University of Sussex
Browse
Falls,_Kevin.pdf (3.04 MB)

Asymptotic safety and black holes

Download (3.04 MB)
thesis
posted on 2023-06-08, 15:08 authored by KevinGeoffrey Falls
We study the ultraviolet properties of quantum gravity and its consequences for black hole physics using the functional renormalisation group (RG). In particular we concentrate on the asymptotic safety scenario for quantum gravity put forward by S. Weinberg. This approach relies on the existence of an ultraviolet fixed point in the renormalisation group flow. In chapter 2 we review the functional renormalisation group formalism that is used in order to search for the existence of a fixed point with the properties required for asymptotic safety. Following this introduction, in chapter 3 we use these methods to find ultraviolet fixed points in four-dimensional quantum gravity to high order in a polynomial approximation in the Ricci scalar. In the following three chapters we concentrate on the implications of the renormalisation group for black hole physics. In chapter 4 we study quantum gravitational corrections to black holes in four and higher dimensions using a renormalisation group improvement of the metric. The quantum effects are worked out in detail for asymptotically safe gravity, where the short distance physics is characterised by a weakening of gravity due to the nontrivial fixed point. Furthermore, mini-black hole production in particle collisions, such as those at the Large Hadron Collider (LHC), is analysed within low-scale quantum gravity models. In chapter 5 we investigate the thermodynamical properties of the RG improved metrics in detail and study their evaporation process. In chapter 6 we study renormalisation group improved black hole thermodynamics in a metric free approach. Conditions are formulated under which the thermodynamic properties of four dimensional Kerr-Newman type black holes persist under the RG evolution of couplings. We show that the RG scale must be set by the horizon area of the black hole which acts as a diffeomorphism invariant cut-off for the underlying Wilsonian action.

History

File Version

  • Published version

Pages

214.0

Department affiliated with

  • Physics and Astronomy Theses

Qualification level

  • doctoral

Qualification name

  • phd

Language

  • eng

Institution

University of Sussex

Full text available

  • Yes

Legacy Posted Date

2013-06-28

Usage metrics

    University of Sussex (Theses)

    Categories

    No categories selected

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC