2022/12/30 by Pavel Jiroušek, Keigo Shimada, Jiroušek, Pavel +5
Earth and Planetary Sciences · Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Geophysics and Gravity Measurements #High Energy Physics - Theory (hep-th) #Solar and Space Plasma Dynamics
paper · pdf · doi:10.48550/arxiv.2212.14867
openalex publication_date 2022/12/30 · openalex created_date 2023/01/06 · openalex updated_date 2026/07/28
We propose a new non-trivial way to combine mimetic dark matter with the mimetic formulation of unimodular gravity. This yields a Weyl-invariant higher-derivative scalar-vector-tensor theory. We demonstrate that on-shell its behavior mimics GR with an additional k-essence scalar. The overall scale of the k-essence arises as an integration constant -- a global degree of freedom. Interestingly, we find that the resulting fluid cannot make transition through ultra-relativistic equation of state. We develop a method to find a mimetic theory corresponding to any eligible k-essence and identify, which k-essences can or cannot be reproduced this way. Finally, we show that abandoning the Weyl symmetry of the setup allows us to obtain both unimodular gravity and mimetic dark matter simultaneously, from one conformal redefinition of the metric.