Vector and tensor perturbations in Horava-Lifshitz cosmology - High Energy Physics - TheoryReport as inadecuate




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Abstract: We study cosmological vector and tensor perturbations in Horava-Lifshitzgravity, adopting the most general Sotiriou-Visser-Weinfurtner generalizationwithout the detailed balance but with projectability condition. After derivingthe general formulas in a flat FRW background, we find that the vectorperturbations are identical to those given in general relativity. This is truealso in the non-flat cases. For the tensor perturbations, high orderderivatives of the curvatures produce effectively an anisotropic stress, whichcould have significant efforts on the high-frequency modes of gravitationalwaves, while for the low-frenquency modes, the efforts are negligible. Thepower spectrum is scale-invariant in the UV regime, because of the particulardispersion relations. But, due to lower-order corrections, it will eventuallyreduce to that given in GR in the IR limit. Applying the general formulas tothe de Sitter and power-law backgrounds, we calculate the power spectrum andindex, using the uniform approximations, and obtain their analyticalexpressions in both cases.



Author: Anzhong Wang

Source: https://arxiv.org/







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