共查询到20条相似文献，搜索用时 31 毫秒
1.
Using the quantum statistical method, we calculate quantum statistical entropy between the black hole horizon and the cosmological horizon in Schwarzchild spacetime and derive the expression of quantum statistical entropy in de Sitter spacetime. Under the Unruh-Verlinde temperature of Schwarzchild-de Sitter spacetime in the entropic force views, we obtain the expression of quantum statistical entropy in de Sitter spacetime. It is shown that in de Sitter spacetime quantum statistical entropy is the sum of thermodynamic entropy corresponding black hole horizon and the one corresponding cosmological horizon. And the correction term of de Sitter spacetime entropy is obtained. Therefore, it is confirmed that the black hole entropy is the entropy of quantum field outside the black hole horizon. The entropy of de Sitter spacetime is the entropy of quantum field between the black hole horizon and the cosmological horizon. 相似文献
2.
Using the analytic extension method, we study Hawking radiation of an (n+4)-dimensional Schwarzschild-de Sitter black hole. Under the condition that the total energy is conserved, taking the reaction of the radiation of particles to the spacetime into consideration and considering the relation between the black hole event horizon and cosmological horizon, we obtain the radiation spectrum of de Sitter spacetime. This radiation spectrum is no longer a strictly pure thermal spectrum. It is related to the change of the Bekenstein-Hawking (B-H) entropy corresponding the black hole event horizon and cosmological horizon. The result satisfies the unitary principle. At the same time, we also testify that the entropy of de Sitter spacetime is the sum of the entropy of black hole event horizon and the one of cosmological horizon. 相似文献
3.
In this paper we present a class of non-stationary solutions of Einstein’s field equations describing embedded Vaidya-de Sitter black holes with a cosmological variable function Λ(u). The Vaidya-de Sitter black hole is interpreted as the radiating Vaidya black hole is embedded into the non-stationary de Sitter space with variable Λ(u). The energy-momentum tensor of the Vaidya-de Sitter black hole is expressed as the sum of the energy-momentum tensors of the Vaidya null fluid and that of the non-stationary de Sitter field, and satisfies the energy conservation law. We study the energy conditions (like weak, strong and dominant conditions) for the energy-momentum tensor. We find the violation of the strong energy condition due to the negative pressure and leading to a repulsive gravitational force of the matter field associated with Λ(u) in the space-time. We also find that the time-like vector field for an observer in the Vaidya-de Sitter space is expanding, accelerating, shearing and non-rotating. It is also found that the space-time geometry of non-stationary Vaidya-de Sitter solution with variable Λ(u) is Petrov type D in the classification of space-times. We also find the Vaidya-de Sitter black hole radiating with a thermal temperature proportional to the surface gravity and entropy also proportional to the area of the cosmological black hole horizon. 相似文献
4.
We investigate the influence of the cosmological constant, Λ, on the bending of light by a charged black hole in a de Sitter spacetime. Despite vanishing of the cosmological constant in the second order null geodesic equation, considering the method introduced by Rindler and Ishak (2007), we obtain an expression for the deflection angle, consistent with previous results for Schwarzschild, Schwarzschild-de Sitter (SdS), and Reissner-Nordstrom (RN) spacetimes. 相似文献
5.
Using Unruh-Verlinde temperature obtained by entropic force, we directly calculate partition functions of quantum field in Schwarzschild spacetime via quantum statistical method and derive the expression of the black hole statistical entropy. In our calculation the lower limit of integral is the location of isolated horizon introduced in loop quantum gravity and the upper limit of integral is infinity. So the obtained entropy is the statistical entropy from isolated horizon to the infinite. In our calculation there are not the cutoff and approximation. The results showed that, as long as proper Immirzi parameters are selected, the entropy obtained by loop quantum gravity is consistent with the quantum statistical entropy outside the black hole horizon. Therefore the black hole entropy is a quantum entanglement entropy outside the isolated horizon. 相似文献
6.
