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[{"key": "dc.contributor.advisor", "value": "Nurmi, Sami", "language": "", "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.author", "value": "Rantam\u00e4ki, Julia", "language": "", "element": "contributor", "qualifier": "author", "schema": "dc"}, {"key": "dc.date.accessioned", "value": "2023-11-24T08:27:49Z", "language": null, "element": "date", "qualifier": "accessioned", "schema": "dc"}, {"key": "dc.date.available", "value": "2023-11-24T08:27:49Z", "language": null, "element": "date", "qualifier": "available", "schema": "dc"}, {"key": "dc.date.issued", "value": "2023", "language": "", "element": "date", "qualifier": "issued", "schema": "dc"}, {"key": "dc.identifier.uri", "value": "https://jyx.jyu.fi/handle/123456789/92074", "language": null, "element": "identifier", "qualifier": "uri", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Kevyiden ja energiatiheydelt\u00e4\u00e4n pienten spektaattorikenttien kvanttifluktuaatiot kasvavat inflaation aikana Hubblen horisontin ulkopuolisilla skaaloilla ja k\u00e4ytt\u00e4ytyv\u00e4t efektiivisesti kuten klassiset kent\u00e4n h\u00e4iri\u00f6t. N\u00e4m\u00e4 inflaation aikana syntyneet h\u00e4iri\u00f6t voivat potentiaalisesti vaikuttaa maailmankaikkeuden rakenteen muodostumiseen, pime\u00e4n aineen m\u00e4\u00e4r\u00e4\u00e4n tai esimerkiksi primordiaalisten mustien aukkojen syntyyn. H\u00e4iri\u00f6it\u00e4 voidaan mallintaa stokastisen formalismin avulla, jossa kentt\u00e4 jaetaan horisontin ulkopuoliseen, efektiivisesti klassiseen (IR) kentt\u00e4\u00e4n ja horisontin sis\u00e4puolella olevaan kvanttikentt\u00e4\u00e4n (UV). IR-kentt\u00e4\u00e4 voidaan johtavana approksimaationa kuvata klassisena stokastisena suureena. Stokastisessa formalismissa mink\u00e4 tahansa kent\u00e4n \u03c6 funktion 2-pistekorrelaattori horisonttia suuremmilla skaaloilla voidaan esitt\u00e4\u00e4 spektraalihajotelmana, jonka termit saadaan Schr\u00f6dinger-tyyppisen ominaisarvoyht\u00e4l\u00f6n ratkaisuina. T\u00e4ss\u00e4 tutkielmassa esitell\u00e4\u00e4n stokastisen formalismin perusteita ja sovelletaan sit\u00e4 \u03bb\u03c6^4-potentiaalille juoksevalla kytkenn\u00e4ll\u00e4 \u03bb(\u03c6). Numeerisen analyysin avulla ty\u00f6ss\u00e4 tarkastellaan miten kytkenn\u00e4n juoksusta kent\u00e4n potentiaaliin muodostuvat metastabiilit minimit vaikuttavat sen 2-pistekorrelattoriin. T\u00e4llainen kentt\u00e4 on erityisen mielenkiintoinen, koska Higgsin potentiaalissa voi olla kvalitatiivisesti saman tyyppisi\u00e4 metstabiileja minimej\u00e4 ja Higgs on voinut toimia spektaattorina inflaation aikana. Metastabiilien minimien vaikutuksesta spektri on l\u00e4hes skaalainvariantti ja taittaa siniseen. Spektri-indeksi pienenee jopa 80 % verrattuna tapaukseen, miss\u00e4 \u03bb pysyy vakiona.", "language": "fi", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.abstract", "value": "The quantum fluctuations of light and energetically subdominant scalar fields grow during inflation to scales larger than the Hubble horizon becoming effectively classical perturbations. These perturbations could influence on structure formation in the universe, dark matter abundance or for example generate primordial blackholes. Scalar field fluctuations can be modelled by means of stochastic formalism where the field is divided into long-wavelength (IR) field outside the horizon and short-wavelength (UV) field inside the horizon. IR-field can then be treated effectively classical stochastic quantity. Two-point correlation functions for some function of a scalar field \u03c6 can in stochastic formalism be expressed as a spectral expansion. The terms for this expansion are obtained from a Schr\u00f6dinger-like eigenvalue equation. In this thesis, we introduce the relevant parts of stochastic inflation formalism and apply it to a \u03bb\u03c6^4 potential with a running coupling \u03bb(\u03c6), resulting in the formation of metastable minima. We then analyse the influence of these metastable minima on the two-point correlators of the scalar field with numerical methods. This type of field is particularly interesting since the Higgs potential may have qualitatively similar metastable minima and the Higgs field could have