arXiv subjects

Qiyuan Pan

Publications and source records attributed to Qiyuan Pan.

At least 91 records · Page 5Linked to original sources

arXiv2013

Holographic insulator/superconductor phase transition with Weyl corrections

We analytically investigate the phase transition between the holographic insulator and superconductor with Weyl corrections by using the variational method for the Sturm-Liouville eigenvalue problem. We find that similar to the curvature corrections, in p-wave model, the higher Weyl couplings make the insulator/superconductor phase transition harder to occur. However, in s-wave case the Weyl corrections do not influence the critical chemical potential, which is in contrast to the effect caused by the curvature corrections. Moreover, we observe that the Weyl corrections will not affect the critical phenomena and the critical exponent of the system always takes the mean-field value in both models. Our analytic results are found to be in good agreement with the numerical findings.

hep-th↗

arXiv2013

Holographic superconductor models with $RF^{2}$ corrections

We investigate the effect of the $RF^2$ correction on the holographic superconductor model in the background of AdS black hole. We find that, similar to the effect caused by the Weyl correction, the higher $RF^2$ correction term can make it easier for the scalar operator to condense and result in the larger deviations from the expected relation in the gap frequency. However, if a non-trivial hair for the black hole has been triggered, we observe that the $RF^2$ correction and the Weyl correction do play different roles in the behavior of the condensation, which can be used to support the existing findings.

gr-qc↗

arXiv2012

Holographic Superconductor/Insulator Transition with logarithmic electromagnetic field in Gauss-Bonnet gravity

The behaviors of the holographic superconductors/insulator transition are studied by introducing a charged scalar field coupled with a logarithmic electromagnetic field in both the Einstein-Gauss-Bonnet AdS black hole and soliton. For the Einstein-Gauss-Bonnet AdS black hole, we find that: i) the larger coupling parameter of logarithmic electrodynamic field $b$ makes it easier for the scalar hair to be condensated; ii) the ratio of the gap frequency in conductivity $ω_g$ to the critical temperature $T_c$ depends on both $b$ and the Gauss-Bonnet constant $α$; and iii) the critical exponents are independent of the $b$ and $α$. For the Einstein-Gauss-Bonnet AdS Soliton, we show that the system is the insulator phase when the chemical potential $μ$ is small, but there is a phase transition and the AdS soliton reaches the superconductor (or superfluid) phase when $μ$ larger than critical chemical potential. A special property should be noted is that the critical chemical potential is not changed by the coupling parameter $b$ but depends on $α$.

hep-th↗

arXiv2012

Effects of quintessence on holographic p-wave superconductors

We construct a holographic p-wave superconductor model in the background of quintessence AdS black hole with an SU(2) Yang-Mills gauge field and then probe the effects of quintessence on the holographic p-wave superconductor. We investigate the relation between the critical temperature and the state parameter of quintessence, and present the numerical results for electric conductivity. It is shown that the condensation of the vector field becomes harder as the absolute value of the state parameter increases. Unlike the scalar condensate in the s-wave model, the condensation of the vector field in p-wave model can occur in the total value range of the state parameter $w_q$ of quintessence. These results could help us know more about holographic superconductor and dark energy.

gr-qc↗

arXiv2012

Analytical study on holographic superconductors with backreactions

We employ the variational method for the Sturm-Liouville eigenvalue problem to analytically investigate the properties of the holographic superconductors. We find that the analytic method is still powerful when the backreaction is turned on. Reducing step size in the iterative procedure, we observe that the consistency of results between the analytic and numerical computations can be further improved. The obtained analytic result can be used to back up the numerical computations in the holographic superconductor in the fully backreacted spacetime.

hep-th↗

arXiv2011

Holographic superconductor models with the Maxwell field strength corrections

We study the effect of the quadratic field strength correction to the usual Maxwell field on the holographic dual models in the backgrounds of AdS black hole and AdS soliton. We find that in the black hole background, the higher correction to the Maxwell field makes the condensation harder to form and changes the expected relation in the gap frequency. This effect is similar to that caused by the curvature correction. However, in the soliton background we find that different from the curvature effect, the correction to the Maxwell field does not influence the holographic superconductor and insulator phase transition.

gr-qc↗

arXiv2011

Analytical investigation of the phase transition between holographic insulator and superconductor in Gauss-Bonnet gravity

We employ the variational method for the Sturm-Liouville eigenvalue problem to analytically study the phase transition between the holographic insulator and superconductor in the Gauss-Bonnet gravity. By investigating the s-wave and p-wave holographic insulator/superconductor models, we find that this analytic method is more effective to obtain the analytic results on the condensation and the critical phenomena in the AdS soliton background in Gauss-Bonnet gravity. Our analytic result can be used to back up the numerical computations in the AdS soliton with Gauss-Bonnet correction.

gr-qc↗

arXiv2011

Holographic Superconductors with Power-Maxwell field

With the Sturm-Liouville analytical and numerical methods, we investigate the behaviors of the holographic superconductors by introducing a complex charged scalar field coupled with a Power-Maxwell field in the background of $d$-dimensional Schwarzschild AdS black hole. We note that the Power-Maxwell field takes the special asymptotical solution near boundary which is different from all known cases. We find that the larger power parameter $q$ for the Power-Maxwell field makes it harder for the scalar hair to be condensated. We also find that, for different $q$, the critical exponent of the system is still 1/2, which seems to be an universal property for various nonlinear electrodynamics if the scalar field takes the form of this paper.

