The relation between a black hole and a general blackbody system

Taking a black hole as a black body system, using general black body radiation theory, a Schwarzschild black hole and a Kerr--Newman black hole are investigated respectively. It is concluded that a black hole can be regarded as an ideal general black body system exactly for the changing process only. However, a stationary global black hole cannot be smoothly regarded as a general black body system. A black hole has some special characteristics which different from a general thermodynamics system. This conclusion means that a black hole should be inherently dynamical, at least when it is taken as a black body system.     

f(R) Black Holes as Heat Engines

With the cosmological constant considered as a thermodynamic variable in the extended phase space, it is natural to study the thermodynamic cycles of the black hole, which is conjectured to be performed using renormalization group flow. We first investigate the thermodynamic cycles of a 4-dimensional asymptotically AdS f(R) black hole. Then we study the thermodynamic cycles of higher dimensional asymptotically AdS f(R) black holes. It is found that when ΔV ? ΔP, the efficiency of isobar-isochore cycles running between high temperature T_H and low temperature T_C will increase to its maximum value, which is exactly the Carnot cycles’ efficiency both in 4-dimensional and in higher dimensional cases. We speculate that this property is universal for AdS black holes, if there is no phase transition in the thermodynamic cycle. This result may deepen our understanding of the thermodynamics of the AdS black holes.     

Black Hole Phase Transition in Massive Gravity

In massive gravity, some new phenomena of black hole phase transition are found. There are more than one critical points under appropriate parameter values and the Gibbs free energy near critical points also has some new properties. Moreover, the Maxwell equal area rule is also investigated and the coexistence curve of the black hole is given.     

Black Hole Thermodynamics of Hořava-Lifshitz and IR Modified Ho řava-Lifshitz Gravity Theory

Recently, a renormalizable model of gravity has been proposed by Hoř ava, which might be an ultraviolet completion of general relativity and it reduces to Einstein gravity with a non-vanishing cosmological constant in infrared approximation. Kehagias and Sfetsos have added a relevant operator proportional to the 3D geometry Ricci scalar to the original Hoř ava-Lifshitz theory action, which “softly” deviated from detailed-balance. This does not modify the ultraviolet properties of the theory. However, it modifies the infrared approximation and the Minkowski vacuum can be allowed in the infrared Hořava-Lifshitz gravity theory. The static spherical symmetric black hole solutions have been obtained in the Hořava-Lifshitz and infrared Hořava-Lifshitz gravity theory. Based on the metric of the black holes, Hawking radiation of massless scalar particles is investigated using Damour-Ruffini method. Then the black hole thermodynamics property will also be discussed.     

Dynamics of extended bodies with spin-induced quadrupole in Kerr spacetime: generic orbits

We discuss motions of extended bodies in Kerr spacetime by using Mathisson–Papapetrou–Dixon equations. We firstly solve the conditions for circular orbits, and calculate the orbital frequency shift due to the mass quadrupoles. The results show that we need not consider the spin-induced quadrupoles in extreme-mass-ratio inspirals for space-based gravitational wave detectors. We quantitatively investigate the temporal variation of rotational velocity of the extended body due to the coupling of quadrupole and background gravitational field. For generic orbits, we numerically integrate the Mathisson–Papapetrou–Dixon equations for evolving the motion of an extended body orbiting a Kerr black hole. By comparing with the monopole–dipole approximation, we reveal the influences of quadrupole moments of extended bodies on the orbital motion and chaotic dynamics of extreme-mass-ratio systems. We do not find any chaotic orbits for the extended bodies with physical spins and spin-induced quadrupoles. Possible implications for gravitational wave detection and pulsar timing observation are outlined.     

高效平面异质结有机-无机杂化钙钛矿太阳电池的质量管理

基于有机-无机杂化钙钛矿材料的太阳电池具有能量转换效率高和制备工艺简单等优点,引起了学术界的高度关注.其中平面异质结结构太阳电池具有结构简单,可与其他类型电池相兼容以构筑叠层电池设计,以及可低温制备等诸多优点,成为当前的一个重要研究方向.然而,电池性能的优劣与钙钛矿薄膜质量的高低有着直接的联系.本文对钙钛矿材料的特性、一步溶液法制备薄膜的成核-生长机理、电池结构的演变等进行了概述,其中重点介绍了高质量钙钛矿薄膜溶液法制备过程的一些最新的质量控制方法;最后对钙钛矿太阳电池的发展及存在问题进行了总结和展望,为今后的研究提供参考.     

Casimir Effect for a Massless Spin-3/2 Field in Minkowski Spacetime

The Casimir effect has been studied for various quantum fields in both fiat and curved spacetimes. As a further step along this line, we provide an explicit derivation of Casimlr effect for massless spin-3/2 field with periodic boundary condition imposed in four-dimensional Minkowski spacetime. The corresponding results with Dirichlet and Neumann boundary conditions are also discussed.     

Unthermal Hawking Radiation from a General Stationary Black Hole

Using Damour-Ruflini＇s method, Hawking radiation from a general stationary black hole is investigated again deeply. Considering the back reaction of the particle to the space-time and energy conservation, we find that the radiation is not exactly thermal and can take out information from the black hole. This can be used to explain the information loss paradox, and the result is consistent with the works finished before.     

Photon sphere and phase transition of d-dimensional (d ≥ 5) charged Gauss-Bonnet AdS black holes

Motivated by recent work, nonmonotonic behaviors of photon sphere radius can be used to reflect black hole phase transition for Reissner-Nordström-AdS (RN-AdS) black holes, we study the case of five-dimensional charged Gauss-Bonnet-AdS black holes in the reduced parameter space. We find that the nonmonotonic behaviors of photon sphere radius still exist. Using the coexistence line calculated from P-V plane, we capture the photon sphere radius of saturated small and large black holes (the boundary of the coexistence phase), then illustrate the reduced coexistence region. The results show that, reduced coexistence region decreases with charge Q but increases with Gauss-Bonnet coefficient α. When the charge vanishes, reduced coexistence region does not vary with Gauss-Bonnet coefficient α any more. In this case, the Gauss-Bonnet coefficient α plays the same role as the charge of five-dimensional RN-AdS black holes. Also, the situation of higher dimension is studied in the end.