scholarly journals Black Hole Evaporation: Sparsity in Analogue and General Relativistic Space-Times

2021 ◽  
Author(s):  
◽  
Sebastian Schuster
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Dynamics ◽  
Black Body ◽  
Black Body Radiation ◽  
Physical Models ◽  
New Paradigm ◽  
Rigorous Results ◽  
Stephen Hawking ◽  
Grey Body

<p>Our understanding of black holes changed drastically, when Stephen Hawking discovered their evaporation due to quantum mechanical processes. One core feature of this effect, later named after him, is both its similarity and simultaneous dissimilarity to classical black body radiation as known from thermodynamics: A black hole’s spectrum certainly looks like that of a black (or at least grey) body, yet the number of emitted particles per unit time differs greatly. However it is precisely this emission rate that determines — together with the frequency of the emitted radiation — whether the resulting radiation field behaves classical or non-classical. It has been known nearly since the Hawking effect’s discovery that the radiation of a black hole is in this sense non-classical (unlike the radiation of a classical black or grey body). However, this has been an utterly underappreciated property. In order to give a more readily quantifiable picture of this, we introduced the notion of ‘sparsity’, which is easily evaluated, and interpreted, and agrees with more rigorous results despite a semi-classical, semi-analytical origin. Sadly, and much to relativists’ chagrin, astrophysical black holes (and their Hawking evaporation) have a tendency to be observationally elusive entities. Luckily, Hawking’s derivation lends itself to reformulations that survive outside its astrophysical origin — all one needs, are three things: a universal speed limit (like the speed of sound, the speed of light, the speed of surface waves, . . . ), a notion of a horizon (the ‘black hole’), and lastly a sprinkle of quantum dynamics on top. With these ingredients at hand, the last thirty-odd years have seen a lot of work to transfer Hawking radiation into the laboratory, using a range of physical models. These range from fluid mechanics, over electromagnetism, to Bose–Einstein condensates, and beyond. A large part of this thesis was then aimed at providing electromagnetic analogues to prepare an analysis of our notion of sparsity in this new paradigm. For this, we developed extensively a purely algebraic (kinematical) analogy based on covariant meta-material electrodynamics, but also an analytic (dynamical) analogy based on stratified refractive indices. After introducing these analogue space-time models, we explain why the notion of sparsity (among other things) is much</p>

scholarly journals Black Hole Evaporation: Sparsity in Analogue and General Relativistic Space-Times

2021 ◽  
Author(s):  
◽  
Sebastian Schuster
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Dynamics ◽  
Black Body ◽  
Black Body Radiation ◽  
Physical Models ◽  
New Paradigm ◽  
Rigorous Results ◽  
Stephen Hawking ◽  
Grey Body

<p>Our understanding of black holes changed drastically, when Stephen Hawking discovered their evaporation due to quantum mechanical processes. One core feature of this effect, later named after him, is both its similarity and simultaneous dissimilarity to classical black body radiation as known from thermodynamics: A black hole’s spectrum certainly looks like that of a black (or at least grey) body, yet the number of emitted particles per unit time differs greatly. However it is precisely this emission rate that determines — together with the frequency of the emitted radiation — whether the resulting radiation field behaves classical or non-classical. It has been known nearly since the Hawking effect’s discovery that the radiation of a black hole is in this sense non-classical (unlike the radiation of a classical black or grey body). However, this has been an utterly underappreciated property. In order to give a more readily quantifiable picture of this, we introduced the notion of ‘sparsity’, which is easily evaluated, and interpreted, and agrees with more rigorous results despite a semi-classical, semi-analytical origin. Sadly, and much to relativists’ chagrin, astrophysical black holes (and their Hawking evaporation) have a tendency to be observationally elusive entities. Luckily, Hawking’s derivation lends itself to reformulations that survive outside its astrophysical origin — all one needs, are three things: a universal speed limit (like the speed of sound, the speed of light, the speed of surface waves, . . . ), a notion of a horizon (the ‘black hole’), and lastly a sprinkle of quantum dynamics on top. With these ingredients at hand, the last thirty-odd years have seen a lot of work to transfer Hawking radiation into the laboratory, using a range of physical models. These range from fluid mechanics, over electromagnetism, to Bose–Einstein condensates, and beyond. A large part of this thesis was then aimed at providing electromagnetic analogues to prepare an analysis of our notion of sparsity in this new paradigm. For this, we developed extensively a purely algebraic (kinematical) analogy based on covariant meta-material electrodynamics, but also an analytic (dynamical) analogy based on stratified refractive indices. After introducing these analogue space-time models, we explain why the notion of sparsity (among other things) is much</p>

