We study aspects of holographic superconductors analytically in the presence of a constant external magnetic field. It is shown that the critical temperature and the critical magnetic field can be calculated at nonzer...We study aspects of holographic superconductors analytically in the presence of a constant external magnetic field. It is shown that the critical temperature and the critical magnetic field can be calculated at nonzero temperature. We detect the Meissner effect in such superconductors. A universal relation between black hole mass and critical magnetic field Hc is proposed to be Hc/M2/3≤0.687365. We also discuss some aspects of phase transition in terms of black hole entropy and Bekenstein＇s entropy to the energy upper bound.展开更多
We investigated some Friedmann-Lemaître-Robertson-Walker(FLRW)cosmological models in the context of metric-affine F(R,Q)gravity,as proposed in[arXiv:1205.5266v6].Here,R and Q are the curvature and nonmetricity sc...We investigated some Friedmann-Lemaître-Robertson-Walker(FLRW)cosmological models in the context of metric-affine F(R,Q)gravity,as proposed in[arXiv:1205.5266v6].Here,R and Q are the curvature and nonmetricity scalars using non-special connections,respectively.We obtained the modified field equations using a flat FLRW metric.We then found a connection between the Hubble constant H_(0),density parameter Ω_(m0),and other model parameters in two different situations involving scalars u and w.Next,we used new observational datasets,such as the cosmic chronometer(CC)Hubble and Pantheon SNe Ia datasets,to determine the optimal model parameter values through a Markov chain Monte Carlo(MCMC)analysis.Using these best-fit values of the model parameters,we discussed the results and behavior of the derived models.Further,we discussed the Akaike information criterion(AIC)and Bayesian information criterion(BIC)for the derived models in the context of the Lambda cold dark matter(ΛCDM).We found that the geometrical sector dark equation of state parameter ω_(de)behaves just like a dark energy candidate.We also found that both models are transit phase models.Model-Ⅰ approaches the ΛCDM model in the late-time universe,whereas Model-Ⅱ approaches quintessence scenarios.展开更多
文摘We study aspects of holographic superconductors analytically in the presence of a constant external magnetic field. It is shown that the critical temperature and the critical magnetic field can be calculated at nonzero temperature. We detect the Meissner effect in such superconductors. A universal relation between black hole mass and critical magnetic field Hc is proposed to be Hc/M2/3≤0.687365. We also discuss some aspects of phase transition in terms of black hole entropy and Bekenstein＇s entropy to the energy upper bound.
基金Supported by the Ministry of Science and Higher Education of the Republic of Kazakhstan(AP14870191)。
文摘We investigated some Friedmann-Lemaître-Robertson-Walker(FLRW)cosmological models in the context of metric-affine F(R,Q)gravity,as proposed in[arXiv:1205.5266v6].Here,R and Q are the curvature and nonmetricity scalars using non-special connections,respectively.We obtained the modified field equations using a flat FLRW metric.We then found a connection between the Hubble constant H_(0),density parameter Ω_(m0),and other model parameters in two different situations involving scalars u and w.Next,we used new observational datasets,such as the cosmic chronometer(CC)Hubble and Pantheon SNe Ia datasets,to determine the optimal model parameter values through a Markov chain Monte Carlo(MCMC)analysis.Using these best-fit values of the model parameters,we discussed the results and behavior of the derived models.Further,we discussed the Akaike information criterion(AIC)and Bayesian information criterion(BIC)for the derived models in the context of the Lambda cold dark matter(ΛCDM).We found that the geometrical sector dark equation of state parameter ω_(de)behaves just like a dark energy candidate.We also found that both models are transit phase models.Model-Ⅰ approaches the ΛCDM model in the late-time universe,whereas Model-Ⅱ approaches quintessence scenarios.
