Detecting a Lorentz-violating field in cosmology

Journal Article · Tue Jan 15 00:00:00 EST 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.77.024032· OSTI ID:21038921

Baojiu, Li; Barrow, John D ^[1]; Mota, David F ^[2]

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1. Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
2. Institute of Theoretical Physics, University of Heidelberg, 69120 Heidelberg (Germany)

We consider cosmology in the Einstein-Aether theory (the generally covariant theory of gravitation coupled to a dynamical timelike Lorentz-violating vector field) with a linear Ae-Lagrangian. The 3+1 spacetime splitting approach is used to derive covariant and gauge invariant perturbation equations which are valid for a general class of Lagrangians. Restricting attention to the parameter space of these theories which is consistent with local gravity experiments, we show that there are tracking behaviors for the Ae field, both in the background cosmology and at the linear perturbation level. The primordial power spectrum of scalar perturbations in this model is shown to be the same as that predicted by standard general relativity. However, the power spectrum of tensor perturbation is different from that in general relativity, but has a smaller amplitude and so cannot be detected at present. We also study the implications for late-time cosmology and find that the evolution of photon and neutrino anisotropic stresses can source the Ae field perturbation during the radiation and matter dominated epochs, and as a result the CMB and matter power spectra are modified. However, these effects are degenerate with respect to other cosmological parameters, such as neutrino masses and the bias parameter in the observed galaxy spectrum.

• OSTI ID: 21038921
• Journal Information: Physical Review. D, Particles Fields, Vol. 77, Issue 2; Other Information: DOI: 10.1103/PhysRevD.77.024032; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AMPLITUDES
ANISOTROPY
COSMOLOGY
DISTURBANCES
ENERGY SPECTRA
GAUGE INVARIANCE
GENERAL RELATIVITY THEORY
GRAVITATION
LAGRANGIAN FUNCTION
LORENTZ INVARIANCE
NEUTRINOS
QUANTUM FIELD THEORY
RELICT RADIATION
SCALARS
SPACE
SPACE-TIME
STRESSES
TENSORS
VECTOR FIELDS