scholarly journals X-Ray Heated Accretion Discs Around Stellar Mass Black Holes

2004 ◽  
Vol 194 ◽  
pp. 200-201
Author(s):  
Ivan Hubeny ◽  
Dayal T. Wickramasinghe
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Vertical Structure ◽  
Black Body ◽  
Incident Radiation ◽  
Accretion Discs ◽  
Distribution Models ◽  
Solar Mass ◽  
X Ray ◽  
Low Mass

We investigate the effects of irradiation on the vertical structure of accretion discs around black holes and its impact on the emergent energy distribution. Models are presented for a 10 Solar mass black hole in a low mass X-ray binary assuming a black body spectrum for the incident radiation. We show that for a disc annulus at a given radius, the spectra become increasingly distorted as the incident flux increases relative to the viscously generated heating flux in the disc. Significant effects are apparent for rings even at distances of ~ 10,000 Schwarzschild radii from the black hole for realistic dilution factors.

scholarly journals Ten shades of black

2015 ◽  
Vol 24 (12) ◽  
pp. 1544007 ◽  
Author(s):  
Shahar Hod
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Radiation Spectrum ◽  
Black Hole Physics ◽  
Black Body ◽  
Black Hole Radiation ◽  
Dimensional Spacetime ◽  
Opposite Behavior ◽  
Curvature Potential ◽  
Energy Dependent

The holographic principle has taught us that, as far as their entropy content is concerned, black holes in (3 + 1)-dimensional curved spacetimes behave as ordinary thermodynamic systems in flat (2 + 1)-dimensional spacetimes. In this paper, we point out that the opposite behavior can also be observed in black-hole physics. To show this we study the quantum Hawking evaporation of near-extremal Reissner–Nordström (RN) black holes. We first point out that the black-hole radiation spectrum departs from the familiar radiation spectrum of genuine (3 + 1)-dimensional perfect black-body emitters. In particular, the would be black-body thermal spectrum is distorted by the curvature potential which surrounds the black-hole and effectively blocks the emission of low-energy quanta. Taking into account the energy-dependent gray-body factors which quantify the imprint of passage of the emitted radiation quanta through the black-hole curvature potential, we reveal that the (3 + 1)-dimensional black holes effectively behave as perfect black-body emitters in a flat (9 + 1)-dimensional spacetime.

ABOUT THE GENERALIZED UNCERTAINTY PRINCIPLE

2004 ◽  
Vol 19 (23) ◽  
pp. 1767-1779 ◽  
Author(s):  
LI XIANG ◽  
YOU-GEN SHEN
Keyword(s):  
Black Holes ◽  
Uncertainty Principle ◽  
Generalized Uncertainty Principle ◽  
Heuristic Method ◽  
Black Body ◽  
Black Body Radiation ◽  
State Equations ◽  
Black Hole Radiation ◽  
Logarithmic Corrections ◽  
Thermodynamics Of Black Holes

Some consequences of the generalized uncertainty principle (GUP) are investigated, including the deformations of the Wein's law and the state equations of black body radiation. The effects of the GUP on the thermodynamics of black holes are investigated by a heuristic method. A bound on the luminosity of the black hole radiation is obtained. The logarithmic corrections to the Bekenstein–Hawking entropy are obtained in three cases. The potential relation between the GUP and the holographic principle is also briefly discussed.

scholarly journals External energy paradigm for black holes

2018 ◽  
Vol 33 (31) ◽  
pp. 1844025 ◽  
Author(s):  
Yuan K. Ha
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Energy ◽  
Electrostatic Energy ◽  
New Paradigm ◽  
External Energy ◽  
Quantum Particles ◽  
Remarkable Result ◽  
The Moment ◽  
Constituent Mass