hep-th↗

arXiv2011

Holographic superconductor developed in BTZ black hole background with backreactions

We develop a holographic superconductor in BTZ black hole background with backreactions. We investigate the influence of the backreaction on the condensation of the scalar hair and the dynamics of perturbation in the background spacetime. When the Breitenlohner-Freedman bound is approached, we argue that only one of two possible operators can reflect the real property of the condensation in the holographic superconductor. This argument is supported by the investigation in dynamics.

hep-th↗

arXiv2011

Various types of phase transitions in the AdS soliton background

We study the basic holographic insulator and superconductor phase transition in the AdS soliton background by generalizing the spontaneous breaking of a global U(1) symmetry to occur via St$\ddot{u}$ckelberg mechanism. We construct the soliton solutions with backreaction and examine the effects of the backreaction on the condensation of the scalar hair in the generalized St$\ddot{u}$ckelberg Lagrangian. We disclose rich physics in various phase transitions. In addition to the AdS soliton configuration, we also examine the property of the phase transition in the AdS black hole background.

hep-th↗

arXiv2011

Holographic Superconductors in Gauss-Bonnet gravity with Born-Infeld electrodynamics

We investigate the holographic superconductors in Gauss-Bonnet gravity with Born-Infeld electrodynamics. We find that the Gauss-Bonnet constant, the model parameters and the Born-Infeld coupling parameter will affect the formation of the scalar hair, the transition point of the phase transition from the second order to the first order, and the relation connecting the gap frequency in conductivity with the critical temperature. The combination of the Gauss-Bonnet gravity and the Born-Infeld electrodynamics provides richer physics in the phase transition and the condensation of the scalar hair.

gr-qc↗

arXiv2010

General holographic superconductor models with backreactions

We study general models of holographic superconductors away from the probe limit. We find that the backreaction of the spacetime can bring richer physics in the phase transition. Moreover we observe that the ratio $ω_g/T_c$ changes with the strength of the backreaction and is not a universal constant.

hep-th↗

arXiv2010

Holographic superconductor models in the non-minimal derivative coupling theory

We study a general class of holographic superconductor models via the Stückelberg mechanism in the non-minimal derivative coupling theory in which the charged scalar field is kinetically coupling to Einstein's tensor. We explore the effects of the coupling parameter on the critical temperature, the order of phase transitions and the critical exponents near the second-order phase transition point. Moreover, we compute the electric conductive using the probe approximation and check the ratios $ω_g/T_c$ for the different coupling parameters.

gr-qc↗

arXiv2010

Influence on the entropic force by the virtual degree of freedom on the holographic screen

We generalize the study of entropic force to a general static spherical spacetime and examine the acceleration, temperature, equation of gravity and the energy associated with the holographic screen in this general background. We show that the virtual degree of freedom on the holographic screen plays a crucial role in interpreting field equations of gravity based on thermodynamical perspective.

hep-th↗

arXiv2010

Dynamical perturbations and critical phenomena in Gauss-Bonnet-AdS black holes

We investigate the perturbations of charged scalar field in $5$-dimensional Gauss-Bonnet AdS black hole backgrounds. From the perturbation behaviors we obtain the objective picture on how the high curvature influence the spacetime perturbation and the condensation of the scalar hair. The high curvature effects can also be read from the linear response function such as the susceptibility and the correlation length, when the system approaches the critical point. We find that the Gauss-Bonnet term does not affect the critical exponents of the system and they still take the mean-field values.

hep-th↗

arXiv2010

General holographic superconductor models with Gauss-Bonnet corrections

We study general models for holographic superconductors in Einstein-Gauss-Bonnet gravity. We find that different values of Gauss-Bonnet correction term and model parameters can determine the order of phase transitions and critical exponents of second-order phase transitions. Moreover we find that the size and strength of the conductivity coherence peak can be controlled. The ratios $ω_g/Tc$ for various model parameters have also been examined.

hep-th↗

arXiv2010

Entanglement redistribution in the Schwarzschild spacetime

The effect of Hawking radiation on the redistribution of the entanglement and mutual information in the Schwarzschild spacetime is investigated. Our analysis shows that the physically accessible correlations degrade while the unaccessible correlations increase as the Hawking temperature increases because the initial correlations described by inertial observers are redistributed between all the bipartite modes. It is interesting to note that, in the limit case that the temperature tends to infinity, the accessible mutual information equals to just half of its initial value, and the unaccessible mutual information between mode $A$ and $II$ also equals to the same value.

quant-ph↗

arXiv2010

Projective measurements and generation of entangled Dirac particles in Schwarzschild Spacetime

It is shown that the projective measurements made by Bob who locates near the event horizon of the Schwarzschild black hole will create entangled particles detected by Alice who stays stationary at the asymptotically flat region. It is found that the degree of entanglement decreases as the frequency of the detected particles increases and approaches to zero as the frequency $ω_\mathbf{k} \to\infty$. It is also noted that the degree of entanglement increases as the Hawking temperature increases. Especially, the particle state is unentangled when the Hawking temperature is zero and approaches a maximally entangled Bell state when the black hole evaporates completely.

gr-qc↗