2026-09-19T22:58:27Zhttps://dspace.mit.edu/server/oai/request

oai:dspace.mit.edu:1721.1/1056472022-01-13T07:54:07Zcom_1721.1_7582com_1721.1_7581col_1721.1_131024

David Kaiser. Prabhu, Anirudh, S.B. Massachusetts Institute of Technology Massachusetts Institute of Technology. Department of Physics. Massachusetts Institute of Technology. Department of Physics 2016-12-05T19:56:23Z 2016-12-05T19:56:23Z 2016 2016 http://hdl.handle.net/1721.1/105647 963848214 Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016. Cataloged from PDF version of thesis. Includes bibliographical references (pages 81-83). The theory of cosmic inflation was proposed to address problems with Standard Big Bang cosmology. The theory suggests the existence of an epoch during which the universe underwent an exponential expansion, followed by an epoch of slower expansion. Realistic models of high-energy physics require multiple scalar fields. Renormalization of these fields in curved space-time requires these fields to be nonminimally coupled to the space-time Ricci scalar. These couplings induce a nontrivial field-space manifold when we move from the Jordan frame to the Einstein frame. In the Einstein frame, the potential becomes asymptotically flat, leading to ridges and valleys in field-space. The existence of these ridges and valleys results in a strong single-field attractor behavior of the fields. We study preheating in multifield models of inflation with nonminimal couplings. In this phase, we find an efficient transfer of energy from the oscillating background fields to the coupled fluctuations. We identify features of preheating that are not present in the minimally coupled case. In particular, we observe how the Fourier structure of the background field oscillations changes as the value of the dimensionless non-minimal coupling, [zeta]1 changes. We also observe how the resonance structure of perturbations changes as we tune [zeta]1. by Anirudh Prabhu. S.B. 83 pages eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Physics. Preheating in multifield inflation Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="fcd8e7a9-3add-4774-a8d0-7364e8b07e4e"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Preheating in multifield inflation</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2016</PublicationDate> <Authors> <Author> <DisplayName>Prabhu, Anirudh, S.B. Massachusetts Institute of Technology</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Physics.</Keyword> <Abstract>The theory of cosmic inflation was proposed to address problems with Standard Big Bang cosmology. The theory suggests the existence of an epoch during which the universe underwent an exponential expansion, followed by an epoch of slower expansion. Realistic models of high-energy physics require multiple scalar fields. Renormalization of these fields in curved space-time requires these fields to be nonminimally coupled to the space-time Ricci scalar. These couplings induce a nontrivial field-space manifold when we move from the Jordan frame to the Einstein frame. In the Einstein frame, the potential becomes asymptotically flat, leading to ridges and valleys in field-space. The existence of these ridges and valleys results in a strong single-field attractor behavior of the fields. We study preheating in multifield models of inflation with nonminimal couplings. In this phase, we find an efficient transfer of energy from the oscillating background fields to the coupled fluctuations. We identify features of preheating that are not present in the minimally coupled case. In particular, we observe how the Fourier structure of the background field oscillations changes as the value of the dimensionless non-minimal coupling, [zeta]1 changes. We also observe how the resonance structure of perturbations changes as we tune [zeta]1.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>