Li-Qin Mi 《Astrophysics and Space Science》2013,343(2):599-603
Quantum entropy of extremal black holes has been discussed by many authors. However the contribution of inner event horizon has not been considered. In this paper, we consider the Reissner-Nordström-anti-de Sitter black hole, and show that the contributions lead extremal black hole entropy to obey the Nernst theorem, naturally. Therefore the contributions are important and cannot be neglected in near-extremal and extremal black hole cases. 相似文献
7.
As is well known, black hole entropy is proportional to the area of the horizon suggesting a holographic principle wherein all degrees of freedom contributing to the entropy reside on the surface. In this note, we point out that large scale dark energy (such as a cosmological constant) constraining cosmic structures can imply a similar situation for the entropy of a hierarchy of such objects. 相似文献
8.
The massive particles tunneling method has been used to investigate the Hawking non-thermal and purely thermal radiations of Schwarzschild Anti-de Sitter (SAdS) black hole. Considering the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has been derived from Hamilton-Jacobi equation. Using the conservation laws of energy and angular momentum we have showed that the non-thermal and purely thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The result obtained for SAdS black hole is also in accordance with Parikh and Wilczek’s opinion and gives a correction to the Hawking radiation of SAdS black hole. 相似文献
9.
We have investigated Hawking non-thermal and purely thermal Radiations of Reissner Nordström anti-de Sitter (RNAdS) black hole by massive particles tunneling method. The spacetime background has taken as dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has derived from Hamilton-Jacobi equation. We have supposed that energy and angular momentum are conserved and have shown that the non-thermal and thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The results for RNAdS black hole is also in the same manner with Parikh and Wilczek’s opinion and explored the new result for Hawking radiation of RNAdS black hole. 相似文献
10.
De Sitter背景时空中NUT-Kerr-Newman黑洞的玻色子熵 总被引：1，自引：0，他引：1
众所周知，一般黑洞的欧拉示性数都为2(或者为0)，而NUT—Kerr—Newman黑洞是个例外，其欧拉示性数大于2.因此计算NUT—Kerr—Newman黑洞的玻色子熵有特殊的意义．运用在brick-wall方法的基础上发展起来的膜模型计算了NUT-Kerr—Newman黑洞在de Sitter时空背景下的玻色子熵．结果表明，在选取适当的截断因子的情况下，该黑洞的熵仍满足Bekenstein—Hawking面积定律． 相似文献
11.
Using a static massive spherically symmetric scalar field coupled to gravity in the Schwarzschild-de Sitter (SdS) background, first we consider some asymptotic solutions near horizon and their local equations of state (E.O.S.) on them. We show that near cosmological and event horizons our scalar field behaves as a dust. At the next step near two pure de Sitter or Schwarzschild horizons we obtain a coupling dependent pressure to energy density ratio. In the case of a minimally coupling this ratio is ?1 which springs to the mind thermodynamical behavior of dark energy. If having a negative pressure behavior near these horizons we concluded that the coupling constant must be ξ<¼. Therefore we derive a new constraint on the value of our coupling ξ. These two different behaviors of unique matter in the distinct regions of spacetime at present era can be interpreted as a phase transition from dark matter to dark energy in the cosmic scales and construct a unified scenario. 相似文献
12.
Malihe Heydari-Fard 《Astrophysics and Space Science》2010,325(2):287-292
Using the effective gravitational field equations in the warped DGP brane-world scenario (Maeda et al. in Phys. Rev. D 68:024033,
2003), we study spherically symmetric vacuum (static black hole) solutions on the brane. Working with a conformally flat bulk,
we have obtained an exact Schwarzschild–de Sitter black hole solution similar to the standard solution in the presence of
a cosmological constant, which confirms the idea that an extra term in the effective vacuum field equations on the warped
DGP brane can play the role of a positive cosmological constant. 相似文献
13.
14.
R. Chan M. F. A. da Silva Jaime F. Villas?da?Rocha 《Astrophysics and Space Science》2012,337(1):185-191
Using the conventional gravastar model, that is, an object constituted by two components where one of them is a massive infinitely
thin shell and the other one is a de Sitter interior spacetime, we physically interpret a solution characterized by a zero
Schwarzschild mass. No stable gravastar is formed and it collapses without forming an event horizon, originating what we call
a massive non-gravitational object. The most surprise here is that the collapse occurs with an exterior de Sitter vacuum spacetime.
