Direct couplings of mimetic dark matter and their cosmological effects

Shen, Liuyuan; Mou, Yicen; Zheng, Yunlong; Li, Mingzhe

doi:10.1088/1674-1137/42/1/015101

Cited by 12 publications

(11 citation statements)

References 66 publications

(92 reference statements)

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“…This generalized mimetic model has many applications in cosmology, and can provide us inflation, dark energy, bounce and so on with appropriate choice of the potential V (φ). The mimetic constraint can also be applied in various modified gravity models [8][9][10][11][12][13][14][15][16][17][18][19], and mimetic gravity has attracted extensive astrophysical and cosmological interests [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. The Hamiltonian analysis of various mimetic models have also been investigated in refs.…”

Section: Introductionmentioning

confidence: 99%

Hamiltonian analysis of Mimetic gravity with higher derivatives

Zheng

2021

J. High Energ. Phys.

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Two types of mimetic gravity models with higher derivatives of the mimetic field are analyzed in the Hamiltonian formalism. For the first type of mimetic gravity, the Ricci scalar only couples to the mimetic field and we demonstrate the number of degrees of freedom (DOFs) is three. Then in both Einstein frame and Jordan frame, we perform the Hamiltonian analysis for the extended mimetic gravity with higher derivatives directly coupled to the Ricci scalar. We show that different from previous studies working at the cosmological perturbation level, where only three propagating DOFs show up, this generalized mimetic model, in general, has four DOFs. To understand this discrepancy, we consider the unitary gauge and find out that the number of DOFs reduces to three. We conclude that the reason why this system looks peculiar is that the Dirac matrix of all secondary constraints becomes singular in the unitary gauge, resulting in extra secondary constraints and thus reducing the number of DOFs. Furthermore, we give a simple example of a dynamic system to illustrate how gauge choice can affect the number of secondary constraints as well as the DOFs when the rank of the Dirac matrix is gauge dependent.

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Section: Introductionmentioning

confidence: 99%

Hamiltonian analysis of Mimetic gravity with higher derivatives

Zheng

2021

J. High Energ. Phys.

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“…As commented in [12], the role of the Lagrange multiplier in the mimetic gravity formulation is to mimic a matter sector contribution that deviates from the standard behavior, 3 , given that we are considering the inclusion of a potential for the mimetic field. The explicit expression for the Lagrange multiplier is given in (11). One could assume that the observed deviation from the usual term can be due to an possible interaction of the matter sector with other components.…”

Section: Second Scenario: Interaction In the Dark Sectormentioning

confidence: 99%

“…In Ref. [11] was found that these kind of interactions can be possible only with derivative couplings of the mimetic field, but, these interactions can have a direct impact on observables of our Universe such as the CMB.…”

Section: Introductionmentioning

confidence: 99%

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

Cárdenas,

Cruz,

Lepe

2021

Preprint

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In this work we explore two possible scenarios that can be considered in 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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“…In Ref. [20] was found that these kind of interactions can be possible only with derivative couplings of the mimetic field, but, these interactions can have a direct impact on observables of our Universe such as the CMB.…”

Section: Introductionmentioning

confidence: 99%

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

2021

View full text Add to dashboard Cite

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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Direct couplings of mimetic dark matter and their cosmological effects

Cited by 12 publications

References 66 publications

Hamiltonian analysis of Mimetic gravity with higher derivatives

Hamiltonian analysis of Mimetic gravity with higher derivatives

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

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

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