acted as a spectator during inflation. In the presence of metastable minima, we find close to scale invariant slightly blue tilted spectrum. The change in the spectral index can be up to 80% compared to the case with constant \u03bb.", "language": "en", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Submitted by Miia Hakanen (mihakane@jyu.fi) on 2023-11-24T08:27:49Z\nNo. of bitstreams: 0", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Made available in DSpace on 2023-11-24T08:27:49Z (GMT). No. of bitstreams: 0\n Previous issue date: 2023", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.format.extent", "value": "76", "language": "", "element": "format", "qualifier": "extent", "schema": "dc"}, {"key": "dc.language.iso", "value": "eng", "language": null, "element": "language", "qualifier": "iso", "schema": "dc"}, {"key": "dc.rights", "value": "In Copyright", "language": null, "element": "rights", "qualifier": null, "schema": "dc"}, {"key": "dc.subject.other", "value": "Stochastic formalism", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "Inflation", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "Spectator field", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.title", "value": "Application of the stochastic formalism for spectator scalars during inflation", "language": "", "element": "title", "qualifier": null, "schema": "dc"}, {"key": "dc.type", "value": "master thesis", "language": null, "element": "type", "qualifier": null, "schema": "dc"}, {"key": "dc.identifier.urn", "value": "URN:NBN:fi:jyu-202311248089", "language": "", "element": "identifier", "qualifier": "urn", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Master\u2019s thesis", "language": "en", "element": "type", "qualifier": "ontasot", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Pro gradu -tutkielma", "language": "fi", "element": "type", "qualifier": "ontasot", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Matemaattis-luonnontieteellinen tiedekunta", "language": "fi", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Faculty of Sciences", "language": "en", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Fysiikan laitos", "language": "fi", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Department of Physics", "language": "en", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "Jyv\u00e4skyl\u00e4n yliopisto", "language": "fi", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "University of Jyv\u00e4skyl\u00e4", "language": "en", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Teoreettinen fysiikka", "language": "fi", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Theoretical Physics", "language": "en", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "yvv.contractresearch.funding", "value": "0", "language": "", "element": "contractresearch", "qualifier": "funding", "schema": "yvv"}, {"key": "dc.type.coar", "value": "http://purl.org/coar/resource_type/c_bdcc", "language": null, "element": "type", "qualifier": "coar", "schema": "dc"}, {"key": "dc.rights.copyright", "value": "\u00a9 The Author(s)", "language": null, "element": "rights", "qualifier": "copyright", "schema": "dc"}, {"key": "dc.rights.accesslevel", "value": "openAccess", "language": null, "element": "rights", "qualifier": "accesslevel", "schema": "dc"}, {"key": "dc.type.publication", "value": "masterThesis", "language": null, "element": "type", "qualifier": "publication", "schema": "dc"}, {"key": "dc.subject.oppiainekoodi", "value": "4024", "language": "", "element": "subject", "qualifier": "oppiainekoodi", "schema": "dc"}, {"key": "dc.subject.yso", "value": "kosmologia", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "kosminen inflaatio", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "stokastiset prosessit", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "cosmology", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "cosmic inflation", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "stochastic processes", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.rights.url", "value": "https://rightsstatements.org/page/InC/1.0/", "language": null, "element": "rights", "qualifier": "url", "schema": "dc"}]
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