排序方式: 共有48条查询结果,搜索用时 62 毫秒
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Mubasher Jamil D. Momeni Ratbay Myrzakulov 《The European Physical Journal C - Particles and Fields》2012,72(3):1-10
We present the results of three-dimensional simulations of quasar polarizations in the presence of pseudoscalar?Cphoton mixing in the intergalactic medium. The intergalactic magnetic field is assumed to be uncorrelated in wave vector space but correlated in real space. Such a field may be obtained if its origin is primordial. Furthermore we assume that the quasars, located at cosmological distances, have negligible initial polarization. In the presence of pseudoscalar?Cphoton mixing we show, through a direct comparison with observations, that this may explain the observed large scale alignments in quasar polarizations within the framework of big bang cosmology. We find that the simulation results give a reasonably good fit to the observed data. 相似文献
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D. Momeni M. Raza H. Gholizade R. Myrzakulov 《International Journal of Theoretical Physics》2016,55(11):4751-4758
Computing the holographic entanglement entropy proposed by Ryu-Takayanagi shows that thermal energy near boundary region in AdS3 gain maximum of the temperature. The absolute maxima of temperature is \(T^{Max}_{E}= \frac {4G_{3} \epsilon _{\infty }}{l}\). By simple physical investigations it has become possible to predict a phase transition of first order at critical temperature Tc ≤ TE. As they predict a tail or root towards which the AdS space ultimately tend, the boundary is considered thermalized. The Phase transitions of this form have received striking theoretical and experimental verifications so far. 相似文献
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Mubasher Jamil D. Momeni Ratbay Myrzakulov 《International Journal of Theoretical Physics》2013,52(9):3283-3294
In this paper, we have calculated the statefinder parameters for the Friedmann-Robertson-Walker (FRW) Universe in the gravitational framework of loop quantum cosmology (LQC). As examples, we study two types of dark energy models namely Holographic dark energy and New-Agegraphic dark energy. 相似文献
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Davood Momeni Muhammad Raza Mohammad Reza Setare Ratbay Myrzakulov 《International Journal of Theoretical Physics》2013,52(8):2773-2783
The holographic model for a two-dimensional superconductor has been investigated by considering the three-dimensional gravity in the bulk. To find the critical temperature, we used the Sturm–Liouville variational method. Where as the same method is applied for calculating the condensation of the dual operators on the boundary. We included the back reactions on the metric by a combination of the perturbation method of the fields with respect to the small parameter and then applying the variational integrals on the resulting equations of the motion. The critical temperature has been successfully obtained on the backreaction effects, and we showed that it dropped with a rise in the backreaction of the fields, and it makes the condensation harder. We can use our analytical results to support the numerical data which was reported previously. 相似文献
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Alessandro Bravetti Davood Momeni Ratbay Myrzakulov Hernando Quevedo 《General Relativity and Gravitation》2013,45(8):1603-1617
We study the thermodynamics and geometrothermodynamics of different black hole configurations in more than four spacetime dimensions. We use the response functions to find the conditions under which second order phase transitions occur in higher-dimensional static Reissner–Nordström and stationary Kerr black holes. Our results indicate that the equilibrium manifold of all these black hole configurations is in general curved and that curvature singularities appear exactly at those places where second order phase transitions occur. 相似文献
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Ratbay Myrzakulov 《General Relativity and Gravitation》2012,44(12):3059-3080
Modified teleparallel gravity theory with the torsion scalar has recently gained a lot of attention as a possible candidate of dark energy. We perform a thorough reconstruction analysis on the so-called $F(T)$ models, where $F(T)$ is some general function of the torsion term. We derive conditions for the equivalence between of $F(T)$ models with purely kinetic k-essence. We present a new class models of $F(T)$ gravity and k-essence. 相似文献
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P. Y. Tsyba I. I. Kulnazarov K. K. Yerzhanov R. Myrzakulov 《International Journal of Theoretical Physics》2011,50(6):1876-1886
In this paper, we consider three types of k-essence. These k-essence models were presented in the parametric forms. The exact
analytical solutions of the corresponding equations of motion are found. It is shown that these k-essence models for the presented
solutions can give rise to cosmic acceleration. 相似文献