arXiv subjects

Wen-Yu Wen

Publications and source records attributed to Wen-Yu Wen.

At least 37 records · Page 2Linked to original sources

arXiv2016

Offshell thermodynamic metrics of the Schwarzschild black hole

Thermodynamic metric usually works only for those black holes with more than one conserved charge, therefore the Schwarzschild black hole was excluded. In this letter, we compute and compare different versions of offshell thermodynamic metric for the Schwarzschild-like black hole by introducing a new degree of freedom. This new degree of freedom could be the running Newton constant, a cutoff scale for regular black hole, a noncommutative deformation, or the deformed parameter in the nonextensive Tsallis-Renyi entropy. The onshell metric of the deformed Schwarzschild solution would correspond to the submanifold by gauge fixing of this additional degree of freedom. In particular, the thermal Ricci scalar for the Schwarzschild black hole, though different for various deformation, could be obtained by switching off the deformation.

gr-qc↗

arXiv2015

Black hole remnant in asymptotic Anti-de Sitter space

It is known that a solution of remnant were suggested for black hole ground state after surface gravity is corrected by loop quantum effect. On the other hand, a Schwarzschild black hole in asymptotic Anti-de Sitter space would tunnel into the thermal soliton solution known as the Hawking-Page phase transition. In this letter, we investigate the low temperature phase of three-dimensional BTZ black hole and four-dimensional AdS Schwarzschild black hole. We find that the thermal soliton is energetically favored than the remnant solution at low temperature in three dimensions, while Planck-size remnant is still possible in four dimensions. Though the BTZ remnant seems energetically disfavored, we argue that it is still possible to be found in the overcooled phase if strings were present and its implication is discussed.

hep-th↗

arXiv2014

n-partite information in Hawking radiation

We study the entanglement among sequential Hawking radiations in the Parikh-Wilczek tunneling model of Schwarzschild black hole. We identify the part of classical correlation and that of quantum entanglement in bipartite information and point out its imitated relation to quantum gravity correction. Explicit computation of n-partite information shows that it is positive (negative) for even (odd) $n$, which happens to agree with the holographic computation. The fact that entanglement in the mutual information grows with time mimics the second law of thermodynamics. Later we extend our study to the AdS black hole and find the total mutual information which includes the classical correlation is sensible to the Hawking-Page phase transition.

hep-th↗

arXiv2014

Nonthermal correction to black hole spectroscopy

Area spectrum of black holes have been obtained via various methods such as quasinormal modes, adiabatic invariance and angular momentum. Among those methods, calculations were done by assuming black holes in thermal equilibrium. Nevertheless, black holes in the asymptotically flat space usually have negative specific heat and therefore tend to stay away from thermal equilibrium. Even for those black holes with positive specific heat, temperature may still not be well defined in the process of radiation, due to the back reaction of decreasing mass. Respect to these facts, it is very likely that Hawking radiation is nonthermal and the area spectrum is no longer equidistant. In this note, we would like to illustrate how the area spectrum of black holes is corrected by this nonthermal effect.

gr-qc↗

arXiv2014

The small and large D limit of Parikh-Wilczek tunneling model for Hawking radiation

In this note, we study both the small and large dimension $D$ limit of the tunneling model of Hwaking radiation proposed by Parikh and Wilczek\cite{Parikh:1999mf}. We confirm that the result $Γ\sim e^{ΔS}$ is still valid for arbitrary $D>3$. The sensible large $D$ limit is given by $\sqrt{D} \ll r_0$ in order to have nonzero radiation. On the other hand, the sensible small $D$ limit is given by taking $D=3+ε$ as a continuous parameter. We also explicitly show the leading order correction to the thermal radiation and discuss its connection to the two-dimensional dilaton gravity.

gr-qc↗

arXiv2014

Thoughts on entropic gravity in the Parikh-Wilczek tunneling model of Hawking radiation

In this letter, we use the Parikh-Wilczek tunneling model of Hawking radiation to illustrate that a reformulation of Verlinde's entropic gravity is needed to derive the Newton's law for a temperature-varying screen, demanded by the conservation of energy. Furthermore, the entropy stored in the holographic screen is shown to be additive and its temperature dependence can be obtained.

gr-qc↗

arXiv2014

Charge-mass ratio bound and optimization in the Parikh-Wilczek tunneling model of Hawking radiation

In this letter, we study the mutual information hidden in the Parikh-Wilczek tunneling model of Hawking radiation for Reissner-Norstrom black holes. We argue that the condition of nonnegativity of mutual information suggests bound(s) for charge-mass ratio of emitted particles. We further view the radiation as an optimization process and discuss its effect on time evolution of a charged black hole.

gr-qc↗

arXiv2014

Area spectrum of extremal black holes with warped AdS near-horizon geometry

In this letter, we provide an alternative method to study the area spectrum of certain classes of extremal black holes which have near-horizon geometry as warped AdS. We argue that previous methods which are based on the existence of quasinormal modes may not be applicable in the extremal limit. The topology difference of the near-horizon geometry between non-extremal and extremal black holes implies a separate treatment is needed to study the area discreteness in the extremal limit. To be specific, we will study area spectrum of supersymmetric BMPV black holes/black rings and Reissner-Norstroem black holes at the extremal limit. Inspired by the recently established Kerr/CFT and RN/CFT correspondence, we propose a new way to quantize the area regardless of the (non-)existence of quasinormal modes or zero Hawking temperature. At last, we propose a dilute gas model and harmonic oscillator model which have same degrees of freedom as the dual CFT.

