Fri - 12/16/22

There is no new related paper today

There is no new related paper today

  1. [2212.07458] - Comment on “Stability properties of Regular Black Holes” - Raúl Carballo-Rubio, Francesco Di Filippo, Stefano Liberati, Costantino Pacilio, Matt Visser

  2. [2212.07800] - Locally covariant approach to effective quantum gravity - Romeo Brunetti, Klaus Fredenhagen, Kasia Rejzner

  3. [2212.07436] - CFTs dual to quantum gravity with strongly coupled matter - Luis Apolo, Alexandre Belin, Suzanne Bintanja, Alejandra Castro, Christoph A. Keller

  4. [2212.07446] - An Inner Product for 4D Quantum Gravity and the Chern-Simons-Kodama State - Stephon Alexander, Laurent Freidel, Gabriel Herczeg

Thu - 12/15/22

There is no new related paper today

There is no new related paper today

  1. [2212.06970] - Measuring gravitational force from Femto-gram source masses - Ahmed Roman, Asem Hassan, Mohamed ElKabbash

  2. [2212.06841] - Moduli-dependent Species Scale - Damian van de Heisteeg, Cumrun Vafa, Max Wiesner, David H. Wu

  3. [2212.07089] - Narain CFTs from qudit stabilizer codes - Kohki Kawabata, Tatsuma Nishioka, Takuya Okuda

Wed - 12/14/22

Generic features of a polymer quantum black hole

  • Authors: Johannes Münch, Alejandro Perez, Simone Speziale, Sami Viollet
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2212.06708
  • Abstract Non-singular black holes models can be described by modified classical equations motivated by loop quantum gravity. We investigate what happens when the sine function typically used in the modification is replaced by an arbitrary bounded function, a generalization meant to study the effect of ambiguities such as the choice of representation of the holonomy. A number of features can be determined without committing to a specific choice of functions. We find generic singularity resolution. The presence and number of horizons is determined by global features of the function regularizing the angular components of the connection, and the presence and number of bounces by global features of the function regularizing the time component. The trapping or anti-trapping nature of regions inside horizons depends on the relative location with respect to eventual bounces. We use these results to comment on some of the ambiguities of polymer black hole models.

There is no new related paper today

  1. [2212.06187] - Lectures on the string landscape and the Swampland - Nathan Benjamin Agmon, Alek Bedroya, Monica Jinwoo Kang, Cumrun Vafa

  2. [2212.06677] - Effective Field Theory for Compact Binary Dynamics - Walter D. Goldberger

  3. [2212.06774] - Path Integral for Mixed Tunneling, Polychronic Tunneling and Quantum Gravity - Yutaro Shoji

  4. [2212.06533] - C-algebraic results in the search for quantum gauge fields* - Teun D. H. van Nuland

  5. [2212.06661] - Hierarchies in relative Picard-Lefschetz theory - Marko Berghoff, Erik Panzer

Tue - 12/13/22

A non-singular generalized entropy and its implications on bounce cosmology

  • Authors: Sergei D. Odintsov, Tanmoy Paul
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2212.05531
  • Abstract We propose a new five-parameter entropy function that proves to be singular-free during the entire cosmic evolution of the universe, and at the same time, also generalizes the Tsallis, Barrow, R'{e}nyi, Sharma-Mittal, Kaniadakis and Loop Quantum Gravity entropies for suitable limits of the parameters. In particular, all the above mentioned known entropies become singular (or diverge) when the Hubble parameter vanishes in course of the universe’s evolution (for instance, in bounce cosmology at the instant of bounce), while the newly proposed entropy function seems to be singular-free even at $H = 0$ (where $H$ represents the Hubble parameter of the universe). Such non-singular behaviour of the entropy function becomes useful in describing bouncing scenario, in which case, the universe undergoes through $H = 0$ at the instant of bounce. It turns out that the entropic cosmology corresponding to the singular-free generalized entropy naturally allows symmetric bounce scenarios, such as – exponential bounce and quasi-matter bounce scenario respectively. In the case of exponential bounce, the perturbation modes are in the super-Hubble domain at the distant past, while for the quasi-matter bounce, the perturbation modes generate in the deep sub-Hubble regime far before the bounce and hence resolves the ``horizon issue’’. Based on this fact, we perform a detailed perturbation analysis for the quasi-matter bounce in the present context of singular-free entropic cosmology. Furthermore the entropic cosmology in the present context is shown to be equivalent with the generalized holographic cosmology where the holographic cut-offs are determined in terms of either future horizon and its derivative or the particle horizon and its derivative.

