Archived weekly pre-print 21-11-01

Authors: Samuel Barroso Bellido
Subjects: General Relativity and Quantum Cosmology (gr-qc)
Arxiv link: https://arxiv.org/abs/2110.14736
Abstract Using the formalism of the third quantization in canonical quantum gravity, the entropy of entanglement of a pair of universes created in the multiverse from the vacuum has lately been calculated. Here, we examine the differences between considering a scalar field as quantum or classical on the entanglement entropy of three different pairs: de-Sitter universes, flat stiff matter dominated universes, and closed universes with a scalar field. We find that the entanglement entropy is unchanged, zero, or dependent on the treatment of the scalar field, respectively.

Authors: Luca Marchetti, Daniele Oriti, Andreas G. A. Pithis, Johannes Thürigen
Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
Arxiv link: https://arxiv.org/abs/2110.15336
Abstract In the tensorial group field theory approach to quantum gravity, the theory is based on discrete building blocks and continuum spacetime is expected to emerge from their collective dynamics, possibly at criticality, via a phase transition. On a compact group of fixed volume this can be expected to be only possible in a large-volume or thermodynamic limit. Here we show how phase transitions are possible in TGFTs in two cases: a) considering the non-local group degrees of freedom on a non-compact Lie group instead of a compact one (or taking a large-volume limit of a compact group); b) in models including $\mathbb{R}$-valued local degrees of freedom (that can be interpreted as discrete scalar fields, often used in this context to provide a matter reference frame). After adapting the Landau-Ginzburg approach to this setting of mixed local/non-local degrees of freedom, we determine the critical dimension beyond which there is a Gaussian fixed point and a continuous phase transition which can be described by mean-field theory. This is an important step towards the realization of a phase transition to continuum spacetime in realistic TGFT models for quantum gravity.

Authors: Goffredo Chirco, Eugenia Colafranceschi, Daniele Oriti
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
Arxiv link: https://arxiv.org/abs/2110.15166
Abstract For quantum gravity states associated to open spin network graphs, we study how the entanglement entropy of the boundary degrees of freedom (spins on open edges) is affected by the bulk data, specifically by its combinatorial structure and by the quantum correlations among intertwiner degrees of freedom. For a specific assignment of bulk edge spins and slightly entangled intertwiners, we recover the Ryu-Takayanagi formula (with a properly (discrete) geometric notion of area, thanks to the underlying quantum gravity formalism) and its corrections due to the entanglement entropy of the bulk state. We also show that the presence of a region with highly entangled intertwiners deforms the minimal-area surface, which is then prevented from entering that region when the entanglement entropy of the latter exceeds a certain bound. This entanglement-based mechanism leads thus to the formation of a black hole-like region in the bulk.

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[2110.15325] - Impact of a modified Entropy-Area law on Schwarzschild-de Sitter metric - Luca Marchetti, Giancarlo Cella
[2110.14669] - Holographic spacetime, black holes and quantum error correcting codes: A review - Tanay Kibe, Prabha Mandayam, Ayan Mukhopadhyay
[2110.14672] - Quantum Computational Complexity – From Quantum Information to Black Holes and Back - Shira Chapman, Giuseppe Policastro
[2110.14897] - Holographic index calculation for Argyres-Douglas and Minahan-Nemeschansky theories - Yosuke Imamura, Shuichi Murayama
[2110.15009] - Coulomb gas integrals, classical conformal blocks and Richardson-Gaudin models - M.R. Piatek, R.G. Nazmitdinov, A. Puente, A.R. Pietrykowski
[2110.15256] - Application of Lorentzian CFT Principal Series Representation to Near Forward Scattering - Pulkit Agarwal, Richard C. Brower, Timothy G. Raben, Chung-I Tan
[2110.15297] - OPE’s and recoil - David Berenstein, Ruwanmali Bernadette de Zoysa
[2110.15306] - Growth of a renormalized operator as a probe of chaos - Xing Huang, Binchao Zhang

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[2110.14201] - The center of a regular AdS black hole as a holographic RG fixed point - Yang Li, Yan-Gang Miao
[2110.14263] - Universal leading quantum correction to the Newton potential - Tibério de Paula Netto, Ilya L. Shapiro, Leonardo Modesto

Authors: Francesco Sartini
Subjects: General Relativity and Quantum Cosmology (gr-qc)
Arxiv link: https://arxiv.org/abs/2110.13756
Abstract The emergence of non trivial symmetries for black holes minisuperspaces has been recently pointed out. These Noether symmetries possess non null charges and hence map physical solutions to different ones. The symmetry group is isomorphic to the finite dimensional Poincar'e group ISO(2,1), whose irreducible representations are well known. This structure is used to build a consistent quantum theory of black hole minisuperspace. This has, among others, the striking consequence of implying a continuous spectrum for the mass operator. Following loop quantum cosmology, we obtain a regularization scheme compatible with the symmetry structure. It is possible to study the evolution of coherent states following the classical trajectories in the low curvature regime. We show that this produces an effective metric where the singularity is replaced by a Killing horizon merging two asymptotically flat regions. The quantum correction comes from a fundamental discreteness of spacetime, and the uncertainty on the energy of the system. Remarkably the effective evolution of semiclassical states is described by an effective Hamiltonian, related to the original one through a canonical transformation.

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[2110.13174] - Operator product expansion coefficients from the nonperturbative functional renormalization group - Félix Rose, Carlo Pagani, Nicolas Dupuis
[2110.13898] - Entanglement entropy and vacuum states in Schwarzschild geometry - Yoshinori Matsuo

There is no new related paper today

There is no new related paper today