gr-qc↗

arXiv2014

Spin chains and classical strings in rotating Rindler-AdS space

In this paper, we study the spin chain and string excitation in the rotating Rindler-$AdS_3$ proposed in [12]. We obtain a one-parameter deformed $SL(2)$ spin chain at the fast spin limit. Two-spin GKP-like solutions are studied at short and long string limits. General ansatz for the giant magnons and the spiky strings are analyzed in detail for various $β$. At last, we explore its counterpart in analytic continuation and pp-wave limit.

hep-th↗

arXiv2014

A Holographic Model of Two-Band Superconductor

We construct a holographic two-band superconductor model with interband Josephson coupling. We investigate the effects the Josephson coupling has on the superconducting condensates and the critical temperature for their formation numerically, as well as analytically where possible. We calculate the AC conductivity and find it qualitatively similar to the single band superconductor. We investigate the nodal structure of our holographic two-band superconductor from the low temperature behavior of the thermal conductivity and find it nodeless.

hep-th↗

arXiv2013

Hawking radiation as irreversible tunneling through self-interaction

In this letter, we study the self-force in the Parikh-Wilczek tunneling model of Hawking radiation for Reissner-Nordstroem black holes. We conclude that the repulsive self-force speeds up the emission and the radiation becomes an irreversible process. We also find an upper bound of charge-mass ratio for emitted particles.

gr-qc↗

arXiv2012

A Holographic Model For Hall Viscosity

We have modified the holographic model of Saremi and Son by using a charged black brane, instead of a neutral one, such that when the bulk pseudo scalar potential is made of quadratic and quartic terms, parity can still be broken spontaneously in the boundary theory. In our model, the 3+1 dimensional bulk has a pseudo scalar coupled to the gravitational Chern-Simons term in the anti de Sitter charged black brane back ground. Parity could be broken spontaneously in the bulk by the pseudo scalar hairy solution and give rise to non-zero Hall viscosity at the boundary theory.

hep-th↗

arXiv2012

Dipole Coupling Effect of Holographic Fermion in Charged Dilatonic Gravity

In this note, we study the dipole coupling effect of holographic fermion in a charged dilatonic black hole proposed by Gubser and Rocha (arXiv:0911.2898). It is found that the property of Fermi liquid is rigid under perturbation of dipole coupling, and the Fermi momentum is linearly shifted. A gap is dynamically generated as the coupling becomes large enough and the Fermi surface ceases to exist as the bulk dipole coupling further increases.

hep-th↗

arXiv2011

Analytical study of critical magnetic field in a holographic superconductor

We analytically sutdy the effect of external magnetic field in a Holographic superconductor by using Sturm-Liouville method. We estimate the coefficient of proportionality at critical temperature and find its denpendence on external magnetic field. By exploring phase diagrams of critical temperature and magnetic field for various condensates, we conclude that a Meissner-like effect is a general feature in Holographic superconductors. We also study the quantum phase transition at zero temperature and find that critical charge density increases linearly with the condensate dimension.

hep-th↗

arXiv2010

Quantum Criticality in Einstein-Maxwell-Dilaton Gravity

We investigate the quantum Lifshitz criticality in a general background of Einstein-Maxwell-Dilaton gravity. In particular, we demonstrate the existence of critical point with dynamic critical exponent z by tuning a nonminimal coupling to its critical value. We also study the effect of nonminimal coupling and exponent z to the Efimov states and holographic RG flow in the overcritical region. We have found that the nonminimal coupling increases the instability for a probe scalar to condensate and its back reaction is discussed. At last, we give a quantum mechanics treatment to a solvable system with z=2, and comment for generic z>2.

hep-th↗

arXiv2010

Towards A Holographic Model of D-Wave Superconductors

The holographic model for S-wave high T_c superconductors developed by Hartnoll, Herzog and Horowitz is generalized to describe D-wave superconductors. The 3+1 dimensional gravitational theory consists a symmetric, traceless second-rank tensor field and a U(1) gauge field in the background of the AdS black hole. Below T_c the tensor field which carries the U(1) charge undergoes the Higgs mechanism and breaks the U(1) symmetry of the boundary theory spontaneously. The phase transition characterized by the D-wave condensate is second order with the mean field critical exponent beta = 1/2. As expected, the AC conductivity is isotropic below T_c and the system becomes superconducting in the DC limit but has no hard gap.

hep-th↗

arXiv2009

Peak-Dip-Hump from Holographic Superconductivity

We study the fermionic spectral function in a holographic superconductor model. At zero temperature, the black hole has zero horizon and hence the entropy of the system is zero after the back reaction of the condensate is taken into account. We find the system exhibits the famous peak-dip-hump lineshape with a sharp low-energy peak followed by a dip then a hump at higher energies. This feature is widely observed in the spectrum of several high-T_c superconductors. We also find a linear relation between the gap in the fermionic spectrum and the condensate, indicating the condensate is formed by fermion pairing.

hep-th↗

arXiv2009

Absorption cross section in warped AdS_3 black hole revisited

We investigate the absorption cross section for minimal-coupled scalars in the warped AdS_3 black hole. According to our calculation, the cross section reduces to the horizon area in the low energy limit as usually expected in contrast to what was previously found. We also calculate the greybody factor and find that the effective temperatures for the two chiral CFT's are consistent with that derived from the quasinormal modes. Observing the conjectured warped AdS/CFT correspondence, we suspect that a specific sector of the CFT operators with the desired conformal dimension could be responsible for the peculiar thermal behaviour of the warped AdS_3 black hole.

hep-th↗