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1. Visions in Quantum Gravity

   Buoninfante, L; Donoghue, J (December 2024, arXiv)
2. 3D gravity in a box

   https://doi.org/10.21468/SciPostPhys.11.3.070  

   Kraus, Per; Monten, Ruben; Myers, Richard M. (January 2021, SciPost Physics)

   The quantization of pure 3D gravity with Dirichlet boundaryconditions on a finite boundary is of interest both as a model ofquantum gravity in which one can compute quantities which are ``morelocal" than S-matrices or asymptotic boundary correlators, and forits proposed holographic duality to T\overline{T} T T ¯ -deformedCFTs. In this work we apply covariant phase space methods to deduce thePoisson bracket algebra of boundary observables. The result is aone-parameter nonlinear deformation of the usual Virasoro algebra ofasymptotically AdS _3 3 gravity. This algebra should be obeyed by the stress tensor in any T\overline{T} T T ¯ -deformedholographic CFT. We next initiate quantization of this system within thegeneral framework of coadjoint orbits, obtaining — in perturbationtheory — a deformed version of the Alekseev-Shatashvili symplectic formand its associated geometric action. The resulting energy spectrum isconsistent with the expected spectrum of T\overline{T} T T ¯ -deformedtheories, although we only carry out the explicit comparison to \mathcal{O}(1/\sqrt{c}) 𝒪 ( 1 / c ) in the 1/c 1 / c expansion. 

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3. Maximal Tests in Minimal Gravity

   Tasson, Jay (January 2020, Proceedings of the Eighth Meeting on CPT and Lorentz Symmetry)

   Recent tests have generated impressive reach in the gravity sector of the Standard-Model Extension. This contribution to the CPT’19 proceedings sum- marizes this progress and maps the structure of work in the gravity sector. 

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4. Scalar curvature in discrete gravity

   https://doi.org/10.1140/epjc/s10052-022-10605-5  

   Chamseddine, Ali H.; Malaeb, Ola; Najem, Sara (July 2022, The European Physical Journal C)

   Abstract We focus on studying, numerically, the scalar curvature tensor in a two-dimensional discrete space. The continuous metric of a two-sphere is transformed into that of a lattice using two possible slicings. In the first, we use two integers, while in the second we consider the case where one of the coordinates is ignorable. The numerical results of both cases are then compared with the expected values in the continuous limit as the number of cells of the lattice becomes very large. 

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5. Black hole in discrete gravity

   https://doi.org/10.1140/epjc/s10052-024-12648-2  

   Chamseddine, Ali H.; Malaeb, Ola; Najem, Sara (March 2024, The European Physical Journal C)

   Abstract We study the metric corresponding to a three-dimensional coset spaceSO(4)/SO(3) in the lattice setting. With the use of three integers$$n_1, n_2$$ $n_1,n_2$, and$$n_3$$ $n_3$, and a length scale,$$l_{\mu }$$ $l_{\mu }$, the continuous metric is transformed into a discrete space. The numerical outcomes are compared with the continuous ones. The singularity of the black hole is explored and different domains are studied. 

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