scholarly journals Correspondences of matter fluctuations in semiclassical and classical gravity for cosmological spacetime

2019 ◽  
Vol 100 (4) ◽  
Author(s):  
Seema Satin
2021 ◽  
Vol 103 (12) ◽  
Author(s):  
I. Prasetyo ◽  
H. S. Ramadhan ◽  
A. Sulaksono

2011 ◽  
Vol 21 (08) ◽  
pp. 2279-2283 ◽  
Author(s):  
PIERFRANCESCO DI CINTIO ◽  
LUCA CIOTTI

The process of relaxation of a system of particles interacting with long-range forces is relevant to many areas of physics. For obvious reasons, in Stellar Dynamics much attention has been paid to the case of r-2force law. However, recently the interest in alternative gravities has emerged, and significant differences with respect to Newtonian gravity have been found in relaxation phenomena. Here we begin to explore this matter further, by using a numerical model of spherical shells interacting with an r-αforce law obeying the superposition principle. We find that the virialization and phase-mixing times depend on the exponent α, with small values of α corresponding to longer relaxation times, similarly to what happens when comparing for N-body simulations in classical gravity and in Modified Newtonian Dynamics.


1998 ◽  
Vol 39 (1) ◽  
pp. 423-442 ◽  
Author(s):  
J. Madore ◽  
J. Mourad

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1001-1004
Author(s):  
SAMIR D. MATHUR

Results from string theory strongly suggest that formation and evaporation of black holes is a unitary process. Thus we must find a flaw in the semiclassical reasoning that implies a loss of information. We propose a new criterion that limits the domain of classical gravity: the hypersurfaces of a foliation cannot be stretched too much.


Innotrans ◽  
2020 ◽  
pp. 31-36
Author(s):  
Alexander V. Martynenko ◽  
◽  
Alexander A. Shevtsov ◽  

This paper is devoted to the quantitative description of the spatial distribution of passenger traffic based on the classical gravity model on the example of interurban bus service between Yekaterinburg and other cities of the Sverdlovsk region. The influence of factors such as population, distance between localities, and ticket price on the volume of passenger traffic was studied. As a result of the correlation and regression analysis, it was found that both the distance between localities and the ticket price can be used as a measure of the remoteness of localities. However, the quality of the resulting regression model does not change. The spatial distribution of interurban bus passenger traffic depends on the measure of distance of localities from each other and the size of their population. Moreover, the size of the population is a much more significant factor than the measure of distance. From a practical point of view, this means that when predicting passenger traffic, demographic factors must first be taken into account.


2019 ◽  
Vol 16 (04) ◽  
pp. 1950057
Author(s):  
D. J. Hurley ◽  
M. A. Vandyck

The Newton–Cartan theory of gravity is expressed in the language of [Formula: see text]-differentiation. A characteristic of this approach is that the same framework accommodates, together with classical gravity, also non-relativistic Quantum Mechanics (coupled to gravity), both in its standard Schrödingerian form and in that of de Broglie and Bohm.


2020 ◽  
Vol 35 (39) ◽  
pp. 2050326
Author(s):  
Abdul Jawad ◽  
Shahid Chaudhary

Among many open questions in theoretical physics, consistent quantum gravity theory is still a major issue to be solved. Recent major works in phase transitions of black holes (BH) can be helpful for quantum interpretation of classical gravity. We study the new effective method to discuss the thermodynamic phase transitions onto well renowned regular BHs. Ordinary approaches of phase transitions depend upon equation of state and it is impossible to obtain all critical points with ordinary approaches. This study is derived from the slope of temperature versus entropy and it provides the possibility of finding all the critical points analytically. This technique provides pressure, which is different from standard relation of pressure and independent of other thermodynamical relations. We discuss some issues in ordinary methods and provide an easy approach to investigate the critical behavior of thermodynamical quantities. We find out the phase transitions points and horizon radii of non-physical range for BHs. We also use the new thermodynamical relations to briefly study well-known Joule–Thomson (JT) effect on regular BH.


2007 ◽  
Vol 22 (38) ◽  
pp. 2939-2946
Author(s):  
M. O. TAHIM ◽  
C. A. S. ALMEIDA

In the celebrated Plebanski formalism of topological gravity, the constraints connecting topological field theories and gravity are imposed in spacetimes with trivial topology. In the braneworld context there are two distinct regions of the spacetime, namely, the bulk and the braneworld volume. In this work we show how to construct topological classical gravity in a scenario containing one extra dimension and a δ-function like three-brane which naturally emerges from a spontaneously broken discrete symmetry. Starting from a D = 5 theory we obtain the action for General Relativity in the Palatini form in the bulk as well as in the braneworld volume. This result is important for future insights about quantum gravity on brane scenarios.


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