scholarly journals QUANTUM CORRECTIONS TO ENTROPY OF CHARGED DILATONIC BLACK HOLES IN ARBITRARY DIMENSIONS

1994 ◽  
Vol 09 (38) ◽  
pp. 3509-3516 ◽  
Author(s):  
KIYOSHI SHIRAISHI

The quantum contribution of a scalar field to entropy of a dilatonic black hole is calculated in the brick wall model by the WKB method and analyzed by a high-temperature expansion. If the cutoff distance from the horizon approaches zero, the leading divergent piece of entropy turns out to be proportional to the “area” of the horizon surface (which has (N−1)-dimensional extension in (N+1)-dimensional space-time) and independent of other properties of black holes even in the case of general dilaton coupling. There is also qualitative argument with the known result of subleading divergence for N=3.

2019 ◽  
Vol 97 (12) ◽  
pp. 1317-1322
Author(s):  
Abeer Al-Modlej ◽  
Salwa Alsaleh ◽  
Hassan Alshal ◽  
Ahmed Farag Ali

Virtual black holes in noncommutative space–time are investigated using coordinate coherent state formalism such that the event horizon of a black hole is manipulated by smearing it with a Gaussian of width [Formula: see text], where θ is the noncommutativity parameter. Proton lifetime, the main associated phenomenology of the noncommutative virtual black holes, has been studied, first in four-dimensional space–time and then generalized to D dimensions. The lifetime depends on θ and the number of space–time dimensions such that it emphasizes on the measurement of proton lifetime as a potential probe for the microstructure of space–time.


2013 ◽  
Vol 91 (1) ◽  
pp. 64-70 ◽  
Author(s):  
J. Sadeghi ◽  
A. Banijamali ◽  
E. Reisi

In this paper, using the Hamilton–Jacobi method we first calculate the Hawking temperature for a Horava–Lifshitz black hole. Then by utilizing the radial null geodesic method we obtain the entropy of such a black hole in four-dimensional space–time. We also consider the effect of back reaction on the surface gravity and compute modifications of entropy and Hawking temperature because of such an effect. Our calculations are for two kinds of Horava–Lifshitz black holes: Kehagias–Sfetsos and Lu–Mei–Pope.


2007 ◽  
Vol 22 (11) ◽  
pp. 2021-2045 ◽  
Author(s):  
C. CASTRO ◽  
J. A. NIETO

We study black hole-like solutions (space–times with singularities) of Einstein field equations in 3+1 and 2+2 dimensions. We find three different cases associated with hyperbolic homogeneous spaces. In particular, the hyperbolic version of Schwarzschild's solution contains a conical singularity at r = 0 resulting from pinching to zero size r = 0 the throat of the hyperboloid [Formula: see text] and which is quite different from the static spherically symmetric (3+1)-dimensional solution. Static circular symmetric solutions for metrics in 2+2 are found that are singular at ρ = 0 and whose asymptotic ρ→∞ limit leads to a flat (1+2)-dimensional boundary of topology S1 × R2. Finally we discuss the (1+1)-dimensional Bars–Witten stringy black hole solution and show how it can be embedded into our (3+1)-dimensional solutions. Black holes in a (2+2)-dimensional "space–time" from the perspective of complex gravity in 1+1 complex dimensions and their quaternionic and octonionic gravity extensions deserve furher investigation. An appendix is included with the most general Schwarzschild-like solutions in D ≥ 4.


2010 ◽  
Vol 19 (08n10) ◽  
pp. 1253-1258
Author(s):  
I. RADINSCHI ◽  
T. GRAMMENOS

The energy distribution of black holes with a dilaton and a pure monopole field is calculated by using Møller's energy–momentum complex. The four-dimensional space–times considered are static, spherically symmetric and asymptotically flat, exact solutions stemming from an action that besides gravity contains a dilaton field and a pure monopole field. The resulting "hairy" black holes have an essential singularity at the origin and two horizons. The energy obtained depends on the value of the dilaton field, the monopole charge and the ADM mass. All the momenta vanish for the space–time geometries considered.


2019 ◽  
Author(s):  
Vitaly Kuyukov

Many approaches to quantum gravity consider the revision of the space-time geometry and the structure of elementary particles. One of the main candidates is string theory. It is possible that this theory will be able to describe the problem of hierarchy, provided that there is an appropriate Calabi-Yau geometry. In this paper we will proceed from the traditional view on the structure of elementary particles in the usual four-dimensional space-time. The only condition is that quarks and leptons should have a common emerging structure. When a new formula for the mass of the hierarchy is obtained, this structure arises from topological quantum theory and a suitable choice of dimensional units.


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