120034276
de Broglie–Bohm interpretation for wave function of a toroidal black hole
The mass function of a toroidal black hole as a dynamical variable is given by using Kuchar’s approach. Then the toroidal black hole is investigated by using the de Broglie–Bohm approach, and its quantum potential and quantum trajectories are obtained. In our process the vector potential of the electromagnetic field in the toroidal black hole is treated as a canonical variable.
126084815
Entropy of quantum field in toroidal black hole without brick wall
The calculation of the brick-wall model gives the entropy as two terms: one is proportional to the horizon area and the other is a constant. Then they renormalized the entropy by introducing the Newton’s constant and the entropy correction arising from the higher curvature effective gravitational action. Finally, they got the renormalized entropy whose leading term is proportional to the horizon area of the black hole and the others is precisely the one-loop correction arising from the higher curvature terms of the gravitational action. Their work confirmed the suggestion by Susskind and Uglum [25] that these divergences have the correct form to be absorbed in the Bekenstein–Hawking formula as a renormalization of Newton’s constant.
121278811
Entropies of a Toroidal Black Hole Due to Scalar and Dirac Fields
Using the thin film brick-wall model, the entropies of a toroidal black hole due to scalar and Dirac fields are investigated. The entropy due to the scalar field is one fourth of the horizon area, and that due to the Dirac field is seven eighth of the area. These results are similar to that in black holes with horizon topology S2. The cutoff in toroidal black hole is chosen as the same as one in black holes with horizon topology S2, which seems to mean that the thin film brick-wall model is universal.
122100665
Modified de Broglie-Bohm approach to the Schwarzschild black hole
A modified de Broglie?Bohm approach is generalized to the Schwarzschild black hole. By using this method, the quantum potential and the quantum trajectories of the black hole are investigated. And we find that the linear combination of two particular solutions of the black hole wavefunction is not physical although each of them is physical, if we think that the quantum gravity should reduce into its corresponding classical counterpart in which the gravity vanishes. It seems to confirm the argument, given by Alwis and MacIntire, that a possible resolution on the quantum gravity is to give up the superposition principle.
5474368
Numerical simulation of the massive scalar field evolution in the Reissner-Nordstrom black hole background
We studied the massive scalar wave propagation in the background of Reissner-Nordstr\"{o}m black hole by using numerical simulations. We learned that the value $Mm$ plays an important role in determining the properties of the relaxation of the perturbation. For $Mm > 1$, the dependence of the relaxation on the black hole parameters appears. The bigger mass of the black hole, the faster the perturbation decays. The difference of the relaxation process caused by the black hole charge $Q$ has also been exhibited.
119434810
Ly-alpha forests and cooling outflow from dwarf galaxies
We propose that cooling outflows from star-forming dwarf galaxies that are spatially correlated with but unbound to bright galaxies may account for the low column QSO Ly$\alpha$ forests, providing an explanation for both the heavy elements recently detected in them and the large sizes associated with them. Thus, we suggest that structure formations in the early universe on scales where matters collapse gravitationally and the gas forms stars are responsible for the Ly$\alpha$ forests (cf. the mini-halo model). Supernovae shock the interstellar gas to high temperature, and the resulting gas outflows from the dwarfs owing to their shallow potential wells. The gas cools radiatively as the radiative cooling time shortens because of adiabatic expansion. Subsequent thermal instability results in condensation of clouds. The clouds inherit the kinetic energy of the flow and coast to large distances, providing regions of the absorbing gas with sizes of up to hundreds of kpc. We calculate the Ly$\alpha$ absorption line profiles and the neutral column distribution, and show that they are consistent with observations. We suggest that the Ly$\alpha$ forests are caused by the faint blue galaxies found in the deep extragalactic surveys.
14188747
Ricci flat black holes and Hawking-Page phase transition in Gauss-Bonnet gravity and dilaton gravity
It is well known that there exists a Hawking-Page phase transition between a spherical anti-de Sitter (AdS) black hole and a thermal AdS space. The phase transition does not happen between a Ricci flat AdS black hole whose horizon is a Ricci flat space and a thermal AdS space in the Poincare coordinates. However, the Hawking-Page phase transition occurs between a Ricci flat AdS black hole and an AdS soliton if at least one of the horizon coordinates for the Ricci flat black hole is compact. We show a similar phase transition between the Ricci flat black holes and deformed AdS solitons in the Gauss-Bonnet gravity and the dilaton gravity with a Liouville-type potential including the gauged supergravity coming from the spherical reduction of Dp branes in type II supergravity. In contrast to Einstein gravity, we find that the high temperature phase can be dominated either by black holes or deformed AdS solitons depending on parameters.
120889836
QUANTUM CORRECTIONS TO THE ENTROPY OF EXTREME REISSNER–NORDSTRÖM BLACK HOLES
Using brick wall model, the first quantum corrections to the extreme Reissner–Nordstrom black hole entropy due to scalar field as well as electromagnetic field have been calculated. Different quantum entropy values have been obtained for two different kinds of extreme black holes.
122210021
The interaction between dark energy and dark matter
In this review we first present a general formalism to study the growth of dark matter perturbations in the presence of interactions between dark matter(DM) and dark energy(DE). We also study the signature of such interaction on the temperature anisotropies of the large scale cosmic microwave background (CMB). We find that the effect of such interaction has significant signature on both the growth of dark matter structure and the late Integrated Sachs Wolfe effect(ISW). We further discuss the potential possibility to detect the coupling by cross-correlating CMB maps with tracers of the large scale structure. We finally confront this interacting model with WMAP 5-year data as well as other data sets. We find that in the 1σ range, the constrained coupling between dark sectors can solve the coincidence problem.