Invariant Construction of Cosmological Models

Solutions to the Einstein field equations can be constructed from invariant objects. If a solution is found it is locally equivalent to all solutions constructed from the same set. Here the method is applied to spatially-homogeneous solutions with pre-determined algebras, under the assumption that t...

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Bibliographic Details
Main Author: Jörgenfelt, Erik
Format: Others
Language:English
Published: Umeå universitet, Institutionen för fysik 2016
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-125403
Description
Summary:Solutions to the Einstein field equations can be constructed from invariant objects. If a solution is found it is locally equivalent to all solutions constructed from the same set. Here the method is applied to spatially-homogeneous solutions with pre-determined algebras, under the assumption that the invariant frame field of standard vectors is orthogonal on the orbits. Solutions with orthogonal fluid flow of Bianchi type III are investigated and two classes of orthogonal dust (zero pressure) solutions are found, as well as one vacuum energy solution. Tilted dust solutions with non-vanishing vorticity of Bianchi types I--III are also investigated, and it is shown that no such solution exist given the assumptions. === Lösningar till Einsteins fältekvationer kan konstrueras från invarianta objekt. Om en lösning hittas är den lokalt ekvivalent till alla andra lösningar konstruerade från samma mängd. Här appliceras metoden på spatialt homogena lösningar med förbestämda algebror, under antagandet att den invarianta ramen med standard-vektorer är ortogonal på banorna. Lösningar med ortogonalt fluidflöde av Bianchi typ III undersöks och två klasser av dammlösningar (noll tryck) hittas, liksom en vakum-energilösning. Dammlösningar med lut och noll-skild vorticitet av Bianchi typ I--III undersöks också, och det visas att inga sådana lösningar existerar givet antagandena.