model: the quantum Kasner map

Cited by in corpus (1)

• Effective dynamics of quantum fluctuations in field theory: with applications to cosmology