arXiv subjects

Qiyuan Pan

Publications and source records attributed to Qiyuan Pan.

100 records · Page 6Linked to original sources

arXiv2010

Holographic Superconductors with various condensates in Einstein-Gauss-Bonnet gravity

We study holographic superconductors in Einstein-Gauss-Bonnet gravity. We consider two particular backgrounds: a $d$-dimensional Gauss-Bonnet-AdS black hole and a Gauss-Bonnet-AdS soliton. We discuss in detail the effects that the mass of the scalar field, the Gauss-Bonnet coupling and the dimensionality of the AdS space have on the condensation formation and conductivity. We also study the ratio $ω_g/T_c $ for various masses of the scalar field and Gauss-Bonnet couplings.

hep-th↗

arXiv2009

Entanglement of coupled massive scalar field in background of dilaton black hole

The entanglement of the coupled massive scalar field in the spacetime of a Garfinkle-Horowitz-Strominger(GHS) dilaton black hole has been investigated. It is found that the entanglement does not depend on the mass of the particle and the coupling between the scalar field and the gravitational field, but it decreases as the dilaton parameter $D$ increases. It is interesting to note that in the limit of $D\to M$, corresponding to the case of an extreme black hole, the state has no longer distillable entanglement for any state parameter $α$, but the mutual information equals to a nonvanishing minimum value, which indicates that the total correlations consist of classical correlations plus bound entanglement in this limit.

gr-qc↗

arXiv2008

Wave dynamics of phantom scalar perturbation in the background of Schwarzschild black hole

Using Leaver's continue fraction and time domain method, we investigate the wave dynamics of phantom scalar perturbation in the background of Schwarzschild black hole. We find that the presence of the negative kinetic energy terms modifies the standard results in quasinormal spectrums and late-time behaviors of the scalar perturbations. The phantom scalar perturbation in the late-time evolution will grow with an exponential rate.

gr-qc↗

arXiv2008

Hawking radiation, Entanglement and Teleportation in background of an asymptotically flat static black hole

The effect of the Hawking temperature on the entanglement and teleportation for the scalar field in a most general, static and asymptotically flat black hole with spherical symmetry has been investigated. It is shown that the same "initial entanglement" for the state parameter $α$ and its "normalized partners" $\sqrt{1-α^{2}}$ will be degraded by the Hawking effect with increasing Hawking temperature along two different trajectories except for the maximally entangled state. In the infinite Hawking temperature limit, corresponding to the case of the black hole evaporating completely, the state has no longer distillable entanglement for any $α$. It is interesting to note that the mutual information in this limit equals to just half of the "initially mutual information". It has also been demonstrated that the fidelity of teleportation decreases as the Hawking temperature increases, which just indicates the degradation of entanglement.

gr-qc↗

arXiv2008

Degradation of non-maximal entanglement of scalar and Dirac fields in non-inertial frames

The entanglement between two modes of the free scalar and Dirac fields as seen by two relatively accelerated observers has been investigated. It is found that the same initial entanglement for an initial state parameter $α$ and its "normalized partner" $\sqrt{1-α^{2}}$ will be degraded by the Unruh effect along two different trajectories except for the maximally entangled state, which just shows the inequivalence of the quantization for a free field in the Minkowski and Rindler coordinates. In the infinite acceleration limit the state doesn't have the distillable entanglement for any $α$ for the scalar field but always remains entangled to a degree which is dependent of $α$ for the Dirac field. It is also interesting to note that in this limit the mutual information equals to just half of the initially mutual information, which is independent of $α$ and the type of field.

quant-ph↗

arXiv2008

Quasinormal modes and second order thermodynamic phase transition for Reissner-Nordström black hole

