{ "id": "1203.3903", "version": "v2", "published": "2012-03-17T22:54:52.000Z", "updated": "2012-06-18T15:31:08.000Z", "title": "Condensates and quasiparticles in inflationary cosmology: mass generation and decay widths", "authors": [ "Daniel Boyanovsky" ], "comment": "31 pages, 7 figures. Comments and references, matches published version", "journal": "Phys. Rev. D 85, 123525 (2012)", "doi": "10.1103/PhysRevD.85.123525", "categories": [ "hep-ph", "astro-ph.CO", "gr-qc", "hep-th" ], "abstract": "During de Sitter inflation massless particles of minimally coupled scalar fields acquire a mass and a decay width thereby becoming \\emph{quasiparticles}. For bare massless particles non-perturbative infrared radiative corrections lead to a self-consistent generation of mass, for a quartic self interaction $M \\propto \\lambda^{1/4} H$, and for a cubic self-interaction the mass is induced by the formation of a non-perturbative \\emph{condensate} leading to $M \\propto \\lambda^{1/3} H^{2/3}$. These radiatively generated masses restore de Sitter invariance and result in anomalous scaling dimensions of superhorizon fluctuations. We introduce a generalization of the non-perturbative Wigner-Weisskopf method to obtain the time evolution of quantum states that include the self-consistent generation of mass and regulate the infrared behavior. The infrared divergences are manifest as poles in $\\Delta=M^2/3H^2$ in the single particle self-energies, leading to a re-arrangement of the perturbative series non-analytic in the couplings. A set of simple rules that yield the leading order infrared contributions to the decay width are obtained and implemented. The lack of kinematic thresholds entail that all particle states acquire a decay width, dominated by the emission and absorption of superhorizon quanta $\\propto (\\lambda/H)^{4/3}\\,[H/k_{ph}(\\eta)]^6 ; \\lambda\\,[H/k_{ph}(\\eta)]^6 $ for cubic and quartic couplings respectively to leading order in $M/H$. The decay of single particle quantum states hastens as their wavevectors cross the Hubble radius and their width is related to the highly squeezed limit of the bi- or tri-spectrum of scalar fluctuations respectively.", "revisions": [ { "version": "v2", "updated": "2012-06-18T15:31:08.000Z" } ], "analyses": { "subjects": [ "11.10.-z", "98.80.-k", "98.80.Cq" ], "keywords": [ "decay width", "mass generation", "inflationary cosmology", "coupled scalar fields acquire", "particles non-perturbative" ], "tags": [ "journal article" ], "publication": { "publisher": "APS", "journal": "Physical Review D", "year": 2012, "month": "Jun", "volume": 85, "number": 12, "pages": 123525 }, "note": { "typesetting": "TeX", "pages": 31, "language": "en", "license": "arXiv", "status": "editable", "inspire": 1094148, "adsabs": "2012PhRvD..85l3525B" } } }