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arXiv · 1103.2197

The Music of the Aetherwave - B-mode Polarization in Einstein-Aether Theory

Masahiro Nakashima·Tsutomu Kobayashi
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Abstract

We study how the dynamical vector degree of freedom in modified gravity affects the CMB B-mode polarization in terms of the Einstein-aether theory. In this theory, vector perturbations can be generated from inflation, which can grow on superhorizon scales in the subsequent epochs and thereby leaves imprints on the CMB B-mode polarization. We derive the linear perturbation equations in a covariant formalism, and compute the CMB B-mode polarization using the CAMB code modified so as to incorporate the effect of the aether vector field. We find that the amplitude of the B-mode signal from the aether field can surpass the contribution from the inflationary gravitational waves for a viable range of model parameters. We also give an analytic argument explaining the shape of the spectrum based on the tight coupling approximation.

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Masahiro Nakashima, Tsutomu Kobayashi. 2011-03-11. The Music of the Aetherwave - B-mode Polarization in Einstein-Aether Theory. https://doi.org/10.1103/physrevd.84.084051

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