This creates an object which does not interact gravitationally with an outside test particle and it may evolve to a point-like
topological defect. 相似文献
15.
《New Astronomy》2021
This paper explores the collapsing process of a unidirectional isotropic matter configuration. The junction conditions for a static exterior geometry and the non-static interior geometry are expressed in terms of the cosmological constant. The time-lapse for the appearance of the black hole and the cosmological horizon is calculated. It is observed that in the de-Sitter space, the unidirectional perfect fluid flow does not make the collapse disappear. The vacuum energy of the cosmological constant makes the collapsing process quite slow and affects the time-lapse of horizon formation. Moreover, the presence of string tension increases the time-lapse of horizon formation. 相似文献
16.
We obtain renormalized stress tensor of a mass-less, charge-less dynamical quantum scalar field, minimally coupled with a spherically symmetric static Lukewarm black hole. In two dimensional analog the minimal coupling reduces to the conformal coupling and the stress tensor is found to be determined by the nonlocal contribution of the anomalous trace and some additional parameters in close relation to the work presented by Christensen and Fulling. Lukewarm black holes are a special class of Reissner-Nordström-de Sitter space times where its electric charge is equal to its mass. Having the obtained renormalized stress tensor we attempt to obtain a time-independent solution of the well known metric back reaction equation. Mathematical derivations predict that the final state of an evaporating quantum Lukewarm black hole reduces to a remnant stable mini black hole with moved locations of the horizons. Namely the perturbed black hole (cosmological) horizon is compressed (extended) to scales which is smaller (larger) than the corresponding classical radius of the event horizons. Hence there is not obtained an deviation on the cosmic sensor-ship hypothesis. 相似文献
17.
Kourosh Nozari 《Astrophysics and Space Science》2012,341(2):421-427
We study the relation between the existence of the logarithmic prefactor and spacetime dimensionality in black hole entropy relation by a detailed study of a TeV-scale black hole entropy. In a model universe with large extra dimensions and within the Generalized Uncertainty Principle (GUP) framework, we show that probability of black hole production in the Large Hadronic Collider (LHC) decreases for sufficiently large values of the GUP parameter. In this regard, even observation of micro-black holes may be suppressed at TeV energy scale. We determine also the GUP parameter in an extra dimensional scenario by comparing black hole entropy calculated within the GUP and loop quantum gravity frameworks. 相似文献
18.
The thermal character of inner horizon in a Reissner-Nordstrom black hole is studied via Hamilton-Jacobi method. There is
“Hawking absorption” as a quantum effect near the inner horizon, and a negative temperature of the inner horizon was attained
by choosing an observer outside the black hole. Using a redefined entropy of the black hole, we give a new expression of Bekenstein-Smarr
formula. The redefined entropy satisfies Nernst Theorem, so it can be regarded as Planck absolute entropy of the Reissner-Nordstrom
black hole. 相似文献
19.
We study a black hole in an expanding Universe during the radiation-dominated stage. In particular, such a black hole may be of the primordial origin. In the case when the black hole radius is much smaller than the cosmological horizon, we found a self-consistent solution for the metric and the matter distribution and its velocity far from the black hole. At distances much smaller than the cosmological horizon our solution coincides with the previously obtained solution for quasi-stationary accretion. Our results can be applied, in particular, for the formation of dark matter density spikes around primordial black holes, and for the evolution of dark matter clumps during the radiation-dominated stage. 相似文献
20.
In this paper, the generalized second law (GSL) of thermodynamics and entropy is revisited in the context of cosmological
models with bouncing behavior such as chameleon cosmology where the boundary of the universe is assumed to be enclosed by
the dynamical apparent horizon. From a thermodynamic point of view, to link between thermodynamic and geometric parameters
in cosmological models, we introduce “entropy rate of change multiplied by the temperature” as a model independent thermodynamic
state parameter together with the well known {r,s} statefinder to differentiate the dark energy models. 相似文献