Alternative $k=-1$ loop quantum cosmology

  • Authors: Jinsong Yang, Cong Zhang, Xiangdong Zhang
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2212.05748
  • Abstract An alternative quantization of the gravitational Hamiltonian constraint of the $k=-1$ Friedmann-Robertson-Walker model is proposed by treating the Euclidean term and the Lorentzian term independently, mimicking the treatment of full loop quantum gravity. The resulting Hamiltonian constraint operator for the $k=-1$ model with a massless scalar field is successfully constructed, and is shown to have the corrected classical limit. Compared to the former quantization schemes in the literature where only the Euclidean term is quantized, the new quantum dynamics of the $k=-1$ model with a massless scalar field indicates that the classical big-bang singularity is replaced by an asymmetric quantum bounce.

Entanglement Negativity on Random Spin Networks

  • Authors: Goffredo Chirco, Simone Cepollaro, Gianluca Cuffaro, Vittorio D’Esposito
  • Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2212.06083
  • Abstract We investigate multipartite entanglement for quantum states of 3d space geometry, described via generalised random spin networks with fixed areas, in the context of background independent approaches to quantum gravity. We focus on entanglement negativity as a well defined witness of quantum correlations for mixed states, in our setting describing generic subregions of the boundary of a quantum 3d region of space. In particular, we consider a generic tripartition of the boundary of an open spin network state and we compute the typical R'enyi negativity of two boundary subregions A and B immersed in the environment C, explicitly for a set of simple open random spin network states. We use the random character of the spin network to exploit replica and random average techniques to derive the typical R'enyi negativty via a classical generalised Ising model correspondence, generally used for random tensor networks in the large bond regime. For trivially correlated random spin network states, with only local entanglement between spins located on the network edges, we find that typical log negativity displays a holographic character, in agreement with the results for random tensor networks, in large spin limit. When non-local bulk entanglement between intertwiners at the vertices is considered the negativity increases, while at the same time the holographic scaling is generally perturbed by the bulk contribution.

There is no new related paper today

  1. [2212.05649] - Functional renormalization group for multilinear disordered Langevin dynamics II: Revisiting the $p=2$ spin dynamics for Wigner and Wishart ensembles - Vincent Lahoche, Dine Ousmane Samary, Mohamed Tamaazousti

  2. [2212.05877] - A proof for string three-point functions in AdS$_3$ - Davide Bufalini, Sergio Iguri, Nicolas Kovensky

  3. [2212.05999] - Deriving the Simplest Gauge-String Duality – I: Open-Closed-Open Triality - Rajesh Gopakumar, Edward A. Mazenc

Mon - 12/12/22

Covariant ${\barμ}$-scheme effective dynamics, mimetic gravity, and non-singular black holes: Applications to spherical symmetric quantum gravity and CGHS model

  • Authors: Muxin Han, Hongguang Liu
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2212.04605
  • Abstract We propose a new $\bar{\mu}$-scheme Hamiltonian effective dynamics in the spherical symmetric sector of Loop Quantum Gravity (LQG). The effective dynamics is generally covariant as derived from a covariant Lagrangian. The Lagrangian belongs to the class of extended mimetic gravity Lagrangians in 4 dimensions. We apply the effective dynamics to both cosmology and black hole. The effective dynamics reproduces the non-singular Loop-Quantum-Cosmology (LQC) effective dynamics. From the effective dynamics, we obtain the non-singular black hole solution, which has a killing symmetry in addition to the spherical symmetry and reduces to the Schwarzschild geometry asymptotically near the infinity. The black hole spacetime resolves the classical singularity and approaches asymptotically the Nariai geometry $\mathrm{dS}_2\times S^2$ at the future infinity in the interior of the black hole. The resulting black hole spacetime has the complete future null infinity $\mathscr{I}^+$. Thanks to the general covariance, the effective dynamics can be reformulated in the light-cone gauge. We generalize the covariant $\bar{\mu}$-scheme effective dynamics to the Callan-Giddings-Harvey-Strominger (CGHS) model and apply the light-cone formulation to the CGHS black hole solution with the null-shell collapse. We focus on the effective dynamics projected along the null shell. The result shows that both the 2d scalar curvature and the derivative of dilaton field are finite, in contrast to the divergence in the CGHS model.

There is no new related paper today

  1. [2212.04517] - Negative scalar potentials and the swampland: an Anti-Trans-Planckian Censorship Conjecture - David Andriot, Ludwig Horer, George Tringas

  2. [2212.04669] - Experimental test of Non-Commutative Quantum Gravity by VIP-2 Lead - Kristian Piscicchia, Andrea Addazi, Antonino Marciano, Massimiliano Bazzi, Michael Cargnelli, Alberto Clozza, Luca De Paolis, Raffaele Del Grande, Carlo Guaraldo, Mihail Antoniu Iliescu, Matthias Laubenstein, Johann Marton, Marco Miliucci, Fabrizio Napolitano, Alessio Porcelli, Alessandro Scordo, Diana Laura Sirghi, Florin Sirghi, Oton Vazquez Doce, Johann Zmeskal, Catalina Curceanu

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