BARYOGENESIS FROM BLACK HOLE EVAPORATION

1995 ◽  
Vol 04 (04) ◽  
pp. 517-529 ◽  
Author(s):  
A.S. MAJUMDAR ◽  
P. DAS GUPTA ◽  
R.P. SAXENA

The possibility of baryogenesis through the evaporation of black holes formed during extended inflation is explored. These black holes are produced due to the collapse of trapped regions of false vacuum during the inflationary phase transition. Immediately after formation, the accretion of mass from the surrounding hot radiation bath in the universe is shown to be an important effect. This causes the lifetime of the black holes to be considerably elongated before they evaporate out through the process of Hawking radiation. It is shown that a sufficient number of black holes last up to well past the electroweak era and hence contribute to the surviving baryon asymmetry in the universe.

2019 ◽  
Vol 28 (08) ◽  
pp. 1950102
Author(s):  
Muhammad Rizwan ◽  
Khalil Ur Rehman

By considering the quantum gravity effects based on generalized uncertainty principle, we give a correction to Hawking radiation of charged fermions from accelerating and rotating black holes. Using Hamilton–Jacobi approach, we calculate the corrected tunneling probability and the Hawking temperature. The quantum corrected Hawking temperature depends on the black hole parameters as well as quantum number of emitted particles. It is also seen that a remnant is formed during the black hole evaporation. In addition, the corrected temperature is independent of an angle [Formula: see text] which contradicts the claim made in the literature.


2020 ◽  
Vol 10 (24) ◽  
pp. 8868
Author(s):  
Stefano Liberati ◽  
Giovanni Tricella ◽  
Andrea Trombettoni

We study the back-reaction associated with Hawking evaporation of an acoustic canonical analogue black hole in a Bose–Einstein condensate. We show that the emission of Hawking radiation induces a local back-reaction on the condensate, perturbing it in the near-horizon region, and a global back-reaction in the density distribution of the atoms. We discuss how these results produce useful insights into the process of black hole evaporation and its compatibility with a unitary evolution.


2002 ◽  
Vol 17 (20) ◽  
pp. 2721-2725 ◽  
Author(s):  
RENAUD PARENTANI

The study of acoustic black holes has been undertaken to provide new insights about the role of high frequencies in black hole evaporation. Because of the infinite gravitational redshift from the event horizon, Hawking quanta emerge from configurations which possessed ultra high (trans-Planckian) frequencies. Therefore Hawking radiation cannot be derived within the framework of a low energy effective theory; and in all derivations there are some assumptions concerning Planck scale physics. The analogy with condensed matter physics was thus introduced to see if the asymptotic properties of the Hawking phonons emitted by an acoustic black hole, namely stationarity and thermality, are sensitive to the high frequency physics which stems from the granular character of matter and which is governed by a non-linear dispersion relation. In 1995 Unruh showed that they are not sensitive in this respect, in spite of the fact that phonon propagation near the (acoustic) horizon drastically differs from that of photons. In 2000 the same analogy was used to establish the robustness of the spectrum of primordial density fluctuations in inflationary models. This analogy is currently stimulating research for experimenting Hawking radiation. Finally it could also be a useful guide for going beyond the semi-classical description of black hole evaporation.


2018 ◽  
Vol 27 (14) ◽  
pp. 1847028 ◽  
Author(s):  
Ana Alonso-Serrano ◽  
Mariusz P. Da̧browski ◽  
Hussain Gohar

The existence of a minimal length, predicted by different theories of quantum gravity, can be phenomenologically described in terms of a generalized uncertainty principle. We consider the impact of this quantum gravity motivated effect onto the information budget of a black hole and the sparsity of Hawking radiation during the black hole evaporation process. We show that the information is not transmitted at the same rate during the final stages of the evaporation, and that the Hawking radiation is not sparse anymore when the black hole approaches the Planck mass.


2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Kohki Kawabata ◽  
Tatsuma Nishioka ◽  
Yoshitaka Okuyama ◽  
Kento Watanabe

Abstract We consider the capacity of entanglement in models related with the gravitational phase transitions. The capacity is labeled by the replica parameter which plays a similar role to the inverse temperature in thermodynamics. In the end of the world brane model of a radiating black hole the capacity has a peak around the Page time indicating the phase transition between replica wormhole geometries of different types of topology. Similarly, in a moving mirror model describing Hawking radiation the capacity typically shows a discontinuity when the dominant saddle switches between two phases, which can be seen as a formation of island regions. In either case we find the capacity can be an invaluable diagnostic for a black hole evaporation process.


