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[{"key": "dc.contributor.advisor", "value": "Nurmi, Sami", "language": "", "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.author", "value": "Aalto, Tuomas", "language": "", "element": "contributor", "qualifier": "author", "schema": "dc"}, {"key": "dc.date.accessioned", "value": "2019-10-23T06:21:05Z", "language": null, "element": "date", "qualifier": "accessioned", "schema": "dc"}, {"key": "dc.date.available", "value": "2019-10-23T06:21:05Z", "language": null, "element": "date", "qualifier": "available", "schema": "dc"}, {"key": "dc.date.issued", "value": "2019", "language": "", "element": "date", "qualifier": "issued", "schema": "dc"}, {"key": "dc.identifier.uri", "value": "https://jyx.jyu.fi/handle/123456789/65993", "language": null, "element": "identifier", "qualifier": "uri", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Nykytiet\u00e4myksen mukaan kosminen inflaatio j\u00e4tti pieni\u00e4 h\u00e4iri\u00f6it\u00e4 l\u00e4hes homogeeniseen varhaiseen maailmankaikkeuteen. Nyky\u00e4\u00e4n havaittavien kosmisten rakenteiden kehittyminen n\u00e4ist\u00e4 h\u00e4iri\u00f6ist\u00e4 on yksi kosmologian keskeisist\u00e4 osa-alueista.\n\nRakenteiden muodostumisen kannalta keskeisimpi\u00e4 ovat skalaarityyppiset h\u00e4iri\u00f6t, joihin maailmankaikkeuden energiatiheyden h\u00e4iri\u00f6t p\u00e4\u00e4asiallisesti kytkeytyv\u00e4t. T\u00e4m\u00e4 tutkielma on katsaus lineaarisen kosmologisen h\u00e4iri\u00f6teorian antamaan hyvin tunnettuun kuvaukseen skalaarih\u00e4iri\u00f6iden kehittymiselle. Skalaarih\u00e4iri\u00f6iden kehittymist\u00e4 kuvaavien yht\u00e4l\u00f6iden johto esitet\u00e4\u00e4n kosmologisesta h\u00e4iri\u00f6teoriasta alkaen. Yht\u00e4l\u00f6t on johdettu newtonilaista mittaa k\u00e4ytt\u00e4en.\n\nH\u00e4iri\u00f6iden kehityst\u00e4 kuvaaville yht\u00e4l\u00f6ille esitet\u00e4\u00e4n sek\u00e4 analyyttisill\u00e4 approksimaatioilla ett\u00e4 numeerisella laskennalla saatavia viitteellisi\u00e4 ratkaisuja. Muodostuvassa mallissa rakenteiden syntyminen alkaa pime\u00e4n aineen kasautumisella s\u00e4teilyn dominanssin aikana. Baryonisen aineen kasautuminen p\u00e4\u00e4see alkamaan vasta sen irtikytkeydytty\u00e4 fotoneista punasiirtym\u00e4n z \u2248 1000 kohdalla.\n\nH\u00e4iri\u00f6teoriaan perustuvan menetelm\u00e4n validisuutta tarkastellaan vertaamalla saatuja tuloksia rakenteenmuodostumisen pallomaisen romahdusmallin kanssa. T\u00e4m\u00e4 entuudestaan tunnettu vertailu n\u00e4ytt\u00e4\u00e4, kuinka lineaarinen h\u00e4iri\u00f6teoria aliarvioi energiatiheyden h\u00e4iri\u00f6iden kasvua.", "language": "fi", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.abstract", "value": "According to the current understanding, the early universe was close to homogeneity with small perturbations left as remnants of the inflation. How these small perturbations evolved into the cosmic structures we observe today is one of the central topics in cosmology.\n\nOf different types of perturbations, it is the scalar ones that most dominantly couple to perturbations in energy density and lead to structure formation. This thesis is a review of the well-established evolution of the cosmic scalar perturbations within the context of linear cosmological perturbation theory. We present the derivation of the equations governing the evolution of the scalar perturbations starting from the cosmological perturbation theory. The derivation is done in the Newtonian gauge.\n\nRudimentary solutions to the evolution equations are also presented, both through analytical approximations and numerical computations. In the emerging picture, the structure formation starts with the accumulation of dark matter in radiation dominance. Baryonic matter is prevented from accumulation until decoupling from the photons at the redshift z \u2248 1000.\n\nThe validity of the perturbative method is examined through a comparison with the spherical collapse model of structure formation. This well known comparison shows how the linear perturbation theory underestimates the growth of perturbations in the energy density.", "language": "en", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Submitted by Paivi Vuorio (paelvuor@jyu.fi) on 2019-10-23T06:21:05Z\nNo. of bitstreams: 0", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Made available in DSpace on 2019-10-23T06:21:05Z (GMT). No. of bitstreams: 0\n Previous issue date: 2019", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.format.extent", "value": "89", "language": "", "element": "format", "qualifier": "extent", "schema": "dc"}, {"key": "dc.format.mimetype", "value": "application/pdf", "language": null, "element": "format", "qualifier": "mimetype", "schema": "dc"}, {"key": "dc.language.iso", "value": "eng", "language": null, "element": "language", "qualifier": "iso", "schema": "dc"}, {"key": "dc.rights", "value": "In Copyright", "language": "en", "element": "rights", "qualifier": null, "schema": "dc"}, {"key": "dc.subject.other", "value": "large scale structure", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "structure formation", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "cosmological perturbation theory", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.title", "value": "The first-order evolution of cosmic scalar perturbations", "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-201910234573", "language": "", "element": "identifier", "qualifier": "urn", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Pro gradu -tutkielma", "language": "fi", "element": "type", "qualifier": "ontasot", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Master\u2019s thesis", "language": "en", "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.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": "cosmology", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.format.content", "value": "fulltext", "language": null, "element": "format", "qualifier": "content", "schema": "dc"}, {"key": "dc.rights.url", "value": "https://rightsstatements.org/page/InC/1.0/", "language": null, "element": "rights", "qualifier": "url", "schema": "dc"}, {"key": "dc.type.okm", "value": "G2", "language": null, "element": "type", "qualifier": "okm", "schema": "dc"}]
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