Semiclassical analysis of black holes in loop quantum gravity: Modeling Hawking radiation with volume fluctuations

Heidmann, Pierre; Liu, Hongguang; Noui, Karim

doi:10.1103/physrevd.95.044015

Cited by 3 publications

(3 citation statements)

References 80 publications

(120 reference statements)

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“…It was also shown in [45] how the self dual formulation allows to recover naturally the thermal character of the near-horizon radiation. Additional results have been obtained in this context, reinforcing the status of the self dual variables as well suited to capture the right semi-classical result in the context of black hole thermodynamics in LQG [46][47][48][49]. See also [50][51][52][53] for related investigations in different contexts.…”

Section: Why Use Self-dual Ashtekar Variables?supporting

confidence: 55%

Covariance in self-dual inhomogeneous models of effective quantum geometry: Spherical symmetry and Gowdy systems

Achour¹,

Brahma

2018

Phys. Rev. D

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When applying the techniques of Loop Quantum Gravity (LQG) to symmetry-reduced gravitational systems, one first regularizes the scalar constraint using holonomy corrections, prior to quantization. In inhomogeneous system, where a residual spatial diffeomorphism symmetry survives, such modification of the gauge generator generating time reparametrization can potentially lead to deformations or anomalies in the modified algebra of first class constraints. When working with self-dual variables, it has already been shown that, for spherically symmetric geometry coupled to a scalar field, the holonomy-modified constraints do not generate any modifications to general covariance, as one faces in the real variables formulation, and can thus accommodate local degrees of freedom in such inhomogeneous models. In this paper, we extend this result to Gowdy cosmologies in the self-dual Ashtekar formulation. Furthermore, we show that the introduction of aμ−scheme in midisuperspace models, as is required in the 'improved dynamics' of LQG, is possible in the self-dual formalism while being out of reach in the current effective models suing real-valued Ashtekar-Barbero variables.Our results indicate the advantages of using the self-dual variables to obtain a covariant loop regularization prior to quantization in inhomogeneous symmetry reduced polymer models, implementing additionally the crucialμ-scheme, and thus a consistent semiclassical limit. 2

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Section: Why Use Self-dual Ashtekar Variables?supporting

confidence: 55%

Covariance in self-dual inhomogeneous models of effective quantum geometry: Spherical symmetry and Gowdy systems

Achour¹,

Brahma

2018

Phys. Rev. D

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“…Beside, we deeply think that this new formulation will allow us to understand better the physics of quantum black holes in Loop Quantum Gravity. In the usual treatment [23][24][25][26][27][28][29][30], black holes are considered as isolated horizons and they appear as boundary of a 3 dimensional space-like hypersurface Σ. Their effective dynamics has been shown to be governed by an SU (2) Chern-Simons theory whose quantization leads to the construction and the counting of the quantum microstates for the black holes.…”

Section: Discussionmentioning

confidence: 99%

Gravity as an SU (1, 1) gauge theory in four dimensions

Liu

Noui

2017

Class. Quantum Grav.

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We start with the Hamiltonian formulation of the first order action of pure gravity with a full sl(2, C) internal gauge symmetry. We make a partial gauge-fixing which reduces sl(2, C) to its sub-algebra su(1, 1). This case corresponds to a splitting of the space-time M = Σ × R where Σ inherits an arbitrary Lorentzian metric of signature (−, +, +). Then, we find a parametrization of the phase space in terms of an su(1, 1) commutative connection and its associated conjugate electric field. Following the techniques of Loop Quantum Gravity, we start the quantization of the theory and we consider the kinematical Hilbert space on a given fixed graph Γ whose edges are colored with unitary representations of su(1, 1). We compute the spectrum of area operators acting of the kinematical Hilbert space: we show that space-like areas have discrete spectra, in agreement with usual su(2) Loop Quantum Gravity, whereas time-like areas have continuous spectra. We conclude on the possibility to make use of this formulation of gravity to construct a holographic description of black holes in the framework of Loop Quantum Gravity.

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“…One can show that the volume inside measured at the latest possible instant where curvatures remain sub-Planckian (notice that moving Σ to the future implies getting closer to the singularity inside the horizon) is greater than a lower bound that grows like (M/M p ) α 3 p with α > 3, and hence diverges in the → 0 limit. based on simple analogies exist at the moment [180]. Without a detailed account of the emission process, it is still possible to obtain information from a spectroscopical approach (first applied to BHs in [62,197]) that uses as input the details of the area spectrum, in addition to some semiclassical assumptions [50,51].…”

Section: 10hawking Radiationmentioning

confidence: 99%

Black holes in loop quantum gravity

Pérez

2017

Rep. Prog. Phys.

128

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This is a review of results on black hole physics in the context of loop quantum gravity. The key feature underlying these results is the discreteness of geometric quantities at the Planck scale predicted by this approach to quantum gravity. Quantum discreteness follows directly from the canonical quantization prescription when applied to the action of general relativity that is suitable for the coupling of gravity with gauge fields, and especially with fermions. Planckian discreteness and causal considerations provide the basic structure for the understanding of the thermal properties of black holes close to equilibrium. Discreteness also provides a fresh new look at more (at the moment) speculative issues, such as those concerning the fate of information in black hole evaporation. The hypothesis of discreteness leads, also, to interesting phenomenology with possible observational consequences. The theory of loop quantum gravity is a developing program; this review reports its achievements and open questions in a pedagogical manner, with an emphasis on quantum aspects of black hole physics.

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Semiclassical analysis of black holes in loop quantum gravity: Modeling Hawking radiation with volume fluctuations

Cited by 3 publications

References 80 publications

Covariance in self-dual inhomogeneous models of effective quantum geometry: Spherical symmetry and Gowdy systems

Covariance in self-dual inhomogeneous models of effective quantum geometry: Spherical symmetry and Gowdy systems

Gravity as an SU (1, 1) gauge theory in four dimensions

Black holes in loop quantum gravity

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