2013 ◽  
Vol 22 (07) ◽  
pp. 1350037 ◽  
Author(s):  
R. TORRES ◽  
F. FAYOS ◽  
O. LORENTE-ESPÍN

We consider the emission of Hawking radiation by black holes as a consequence of a tunneling process. By requiring energy conservation in the derivation of the emission rate we get a well-known deviation from an exact thermal spectrum. A model that takes into account the implications of energy conservation, as well as the back-scattered radiation, is then constructed in order to describe the evolution of black holes as they evaporate. The evaporation process in this model is compared with the results in the standard "thermal" approximation. This allows us to point out the relevance that energy conservation might have in the last stages of black hole evaporation. We also comment about the possible implications of energy conservation in the information loss paradox.


2020 ◽  
pp. 2150006
Author(s):  
Ivan Arraut

We study the analogy between the Hawking radiation in Black-Holes and the quantum depletion process of a Bose–Einstein condensate by using the Bogoliubov transformations method. We find that the relation between the Bogoliubov coefficients is similar in both cases (in the appropriate regimes). We then connect the condensate variables with those associated to the Black-Hole, demonstrating then that the zero temperature regime of the condensate is equivalent to the existence of an event horizon in gravity.


2021 ◽  
Vol 51 (2) ◽  
Author(s):  
Erik Aurell ◽  
Michał Eckstein ◽  
Paweł Horodecki

AbstractAlmost all of the entropy in the universe is in the form of Bekenstein–Hawking (BH) entropy of super-massive black holes. This entropy, if it satisfies Boltzmann’s equation $$S=\log \mathcal{N}$$ S = log N , hence represents almost all the accessible phase space of the Universe, somehow associated to objects which themselves fill out a very small fraction of ordinary three-dimensional space. Although time scales are very long, it is believed that black holes will eventually evaporate by emitting Hawking radiation, which is thermal when counted mode by mode. A pure quantum state collapsing to a black hole will hence eventually re-emerge as a state with strictly positive entropy, which constitutes the famous black hole information paradox. Expanding on a remark by Hawking we posit that BH entropy is a thermodynamic entropy, which must be distinguished from information-theoretic entropy. The paradox can then be explained by information return in Hawking radiation. The novel perspective advanced here is that if BH entropy counts the number of accessible physical states in a quantum black hole, then the paradox can be seen as an instance of the fundamental problem of statistical mechanics. We suggest a specific analogy to the increase of the entropy in a solvation process. We further show that the huge phase volume ($$\mathcal{N}$$ N ), which must be made available to the universe in a gravitational collapse, cannot originate from the entanglement between ordinary matter and/or radiation inside and outside the black hole. We argue that, instead, the quantum degrees of freedom of the gravitational field must get activated near the singularity, resulting in a final state of the ‘entangled entanglement’ form involving both matter and gravity.


Author(s):  
Charles D. Bailyn

This chapter explores some of the predicted effects of black holes on people's lives and the possibility that they might someday be explored in fact as well as in fiction. These predicted effects include the Hawking radiation, wormholes, and multiverses. The Hawking radiation—in which the interaction between quantum mechanics and relativity has been explored with some success—is a process through which black holes are expected to emit energy and ultimately evaporate. Meanwhile, one of the most enticing possible effects associated with black holes is that they might form wormholes through which widely separated parts of the Universe can be closely connected. Lastly, one final suggestion that might be contemplated is that a separate universe might exist inside the event horizon of a black hole. This is one version of the multiverse concept, in which a variety of universes with a variety of characteristics exist.


2020 ◽  
Vol 18 ◽  
pp. 143-149
Author(s):  
Sayed El-Mongy

Read is the first word and divine order in the Holy Quran. My lovely physics does not answer many mysteries in the universe including black holes. The observed ordinary matter in the universe is only ~5 %. The remaining is 27% dark matter and approximately 68% dark energy of. This paper introduces a developed model and concept to black hole anatomy and entropy-surface area correlation. It considers the stationary black hole a one entity of 4 concentric spheres around the singularity. They are the event horizon, photon sphere at 1.5Rs, unstable light sphere at 2.6Rs and innermost stable particle sphere at 3Rs. An equation (Sayed Ts formula) was derived excluded heuristics of Professor S. Hawking. This formula is based on different proportional constant between entropy and black hole surface area; not ¼ as He conjectured. In spite of my respect and humanity sympathy with Prof. Hawking, his tombstone equation should be corrected. There is neither radiation escape from black holes nor any signal detected due to micro black holes evaporation. Finally, it can be stated that Hawking radiation is Nothing.


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