Inflation and Weyl symmetry in extended theories of gravity: A new take on gauging Weyl symmetry

Stefano Lucat

Research output: ThesisDoctoral thesis 1 (Research UU / Graduation UU)

Abstract

In this thesis we study both classical and quantum properties of a gauge realisation of Weyl symmetry, achieved by endowing the space-time manifold with a torsional connection. Some component of torsion can then act as a gauge connection, thus compensating the local transformations of the metric tensor and the fields. This leads to a rather generic physical theory, described in chapter 2, which features a dilaton and a vector field on top of the usual particle content of the standard model. We then study a possible mechanism that spontaneous breaks conformal symmetry, showing that cosmological inflation can be described in such a framework. The resulting model has notable features and agrees with inflationary observables in a wide range of the parameter space. In chapter 4 we discuss detection of torsion by means of gravitational waves detectors, which is within range of experimental approach once the space based gravitational detectors will be online. Finally in chapter 5 we address the conformal anomaly and present first evidence that the extended Ward identity, which take into account the additional vector field, hold in a perturbative dimensional renormalization scheme, even when anomalous contributions are generated in the energy momentum tensor trace.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Utrecht University
Supervisors/Advisors
  • Vandoren, Stefan, Supervisor
  • Prokopec, Tom, Co-supervisor
Award date9 Sept 2019
Publisher
Print ISBNs978-94-6380-480-6
Publication statusPublished - 9 Sept 2019

Keywords

  • Conformal symmetry
  • Conformal anomaly
  • Inflation

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