Entropy production in inflation from spectator loops

Abstract

Perturbations in cosmic microwave background (CMB) photons and large scale structure of the universe are sourced primarily by the curvature perturbation which is widely believed to be produced during inflation. In this paper we present a 2-field inflationary model in which the inflaton couples bi-quadratically to a spectator field. We show that the spectator induces a rapid growth of the momentum of the curvature perturbation and the associated Gaussian van Neumann entropy during inflation such that the initial conditions at the end of inflation are substantially different from the standard ones. Consequently, one ought to reconsider the kinetic equations describing evolution of the photon, dark matter and baryonic fluids in radiation and matter eras and take account of the fact that the curvature perturbation and its canonical momentum are two a priory independent stochastic fields. We also briefly analyze possible imprints on the CMB temperature fluctuations from the more general inflationary scenario which contains light spectator fields coupled to the inflaton. * Electronic address: p.friedrich@uu.nl ‡ Electronic address: t.prokopec@uu.nl

Entanglement entropy of cosmological perturbations

“…There are some similarities between our work and that of [33], where decoherence through neglecting observationally inaccessible correlators was considered, and that of [34], where decoherence via entropy field loops was studied (decoherence of fluctuations through entropy loops was considered earlier in [35]). There is also a connection with the work of [36] where super-Hubble entanglement through inflaton decay was considered.…”

One loop graviton corrections to dynamical photons in de Sitter

“…The constant contribution also depends on the choice of the initial state and for that reason cannot be fixed. The decaying logarithm does cause the time derivative of the conformally rescaled field to grow relative to its classical value, and that might be significant [55].…”

Field-theoretic derivation of bubble-wall force

“…To consistently include the quantum loop effects on top of such a tree level treatment, one would have to solve the corresponding out-of-equilibrium problem using a perturbative quantum field theoretic framework such as the Schwinger-Keldysh formalism [18][19][20]. While progress has been made in applying such a formalism in baryogenesis/leptogenesis scenarios [21][22][23][24] (for reviews see [4,25]) and in cosmic inflation [26][27][28][29][30], little or no progress has been made in studying cosmological phase transitions.…”