arXiv subjects

Shuang-Qing Wu

Publications and source records attributed to Shuang-Qing Wu.

51 records · Page 3Linked to original sources

arXiv2008

Covariant anomalies and Hawking radiation from charged rotating black strings in anti-de Sitter spacetimes

Motivated by the success of the recently proposed method of anomaly cancellation to derive Hawking fluxes from black hole horizons of spacetimes in various dimensions, we have further extended the covariant anomaly cancellation method shortly simplified by Banerjee and Kulkarni to explore the Hawking radiation of the (3+1)-dimensional charged rotating black strings and their higher dimensional extensions in anti-de Sitter spacetimes, whose horizons are not spherical but can be toroidal, cylindrical or planar, according to their global identifications. It should be emphasized that our analysis presented here is very general in the sense that the determinant of the reduced (1+1)-dimensional effective metric from these black strings need not be equal to one $(\sqrt{-g} \neq 1)$. Our results indicate that the gauge and energy momentum fluxes needed to cancel the (1+1)-dimensional covariant gauge and gravitational anomalies are compatible with the Hawking fluxes. Besides, thermodynamics of these black strings are studied in the case of a variable cosmological constant.

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arXiv2007

General Non-extremal Rotating Charged Godel Black Holes in Minimal Five-Dimensional Gauged Supergravity

We present the general exact solutions for non-extremal rotating charged black holes in the Godel universe of five-dimensional minimal supergravity theory. They are uniquely characterized by four non-trivial parameters, namely the mass $m$, the charge $q$, the Kerr equal rotation parameter $a$, and the Godel parameter $j$. We calculate the conserved energy, angular momenta and charge for the solutions and show that they completely satisfy the first law of black hole thermodynamics. We also study the symmetry and separability of the Hamilton-Jacobi and the massive Klein-Gordon equations in these Einstein-Maxwell-Chern-Simons-Godel black hole backgrounds.

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arXiv2007

Comment on "Hawking Radiation and Covariant Anomalies"

We comment on the consistence of the epsilon anti-symmetric tensor adopted in [R. Banerjee and S. Kulkarni, arXiv:0707.2449] when it is generalized in the general case where $\sqrt{-g} \neq 1$. It is pointed out that the correct non-minimal consistent gauge and gravitational anomalies should by multiplied a factor $\sqrt{-g} \neq 1$. We also sketch the generalization of their work to the $\sqrt{-g} \neq 1$ case.

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arXiv2007

Covariant anomaly and Hawking radiation from the modified black hole in the rainbow gravity theory

Recently, Banerjee and Kulkarni (R. Banerjee, S. Kulkarni, arXiv:0707.2449 [hep-th]) suggested that it is conceptually clean and economical to use only the covariant anomaly to derive Hawking radiation from a black hole. Based upon this simplified formalism, we apply the covariant anomaly cancellation method to investigate Hawking radiation from a modified Schwarzschild black hole in the theory of rainbow gravity. Hawking temperature of the gravity's rainbow black hole is derived from the energy-momentum flux by requiring it to cancel the covariant gravitational anomaly at the horizon. We stress that this temperature is exactly the same as that calculated by the method of cancelling the consistent anomaly.

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arXiv2007

Anomalies and Hawking radiation from the Reissner-Nordström black hole with a global monopole

We extend the work by S. Iso, H. Umetsu and F. Wilczek [Phys. Rev. Lett. 96 (2006) 151302] to derive the Hawking flux via gauge and gravitational anomalies of a most general two-dimensional non-extremal black hole space-time with the determinant of its diagonal metric differing from the unity ($\sqrt{-g} \neq 1$) and use it to investigate Hawking radiation from the Reissner-Nordstrom black hole with a global monopole by requiring the cancellation of anomalies at the horizon. It is shown that the compensating energy momentum and gauge fluxes required to cancel gravitational and gauge anomalies at the horizon are precisely equivalent to the $(1+1)$-dimensional thermal fluxes associated with Hawking radiation emanating from the horizon at the Hawking temperature. These fluxes are universally determined by the value of anomalies at the horizon.

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arXiv2007

Hawking radiation from the Schwarzschild black hole with a global monopole via gravitational anomaly

Hawking flux from the Schwarzschild black hole with a global monopole is obtained by using Robinson and Wilczek's method. Adopting a dimension reduction technique, the effective quantum field in the (3+1)--dimensional global monopole background can be described by an infinite collection of the (1+1)--dimensional massless fields if neglecting the ingoing modes near the horizon, where the gravitational anomaly can be cancelled by the (1+1)--dimensional black body radiation at the Hawking temperature.

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arXiv2007

Hawking radiation from (2+1)-dimensional BTZ black holes

Motivated by the Robinson-Wilczek's recent viewpoint that Hawking radiation can be treated as a compensating energy momentum tensor flux required to cancel gravitational anomaly at the horizon of a Schwarzschild-type black hole, we investigate Hawking radiation from the rotating $(2+1)$-dimensional BTZ black hole and the charged $(2+1)$-dimensional BTZ black hole, via cancellation of gauge and gravitational anomalies at the horizon. To restore gauge invariance and general coordinate covariance at the quantum level, one must introduce the corresponding gauge current and energy momentum tensor fluxes to cancel gauge and gravitational anomalies at the horizon. The results show that the values of these compensating fluxes are exactly equal to those of $(1+1)$-dimensional blackbody radiation at the Hawking temperature.

