5. Entropy and thermodynamics of black holes

2015 ◽  
Author(s):  
Katherine Blundell
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Holes ◽  
Black Hole ◽  
Quantum Field ◽  
Black Hole Evaporation ◽  
Stephen Hawking ◽  
Laws Of Thermodynamics ◽  
Black Hole Information ◽  
Thermodynamics Of Black Holes

‘Entropy and thermodynamics of black holes’ considers how the laws of thermodynamics and entropy can be applied to black holes. It discusses the work of Roger Penrose, James Bardeen, Brandon Carter, and Stephen Hawking, which, using quantum mechanics and quantum field theory, has enabled these scientists to propose likely behaviour in and around black holes. The concepts of black hole evaporation and Hawking radiation are explained to show how black holes lose mass and eventually disappear. It concludes with the black hole information paradox: can the information stored in the matter that fell into the black hole ever be recovered?

scholarly journals A Toy Model of the Information Paradox in Empty Space

2019 ◽  
Vol 6 (6) ◽  
Author(s):  
Suvrat Raju
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Hole ◽  
Empty Space ◽  
Quantum Field ◽  
De Sitter ◽  
Information Paradox ◽  
Black Hole Evaporation ◽  
Local Quantum ◽  
Sharp Version

A sharp version of the information paradox involves a seeming violation of the monogamy of entanglement during black hole evaporation. We construct an analogous paradox in empty anti-de Sitter space. In a local quantum field theory, Bell correlations between operators localized in mutually spacelike regions are monogamous. We show, through a controlled calculation, that this property can be violated by an order-1 factor in a theory of gravity. This example demonstrates that what appears to be a violation of the monogamy of entanglement may just be a subtle violation of locality in quantum gravity.

scholarly journals Classical black hole scattering from a worldline quantum field theory

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Gustav Mogull ◽  
Jan Plefka ◽  
Jan Steinhoff
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Hole ◽  
Quantum Field ◽  
Expectation Values ◽  
Path Integral Representation ◽  
S Matrix ◽  
Feynman Rules ◽  
Definition Of ◽  
Three Body

Abstract A precise link is derived between scalar-graviton S-matrix elements and expectation values of operators in a worldline quantum field theory (WQFT), both used to describe classical scattering of black holes. The link is formally provided by a worldline path integral representation of the graviton-dressed scalar propagator, which may be inserted into a traditional definition of the S-matrix in terms of time-ordered correlators. To calculate expectation values in the WQFT a new set of Feynman rules is introduced which treats the gravitational field hμν(x) and position $$ {x}_i^{\mu}\left({\tau}_i\right) $$ x i μ τ i of each black hole on equal footing. Using these both the 3PM three-body gravitational radiation 〈hμv(k)〉 and 2PM two-body deflection $$ \Delta {p}_i^{\mu } $$ Δ p i μ from classical black hole scattering events are obtained. The latter can also be obtained from the eikonal phase of a 2 → 2 scalar S-matrix, which we show corresponds to the free energy of the WQFT.

scholarly journals A self-consistency check for unitary propagation of Hawking quanta

2017 ◽  
Vol 32 (33) ◽  
pp. 1750198 ◽  
Author(s):  
Daniel Baker ◽  
Darsh Kodwani ◽  
Ue-Li Pen ◽  
I-Sheng Yang
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Hole ◽  
Negative Answer ◽  
Space Time ◽  
Quantum Field ◽  
Consistency Check ◽  
Curved Space ◽  
Self Consistency ◽  
Double Slit

The black hole information paradox presumes that quantum field theory in curved space–time can provide unitary propagation from a near-horizon mode to an asymptotic Hawking quantum. Instead of invoking conjectural quantum-gravity effects to modify such an assumption, we propose a self-consistency check. We establish an analogy to Feynman’s analysis of a double-slit experiment. Feynman showed that unitary propagation of the interfering particles, namely ignoring the entanglement with the double-slit, becomes an arbitrarily reliable assumption when the screen upon which the interference pattern is projected is infinitely far away. We argue for an analogous self-consistency check for quantum field theory in curved space–time. We apply it to the propagation of Hawking quanta and test whether ignoring the entanglement with the geometry also becomes arbitrarily reliable in the limit of a large black hole. We present curious results to suggest a negative answer, and we discuss how this loss of naive unitarity in QFT might be related to a solution of the paradox based on the soft-hair-memory effect.

