Fri - 01/13/23

There is no new related paper today

There is no new related paper today

  1. [2301.04697] - Regular Black Holes and Horizonless Ultra-Compact Objects in Lorentz-Violating Gravity - Jacopo Mazza, Stefano Liberati

  2. [2301.05037] - Dymnikova-Schwinger traversable wormholes - Milko Estrada, Celio R. Muniz

Thu - 01/12/23

There is no new related paper today

There is no new related paper today

  1. [2301.04342] - Massive vector particle tunneling from Kerr-Newman-de Sitter black hole under generalized uncertainty principle - Yenshembam Priyobarta Singh, Telem Ibungochouba Singh

  2. [2301.04448] - Emergent diffeomorphism invariance in toy models - Hrvoje Nikolic

  3. [2301.04575] - Wilson lines construction of $\mathfrak{sl}_3$ toroidal conformal blocks - Vladimir Belavin, Pietro Oreglia, Juan Ramos Cabezas

Wed - 01/11/23

Avoidance of singularity during the gravitational collapse with string T-duality effects

  • Authors: Kimet Jusufi
  • Subjects: General Relativity and Quantum Cosmology (gr-qc)
  • Arxiv link: https://arxiv.org/abs/2301.03590
  • Abstract In this paper, we explore the gravitational collapse of matter (dust) under the effect of zero-point length $l_0$. During the gravitational collapse, we have neglected the backreaction effect of the pre-Hawking radiation (in the sense that it is small effect and cannot prevent the formation of apparent horizon), then we recast the internal metric of a collapsing star as a closed FRW universe for any spherically symmetric case and, finally, we obtain the minimal value for the scale factor meaning that the particles never hit the singularity. We argue that the object emerging at the end of the gravitational collapse can be interpreted as Planck stars (black hole core) hidden inside the event horizon of the black hole, with radius proportional to $(GMl_0^{2}/c^2)^{1/3}$. Quite interestingly, we found the same result for radius of the Planck star using a free falling observer point of view. In addition, we pointed out a correspondence between the modified Friedmann’s equations in loop quantum gravity and the modified Friedmann’s equation in string T-duality. In the end, we discuss two possibilities regarding the final stage of the black hole. The first possibility is that we end up with a Planck-size black hole remnants. The second possibility is that the inner core can be unstable and, due to the quantum tunnelling effect, the spacetime can undergo a black hole-to-white hole transition (a bouncing Planck star).

Modelling quantum particles falling into a black hole: the deep interior limit

  • Authors: Alejandro Perez, Salvatore Ribisi, Sami Viollet
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2301.03951
  • Abstract In this paper we construct a solvable toy model of the quantum dynamics of the interior of a spherical black hole with falling spherical scalar field excitations. We first argue about how some aspects of the quantum gravity dynamics of realistic black holes emitting Hawking radiation can be modelled using Kantowski-Sachs solutions with a massless scalar field when one focuses on the deep interior region $r\ll M$ (including the singularity). Further, we show that in the $r\ll M$ regime, and in suitable variables, the KS model becomes exactly solvable at both the classical and quantum levels. The quantum dynamics inspired by loop quantum gravity is revisited. We propose a natural polymer-quantization where the area $a$ of the orbits of the rotation group is quantized. The polymer (or loop) dynamics is closely related with the Schroedinger dynamics away from the singularity with a form of continuum limit naturally emerging from the polymer treatment. The Dirac observable associated to the mass is quantized and shown to have an infinite degeneracy associated to the so-called $\epsilon$-sectors. Suitable continuum superpositions of these are well defined distributions in the fundamental Hilbert space and satisfy the continuum Schroedinger dynamics.

There is no new related paper today

  1. [2301.03866] - Superradiant (In)stability, Greybody Radiation, and Quasinormal Modes of Rotating Black Holes in non-linear Maxwell f (R) Gravity - Sara Kanzi, İzzet Sakallı

Tue - 01/10/23

There is no new related paper today

Complex critical points in Lorentzian spinfoam quantum gravity: 4-simplex amplitude and effective dynamics on double-$\Delta_3$ complex

  • Authors: Muxin Han, Hongguang Liu, Dongxue Qu
  • Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
  • Arxiv link: https://arxiv.org/abs/2301.02930
  • Abstract The complex critical points are analyzed in the 4-dimensional Lorentzian Engle-Pereira-Rovelli-Livine (EPRL) spinfoam model in the large-$j$ regime. For the 4-simplex amplitude, taking into account the complex critical point generalizes the large-$j$ asymptotics to the situation with non-Regge boundary data and relates to the twisted geometry. For generic simplicial complexes, we present a general procedure to derive the effective theory of Regge geometries from the spinfoam amplitude in the large-$j$ regime by using the complex critical points. The effective theory is analyzed in detail for the spinfoam amplitude on the double-$\Delta_3$ simplicial complex. We numerically compute the effective action and the solution of the effective equation of motion on the double-$\Delta_3$ complex. The effective theory reproduces the classical Regge gravity when the Barbero-Immirzi parameter $\gamma$ is small.

Mon - 01/09/23

There is no new related paper today

There is no new related paper today

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