Loop quantum gravity ≈ Loop quantum gravity
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Spin Entanglement Witness for Quantum Gravity Open
Understanding gravity in the framework of quantum mechanics is one of the great challenges in modern physics. However, the lack of empirical evidence has lead to a debate on whether gravity is a quantum entity. Despite varied proposed prob…
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Emergent Gravity and the Dark Universe Open
Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic theory. These ideas are best understood in Anti-de Sitter space, where they rely on the area law …
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The gravity dual of Rényi entropy Open
A remarkable yet mysterious property of black holes is that their entropy is proportional to the horizon area. This area law inspired the holographic principle, which was later realized concretely in gauge-gravity duality. In this context,…
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Quantum Transfiguration of Kruskal Black Holes Open
We present a new effective description of macroscopic Kruskal black holes that incorporates corrections due to quantum geometry effects of loop quantum gravity. It encompasses both the "interior" region that contains classical singularitie…
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A short review of loop quantum gravity Open
An outstanding open issue in our quest for physics beyond Einstein is the unification of general relativity (GR) and quantum physics. Loop quantum gravity (LQG) is a leading approach toward this goal. At its heart is the central lesson of …
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An Asymptotically Safe Guide to Quantum Gravity and Matter Open
Asymptotic safety generalizes asymptotic freedom and could contribute to understanding physics beyond the Standard Model. It is a candidate scenario to provide an ultraviolet extension for the effective quantum field theory of gravity thro…
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Superrenormalizable quantum gravity with complex ghosts Open
We suggest and briefly review a new sort of superrenormalizable models of\nhigher derivative quantum gravity. The higher derivative terms in the action\ncan be introduced in such a way that all the unphysical massive states have\ncomplex p…
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Entropy, extremality, euclidean variations, and the equations of motion Open
We study the Euclidean gravitational path integral computing the Rényi entropy and analyze its behavior under small variations. We argue that, in Einstein gravity, the extremality condition can be understood from the variational principle …
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Weak gravity conjecture Open
The weak gravity conjecture holds that in a theory of quantum gravity any gauge force must mediate interactions stronger than gravity for some particles. This statement has surprisingly deep and extensive connections to many different area…
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Testing Loop Quantum Gravity from Observational Consequences of Nonsingular Rotating Black Holes Open
The lack of rotating black hole models, which are typically found in nature, in loop quantum gravity (LQG) substantially hinders the progress of testing LQG from observations. Starting with a nonrotating LQG black hole as a seed metric, we…
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Effective line elements and black-hole models in canonical loop quantum gravity Open
Canonical quantization is often used to suggest new effects in quantum\ngravity, in the dynamics as well as the structure of space-time. Usually,\npossible phenomena are first seen in a modified version of the classical\ndynamics, for inst…
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Aspects of asymptotic safety for quantum gravity Open
We study fixed points of quantum gravity with renormalisation group methods, and a procedure to remove convergence-limiting poles from the flow. The setup is tested within the $f(R)$ approximation for gravity by solving exact recursive rel…
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Quantum Chiral Higher Spin Gravity Open
An example of a higher spin gravity in four-dimensional flat space has recently been constructed by D. Ponomarev and E. D. Skvortsov, J. Phys. A, 50, 095401(2017). This theory is chiral and the action is written in the light-cone gauge. Th…
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Effective quantum extended spacetime of polymer Schwarzschild black hole Open
The physical interpretation and eventual fate of gravitational singularities\nin a theory surpassing classical general relativity are puzzling questions that\nhave generated a great deal of interest among various quantum gravity\napproache…
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Effective loop quantum gravity framework for vacuum spherically symmetric spacetimes Open
We develop an effective framework for the $\bar\mu$ scheme of holonomy corrections motivated by loop quantum gravity for vacuum spherically symmetric space-times. This is done by imposing the areal gauge in the classical theory, and then e…
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The gravity duals of modular Hamiltonians Open
