Latosh, Boris (2020) Effective theories of gravity. Doctoral thesis (PhD), University of Sussex.

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Abstract

This thesis is devoted to the study of effective field theory methods for gravitational interactions. Effective field theories were developed in the context of particle physics. They provide a consistent framework to study low energy effects of some high energy fundamental theory. Applying these methods to quantum general relativity enables one to do calculations for processes taking place at energies below the Planck mass without a detailed knowledge of the ultra-violet complete theory of quantum gravity.

Four related topics are considered in this thesis. We first study effects of quantum gravity in particle physics interactions. In particular, we focus on non-local operators involving fields of the standard model generated by quantum gravity. Bounds on the magnitude of the Wilson coefficients of non-local four fermion interactions are established.

Secondly, we calculate the production rate of gravitational waves by binary systems using effective field theory methods. New massive gravitational modes, beyond the massless graviton, appear in the low energy spectrum of the quantum gravitational effctive field theory. These modes could be generated in binary inspirals.

The third direction consists in a study of dark matter candidates within this effective gravity. The non-local operators generated by quantum gravitational interactions lead to new poles in the graviton propagator. These poles describe states with a non-vanishing decay widths. These states may contribute to the contemporary dark matter content provided that their lifetime is comparable with the current age of our universe. Correspondent constraints on the dark matter candidates are established.

The last question addressed in this thesis consists in an implementation of effective field theory techniques to modified gravity models. One of the simplest stable extensions of general relativity is studied. The new interaction lying beyond general relativity significantly changes the correspondent effective theory. Implications of our results for gravitational interactions are discussed.

Item Type:	Thesis (Doctoral)
Schools and Departments:	School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects:	Q Science > QC Physics > QC0170 Atomic physics. Constitution and properties of matter Including molecular physics, relativity, quantum theory, and solid state physics > QC0178 Theories of gravitation
Depositing User:	Library Cataloguing
Date Deposited:	04 Mar 2020 11:34
Last Modified:	04 Mar 2020 11:34
URI:	http://sro.sussex.ac.uk/id/eprint/90072

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