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Piecewise silence in discrete cosmological models
Stockholm University, Faculty of Science, Department of Physics. Max Planck Society, Germany.
Stockholm University, Faculty of Science, Department of Physics.
Number of Authors: 3
2014 (English)In: Classical and quantum gravity, ISSN 0264-9381, E-ISSN 1361-6382, Vol. 31, no 10, 105012- p.Article in journal (Refereed) Published
Abstract [en]

We consider a family of cosmological models in which all mass is confined to a regular lattice of identical black holes. By exploiting the reflection symmetry about planes that bisect these lattices into identical halves, we are able to consider the evolution of a number of geometrically distinguished surfaces that exist within each of them. We find that the evolution equations for the reflection symmetric surfaces can be written as a simple set of Friedmann-like equations, with source terms that behave like a set of interacting effective fluids. We then show that gravitational waves are effectively trapped within small chambers for all time, and are not free to propagate throughout the space-time. Each chamber therefore evolves as if it were in isolation from the rest of the universe. We call this phenomenon 'piecewise silence'.

Place, publisher, year, edition, pages
2014. Vol. 31, no 10, 105012- p.
Keyword [en]
cosmology, cosmological models, mathematical models
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
URN: urn:nbn:se:su:diva-105191DOI: 10.1088/0264-9381/31/10/105012ISI: 000336092700013OAI: oai:DiVA.org:su-105191DiVA: diva2:732520
Note

AuthorCount:3;

Available from: 2014-07-04 Created: 2014-06-24 Last updated: 2017-12-05Bibliographically approved
In thesis
1. Cosmological models, nonideal fluids and viscous forces in general relativity
Open this publication in new window or tab >>Cosmological models, nonideal fluids and viscous forces in general relativity
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis addresses the open questions of providing a cosmological model describing an accelerated expanding Universe without violating the energy conditions or a model that contributes to the physical interpretation of the dark energy. The former case is analyzed considering a closed model based on a regular lattice of black holes using the Einstein equation in vacuum. In the latter case I will connect the dark energy to the Shan-Chen equation of state. A comparison between these two proposals is then discussed. As a complementary topic I will discuss the motion of test particles in a general relativistic spacetime undergoing friction effects. This is modeled following the formalism of Poynting-Robertson whose link with the Stokes’ formula is presented. The cases of geodesic and non-geodesic motion are compared and contrasted for Schwarzschild, Tolman, Pant-Sah and Friedman metrics respectively.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University, 2014. 94 p.
Keyword
gravity, exact model, black hole, friction
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:su:diva-107130 (URN)978-91-7447-982-9 (ISBN)
Public defence
2014-11-07, room FP41, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (English)
Opponent
Supervisors
Available from: 2014-10-14 Created: 2014-09-03 Last updated: 2015-03-17Bibliographically approved

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