DYNAMICAL TIME VARIABLE IN COSMOLOGY

1988 ◽  
Vol 03 (04) ◽  
pp. 333-343
Author(s):  
TAKESHI FUKUYAMA ◽  
KIYOSHI KAMIMURA
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Time Variable ◽  
Gravity Theory ◽  
Two Dimensional ◽  
Maximum Radius ◽  
Dynamical Time ◽  
Dimensional Gravity ◽  
Time Variables ◽  
The Universe

Dynamical time variables are studied in two dimensional gravity theory. Dynamical time and space variables exchange their role at the maximum radius (amax) like a black hole at event horizon. Dynamical arrows of time are directed towards amax in both expanding and contracting phases. Both time flows cannot go beyond amax, and the universe becomes static at amax.

Chiral modular bootstrap

2019 ◽  
Vol 34 (28) ◽  
pp. 1950168 ◽  
Author(s):  
M. Ashrafi
Keyword(s):  
Black Hole ◽  
Upper Bound ◽  
Three Dimensional ◽  
Conformal Weight ◽  
Two Dimensional ◽  
Btz Black Hole ◽  
Conformal Field ◽  
Dimensional Gravity ◽  
Large Spin ◽  
Dimension Ratio

Using modular bootstrap we show the lightest primary fields of a unitary compact two-dimensional conformal field theory (with [Formula: see text], [Formula: see text]) has a conformal weight [Formula: see text]. This implies that the upper bound on the dimension of the lightest primary fields depends on their spin. In particular if the set of lightest primary fields includes extremal or near extremal states whose spin to dimension ratio [Formula: see text], the corresponding dimension is [Formula: see text]. From AdS/CFT correspondence, we obtain an upper bound on the spectrum of black hole in three-dimensional gravity. Our results show that if the first primary fields have large spin, the corresponding three-dimensional gravity has extremal or near extremal BTZ black hole.

scholarly journals A Note on the Observational Evidence for the Existence of Event Horizons in Astrophysical Black Hole Candidates

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Cosimo Bambi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Electromagnetic Radiation ◽  
Event Horizon ◽  
Observational Evidence ◽  
Short Paper ◽  
Event Horizons ◽  
Internal Region ◽  
The Universe ◽  
Black Hole Candidates

Black holes have the peculiar and intriguing property of having an event horizon, a one-way membrane causally separating their internal region from the rest of the Universe. Today, astrophysical observations provide some evidence for the existence of event horizons in astrophysical black hole candidates. In this short paper, I compare the constraint we can infer from the nonobservation of electromagnetic radiation from the putative surface of these objects with the bound coming from the ergoregion instability, pointing out the respective assumptions and limitations.

INTERSECTION THEORY AND TWO-DIMENSIONAL GRAVITY AT GENUS 3 AND 4

1990 ◽  
Vol 05 (26) ◽  
pp. 2127-2134 ◽  
Author(s):  
JAMES H. HORNE
Keyword(s):  
Moduli Space ◽  
Intersection Theory ◽  
Gravity Theory ◽  
Two Dimensional ◽  
Intersection Numbers ◽  
Dimensional Gravity

We show that the k = 1 two-dimensional gravity amplitudes at genus 3 agree precisely with the results from intersection theory on moduli space. Predictions for the genus 4 intersection numbers follow easily from the two-dimensional gravity theory.

scholarly journals On the Identical Simulation of the Entire Universe

2016 ◽  
Author(s):  
Mesut Kavak
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Power Series ◽  
Event Horizon ◽  
Free Space ◽  
Irrational Number ◽  
Quadratic Equations ◽  
Entire Universe ◽  
The Universe ◽  
Irrational Values

A time ago, I published an article about deceleration of the universe. It was especially based on uncertainty, and it explains how does matter work. In this work, it was performed some analysis of the some specific subjects as an approach such as deceleration, uncertainty, possible particle formation, black hole, gravitation, energy, mass and light speed as the elements for identical simulation computations of the entire universe as the most sensitive as possible being related that article. There are some information about escaping from black holes, event horizon lengths, viscosity of free space, re-derivation of Planck constants and infrastructure of some basic laws of existence mathematically as matter is directly dependent of geometric rules. Also, some elements were given for the readers to solve some required constants as the most sensitive manner. As the constants are not enough in the name of engineering, also finally I found a working algorithm out which reduces process number of the power series to process number of the quadratic equations like calculating a root of an integer as an irrational number by solving equation; so also it can be used to calculate trigonometric values in the best manner for simulations of the entire universe besides physical constants as irrational values.

