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arXiv · 2203.00901

Cosmology and perturbations in tachyonic massive gravity

Amin Rezaei Akbarieh·Sobhan Kazempour·Lijing Shao
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Abstract

As massive gravity and its extensions offer physically well-defined gravitational theories with a nonzero graviton mass, we present a new extension of the de Rham-Gabadadze-Tolley (dRGT)massive gravity, which is tachyonic massive gravity theory. We firstly introduce the new extension of the dRGT massive gravity, constructed by adding a tachyonic term. We then find the cosmological background equations, and present the analysis of self-accelerating solutions. We examine the tensor perturbations to calculate the dispersion relation of gravitational waves (GWs). In a special case, we consider a constant tachyon potential for the tachyon field, and calculate the equations of motion and self-accelerating solutions. Finally, we investigate the background perturbations, which include tensor, vector, and scalar perturbations in this case. We calculate the dispersion relation of GWs in the FLRW cosmology in a tachyonic massive gravity theory. These analyses provide potential inputs to future applications in cosmology and GWs propagation.

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Amin Rezaei Akbarieh, Sobhan Kazempour, Lijing Shao. 2022-03-02. Cosmology and perturbations in tachyonic massive gravity. https://doi.org/10.1103/physrevd.105.023501

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