Speaker
Description
A violation of the diffeomorphism (Diff) invariance generically induces an additional degree of freedom. In Horava-Lifshitz (HL) gravity, where the 4D Diff invariance is broken into the foliation preserving Diff, there appears a scalar degree of freedom in the gravity sector, Khronon, which describes the degree of freedom for the time foliation. One may naively expect that during inflation, we need to solve a mixed system with the inflaton and Khronon. By contrast, we find that in the non-projectable version of HL gravity, Khronon acquires a mass which is much larger than the Hubble scale and is decoupled from the adiabatic perturbation, which is sourced by the inflaton. As a result, we obtain a robust prediction for the spectrum of the adiabatic perturbation generated in the Lifshitz regime of gravity. We also discuss a possible imprint of the Lorentz violation in the early universe.
| Presentation type | Parallel talk |
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