Fri - 04/08/22

Twisted geometry coherent states in all dimensional loop quantum gravity: II. Ehrenfest Property

  • Authors: Gaoping Long
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); Mathematical Physics (math-ph)
  • Arxiv link: https://arxiv.org/abs/2204.03056
  • Abstract In the preceding paper of this series of articles we constructed the twisted geometry coherent states in all dimensional loop quantum gravity and established their peakedness properties. In this paper we establish the “Ehrenfest property” of these states which are labelled by the twisted geometry parameters. By this we mean that the expectation values of the polynomials of the elementary operators as well as the operators which is not a polynomial function of the elementary operators, reproduce, to zeroth order in $\hbar$, the values of the corresponding classical and simplicity resloved functions at the point in the twisted geometry parametrized phase space where the coherent state is peaked.

Intertwiner Entanglement Excitation and Holonomy Operator

  • Authors: Qian Chen, Etera R. Livine
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2204.03093
  • Abstract In the loop quantum gravity framework, spin network states carry entanglement between quantum excitations of the geometry at different space points. This intertwiner entanglement is gauge-invariant and comes from quantum superposition of spins and intertwiners. Bipartite entanglement can be interpreted as a witness of distance, while multipartite entanglement reflects the curvature of the quantum geometry. The present work investigates how the bipartite and multipartite intertwiner entanglement changes under the action of the holonomy operator, which is the basic building block of loop quantum gravity’s dynamics. We reveal the relation between entanglement excitation and the dispersion of the holonomy operator. This leads to a new interesting connection between bulk geometry and boundary observables via the dynamics of entanglement.

Quasinormal Modes of Self-dual Black Holes in Loop Quantum Gravity

  • Authors: Mehrab Momennia
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2204.03259
  • Abstract We study the evolution of a test scalar field on the background geometry of a regular loop quantum black hole (LQBH) characterized by two loop quantum gravity (LQG) correction parameters, namely, the polymeric function and the minimum area gap. The calculations of quasinormal frequencies in asymptotically flat spacetime are performed with the help of higher-order WKB expansion and related Pad'{e} approximants, the improved asymptotic iteration method (AIM), and time-domain integration. The effects of free parameters of the theory on the quasinormal modes are studied and deviations from those of the Schwarzschild BHs are investigated. We show that the LQG correction parameters have opposite effects on the quasinormal frequencies and the LQBHs are dynamically stable.

There is no new related paper today

  1. [2204.03043] - Time Evolution in Quantum Cosmology - Anne-Katherine Burns, David E. Kaplan, Tom Melia, Surjeet Rajendran

  2. [2204.02981] - D-instanton Induced Superpotential - Sergei Alexandrov, Atakan Hilmi Fırat, Manki Kim, Ashoke Sen, Bogdan Stefański jr

  3. [2204.03192] - Improved proof-by-contraction method and relative homologous entropy inequalities - Nan Li, Chuan-Shi Dong, Dong-Hui Du, Fu-Wen Shu

Thu - 04/07/22

There is no new related paper today

There is no new related paper today

  1. [2204.02429] - Universal signatures of singularity-resolving physics in photon rings of black holes and horizonless objects - Astrid Eichhorn, Aaron Held, Philipp-Vincent Johannsen

  2. [2204.02454] - $\mathcal{R}^2$ Quantum Corrected Scalar Field Inflation - V.K. Oikonomou, Ifigeneia Giannakoudi

  3. [2204.02723] - Baryogenesis in non-extensive Tsallis Cosmology - Giuseppe Gaetano Luciano, Jaume Gine

Wed - 04/06/22

There is no new related paper today

There is no new related paper today

  1. [2204.01718] - Are There Any Real Problems With Quantum Gravity? - Vlatko Vedral

  2. [2204.02032] - Built-in scordatura in U-DHOST - Antonio De Felice, Shinji Mukohyama, Kazufumi Takahashi

  3. [2204.01747] - The S-Matrix of 2D Type 0B String Theory Part 2: D-Instanton Effects - Bruno Balthazar, Victor A. Rodriguez, Xi Yin

  4. [2204.01764] - Baby Universes born from the Void - Panos Betzios, Nava Gaddam, Olga Papadoulaki

  5. [2204.01989] - Bulk reconstruction from a scalar CFT at the boundary by the smearing with the flow equation - Sinya Aoki, Janos Balog, Tetsuya Onogi, Shuichi Yokoyama

  6. [2204.02266] - Combinatoric topological string theories and group theory algorithms - Sanjaye Ramgoolam, Eric Sharpe

