Carroll, Sean M. and Dulaney, Timothy R. and Gresham, Moira I. and Tam, Heywood (2009) Sigma-model aether. Physical Review D, 79 (6). 065012. ISSN 0556-2821 http://resolver.caltech.edu/CaltechAUTHORS:20090429-113052329
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Theories of low-energy Lorentz violation by a fixed-norm “aether” vector field with two-derivative kinetic terms have a globally bounded Hamiltonian and are perturbatively stable only if the vector is timelike and the kinetic term in the action takes the form of a sigma model. Here we investigate the phenomenological properties of this theory. We first consider the propagation of modes in the presence of gravity and show that there is a unique choice of curvature coupling that leads to a theory without superluminal modes. Experimental constraints on this theory come from a number of sources, and we examine bounds in a two-dimensional parameter space. We then consider the cosmological evolution of the aether, arguing that the vector will naturally evolve to be orthogonal to constant-density hypersurfaces in a Friedmann-Robertson-Walker cosmology. Finally, we examine cosmological evolution in the presence of an extra compact dimension of space, concluding that a vector can maintain a constant projection along the extra dimension in an expanding universe only when the expansion is exponential.
|Additional Information:||© 2009 American Physical Society. Received 16 January 2009; published 13 March 2009. We are very grateful to Ted Jacobson, Alan Kostelecky, and Mark Wise for helpful comments. This research was supported in part by the U.S. Department of Energy and by the Gordon and Betty Moore Foundation. PACS numbers: 11.30.Cp, 04.40.Nr|
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|Deposited By:||Jason Perez|
|Deposited On:||01 May 2009 16:33|
|Last Modified:||26 Dec 2012 10:59|
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