CANONICAL DESCRIPTION OF A TWO-DIMENSIONAL GRAVITY

1992 ◽  
Vol 07 (19) ◽  
pp. 1757-1764 ◽  
Author(s):  
K.G. AKDENIZ ◽  
Ö.F. DAYI ◽  
A. KIZILERSÜ
Keyword(s):  
Degrees Of Freedom ◽  
Mass Shell ◽  
Gravity Theory ◽  
Two Dimensional ◽  
Lagrangian Methods ◽  
Hamiltonian Methods ◽  
Dimensional Gravity ◽  
Conformal Gauge

A two-dimensional gravity theory which was studied before within the Lagrangian methods, in the conformal gauge is investigated in terms of the Hamiltonian methods. Although the reparametrization invariant and the conformal gauge fixed Lagrangians lead to different number of physical degrees of freedom, it is shown that on mass-shell they are equivalent.

scholarly journals Study of black hole as dissipative structure using negentropy

2016 ◽  
Vol 94 (10) ◽  
pp. 960-966
Author(s):  
Shripad P. Mahulikar ◽  
Pallavi Rastogi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Theoretical Investigation ◽  
Infinite Number ◽  
Dissipative Structure ◽  
Dissipative Structures ◽  
Area Theorem ◽  
Entropy Increase ◽  
The Universe

The area of the event horizon of a black hole (Aeh) is so far linked only with its entropy (SBH). In this theoretical investigation, it is shown that relating Aeh only to SBH is inadequate, because Aeh is linked to the black hole’s negentropy, which encompasses its entropy. Increasing Aeh of black holes that grow now follows from the negentropy theorem (NET) and also from the well-known area theorem. The decreasing Aeh of black holes that decay follows from the converse to NET and is not a violation of the area theorem. The corollary to NET is proved for the case when two dissipative structures merge, which is the basis for the coalescence of black holes. The converse of corollary to NET explains negentropy loss due to splitting of a dissipative structure. When applied to black hole explosion (i.e., splitting into an infinite number of parts), converse of corollary to NET reduces to converse of NET. The entropy/energy ratio of the exported Hawking radiance from black holes contributes to the entropy increase of the universe. These aspects justify the consideration of black holes as thermodynamic dissipative structures.

scholarly journals THERMODYNAMICAL LAWS IN HOŘAVA–LIFSHITZ GRAVITY

2011 ◽  
Vol 20 (07) ◽  
pp. 1191-1204 ◽  
Author(s):  
SAMARPITA BHATTACHARYA ◽  
UJJAL DEBNATH
Keyword(s):  
Black Hole ◽  
Dark Energy ◽  
Black Hole Entropy ◽  
Gravity Theory ◽  
Robust Approach ◽  
Barotropic Fluid ◽  
Extra Information ◽  
Thermodynamical Laws ◽  
The Universe

In this work, we investigate the validity of the GSL of thermodynamics in the universe (open, closed and flat) governed by Hořava–Lifshitz (HL) gravity. If the universe contains barotropic fluid, we obtain the corresponding solutions. The validity of the GSL is examined by two approaches: (i) the robust approach and (ii) the effective approach. In the robust approach, we consider that the universe contains only matter fluid. Also, the effect of the gravitational sector of HL gravity is incorporated through the modified black hole entropy on the horizon. The effective approach is that all extra information of HL gravity is cast into an effective dark energy fluid, and so we consider that the universe contains matter fluid plus this effective fluid. This approach is essentially the same as Einstein's gravity theory. The general prescription for the validity of the GSL is discussed. Graphically, we show that the GSL may be satisfied for the open, closed and flat universes on the different horizons with different conditions.

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