The thermodynamics of black holes: from Penrose process to Hawking radiation

Almeida, Carla Rodrigues

doi:10.1140/epjh/s13129-021-00022-9

Cited by 10 publications

(6 citation statements)

References 38 publications

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“…Osmanov (2021c) proposed that the Fermi paradox may be resolved by the existence of many extraterrestrial civilizations hosting ring-like megastructures which produce signals similar to those from natural stellar oscillations and thus go unnoticed by humans. Almeida (2021) discussed Roger Penrose's proposal of a mechanism to extract rotational energy from a Kerr black hole in 1969. Hsiao et al (2021) explored various mechanisms by which a Dyson sphere around a black hole could power a Kardashev Type-II civilization, collecting radiation due to accretion as well as kinetic energy from jets, and described how such a structure might appear in spectral energy distributions.…”

Section: Target and Frequency Selection (12 Papers)mentioning

confidence: 99%

SETI in 2021

Huston,

Wright

2022

Preprint

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In this second installment of SETI in 20xx, we very briefly and subjectively review developments in SETI in 2021. Our primary focus is 93 papers and books published or made public in 2021, which we sort into six broad categories: results from actual searches, new search methods and instrumentation, target and frequency selection, the development of technosignatures, theory of ETIs, and social aspects of SETI.

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Section: Target and Frequency Selection (12 Papers)mentioning

confidence: 99%

SETI in 2021

Huston,

Wright

2022

Preprint

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“…Black holes, whether mathematical (MBH) or regular (RBH), correspond to = 0. UCOs with r 0 < 9 8 rg are excluded by the Buchdal theorem. Therefore the hypothetical horizonless alternatives to black holes whose models violate one or more assumptions of the theorem are exotic compact objects (ECOs).…”

Section: What Is a Black Hole?mentioning

confidence: 99%

“…The notion of a horizon has been particularly perplexing ever since Wheeler asked how black holes could be consistent with the second law of thermodynamics. 9 The problem was that a black hole, emitting nothing, must be an object of zero temperature, and so any hot object thrown into it would not heat up the black hole, in violation of the second law. The introduction of black hole entropy 10 and subsequently temperature 11 ameliorated this paradox and allowed black holes to be understood as thermodynamic objects.…”

Section: Introductionmentioning

confidence: 99%

Black holes and their horizons in semiclassical and modified theories of gravity

Mann,

Murk,

Terno

2021

Preprint

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For distant observers black holes are trapped spacetime domains bounded by apparent horizons. We review properties of the near-horizon geometry emphasizing the consequences of two common implicit assumptions of semiclassical physics. The first is a consequence of the cosmic censorship conjecture, namely that curvature scalars are finite at apparent horizons. The second is that horizons form in finite asymptotic time (i.e. according to distant observers), a property implicitly assumed in conventional descriptions of black hole formation and evaporation. Taking these as the only requirements within the semiclassical framework, we find that in spherical symmetry only two classes of dynamic solutions are admissible, both describing evaporating black holes and expanding white holes. We review their properties and present the implications. The null energy condition is violated in the vicinity of the outer and satisfied in the vicinity of the inner apparent/anti-trapping horizon. Apparent and anti-trapping horizons are timelike surfaces of intermediately singular behavior, which is demonstrated in negative energy density firewalls. These and other properties are also present in axially symmetric solutions. Different generalizations of surface gravity to dynamic spacetimes are discordant and do not match the semiclassical results. We conclude by discussing signatures of these models and implications for the identification of observed ultra-compact objects.

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“…In 1970, the work of Hawking and Bardeen led to the emergence of black hole (BH) thermodynamics [1,2]. The laws governing BH thermodynamics are closely related to thermodynamical laws, like energy and mass, entropy and area, and temperature and surface gravity.…”

Section: Introductionmentioning

confidence: 99%

An alternative approach to study the phase transitions and stability Analysis of Kerr-Newman-Kasuya black hole

Chaudhary¹,

Sultan

Rehman

et al. 2023

Phys. Scr.

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We present the alternative approach to study the thermodynamics of Kerr-Newman-Kasuya spacetime (rotating dyon black hole) through deflection angle. We first compute the deflection angle of the considered model by using the Gauss Bonnet theorem. After calculating the thermodynamical quantities, we observe that temperature fluctuations in the deflection angle can be used to deduce the stable and unstable phases. Then, looking into the Gibbs free energy optical dependency to the Hawking-Page transition. We demonstrate, among other things, that the transition between a large to small black hole takes place at a particular deflection angle value. Moreover, we also observe that heat capacity against deflection angle plays a vital role in the local stability of the Kerr-Newman-Kasuya spacetime.

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The thermodynamics of black holes: from Penrose process to Hawking radiation

Cited by 10 publications

References 38 publications

SETI in 2021

SETI in 2021

Black holes and their horizons in semiclassical and modified theories of gravity

An alternative approach to study the phase transitions and stability Analysis of Kerr-Newman-Kasuya black hole

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