119285485
$P-V$ criticality of AdS black hole in $f(R)$ gravity
We study thermodynamics of a charged AdS black hole in the special $f(R)$ correction with the constant Ricci scalar curvature. Our results show that the the $f(R)$ correction influences the Gibbs free energy and the phase transition of system. The ratio $\rho_c$ occurred at the critical point increases monotonically with the derivative term $f'(R_0)$. We also disclose that the critical exponents are the same as those of the liquid-gas phase transition in the Van der Waals model, which does not depend on the $f(R)$ correction considered here.
121821422
Quasinormal Modes of a Coupled Scalar Field in the Acoustic Black Hole Spacetime
By using the third-order Wentzel–Kramers–Brillouin approximation and the monodromy methods, the quasinormal modes of a coupled scalar field in the canonical non-rotating acoustic black hole spacetime are investigated. It is shown that the coupling between the scalar field and background metric affects the quasinormal frequencies. At low overtones, both the real part and the magnitude of imaginary part increase with the couple factor ξ. For the larger ξ, both of them are almost linearly related to the couple factor. At high overtones, it is found that the frequency formula of the quasinormal modes is 2πω/κ = ln (1+2cos ((9−24ξ)1/2π/5))−i(2n+1)π, which means that when ξ is larger, the real part is the linear function of ξ1/2 .
118397512
Dynamical evolution of scalar perturbation in Hořava-Lifshitz black-hole spacetimes
We study the dynamical evolution of a massless scalar perturbation in the Ho\ifmmode \check{r}\else \v{r}\fi{}ava-Lifshitz black-hole spacetimes with the coupling constants $\ensuremath{\lambda}=\frac{1}{3}$, $\ensuremath{\lambda}=\frac{1}{2}$ and $\ensuremath{\lambda}=3$, respectively. Our calculation shows that, for the three cases, the scalar perturbations decay without any oscillation in which the decay rate imprints the parameter of the Ho\ifmmode \check{r}\else \v{r}\fi{}ava-Lifshitz black hole. The results are quite different from those in the Schwarzschild AdS black hole and can help us understand more about the Ho\ifmmode \check{r}\else \v{r}\fi{}ava-Lifshitz gravity.
125095595
Quasinormal modes and late-time tails of scalar perturbations around a Schwarzschild black hole pierced by a cosmic string
115944897
Entropy and topology of the Kerr-de Sitter black hole
By using the path integral method of Gibbons and Hawking, the entropy of the Kerr-de Sitter black hole is investigated under the microcanonical ensemble. We find that the entropy is one eighth the sum of the products of the Euler number of its cosmological horizon and event horizon with their respective areas. It is shown that the origin of the entropy of the black hole is related to the topology of its instanton.
119252617
Holographic superconductor models with $RF^{2}$ corrections
We investigate the effect of the RF 2 correction on the holographic superconductor model in the background of AdS black hole. We find that, similar to the effect caused by the Weyl correction, the higher RF 2 correction term can make it easier for the scalar operator to condense and result in the larger deviations from the expected relation in the gap frequency. However, if a non-trivial hair for the black hole has been triggered, we observe that the RF 2 correction and the Weyl correction do play different roles in the behavior of the condensation, which can be used to support the existing findings. PACS numbers: 11.25.Tq, 04.70.Bw, 74.20.-z ∗ panqiyuan@126.com † csb3752@hunnu.edu.cn ‡ jljing@hunnu.edu.cn
118839273
Cosmological perturbations in f(T) gravity
We investigate the cosmological perturbations in f(T) gravity. Examining the pure gravitational perturbations in the scalar sector using a diagonal vierbein, we extract the corresponding dispersion relation, which provides a constraint on the f(T) Ansaetze that lead to a theory free of instabilities. Additionally, upon inclusion of the matter perturbations, we derive the fully perturbed equations of motion, and we study the growth of matter overdensities. We show that f(T) gravity with f(T) constant coincides with General Relativity, both at the background as well as at the first-order perturbation level. Applying our formalism to the power-law model we find that on large subhorizon scales (O(100 Mpc) or larger), the evolution of matter overdensity will differ from {Lambda}CDM cosmology. Finally, examining the linear perturbations of the vector and tensor sectors, we find that (for the standard choice of vierbein) f(T) gravity is free of massive gravitons.
195378147
Effects of cosmological constant on motion of UHECR particles
Recent astronomical observations manifest that about two-thirds of the whole energy in the Universe is contributed by a small positive cosmological constant Λ (>0). Then, an asymptotically de Sitter spacetime is premised naturally. However, physics in the de Sitter spacetime is very different from that in the Minkowski spacetime. As the first step, a covariant formalism of the kinematics in the de Sitter spacetime is presented here. By solving exactly the equations of motion for a field, we obtain the dispersion relation of a free particle. It is noticed that the dispersion relation is dependent on the degree of freedom of angular momentum of the particle. We show the threshold anomaly of the ultra high energy cosmic ray disappears naturally in the framework of the de Sitter kinematics.
117444261
The effect of high-order multipole imperfections on the LEP dynamic aperture
195822336
CURRENT STATUS OF THE PROPOSED SHANGHAI SYNCHROTRON RADIATION FACILITY
The Shanghai Synchrotron Radiation Facility (SSRF) was proposed by the Chinese Academy of Sciences and the Shanghai Municipal Government in 1995. The estimated total budget is around US$100 M, and the operation is scheduled to begin in the end of 2003. The whole SSRF project is still awaiting final approval, but its R&D has been approved. The SSRF is a third-generation synchrotron light source designed to produce high brightness VUV and soft X-ray in the energy region of 10 eV~3 keV and high flux X-ray with moderate brightness in the energy region of 3~30 keV. It consists of the injector (including a 100 MeV Linac and a 2.2-2.5 GeV Booster), the 2.2-2.5 GeV storage ring and the synchrotron radiation experimental facilities. In this paper, the main parameters and features of the SSRF are presented.
14192602
Vacuum energy density and cosmological constant in dS brane-world
We discuss the vacuum energy density and the cosmological constant of dS5 brane-world with a dilaton field. It is shown that a stable AdS4 brane can be constructed and gravity localization can be realized. An explicit relation between the dS bulk cosmological constant and the brane cosmological constant is obtained. The discrete mass spectrum of the massive scalar field in the AdS4 brane is used to acquire the relationship between the brane cosmological constant and the vacuum energy density. The vacuum energy density in the brane gotten by this method is in agreement with astronomical observations.