A new paradigm for black holes is introduced. It is known as the External Energy Paradigm. The paradigm asserts that all energies of a black hole are external quantities; they are absent inside the horizon. These energies include constituent mass, gravitational energy, electrostatic energy, rotational energy, heat energy, etc. As a result, quantum particles with charges and spins cannot exist inside the black hole. To validate the conclusion, we derive the moment of inertia of a Schwarzschild black hole and find that it is exactly equal to mass [Formula: see text] (Schwarzschild radius)2, indicating that all mass of the black hole is located at the horizon. This remarkable result can resolve several long-standing paradoxes in black hole theory; such as why entropy is proportional to area and not to volume, the singularity problem, the information loss problem and the perplexing firewall controversy.

scholarly journals The progress of mini black holes: principles and analytical astronomical observation techniques

2021 ◽  
Vol 2083 (2) ◽  
pp. 022040
Author(s):  
Jiatong Tan
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Astronomical Observation ◽  
Quantum Field ◽  
Prospective Development ◽  
Stephen Hawking ◽  
Mini Black Holes ◽  
Background Models ◽  
Shed Light

Abstract Mini-black hole (MBH) is a concept first proposed by Stephen Hawking in the 1970s. Normally, exploring MBHs will enhance the understanding of quantum theory and gravity theory as well as be helpful in predicting the configuration of the early universe. Based on information retrieval, this paper summarizes the progress of MBHs and takes three major aspects: background, models, practical methods for observations, and analysis. Specifically, the descriptive equations are derived, and different models are discussed separately. These results shed light on the prospective development of quantum field theorem, general relativity, and string theory.

scholarly journals HAWKING RADIATION: A PARTICLE PHYSICS PERSPECTIVE

1993 ◽  
Vol 08 (18) ◽  
pp. 1661-1670 ◽  
Author(s):  
MATT VISSER
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Decay Rate ◽  
Hawking Radiation ◽  
Particle Physics ◽  
Naked Singularity ◽  
Black Body ◽  
Large Mass ◽  
High Energy ◽  
Radiation Process

It has recently become fashionable to regard black holes as elementary particles. By taking this suggestion reasonably seriously it is possible to cobble together an elementary particle physics based on estimate for the decay rate (black hole) i → (black hole) f+ (massless quantum) . This estimate of the spontaneous emission rate contains two free parameters which may be fixed by demanding that the high energy end of the spectrum of emitted quanta match a black body spectrum at the Hawking temperature. The calculation, though technically trivial, has important conceptual implications: (1) The existence of Hawking radiation from black holes seems ultimately dependent only on the fact that massless quanta (and all other forms of matter) couple to gravity. (2) The essentially thermal nature of the Hawking spectrum seems to depend only on the fact that the number of internal states of a large mass black hole is enormous. (3) Remarkably, the resulting formula for the decay rate gives meaningful answers even when extrapolated to low mass black holes. The analysis seems to support the scenario of complete evaporation as the end point of the Hawking radiation process (no naked singularity, no stable massive remnant).

scholarly journals Black Hole - A Beginning, not the End

2021 ◽  
Vol 9 (VI) ◽  
pp. 1524-1525
Author(s):  
Purujit Malik
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Quantum Mechanics ◽  
General Theory ◽  
Hawking Radiation ◽  
Black Body ◽  
Physical Aspect ◽  
Theory Of Relativity ◽  
General Theory Of Relativity

A black hole is a region of space from which nothing, not even light, can escape. According to the general theory of relativity[2], it starts existing when spacetime gets curved by a huge mass. There is a sphere around the black hole. If something goes inside the sphere, it can not leave. This sphere is called the event horizon. A black hole is black because it absorbs all the light that hits it. It reflects nothing, just like a perfect black body in thermodynamics. Under quantum mechanics, black holes have a temperature and emit Hawking radiation, which makes them slowly get smaller.Because black holes are very hard to see, people trying to see them look for them by the way they affect other things near them. The place where there is a black hole can be found by tracking the movement of stars that orbit somewhere in space. Or people can find it when gas falls into a black hole, because the gas heats up and is very bright[1].However besides all these theories we still do not know what a black hole and dark matter is because all these theories rely on the much physical aspect of things and not on a unified understanding of creation.

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