Tue - 04/05/22

Towards black hole entropy in chiral loop quantum supergravity

  • Authors: Konstantin Eder, Hanno Sahlmann
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2204.01661
  • Abstract Recently, many geometric aspects of $\mathcal{N}$-extended AdS supergravity in chiral variables have been encountered and clarified. In particular, if the theory is supposed to be invariant under SUSY transformations also on boundaries, the boundary term has to be the action of a $\mathrm{OSp}(\mathcal{N}|2){\mathbb{C}}$ super Chern-Simons theory, and particular boundary conditions must be met. Based on this, we propose a way to calculate an entropy $S$ for surfaces, presumably including black hole horizons, in the supersymmetric version of loop quantum gravity for the minimal case $\mathcal{N}=1$. It proceeds in analogy to the non-supersymmetric theory, by calculating dimensions of quantum state spaces of the super Chern-Simons theory with punctures, for fixed quantum (super) area of the surface. We find $S = a_H/4$ for large areas and determine the subleading correction. Due to the non-compactness of $\mathrm{OSp}(1|2){\mathbb{C}}$ and the corresponding difficulties with the Chern-Simons quantum theory, we use analytic continuation from the Verlinde formula for a compact real form, $\mathrm{UOSp}(1|2)$, in analogy to work by Noui et al. This also entails studying some properties of $\mathrm{OSp}(1|2)_{\mathbb{C}}$ representations that we have not found elsewhere in the literature.

There is no new related paper today

  1. [2204.00859] - Elementary Quantum Geometry - Jan Ambjorn

  2. [2204.01177] - A product picture for quantum electrodynamics - Bernard S. Kay (York)

  3. [2204.00687] - Self-adjoint extensions for a $p^{4}$-corrected Hamiltonian of a particle on a finite interval - B. B. Dilem, J. C. Fabris, J. A. Nogueira

Mon - 04/04/22

Classical dynamics for Loop Gravity: The 2-vertex model

  • Authors: Eneko Aranguren, Iñaki Garay, Etera R. Livine
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2204.00307
  • Abstract The study of toy models in loop quantum gravity (LQG), defined as truncations of the full theory, is relevant to both the development of the LQG phenomenology, in cosmology and astrophysics, and the progress towards the resolution of the open issues of the theory, in particular the implementation of the dynamics. Here, we study the dynamics of spin network states of quantum geometry defined on the family of graphs consisting in 2 vertices linked by an arbitrary number of edges, or 2-vertex model in short. A symmetry reduced sector of this model – to isotropic and homogeneous geometries – was successfully studied in the past, where interesting cosmological insights were found. We now study the evolution of the classical trajectories for this system in the general case, for arbitrary number of edges with random initial configurations. We use the spinorial formalism and its clear interpretation of spin networks in terms of discrete twisted geometries, with the quantum 3d space made of superpositions of polyhedra glued together by faces of equal area. Remarkably, oscillatory and divergent regimes are found with a universal dependence on the coupling constants of the Hamiltonian and independent of the initial spinors or the number of edges. Furthermore, we explore the evolution of the associated polyhedra as well as their volumes and areas.

Cauchy Slice Holography: A New AdS/CFT Dictionary

  • Authors: Goncalo Araujo-Regado, Rifath Khan, Aron C. Wall
  • Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2204.00591
  • Abstract We investigate a new approach to holography in asymptotically AdS spacetimes, in which time rather than space is the emergent dimension. By making a sufficiently large T^2-deformation of a Euclidean CFT, we define a holographic theory that lives on Cauchy slices of the Lorentzian bulk. (More generally, for an arbitrary Hamiltonian constraint equation that closes, we show how to obtain it by an irrelevant deformation from a CFT with suitable anomalies.) The partition function of this theory defines a natural map between the bulk canonical quantum gravity theory Hilbert space, and the Hilbert space of the usual (undeformed) boundary CFT. We argue for the equivalence of the ADM and CFT Hamiltonians. We also explain how bulk unitarity emerges naturally, even though the boundary theory is not reflection-positive. This allows us to reformulate the holographic principle in the language of Wheeler-DeWitt canonical quantum gravity. Along the way, we outline a procedure for obtaining a bulk Hilbert space from the gravitational path integral with Dirichlet boundary conditions. Following previous conjectures, we postulate that this finite-cutoff gravitational path integral agrees with the T^2-deformed theory living on an arbitrary boundary manifold – at least near the semiclassical regime. However, the T^2-deformed theory may be easier to UV complete, in which case it would be natural to take it as the definition of nonperturbative quantum gravity.

There is no new related paper today

  1. [2204.00384] - Schrödinger’s Black Hole Cat - Joshua Foo, Robert B. Mann, Magdalena Zych

  2. [2204.00021] - Looking for structure in the cobordism conjecture - David Andriot, Nils Carqueville, Niccolò Cribiori

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