Tyger
Paranormal Adept
Backreaction of Hawking radiation on a gravitationally collapsing star I: Black holes?
Physics Letters B
Volume 738, 10 November 2014, Pages 61–67
LINK: Backreaction of Hawking radiation on a gravitationally collapsing star I: Black holes?
Physics Letters B
Volume 738, 10 November 2014, Pages 61–67
LINK: Backreaction of Hawking radiation on a gravitationally collapsing star I: Black holes?
TEXT: "Abstract
"Particle creation leading to Hawking radiation is produced by the changing gravitational field of the collapsing star. The two main initial conditions in the far past placed on the quantum field from which particles arise, are the Hartle–Hawking vacuum and the Unruh vacuum. The former leads to a time-symmetric thermal bath of radiation, while the latter to a flux of radiation coming out of the collapsing star. The energy of Hawking radiation in the interior of the collapsing star is negative and equal in magnitude to its value at future infinity. This work investigates the backreaction of Hawking radiation on the interior of a gravitationally collapsing star, in a Hartle–Hawking initial vacuum. It shows that due to the negative energy Hawking radiation in the interior, the collapse of the star stops at a finite radius, before the singularity and the event horizon of a black hole have a chance to form. That is, the star bounces instead of collapsing to a black hole. A trapped surface near the last stage of the star's collapse to its minimum size may still exist temporarily. Its formation depends on the details of collapse. Results for the case of Hawking flux of radiation with the Unruh initial state, will be given in a companion paper II.
1. Introduction
"The backreaction of Hawking radiation onto a star collapsing into a black hole, is a long standing problem of major importance. It carries the tantalizing possibility that black holes may not form at all. Hawking radiation arises as particle creation from curved space–time quantum field theory. Therefore if its backreaction on the star's dynamics is significant, it would provide an example of the crucial role quantum effects play on strong gravitational fields such as those of massive imploding stars.
"In 1939, Oppenheimer and Snyder, found that the ultimate fate of a spherically symmetric collapsing star is a collapse to a black hole. In 1974 and 1975, Hawking, then Parker, found that quantum effects from the curved space time produced by the strong gravitational field of a star collapsing into a black hole, give rise to a thermal flux of particle production, known as Hawking radiation.
"Despite the efforts devoted to understanding the physics of black holes since Hawking's discovery of radiation, the main stumbling block in these efforts has been the issue of information loss paradox stated in various forms. One of the most spectacular paradoxes stemming from the information loss mystery, is the recent 'firewall' problem raised in, then followed by the forecasting of.
"Amidst all the puzzles and paradoxes, a trivial possibility is that black holes may not form. This possibility is the focus of the current study. Within a set of approximations, such as assumptions of spherical symmetry and homogeneity of a star collapsing into a black hole, this work shows that a black hole may not form when the backreaction of the quantum flux of particles created is taken into account in the collapse dynamics of the star.
"In the next stage of this investigation, we drop some of the assumptions made here in solving the 4-dimensional Einstein equations for the interior of the collapsing star with a radiation flux, and use the Unruh vacuum as the initial state of the quantum field in the far past. Those results and their comparison to the method presented here will be given elsewhere."
[See linked article for analysis.]
"Particle creation leading to Hawking radiation is produced by the changing gravitational field of the collapsing star. The two main initial conditions in the far past placed on the quantum field from which particles arise, are the Hartle–Hawking vacuum and the Unruh vacuum. The former leads to a time-symmetric thermal bath of radiation, while the latter to a flux of radiation coming out of the collapsing star. The energy of Hawking radiation in the interior of the collapsing star is negative and equal in magnitude to its value at future infinity. This work investigates the backreaction of Hawking radiation on the interior of a gravitationally collapsing star, in a Hartle–Hawking initial vacuum. It shows that due to the negative energy Hawking radiation in the interior, the collapse of the star stops at a finite radius, before the singularity and the event horizon of a black hole have a chance to form. That is, the star bounces instead of collapsing to a black hole. A trapped surface near the last stage of the star's collapse to its minimum size may still exist temporarily. Its formation depends on the details of collapse. Results for the case of Hawking flux of radiation with the Unruh initial state, will be given in a companion paper II.
1. Introduction
"The backreaction of Hawking radiation onto a star collapsing into a black hole, is a long standing problem of major importance. It carries the tantalizing possibility that black holes may not form at all. Hawking radiation arises as particle creation from curved space–time quantum field theory. Therefore if its backreaction on the star's dynamics is significant, it would provide an example of the crucial role quantum effects play on strong gravitational fields such as those of massive imploding stars.
"In 1939, Oppenheimer and Snyder, found that the ultimate fate of a spherically symmetric collapsing star is a collapse to a black hole. In 1974 and 1975, Hawking, then Parker, found that quantum effects from the curved space time produced by the strong gravitational field of a star collapsing into a black hole, give rise to a thermal flux of particle production, known as Hawking radiation.
"Despite the efforts devoted to understanding the physics of black holes since Hawking's discovery of radiation, the main stumbling block in these efforts has been the issue of information loss paradox stated in various forms. One of the most spectacular paradoxes stemming from the information loss mystery, is the recent 'firewall' problem raised in, then followed by the forecasting of.
"Amidst all the puzzles and paradoxes, a trivial possibility is that black holes may not form. This possibility is the focus of the current study. Within a set of approximations, such as assumptions of spherical symmetry and homogeneity of a star collapsing into a black hole, this work shows that a black hole may not form when the backreaction of the quantum flux of particles created is taken into account in the collapse dynamics of the star.
"In the next stage of this investigation, we drop some of the assumptions made here in solving the 4-dimensional Einstein equations for the interior of the collapsing star with a radiation flux, and use the Unruh vacuum as the initial state of the quantum field in the far past. Those results and their comparison to the method presented here will be given elsewhere."
[See linked article for analysis.]
I circle back a lot on older videos. All good. 
