Effects of fragmentation on post-inflationary reheating

Journal Article · Wed Dec 13 00:00:00 EST 2023 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2023/12/028· OSTI ID:2479307

Garcia, Marcos A. G. ^[1]; Gross, Mathieu ^[2]; Mambrini, Yann ^[2]; Olive, Keith A. ^[3]; Pierre, Mathias ^[4]; Yoon, Jong-Hyun ^[2]

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1. Universidad Nacional Autónoma de México (Mexico)
2. Université Paris-Saclay (France)
3. University of Minnesota, Minneapolis, MN (United States)
4. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

We consider the effects of fragmentation on the post-inflationary epoch of reheating. In simple single field models of inflation, an inflaton condensate undergoes an oscillatory phase once inflationary expansion ends. The equation of state of the condensate depends on the shape of the scalar potential, V(Φ), about its minimum. Assuming V(Φ) ~ Φ^k, the equation of state parameter is given by w = P_Φ/ρ_Φ = (k - 2)/(k + 2). The evolution of condensate and the reheating process depend on k. For k ≥ 4, inflaton self-interactions may lead to the fragmentation of the condensate and alter the reheating process. Indeed, these self-interactions lead to the production of a massless gas of inflaton particles as w relaxes to 1/3. If reheating occurs before fragmentation, the effects of fragmentation are harmless. We find, however, that the effects of fragmentation depend sensitively to the specific reheating process. Reheating through the decays to fermions is largely excluded since perturbative couplings would imply that fragmentation occurs before reheating and in fact could prevent reheating from completion. Reheating through the decays to boson is relatively unaffected by fragmentation and reheating through scatterings results in a lower reheating temperature.

• Research Organization: University of Minnesota, Minneapolis, MN (United States)
• Sponsoring Organization: CONAHCYT “Ciencia de Frontera”; DGAPA-PAPIIT; USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: SC0011842
• OSTI ID: 2479307
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 12 Vol. 2023; ISSN 1475-7516
• Publisher: Institute of Physics (IOP)
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
inflation
particle physics - cosmology connection