Cosmological Particle Production: A Review

Abstract

This article will review quantum particle creation in expanding universes. The emphasis will be on the basic physical principles and on selected applications to cosmological models. The needed formalism of quantum field theory in curved spacetime will be summarized, and applied to the example of scalar particle creation in a spatially flat universe. Estimates for the creation rate will be given and applied to inflationary cosmology models. Analog models which illustrate the same physical principles and may be experimentally realizable are also discussed.

Brans–Dicke Gravity with a Cosmological Constant Smoothes Out ΛCDM Tensions

“…This is the first unmistakable sign that a particle interpretation will become hard in this context, or in other words, it amounts to the phenomenon of particle creation in a time-dependent gravitational field [326][327][328] -for a review see e.g. [329][330][331][332]. If we perform the change of field mode variable ϕ k = φ k /a the above equation simplifies to a more amenable one in which the damping term is absent:…”

Emergent particles of de Sitter: thermal interpretation of the stochastic formalism and beyond

“…Also, the resultant scale-invariant spectrum is far from thermal distribution, making it hard to obtain a thermal interpretation [77,78] (cf. thermal spectrum of gravitationally produced particles for past-asymptotically flat spacetimes [79][80][81][82][83][84]). Despite these differences, [77,78] established a thermal interpretation of the stochastic dynamics.…”