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Infinite derivative gravity:a ghost and singularity-free theory

Conroy, Aindriú (2017) Infinite derivative gravity:a ghost and singularity-free theory. PhD thesis, .

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    The objective of this thesis is to present a viable extension of general relativity free from cosmological singularities. A viable cosmology, in this sense, is one that is free from ghosts, tachyons or exotic matter, while staying true to the theoretical foundations of General Relativity such as general covariance, as well as observed phenomenon such as the accelerated expansion of the universe and inflationary behaviour at later times. To this end, an infinite derivative extension of relativity is introduced, with the gravitational action derived and the non-linear field equations calculated, before being linearised around both Minkowski space and de Sitter space. The theory is then constrained so as to avoid ghosts and tachyons by appealing to the modified propagator, which is also derived. Finally, the Raychaudhuri Equation is employed in order to describe the ghost-free, defocusing behaviour around both Minkowski and de Sitter spacetimes, in the linearised regime.

    Item Type: Thesis (PhD)
    Uncontrolled Keywords: gravity ; infinite derivative gravity ; modified gravity ; ghosts ; singularity-free ; general relativity
    Departments: Faculty of Science and Technology > Physics
    ID Code: 85977
    Deposited By: ep_importer_pure
    Deposited On: 25 Apr 2017 10:04
    Refereed?: No
    Published?: Published
    Last Modified: 24 Jan 2018 00:13
    Identification Number:

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