Unimodular-Mimetic Cosmology

Abstract

We combine the unimodular gravity and mimetic gravity theories into a unified theoretical framework, which is proposed to provide a suggestive proposal for a framework that may assist in the discussion and solution search of the cosmological constant problem and of the dark matter issue. After providing the formulation of the unimodular mimetic gravity and investigating all the new features that the vacuum unimodular gravity implies, by using the underlying reconstruction method, we realize some well known cosmological evolutions, with some of these being exotic for the ordinary Einstein-Hilbert gravity. Specifically we provide the vacuum unimodular mimetic gravity description of the de Sitter cosmology and of the perfect fluid with constant equation of state cosmology. As we demonstrate, these cosmologies can be realized by vacuum mimetic unimodular gravity, without the existence of any matter fluid source. Moreover, we investigate how cosmologically viable cosmologies, which are compatible with the recent observational data, can be realized by the vacuum unimodular mimetic gravity. Since in some cases, the graceful exit from inflation problem might exist, we provide a qualitative description of the mechanism that can potentially generate the graceful exit from inflation in these theories, by searching for the unstable de Sitter solutions in the context of unimodular mimetic theories of gravity.

CQG accepted

References in corpus (10)

• Inflationary cosmology in modified gravity theories
• Transverse Fierz-Pauli symmetry
• Mimetic $F(R)$ gravity: inflation, dark energy and bounce
• Inflationary universe from perfect fluid and $F(R)$ gravity and its comparison with observational data
• Dark energy from modified gravity with Lagrange multipliers
• Direct Detection of Dark Matter Rates for Various Wimps
• Accelerating Cosmology and Phase Structure of F(R) Gravity with Lagrange Multiplier Constraint: Mimetic Approach
• The bounce universe history from unimodular $F(R)$ gravity
• Gauss-Bonnet dark energy by Lagrange multipliers
• Mimetic $F(R)$ inflation confronted with Planck and BICEP2/Keck Array data

Cited by in corpus (40)

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• Covariant Horava-like and mimetic Horndeski gravity: cosmological solutions and perturbations
• Alive and well: mimetic gravity and a higher-order extension in light of GW170817
• Mimicking dark matter and dark energy in a mimetic model compatible with GW170817
• Recovering a MOND-like acceleration law in mimetic gravity
• Finite-time Cosmological Singularities and the Possible Fate of the Universe
• On (in)stabilities of perturbations in mimetic models with higher derivatives
• Ghost-Free $F(R)$ Gravity with Lagrange Multiplier Constraint
• Late time cosmological approach in mimetic $f(R,T)$ gravity
• Braneworld Mimetic Cosmology
• Unimodular $f(R,T)$ Gravity
• Thick branes with inner structure in mimetic gravity
• Thick branes with inner structure in mimetic $f(R)$ gravity
• Two-field mimetic gravity revisited and Hamiltonian analysis
• Analyzing modified unimodular gravity via Lagrange multipliers
• Modifications of gravity via differential transformations of field variables
• Mimetic Inflation
• Inflation and the cosmological (not-so) constant in unimodular gravity
• A clarification on prevailing misconceptions in unimodular gravity
• Reheating and particle creation in unimodular f(R, T) gravity
• Nonconservative traceless type gravity
• Direct couplings of mimetic dark matter and their cosmological effects
• Reissner Nordstrom Metric in Unimodular Theory of Gravity
• Hamiltonian analysis of Mimetic gravity with higher derivatives
• Multi-field Mimetic Gravity
• Black holes with Lagrange multiplier and potential in mimetic-like gravitational theory: multi-horizon black holes
• Cosmological perturbations in a class of fully covariant modified theories: Application to models with the same background as standard LQC
• De Sitter and power-law solutions in some models of modified gravity
• Reconstruction of inflationary scenarios in non-conservative unimodular gravity
• Cosmology of unimodular Born-Infeld-$f(R)$ gravity
• Extensions of two-field mimetic gravity
• Mimetic-$f(Q)$ gravity: cosmic reconstruction and energy conditions
• Higgs Inflation in Unimodular Gravity
• Holographic description of unified early and late universe in viscous mimetic gravity
• Gravitational relaxation of electroweak hierarchy problem
• Unimodular Theory of Gravity in Light of the Latest Cosmological Data
• Matter production effects and interacting scenario within a reconstructed mimetic cosmology for late times
• Cosmology in the mimetic higher-curvature $f(R,R_{\mu \nu }{R}^{\mu \nu })$ gravity