Citation
Gresham, Moira I. (2010) Lorentz Symmetry Breaking in a Cosmological Context. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/9G693Z95. https://resolver.caltech.edu/CaltechTHESIS:05252010135506831
Abstract
This thesis is comprised primarily of work from three independent papers, written in collaboration with Sean Carroll, Tim Dulaney, and Heywood Tam. The original motivation for the projects undertaken came from revisiting the standard assumption of spatial isotropy during inflation. Each project relates to the spontaneous breaking of Lorentz symmetryin early Universe cosmology or in the context of effective field theory, in general. Chapter 1 is an introductory chapter that provides context for the thesis. Chapter 2 is an investigation of the stability of theories in which Lorentz invariance is spontaneously broken by fixednorm vector "aether" fields. It is shown that models with generic kinetic terms are plagued either by ghosts or by tachyons, and are therefore physically unacceptable. Chapter 3 is an investigation of the phenomenological properties of the one lowenergy effective theory of spontaneous Lorentz symmetry breaking found in the previous chapter to have a globally bounded Hamiltonian and a perturbatively stable vacuumthe theory in which the Lagrangian takes the form of a sigma model. In chapter 4 cosmological perturbations in a dynamical theory of inflation in which an Abelian gauge field couples directly to the inflaton are examined. The dominant effects of a small, persistent anisotropy on the primordial gravitational wave and curvature perturbation power spectra are found using the "inin" formalism of perturbation theory. It is found that the primordial power spectra of cosmological perturbations gain significant direction dependence and that the fractional direction dependence of the tensor power spectrum is suppressed in comparison to that of the scalar power spectrum.
Item Type:  Thesis (Dissertation (Ph.D.))  

Subject Keywords:  Lorentz Violation; Cosmology; Inflation; Anisotropy; Bianchi; Aether; CMB; Early Universe; Cosmological Perturbations; Primordial Power Spectrum  
Degree Grantor:  California Institute of Technology  
Division:  Physics, Mathematics and Astronomy  
Major Option:  Physics  
Thesis Availability:  Public (worldwide access)  
Research Advisor(s): 
 
Group:  Caltech Theory  
Thesis Committee: 
 
Defense Date:  6 May 2010  
Funders: 
 
Record Number:  CaltechTHESIS:05252010135506831  
Persistent URL:  https://resolver.caltech.edu/CaltechTHESIS:05252010135506831  
DOI:  10.7907/9G693Z95  
Related URLs: 
 
Default Usage Policy:  No commercial reproduction, distribution, display or performance rights in this work are provided.  
ID Code:  5837  
Collection:  CaltechTHESIS  
Deposited By:  Moira Gresham  
Deposited On:  26 May 2010 15:00  
Last Modified:  26 Oct 2021 17:45 
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