scholarly journals AdS Black Hole with Phantom Scalar Field

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Limei Zhang ◽  
Xiaoxiong Zeng ◽  
Zhonghua Li
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Entanglement Entropy ◽  
Scalar Fields ◽  
Schwarzschild Black Hole ◽  
Ricci Flat ◽  
Large Black Hole ◽  
Phantom Scalar ◽  
Strip Geometry ◽  
Phantom Scalar Field

We present an AdS black hole solution with Ricci flat horizon in Einstein-phantom scalar theory. The phantom scalar fields just depend on the transverse coordinates x and y, which are parameterized by the parameter α. We study the thermodynamics of the AdS phantom black hole. Although its horizon is a Ricci flat Euclidean space, we find that the thermodynamical properties of the black hole solution are qualitatively the same as those of AdS Schwarzschild black hole. Namely, there exists a minimal temperature and the large black hole is thermodynamically stable, while the smaller one is unstable, so there is a so-called Hawking-Page phase transition between the large black hole and the thermal gas solution in the AdS space-time in Poincare coordinates. We also calculate the entanglement entropy for a strip geometry dual to the AdS phantom black holes and find that the behavior of the entanglement entropy is qualitatively the same as that of the black hole thermodynamical entropy.

scholarly journals Hawking Radiation for Non-Minimally Coupled Matter from Generalized 2-D Black Hole Models

1997 ◽  
Vol 12 (35) ◽  
pp. 2683-2689 ◽  
Author(s):  
W. Kummer ◽  
H. Liebl ◽  
D. V. Vassilevich
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Hawking Radiation ◽  
Scalar Fields ◽  
Global Structure ◽  
Spherically Symmetric ◽  
Schwarzschild Black Hole ◽  
Minimal Coupling ◽  
Scalar Matter ◽  
Inherent Ambiguity

It is well known that spherically symmetric reduction of general relativity (SSG) leads to non-minimally coupled scalar matter. We generalize (and correct) recent results to Hawking radiation for a class of dilaton models which share with the Schwarzschild black hole non-minimal coupling of scalar fields and the basic global structure. An inherent ambiguity of such models (if they differ from SSG) is discussed. However, for SSG we obtain the rather disquieting result of a negative Hawking flux at infinity, if the usual recipe for such calculations is applied.

scholarly journals Cosmological isotropic matter–energy generalizations of Schwarzschild and Kerr metrics

2016 ◽  
Vol 25 (10) ◽  
pp. 1650088
Author(s):  
Metin Arik ◽  
Yorgo Senikoglu
Keyword(s):  
Black Hole ◽  
Dark Energy ◽  
Black Hole Solution ◽  
State Parameter ◽  
Time Dependent ◽  
Schwarzschild Black Hole ◽  
Field Equations ◽  
Rotating Black Hole ◽  
Special Solutions ◽  
Matter Energy

We present a time-dependent isotropic fluid solution around a Schwarzschild black hole. We offer the solutions and discuss the effects on the field equations and the horizon. We derive the energy density, pressure and the equation of state parameter. In the second part, we generalize the rotating black hole solution to an expanding universe. We derive from the proposed metric the special solutions of the field equations for the dust approximation and the dark energy solution. We show that the presence of a rotating black hole does not modify the scale factor [Formula: see text] law for dust, nor [Formula: see text] and [Formula: see text] for dark energy.

scholarly journals Schwarzschild black hole states and entropies on a nice slice

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
J. A. Rosabal
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Pure State ◽  
Entanglement Entropy ◽  
The State ◽  
Schwarzschild Black Hole ◽  
Complex Time ◽  
Strong Curvature

AbstractIn this work, we define a quantum gravity state on a nice slice. The nice slices provide a foliation of spacetime and avoid regions of strong curvature. We explore the topology and the geometry of the manifold obtained from a nice slice after evolving it in complex time. We compute its associated semiclassical thermodynamics entropy for a 4d Schwarzschild black hole. Despite the state one can define on a nice slice is not a global pure state, remarkably, we get a similar result to Hawking’s calculation. In the end, we discuss the entanglement entropy of two segments on a nice slice and comment on the relation of this work with the replica wormhole calculation.