scholarly journals CHARGED SECTORS, SPIN AND STATISTICS IN QUANTUM FIELD THEORY ON CURVED SPACETIMES

2001 ◽  
Vol 13 (02) ◽  
pp. 125-198 ◽  
Author(s):  
D. GUIDO ◽  
R. LONGO ◽  
J. E. ROBERTS ◽  
R. VERCH
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Holes ◽  
Rotational Symmetry ◽  
Minkowski Spacetime ◽  
Rotation Group ◽  
Quantum Field ◽  
Covariant Quantum ◽  
Killing Horizon ◽  
Hyperbolic Spacetimes

The first part of this paper extends the Doplicher–Haag–Roberts theory of superselection sectors to quantum field theory on arbitrary globally hyperbolic spacetimes. The statistics of a superselection sector may be defined as in flat spacetime and each charge has a conjugate charge when the spacetime possesses non-compact Cauchy surfaces. In this case, the field net and the gauge group can be constructed as in Minkowski spacetime. The second part of this paper derives spin-statistics theorems on spacetimes with appropriate symmetries. Two situations are considered: First, if the spacetime has a bifurcate Killing horizon, as is the case in the presence of black holes, then restricting the observables to the Killing horizon together with "modular covariance" for the Killing flow yields a conformally covariant quantum field theory on the circle and a conformal spin-statistics theorem for charged sectors localizable on the Killing horizon. Secondly, if the spacetime has a rotation and PT symmetry like the Schwarzschild–Kruskal black holes, "geometric modular action" of the rotational symmetry leads to a spin-statistics theorem for charged covariant sectors where the spin is defined via the SU(2)-covering of the spatial rotation group SO(3).

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 Black Hole Radiation, Greybody Factors, and Generalised Wick Rotation

2021 ◽  
Author(s):  
◽  
Finnian Gray
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Hole ◽  
Hawking Temperature ◽  
Matrix Formalism ◽  
Quantum Field ◽  
Wick Rotation ◽  
Radiation Process ◽  
Black Hole Radiation ◽  
Euclidean Quantum Field Theory

<p>In this thesis we look at the intersection of quantum field theory and general relativity. We focus on Hawking radiation from black holes and its implications. This is done on two fronts. In the first we consider the greybody factors arising from a Schwarzschild black hole. We develop a new way to numerically calculate these greybody factors using the transfer matrix formalism and the product calculus. We use this technique to calculate some of the relevant physical quantities and consider their effect on the radiation process.  The second front considers a generalisation of Wick rotation. This is motivated by the success of Wick rotation and Euclidean quantum field theory techniques to calculate the Hawking temperature. We find that, while an analytic continuation of the coordinates is not well defined and highly coordinate dependent, a direct continuation of the Lorentzian signature metric to Euclidean signature has promising results. It reproduces the Hawking temperature and is coordinate independent. However for consistency, we propose a new action for the Euclidean theory which cannot be simply the Euclidean Einstein-Hilbert action.</p>

scholarly journals Examining a covariant and renormalizable quantum field theory in de Sitter space by studying “black hole radiation”

2016 ◽  
Vol 31 (11) ◽  
pp. 1650052 ◽  
Author(s):  
Hamed Pejhan ◽  
Surena Rahbardehghan
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Hole ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Quantum Field ◽  
De Sitter ◽  
Black Hole Radiation

Respecting that any consistent quantum field theory in curved space–time must include black hole radiation, in this paper, we examine the Krein–Gupta–Bleuler (KGB) formalism as an inevitable quantization scheme in order to follow the guideline of the covariance of minimally coupled massless scalar field and linear gravity on de Sitter (dS) background in the sense of Wightman–Gärding approach, by investigating thermodynamical aspects of black holes. The formalism is interestingly free of pathological large distance behavior. In this construction, also, no infinite term appears in the calculation of expectation values of the energy–momentum tensor (we have an automatic and covariant renormalization) which results in the vacuum energy of the free field to vanish. However, the existence of an effective potential barrier, intrinsically created by black holes gravitational field, gives a Casimir-type contribution to the vacuum expectation value of the energy–momentum tensor. On this basis, by evaluating the Casimir energy–momentum tensor for a conformally coupled massless scalar field in the vicinity of a nonrotating black hole event horizon through the KGB quantization, in this work, we explicitly prove that the hole produces black-body radiation which its temperature exactly coincides with the result obtained by Hawking for black hole radiation.

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