It is shown in the first part of this paper that a combined model comprising ordinary and quintessential matter can support a traversable wormhole in Einstein-Maxwell gravity. Since the solution allows zero tidal forc...It is shown in the first part of this paper that a combined model comprising ordinary and quintessential matter can support a traversable wormhole in Einstein-Maxwell gravity. Since the solution allows zero tidal forces, the wormhole is suitable for a humanoid traveler. The second part of the paper shows that the electric field can be eliminated (Einstein gravity), but only by tolerating enormous tidal forces. Such a wormhole would still be capable of transmitting signals.展开更多
We study the P V critical behavior of a four-dimensional AdS black hole in an Einstein Maxwell gravity with a conformal anomaly by treating the cosmological constant as a variable that is related to the thermodynamic ...We study the P V critical behavior of a four-dimensional AdS black hole in an Einstein Maxwell gravity with a conformal anomaly by treating the cosmological constant as a variable that is related to the thermodynamic pressure, It is shown that there will be no phase transition if k = 0 or -1 are taken. When the charge ql of the conformal field and the coefficient α satisfy a certain relation, the van de Waals like phase transition for the spherical black hole can occur where the temperature is lower than the small critical temperature or higher than the large one. We also evaluate the critical exponents of the phase transitions and find that the thermodynamic exponents associated with this four-dimensional AdS black hole coincide with those of the van de Waals fluid.展开更多
We construct charged black hole solutions with hyperscaling violation in the infrared（IR） region in Einstein-Maxwell-Dilaton-Axion theory and investigate the temperature behavior of the ratio of holographic shear vi...We construct charged black hole solutions with hyperscaling violation in the infrared（IR） region in Einstein-Maxwell-Dilaton-Axion theory and investigate the temperature behavior of the ratio of holographic shear viscosity to the entropy density. When translational symmetry breaking is relevant in the IR, the power law of the ratio is verified numerically at low temperature T, namely, η/s ～ T^κ, where the values of exponent κ coincide with the analytical results. We also find that the exponent κ is not affected by irrelevant current, but is reduced by the relevant current.展开更多
文摘It is shown in the first part of this paper that a combined model comprising ordinary and quintessential matter can support a traversable wormhole in Einstein-Maxwell gravity. Since the solution allows zero tidal forces, the wormhole is suitable for a humanoid traveler. The second part of the paper shows that the electric field can be eliminated (Einstein gravity), but only by tolerating enormous tidal forces. Such a wormhole would still be capable of transmitting signals.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11275099 and 11475135
文摘We study the P V critical behavior of a four-dimensional AdS black hole in an Einstein Maxwell gravity with a conformal anomaly by treating the cosmological constant as a variable that is related to the thermodynamic pressure, It is shown that there will be no phase transition if k = 0 or -1 are taken. When the charge ql of the conformal field and the coefficient α satisfy a certain relation, the van de Waals like phase transition for the spherical black hole can occur where the temperature is lower than the small critical temperature or higher than the large one. We also evaluate the critical exponents of the phase transitions and find that the thermodynamic exponents associated with this four-dimensional AdS black hole coincide with those of the van de Waals fluid.
基金Supported by National Natural Science Foundation of China(11275208,11575195)Opening Project of Shanghai Key Laboratory of High Temperature Superconductors(14DZ2260700)Jiangxi Young Scientists(Jing Gang Star)Program and 555 Talent Project of Jiangxi Province
文摘We construct charged black hole solutions with hyperscaling violation in the infrared（IR） region in Einstein-Maxwell-Dilaton-Axion theory and investigate the temperature behavior of the ratio of holographic shear viscosity to the entropy density. When translational symmetry breaking is relevant in the IR, the power law of the ratio is verified numerically at low temperature T, namely, η/s ～ T^κ, where the values of exponent κ coincide with the analytical results. We also find that the exponent κ is not affected by irrelevant current, but is reduced by the relevant current.
