scholarly journals A nonsingular, anisotropic universe in a black hole with torsion and particle production

2021 ◽  
Vol 53 (2) ◽  
Author(s):  
Nikodem J. Popławski
1992 ◽  
Vol 01 (01) ◽  
pp. 169-191 ◽  
Author(s):  
R. PARENTANI ◽  
R. BROUT

Using tunneling concepts which account for particle production in the cases of an accelerated detector and a static electric Field in Minkowski space, the more elusive case of black hole evaporation is analyzed in terms of a detailed tunneling mechanism. For the case of the incipient black hole (collapsing star) Hawking’s “heuristic” picture in terms of pair creation, wherein one member crosses the horizon to fall into the singularity as the other is emitted to infinity, is established. The inception of tunneling is due to the motion of the star’s surface, but its completion concerns traversal of the horizon, thereby reconciling varying schools of thought concerning this problem.


1987 ◽  
Vol 02 (05) ◽  
pp. 1591-1615 ◽  
Author(s):  
V.A. BEREZIN

A method for the phenomenological description of particle production is proposed. Correspondingly modified equations of motion and energy-momentum tensor are obtained. In order to illustrate this method we reconsider from the new point of view of (i) the C-field Hoyle-Narlikar cosmology, (ii) the influence of the particle production process on metric inside the event horizon of a charged black hole and (iii) a nonsingular cosmological model.


Universe ◽  
2020 ◽  
Vol 6 (10) ◽  
pp. 178
Author(s):  
Kirill Bronnikov ◽  
Sergey Bolokhov ◽  
Milena Skvortsova

We discuss the properties of the previously constructed model of a Schwarzschild black hole interior where the singularity is replaced by a regular bounce, ultimately leading to a white hole. We assume that the black hole is young enough so that the Hawking radiation may be neglected. The model is semiclassical in nature and uses as a source of gravity the effective stress-energy tensor (SET) corresponding to vacuum polarization of quantum fields, and the minimum spherical radius is a few orders of magnitude larger than the Planck length, so that the effects of quantum gravity should still be negligible. We estimate the other quantum contributions to the effective SET, caused by a nontrivial topology of spatial sections and particle production from vacuum due to a nonstationary gravitational field and show that these contributions are negligibly small as compared to the SET due to vacuum polarization. The same is shown for such classical phenomena as accretion of different kinds of matter to the black hole and its further motion to the would-be singularity. Thus, in a clear sense, our model of a semiclassical bounce instead of a Schwarzschild singularity is stable under both quantum and classical perturbations.


2017 ◽  
Vol 26 (03) ◽  
pp. 1750001 ◽  
Author(s):  
Abdel Nasser Tawfik ◽  
Hayam Yassin ◽  
Eman R. Abo Elyazeed

The assumption that the production of quark–antiquark pairs and their sequential string-breaking takes place, likely as a tunneling process, through the event horizon of the color confinement determines the freezeout temperature and gives a plausible interpretation for the thermal pattern of elementary and nucleus–nucleus collisions. When relating the black-hole electric charges to the baryon-chemical potentials, it was found that the phenomenologically deduced parameters from the ratios of various particle species and the higher-order moments of net-proton multiplicity in the statistical thermal models and Polyakov linear-sigma model agree well with the ones determined from the thermal radiation from charged black hole. Accordingly, the resulting freezeout conditions, such as normalized entropy density [Formula: see text] and average energy per particle [Formula: see text][Formula: see text]GeV, are confirmed at finite chemical potentials as well. Furthermore, the problem of strangeness production in elementary collisions can be interpreted by thermal particle production from the Hawking–Unruh radiation. Consequently, the freezeout temperature depends on the quark masses. This leads to a deviation from full equilibrium and thus a suppression of the strangeness production in the elementary collisions. But in nucleus–nucleus collisions, an average temperature should be introduced in order to dilute the quark masses. This nearly removes the strangeness suppression. An extension to finite chemical potentials is introduced. The particle ratios of kaon-to-pion ([Formula: see text]), phi-to-kaon ([Formula: see text]) and antilambda-to-pion ([Formula: see text]) are determined from Hawking–Unruh radiation and compared with the thermal calculations and the measurements in different experiments. We conclude that these particle ratios can be reproduced, at least qualitatively, as Hawking–Unruh radiation at finite chemical potential. With increasing energy, both [Formula: see text] and [Formula: see text] keep their maximum values at low SPS energies. But the further energy decrease rapidly reduces both ratios. For [Formula: see text], there is an increase with increasing [Formula: see text], i.e., no saturation is to be observed.


2005 ◽  
Vol 14 (11) ◽  
pp. 1919-1925 ◽  
Author(s):  
SISIR BHANJA ◽  
SUBENOY CHAKRABORTY ◽  
UJJAL DEBNATH

Here we study an anisotropic model of the universe with constant energy per particle. A decaying cosmological constant and particle production in an adiabatic process are considered as the sources for the entropy. The statefinder parameters {r, s} are defined and their behavior are analyzed graphically in some cases.


Sign in / Sign up

Export Citation Format

Share Document