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Kairat Myrzakulov

Publications and source records attributed to Kairat Myrzakulov.

30 records · Page 2Linked to original sources
arXiv2018

Quintessential Inflation and curvaton reheating

In this paper, we consider a model of quintessential inflation based upon inverse hyperbolic potential. We employ curvaton mechanism for reheating which is more efficient than gravitational particle production; the mechanism complies with nucleosynthesis constraint due to relic gravity waves. We obtain a lower bound on the coupling constant $g$ that governs the interaction of curvaton with matter fields. We study curvaton decay before domination and decay after domination and plot the allowed region in the parameter space in both cases.

gr-qc↗
arXiv2017

Starobinsky model with f-essence

In this paper, we consider a cosmological model of the flat and homogeneous universe for the Starobinsky model $F(R)=αR + βR^{2}$, which is non-minimally coupled with f-essence. For this model we obtained the field equations and considered particular solutions of the coupling and fermionic field functions. It is shown that the fermionic field can describe a nature of the universe.

gr-qc↗
arXiv2016

Compact Stars in Vector-Tensor-Horndeski Theory of Gravity

In this paper, we will analyse a theory of modified gravity, in which the field content of general relativity will be increased to include a vector field. We will use the Horndeski formalism to non-minimally couple this vector field to the metric. As we will be using the Horndeski formalism, this theory will not contain Ostrogradsky ghost degree of freedom. We will analyse compact stars using this Vector-Tensor-Horndeski theory.

physics.gen-ph↗
arXiv2016

Fidelity Susceptibility as Holographic PV-Criticality

It is well known that entropy can be used to holographically establish a connection between geometry, thermodynamics and information theory. In this paper, we will use complexity to holographically establish a connection between geometry, thermodynamics and information theory. Thus, we will analyse the relation between holographic complexity, fidelity susceptibility, and thermodynamics in extended phase space. We will demonstrate that fidelity susceptibility (which is the informational complexity dual to a maximum volume in AdS) can be related to the thermodynamical volume (which is conjugate to the cosmological constant in the extended thermodynamic phase space). Thus, this letter establishes a relation between geometry, thermodynamics, and information theory, using complexity.

hep-th↗
arXiv2016

Cylindrical solutions in Mimetic gravity

This paper is devoted to investigate cylindrical solutions in mimetic gravity. The explicit forms of the metric of this theory, namely mimetic-Kasner (say) have been obtained. In this study we have noticed that the Kasner's family of exact solutions needs to be reconsidered under this type of modified gravity. A no-go theorem is proposed for the exact solutions in the presence of a cosmological constant.

gr-qc↗
arXiv2016

Phase transition via entanglement entropy in $AdS_3/CFT_2$ superconductors

The purpose of this report is to provide a framework for defining phase transition processes in two dimensional holographic superconductors, and to illustrate how they are useful to be described by holographic entanglement entropy. We study holographic entanglement entropy in a two dimensional fully backrected model for holographic superconductors. We prove that phase transition could be observe using a discontinuty in the first order of entropy.

hep-th↗
arXiv2016

Noether symmetry in $F(T)$ gravity with $f$-essence

In $F(T)$ gravity theory, a Friedman-Robertson-Walker cosmological model with $f$-essence where fermion field is non-minimally coupled with the gravitational field is studied. Using the Noether symmetry approach the possible forms of $F(T)$ gravity and the non-canonical fermionic lagrangian $K$ are determined. Cosmological solutions of the condered models describing the accelerated and decelerated periods of the universe are found.

physics.gen-ph↗
arXiv2015

Mimetic Attractors

In this paper, we investigate the mathematical modeling for the cosmological attractors propagated in mimetic gravity upon which an interacting dark energy-dark matter is supposed to be existed. The average value of the interaction of these percentages, namely $Γ_i$ say, may be used to investigate generally the modeling of an attractor; the actual value could only be determined by data in any particular case. We have seen, for example, that it was led to investigate the subject of initially invariant submanifolds.

gr-qc↗
arXiv2011

FRW cosmological models with integrable and nonintegrable differential equations of state

The basic models of modern cosmology work in FRW spacetime. Hence follows that it is important to study the physical and mathematical nature of FRW cosmological models. In this work, we consider FRW models with the differential equations of state. Some new classes integrable and nonintegrable FRW cosmological models were constructed. It is remarkable that all proposed integrable and nonintegrable FRW models admit exact solutions. For some of them, such exact solutions are presented. Some artificial two-dimensional FRW models were also proposed. Finally in Appendix, we extend the obtained results for g-essence models and for its two reductions: k-essence and f-essence.

physics.gen-ph↗
arXiv2007

Thick brane in 7D and 8D spacetimes

We consider a thick brane model supported by two interacting scalar fields in 7D and 8D general relativity. Using the special type of a potential energy, we obtain numerically the regular asymptotically flat vacuum solutions. A possibility of obtaining the similar solutions for an arbitrary number of the extra spatial dimensions is estimated.

gr-qc↗
arXiv2007

Phantom fields: bounce solutions in the early Universe and S-branes

The cosmological model with two phantom scalar fields with the special choice of field's potential is considered. The obtained regular solution describes a bounce with a subsequent transition to the de Sitter stage of the expansion of the Universe. This solution also could be interpreted as a S-brane solution.

gr-qc↗