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arXiv2007

Hawking radiation from dilatonic black holes via anomalies

Recently, Hawking radiation from a Schwarzschild-type black hole via gravitational anomaly at the horizon has been derived by Robinson and Wilczek. Their result shows that, in order to demand general coordinate covariance at the quantum level to hold in the effective theory, the flux of the energy momentum tensor required to cancel gravitational anomaly at the horizon of the black hole, is exactly equal to that of (1+1)-dimensional blackbody radiation at the Hawking temperature. In this paper, we attempt to apply the analysis to derive Hawking radiation from the event horizons of static, spherically symmetric dilatonic black holes with arbitrarily coupling constant $α$, and that from the rotating Kaluza-Klein $(α= \sqrt{3})$ as well as the Kerr-Sen ($α= 1$) black holes via an anomalous point of view. Our results support Robinson-Wilczek's opinion. In addition, the properties of the obtained physical quantities near the extreme limit are qualitatively discussed.

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arXiv2007

Anomalies and de Sitter radiation from the generic black holes in de Sitter spaces

Robinson-Wilczek's recent work shows that, the energy momentum tensor flux required to cancel gravitational anomaly at the event horizon of a Schwarzschild-type black hole has an equivalent form to that of a (1+1)-dimensional blackbody radiation at the Hawking temperature. Motivated by their work, Hawking radiation from the cosmological horizons of the general Schwarzschild-de Sitter and Kerr-de Sitter black holes, has been studied by the method of anomaly cancellation. The result shows that the absorbing gauge current and energy momentum tensor fluxes required to cancel gauge and gravitational anomalies at the cosmological horizon are precisely equal to those of Hawking radiation from it. It should be emphasized that the effective field theory for generic black holes in de Sitter spaces should be formulated within the region between the event horizon (EH) and the cosmological horizon (CH), to integrate out the classically irrelevant ingoing modes at the EH and the classically irrelevant outgoing modes at the CH, respectively.

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arXiv2007

Hawking radiation from rotating black holes in anti-de Sitter spaces via gauge and gravitational anomalies

Robinson-Wilczek's recent work, which treats Hawking radiation as a compensating flux to cancel gravitational anomaly at the horizon of a Schwarzschild-type black hole, is extended to study Hawking radiation of rotating black holes in anti-de Sitter spaces, especially that in dragging coordinate system, via gauge and gravitational anomalies. The results show that in order to restore gauge invariance and general coordinate covariance at the quantum level in the effective field theory, the charge and energy flux by requiring to cancel gauge and gravitational anomalies at the horizon, must have a form equivalent to that of a $(1+1)$-dimensional blackbody radiation at Hawking temperature with an appropriate chemical potential.

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arXiv2006

Hawking Radiation of Charged Particles as Tunneling from Higher Dimensional Reissner-Nordstrom-de Sitter Black Holes

Recent work that treats the Hawking radiation as a semi-classical tunnelling process from the four-dimensional Schwarzschild and Reissner-Nordstrom black holes is extended to the case of higher dimensional Reissner-Nordstrom-de Sitter black holes. The result shows that the tunnelling rate is related to the change of Bekenstein-Hawking entropy and the exact radiant spectrum is no longer precisely thermal after considering the black hole background as dynamical and incorporating the self-gravitation effect of the emitted particles when the energy conservation and electric charge conservation are taken into account.

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arXiv2006

Hawking radiation of charged particles as tunneling from Reissner-Nordstrom-de Sitter black holes with a global monopole

Applying Parikh's semi-classical tunneling method, we consider Hawking radiation of the charged massive particles as a tunneling process from the Reissner-Nordstrom-de Sitter black hole with a global monopole. The result shows that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the radiant spectrum is not a pure thermal one, but is consistent with an underlying unitary theory.

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arXiv2006

Remarks on Hawking radiation as tunneling from the BTZ black holes

Hawking radiation viewed as a semiclassical tunneling process from the event horizon of the (2 + 1)-dimensional rotating BTZ black hole is carefully reexamined by taking into account not only the energy conservation but also the conservation of angular momentum when the effect of the emitted particle's self-gravitation is incorporated. In contrast to previous analysis of this issue in the literature, our result obtained here fits well to the Kraus-Parikh-Wilczek's universal conclusion without any modification to the Bekenstein-Hawking area-entropy formulae of the BTZ black hole.

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arXiv2006

Hawking radiation as tunneling from the Kerr and Kerr-Newman black holes

Recent work, which treats the Hawking radiation as a semi-classical tunneling process at the horizon of the Schwarzschild and Reissner-Nordstrom spacetimes, indicates that the exact radiant spectrum is no longer pure thermal after considering the black hole background as dynamical and the conservation of energy. In this paper, we extend the method to investigate Hawking radiation as massless particles tunneling across the event horizon of the Kerr black hole and that of charged particles from the Kerr-Newman black hole by taking into account the energy conservation, the angular momentum conservation, and the electric charge conservation. Our results show that when self-gravitation is considered, the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum, but is consistent with an underlying unitary theory.

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arXiv2004

The Conformal Version of Black Hole Thermodynamics

The conformal thermodynamics of rotating charged black holes in general relativity and string theory is proposed by considering the first laws of thermodynamics for a pair of systems made up of the two horizons of a Kerr-Newman or Kerr-Sen black hole. These two systems are constructed by only demanding their ``horizon areas'' to be the sum and difference of that of the outer and inner horizons of their prototype. The thermodynamics present here is a ``conformal version'' of black hole thermodynamics, since it is closely related to the near-horizon conformal symmetry of black holes. The concept of non-quasinormal modes recently proposed by D. Birmingham and S. Carlip [9] is compatible with this ``conformal thermodynamics'', rather than the usual ``horizon thermodynamics''. In addition, we show that this conformal thermodynamics resembles to the thermodynamics of effective string or D-brane models, since the two newly-constructed systems bear a striking resemblance to the right- and left-movers in string theory and D-brane physics.

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