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Action-at-a-distance and Cosmology

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dc.contributor.advisor Narlikar, J. V. en_US
dc.contributor.author DESHPANDE, KAUSTUBH en_US
dc.date.accessioned 2013-05-24T08:08:51Z
dc.date.available 2013-05-24T08:08:51Z
dc.date.issued 2013-05 en_US
dc.identifier.uri http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/271
dc.description.abstract Action-at-a-distance is an alternative approach to eld theory in describing all the interactions. It is based on direct interactions between particles rather than through their coupling to a eld having in nite degrees of freedom. First formulated in a relativistically invariant manner by Schwarzschild, Tetrode and Fokker, action- at-a-distance in electrodynamics was provided a paradigm by Wheeler and Feynman through their absorber theory of radiation. This theory, formulated in static and at universe, uses advanced absorber response from the entire universe as the origin for radiation reaction but allows for both retarded and advanced interactions. In the rst part of this work (section 3), we study extension of this formulation in cos- mological models (using conformal invariance of electromagnetism). Self-consistency of advanced and retarded interactions is investigated in these models. Only those models can be considered to be viable which have only retarded interactions. It is found that steady-state and quasi-steady-state models satisfy this criterion while Friedman models don't. Thus the origin of arrow of time in electromagnetism can be attributed to the cosmological structure. In the second part (section 4), we study the formulation of action-at-a-distance electrodynamics in Riemannian space-times using Green's functions. Green's functions in curved space-times have a compon- ent which corresponds to propagation inside the light cone ( tail ), along with the usual propagation along the light cone. We evaluate the explicit expressions for Green's functions in de Sitter and Einstein-de Sitter space-times. This can be used in evaluating the tail in an electromagnetic signal. en_US
dc.language.iso en en_US
dc.subject 2013
dc.subject Action at a distance en_US
dc.subject Cosmology en_US
dc.title Action-at-a-distance and Cosmology en_US
dc.type Thesis en_US
dc.type.degree BS-MS en_US
dc.contributor.department Dept. of Physics en_US
dc.contributor.registration 20081030 en_US


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  • MS THESES [1705]
    Thesis submitted to IISER Pune in partial fulfilment of the requirements for the BS-MS Dual Degree Programme/MSc. Programme/MS-Exit Programme

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