Mimetic gravity: mimicking the dynamics of the primeval universe in the context of loop quantum cosmology

Bezerra, Eunice; Miranda, Oswaldo D.

doi:10.1140/epjc/s10052-019-6823-3

Cited by 8 publications

(7 citation statements)

References 50 publications

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“…As an example, current models of limiting curvature mimetic gravity exactly yield the cosmological background equations of LQC (see, e.g., Refs. [19][20][21][22][23][24][25][26], as well as Refs. [27][28][29][30] in other quantum gravity contexts).…”

Section: Introductionmentioning

confidence: 91%

Theories with limited extrinsic curvature and a nonsingular anisotropic universe

et al. 2020

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We propose a class of theories that can limit scalars constructed from the extrinsic curvature. Applied to cosmology, this framework allows us to control not only the Hubble parameter but also anisotropies without the problem of Ostrogradsky ghost, which is in sharp contrast to the case of limiting spacetime curvature scalars. Our theory can be viewed as a generalization of mimetic and cuscuton theories (thus clarifying their relation), which are known to possess a structure that limits only the Hubble parameter on homogeneous and isotropic backgrounds. As an application of our framework, we construct a model where both anisotropies and the Hubble parameter are kept finite at any stage in the evolution of the universe in the diagonal Bianchi type I setup. The universe starts from a constant-anisotropy phase and recovers Einstein gravity at low energies. We also show that the cosmological solution is stable against a wide class of perturbation wave numbers, though instabilities may remain for arbitrary initial conditions.

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Section: Introductionmentioning

confidence: 91%

Theories with limited extrinsic curvature and a nonsingular anisotropic universe

et al. 2020

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“…from now on we choose the value a 0 = 1. Notice that ω mg (z = 0) = ω mg (a = a 0 ) = ω 0 , which will represent the value at present time for the parameter state (8). Finally, from the expression, ρ mg = λ + V , we find for the Lagrange multiplier…”

Section: Reconstructed Mimetic Cosmologymentioning

confidence: 97%

“…In fact, the mimetic scenario is also viable to describe the early universe, the role of the mimetic scalar field and the curvature invariant in the context of loop quantum gravity is discussed in Refs. [7,8]. The mimetic approach was also adapted for higher dimensional objects also known as branes [9,10].…”

Section: Introductionmentioning

confidence: 99%

Matter production effects and interacting scenario within a reconstructed mimetic cosmology for late times

2021

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In this work we explore two possible scenarios that can be considered to extend a recent proposed model by the authors known as reconstructed mimetic cosmology. This study is complemented with an statistical analysis for each case. The first scenario considers the inclusion of matter production as a possible source of cosmic expansion in the reconstructed mimetic model, at effective level was found that this construction can cross the phantom divide, the model evolves from quintessence to phantom dark energy. The second scenario corresponds to a construction of an interacting scheme for the dark sector which is described by the unified mimetic model. The resulting interaction term (not imposed by an Ansatz), Q, exhibits changes of sign leading to the violation of the second law along the cosmic evolution and non adiabaticity; the temperatures for the components of the dark sector are computed and such components are shown to be out of thermal equilibrium.

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“…As a consequence, the conformal degree of freedom turns out to be dynamical, even in the absence of the standard matter fluids, and may mimic behavior of the cold dark matter. It is worth to remark here, that the mimetic theory has been recently extensively studied in various contexts [36,37,38,39,40,41,42,43,44]. Moreover, the mimetic approach has been combined with other modifications of gravity, such as f (R), f (G) or f (R, T ) theories with emphasis on the cosmological applications [45,46,47,48,49,50,51,52].…”

Section: Introductionmentioning

confidence: 99%

Cosmology in the mimetic higher-curvature $f(R, R_{μν}R^{μν})$ gravity

Kaczmarek,

Szczęśniak

2021

Preprint

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In the framework of the mimetic approach, we study the f (R, Rµν R µν ) gravity with the Lagrange multiplier constraint and the scalar potential. We introduce field equations for the discussed theory and overview their properties. By using the general reconstruction scheme we obtain the power law cosmology model for the f (R, Rµν R µν ) = R + d(Rµν R µν ) p case as well as the model that describes symmetric bounce. Moreover, we reconstruct model, unifying both matter dominated and accelerated phases, where ordinary matter is neglected. Using inverted reconstruction scheme we recover specific f (R, Rµν R µν ) function which give rise to the de-Sitter evolution. Finally, by employing the perfect fluid approach, we demonstrate that this model can realize inflation consistent with the bounds coming from the BICEP2/Keck array and the Planck data. Thus, it is suggested that the introduced extension of the mimetic regime may describe any given cosmological model.

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Mimetic gravity: mimicking the dynamics of the primeval universe in the context of loop quantum cosmology

Cited by 8 publications

References 50 publications

Theories with limited extrinsic curvature and a nonsingular anisotropic universe

Theories with limited extrinsic curvature and a nonsingular anisotropic universe

Matter production effects and interacting scenario within a reconstructed mimetic cosmology for late times

Cosmology in the mimetic higher-curvature $f(R, R_{μν}R^{μν})$ gravity

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