The relation between the quasinormal modes (QNMs) and the second order thermodynamic phase transition (SOTPT) for the Reissner-Nordström (RN) black hole is studied. It is shown that the quasinormal frequencies of the RN black hole start to get a spiral-like shape in the complex $ω$ plane and both the real and imaginary parts become the oscillatory functions of the charge if the real part of the quasinormal frequencies arrives at its maximum at the second order phase transition point of Davies for given overtone number and angular quantum number. That is to say, we can find out the SOTPT point from the QNMs of the RN black hole. The fact shows that the quasinormal frequencies carry the thermodynamical information of the RN black hole.

gr-qc↗

arXiv2008

Evolution of arbitrary spin fields in the Schwarzschild-monopole spacetime

The quasinormal modes (QNMs) and the late-time behavior of arbitrary spin fields are studied in the background of a Schwarzschild black hole with a global monopole (SBHGM). It has been shown that the real part of the QNMs for a SBHGM decreases as the symmetry breaking scale parameter $H$ increases but imaginary part increases instead. For large overtone number $n$, these QNMs become evenly spaced and the spacing for the imaginary part equals to $-i(1-H)^{3/2}/(4M)$ which is dependent of $H$ but independent of the quantum number $l$. It is surprisingly found that the late-time behavior is dominated by an inverse power-law tail $t^{-2[1+\sqrt{(s+1/2)^{2}+ (l-s)(l+s+1)/(1-H)}]}$ for each $l$, and as $H\to0$ it reduces to the Schwarzschild case $t^{-(2l+3)}$ which is independent of the spin number $s$.

gr-qc↗

arXiv2005

Dirac Quasinormal frequencies of the Kerr-Newman black hole

The Dirac quasinormal modes (QNMs) of the Kerr-Newman black hole are investigated using continued fraction approach. It is shown that the quasinormal frequencies in the complex $ω$ plane move counterclockwise as the charge or angular momentum per unit mass of the black hole increases. They get a spiral-like shape, moving out of their Schwarzschild or Reissner-Nordström values and "looping in" towards some limiting frequencies as the charge and angular momentum per unit mass tend to their extremal values. The number of the spirals increases as the overtone number increases but decreases as the angular quantum number increases. It is also found that both the real and imaginary parts are oscillatory functions of the angular momentum per unit mass, and the oscillation becomes faster as the overtone number increases but slower as the angular quantum number increases.

gr-qc↗

arXiv2005

Dirac quasinormal frequencies of Reissner-Nordström black hole in Anti-de Sitter spacetime

The quasinormal modes (QNMs) of Dirac field perturbations of a Reissner-Nordström black hole in an asymptotically Anti-de Sitter spacetime are investigated. We find that both the real and imaginary parts of the fundamental quasinormal frequencies for large black holes are the linear functions of the Hawking temperature, and the slope of the lines for the real parts decreases while that for the magnitude of the imaginary parts increases as the black hole charge increases. According to the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence, the fact shows that different charge presents different time scale in three-dimensional CFT. Another interesting result is that the quasinormal frequencies become evenly spaced for high overtone number, and in the spacing expressions the real part decreases while the magnitude of the imaginary part increases as the charge increases. We also study the relation between quasinormal frequencies and angular quantum number and find that the real part increases while the magnitude of the imaginary part decreases as the angular quantum number increases.

gr-qc↗

arXiv2004

Asymptotic tails of massive scalar fields in a stationary axisymmetric EMDA black hole geometry

The late-time tail behavior of massive scalar fields is studied analytically in a stationary axisymmetric EMDA black hole geometry. It is shown that the asymptotic behavior of massive perturbations is dominated by the oscillatory inverse power-law decaying tail $ t^{-(l+3/2)}\sin(μt)$ at the intermediate late times, and by the asymptotic tail $ t^{-5/6}\sin(μt)$ at asymptotically late times. Our result seems to suggest that the intermediate tails $ t^{-(l+3/2)}\sin(μt)$ and the asymptotically tails $t^{-5/6} \sin(μt)$ may be quite general features for evolution of massive scalar fields in any four dimensional asymptotically flat rotating black hole backgrounds.

gr-qc↗