scholarly journals Thermodynamic properties of Bardeen black holes in dRGT massive gravity

2021 ◽  
Author(s):  
R P Singh ◽  
B K Singh ◽  
B R K Gupta ◽  
S Sachan
Keyword(s):  
Heat Capacity ◽  
Black Hole ◽  
Free Energy ◽  
Black Hole Solution ◽  
Massive Gravity ◽  
Schwarzschild Black Hole ◽  
Regular Black Hole ◽  
Horizon Radius ◽  
Canonical Ensembles ◽  
Grand Canonical

The Bardeen black hole solution is the first spherically symmetric regular black hole based on the Sakharov and Gliner proposal which is the modification of the Schwarzschild black hole. We present the Bardeen black hole solution in presence of the dRGT massive gravity, which is regular everywhere in the presence of a nonlinear source. The obtained solution interpolates with the Bardeen black hole in the absence of massive gravity parameter and the Schwarzschild black hole in the limit of magnetic charge g=0. We investigate the thermodynamical quantities viz. mass (M), temperature (T), entropy (S) and free energy (F) in terms of horizon radius for both canonical and grand canonical ensembles. We check the local and global stability of the obtained solution by studying the heat capacity and free energy. The heat capacity flips the sign at r = r<sub>c</sub>. The black hole is thermodynamically stable with positive heat capacity C>0 for i.e., globally preferred with negative free energy F < 0. In addition, we also study the phase structure of the obtained solution in both ensembles.

scholarly journals Something special at the event horizon

2014 ◽  
Vol 29 (40) ◽  
pp. 1450215 ◽  
Author(s):  
Myungseok Eune ◽  
Yongwan Gim ◽  
Wontae Kim
Keyword(s):  
Black Hole ◽  
Energy Density ◽  
Free Fall ◽  
Scalar Fields ◽  
Negative Energy ◽  
Two Dimensional ◽  
Schwarzschild Black Hole ◽  
Negative Energy Density ◽  
Trace Anomaly ◽  
Physical Consequences

We revisit the free-fall energy density of scalar fields semiclassically by employing the trace anomaly on a two-dimensional Schwarzschild black hole with respect to various black hole states in order to clarify whether something special at the horizon happens or not. For the Boulware state, the energy density at the horizon is always negative divergent, which is independent of initial free-fall positions. However, in the Unruh state the initial free-fall position is responsible for the energy density at the horizon and there is a critical point to determine the sign of the energy density at the horizon. In particular, a huge negative energy density appears when the freely falling observer is dropped just near the horizon. For the Hartle–Hawking state, it may also be positive or negative depending on the initial free-fall position, but it is always finite. Finally, we discuss physical consequences of these calculations.

scholarly journals High-dimensional Schwarzschild black holes in scalar–tensor–vector gravity theory

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
Xin-Chang Cai ◽  
Yan-Gang Miao
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Emission Rate ◽  
Null Geodesic ◽  
High Dimensional ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Spacetime Dimension ◽  
Schwarzschild Black Hole ◽  
Scalar Waves

AbstractWe obtain a high-dimensional Schwarzschild black hole solution in the scalar–tensor–vector gravity (STVG), and then analyze the influence of parameter $$\alpha $$ α associated with a deviation of the STVG theory from General Relativity on event horizons and Hawking temperature. We calculate the quasinormal mode frequencies of massless scalar field perturbations for the high-dimensional Schwarzschild STVG black hole by using the sixth-order WKB approximation method and the unstable null geodesic method in the eikonal limit. The results show that the increase of parameter $$\alpha $$ α makes the scalar waves decay slowly, while the increase of the spacetime dimension makes the scalar waves decay fast. In addition, we study the influence of parameter $$\alpha $$ α on the shadow radius of this high-dimensional Schwarzschild STVG black hole and find that the increase of parameter $$\alpha $$ α makes the black hole shadow radius increase, but the increase of the spacetime dimension makes the black hole shadow radius decrease. Finally, we investigate the energy emission rate of the high-dimensional Schwarzschild STVG black hole, and find that the increase of parameter $$\alpha $$ α makes the evaporation process slow, while the increase of the spacetime dimension makes the process fast.

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