Nonequilibrium dynamics of quantum fields in inflationary cosmology
| dc.creator | Ramsey, Stephen A. | |
| dc.date | 2002-09-03 | |
| dc.date | 2002-09-03 | |
| dc.date.accessioned | 2026-07-07T03:27:09Z | |
| dc.date.available | 2026-07-07T03:27:09Z | |
| dc.description | The nonequilibrium dynamics of quantum fields is studied in inflationary cosmology, with particular emphasis on applications to the problem of post-inflation reheating. The Schwinger-Keldysh closed-time-path (CTP) formalism is utilized along with the two-particle-irreducible (2PI) effective action in order to obtain coupled, nonperturbative equations for the mean field and variance in a general curved background spacetime. For a model consisting of a quartically self-interacting O(N) field theory (with unbroken symmetry) in spatially flat FRW spacetime, the dynamics of the mean field is studied numerically, at leading order in the large-N expansion. The time evolution of the scale factor is determined self-consistently using the semiclassical Einstein equation. It is found that cosmic expansion can dramatically affect the efficiency of parametric resonance-induced particle production. The production of fermions due to the oscillating inflaton mean field is studied for the case of a scalar inflaton coupled to a fermion field via a Yukawa coupling $f$. The dissipation and noise kernels appearing at $O(f^2)$ in the one-loop CTP effective action are shown to satisfy a zero-temperature fluctuation-dissipation relation (FDR). The effective stochastic equation obeyed by the inflaton zero mode at $O(f^4)$ contains multiplicative noise. It is shown that stochasticity becomes important to the dynamics of the inflaton zero mode before the end of reheating. The thermalization problem is discussed, and a strategy is presented for obtaining time-local equations for equal-time correlation functions which goes beyond the Hartree-Fock approximation. | |
| dc.description | Doctoral dissertation published in December 1997, University of Maryland, College Park, MD, USA. 212 pages; 23 figures; AMS-LaTeX format | |
| dc.identifier | https://arxiv.org/abs/gr-qc/0209010 | |
| dc.identifier | http://arxiv.org/abs/gr-qc/0209010 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/34320 | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.title | Nonequilibrium dynamics of quantum fields in inflationary cosmology | |
| dc.type | text |