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arXiv · 2205.00496

Explicit spacetime-symmetry breaking and the dynamics of primordial fields

Nils A. Nilsson
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Abstract

We study the effects of explicit spacetime-symmetry breaking on primordial tensor fluctuations using an effective-field theory for Lorentz/CPT violation. We find that the graviton is still massless, but that the propagation speed of tensor modes is modified, and we obtain a constraint on the coefficient determining the symmetry breaking on the order of $10^{-15}$ from the recent measurements of the speed of gravity. Due to the symmetry breaking, the de-Sitter phase is modified, and during this inflationary epoch, the power spectrum assumes a slow oscillation around the general-relativity limit; further, we find that the primordial tensor power spectrum retains its scale invariance, but that the amplitude is modified. We also find that the modes which become subhorizon during radiation domination acquire a phase shift proportional to the coefficient for Lorentz violation.

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Nils A. Nilsson. 2022-10-27. Explicit spacetime-symmetry breaking and the dynamics of primordial fields. https://doi.org/10.1103/physrevd.106.104036

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