In this work, we investigate modular Hamiltonians defined with respect to arbitrary spatial regions in quantum field theory states which have semi-classical gravity duals. We find prescriptions in the gravity dual for calculating the actio…
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Planck star tunneling time: An astrophysically relevant observable from background-free quantum gravity Open
A gravitationally collapsed object can bounce-out from its horizon via a\ntunnelling process that violates the classical equations in a finite region.\nSince tunnelling is a non-perturbative phenomenon, it cannot be described in\nterms of …
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Tests of Loop Quantum Gravity from the Event Horizon Telescope Results of Sgr A* Open
The Event Horizon Telescope (EHT) collaboration’s image of the compact object at the Galactic center is the first direct evidence of the supermassive black hole (BH) Sgr A*. The shadow of Sgr A* has an angular diameter d sh = 48.7 ± 7 μ as…
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Towards cosmological dynamics from loop quantum gravity Open
We present a systematic study of the cosmological dynamics resulting from an\neffective Hamiltonian, recently derived in loop quantum gravity using\nThiemann's regularization and earlier obtained in loop quantum cosmology (LQC)\nby keeping…
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Numerical Evidence for a Phase Transition in 4D Spin-Foam Quantum Gravity Open
Building on recent advances in defining Wilsonian renormalization group (RG) flows, and the notion of scales in particular, for background-independent theories, we present a first investigation of the renormalization of the 4D spin-foam pa…
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Bouncing cosmologies from quantum gravity condensates Open
We show how the large-scale cosmological dynamics can be obtained from the\nhydrodynamics of isotropic group field theory condensate states in the\nGross-Pitaevskii approximation. The correct Friedmann equations are recovered\nin the semi-…
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A consistent model of non-singular Schwarzschild black hole in loop quantum gravity and its quasinormal modes Open
We investigate the interior structure, perturbations, and the associated\nquasinormal modes of a quantum black hole model recently proposed by\nBodendorfer, Mele, and M\\"unch (BMM). Within the framework of loop quantum\ngravity, the quant…
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Locally Mediated Entanglement in Linearized Quantum Gravity Open
The current interest in laboratory detection of entanglement mediated by gravity was sparked by an information-theoretic argument: entanglement mediated by a local field certifies that the field is not classical. Previous derivations of th…
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QCD analogy for quantum gravity Open
Quadratic gravity presents us with a renormalizable, asymptotically free theory of quantum gravity. When its couplings grow strong at some scale, as in QCD, then this strong scale sets the Planck mass. QCD has a gluon that does not appear …
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Global symmetry, Euclidean gravity, and the black hole information problem Open
A bstract In this paper we argue for a close connection between the non-existence of global symmetries in quantum gravity and a unitary resolution of the black hole information problem. In particular we show how the essential ingredients o…
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Opening the Pandora’s box at the core of black holes Open
We present a geometric classification of all spherically symmetric spacetimes that could result from singularity regularization, using a kinematic construction that is both exhaustive and oblivious to the dynamics of the fields involved. D…
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Quantum gravity predictions for black hole interior geometry Open
In a previous work we derived an effective Hamiltonian constraint for the\nSchwarzschild geometry starting from the full loop quantum gravity Hamiltonian\nconstraint and computing its expectation value on coherent states sharply\npeaked ar…
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Effective entropy of quantum fields coupled with gravity Open
Entanglement entropy, or von Neumann entropy, quantifies the amount of uncertainty of a quantum state. For quantum fields in curved space, entanglement entropy of the quantum field theory degrees of freedom is well-defined for a fixed back…
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Lecture notes: Functional Renormalisation Group and Asymptotically Safe Quantum Gravity Open
These lecture notes give an introduction to the functional renormalisation group and asymptotically safe quantum gravity. We cover the basics of generating functionals in quantum field theories and derive the Wetterich equation. The anharm…
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A holographic derivation of the weak gravity conjecture Open
A bstract The Weak Gravity Conjecture (WGC) demands the existence of superextremal particles in any consistent quantum theory of gravity. The standard lore is that these particles are introduced to ensure that extremal black holes are eith…