Fri - 06/07/24

**Title:

      A generalized uncertainty-inspired quantum black hole**  - **Authors:** Federica Fragomeno, Douglas M. Gingrich, Samantha Hergott, Saeed Rastgoo, Evan Vienneau  - **Subjects:** Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)  - **Arxiv link:** [https://arxiv.org/abs/](https://arxiv.org/abs/)  - **Abstract**  We derive the full spacetime metric of a generalized uncertainty-inspired quantum black hole. We examine a previous model of the interior in this approach and show that extending its metric to the full spacetime leads to serious issues in the asymptotic region. To remedy this, we introduce an "improved scheme" mimicking a similar prescription used in loop quantum gravity, where the quantum parameters are made momentum-dependent. Under this scheme, we rework the interior of the black hole and extend it to the full spacetime. We find that the resulting metric is asymptotically flat and its associated Kretschmann scalar is regular everywhere. We also show that the null expansion and Raychaudhuri equation are regular everywhere in this spacetime, implying that the classical singularity is resolved.

There is no new related paper today

Thu - 06/06/24

**Title:

      Knotted 4-regular graphs II: Consistent application of the Pachner moves**  - **Authors:** Daniel Cartin  - **Subjects:** Subjects: General Relativity and Quantum Cosmology (gr-qc); Mathematical Physics (math-ph)  - **Arxiv link:** [https://arxiv.org/abs/](https://arxiv.org/abs/)  - **Abstract**  A common choice for the evolution of the knotted graphs in loop quantum gravity is to use the Pachner moves, adapted to graphs from their dual triangulations. Here, we show that the natural way to consistently use these moves is on framed graphs with edge twists, where the Pachner moves can only be performed when the twists, and the vertices the edges are incident on, meet certain criteria. For other twists, one can introduce an algebraic object, which allow any knotted graph with framed edges to be written in terms of a generalized braid group.

**Title:

      Matter coupled to 3d Quantum Gravity: One-loop Unitarity**  - **Authors:** Etera R. Livine, Valentine Maris  - **Subjects:** Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)  - **Arxiv link:** [https://arxiv.org/abs/](https://arxiv.org/abs/)  - **Abstract**  We expect quantum field theories for matter to acquire intricate corrections due to their coupling to quantum fluctuations of the gravitational field. This can be precisely worked out in 3d quantum gravity: after integrating out quantum gravity, matter fields are effectively described as noncommutative quantum field theories, with quantum-deformed Lorentz symmetries. An open question remains: Are such theories unitary or not? On the one hand, since these are effective field theories obtained after integrating out high energy degrees of freedom, we may expect the loss of unitarity. On the other hand, as rigorously defined field theories built with Lorentz symmetries and standing on their own, we naturally expect the conservation of unitarity. In an effort to settle this issue, we explicitly check unitarity for a scalar field at one-loop level in both Euclidean and Lorentzian space-time signatures. We find that unitarity requires adding an extra-term to the propagator of the noncommutative theory, corresponding to a massless mode and given by a representation with vanishing Plancherel measure, thus usually ignored in spinfoam path integrals for quantum gravity. This indicates that the inclusion of matter in spinfoam models, and more generally in quantum gravity, might be more subtle than previously thought.

Wed - 06/05/24

There is no new related paper today

There is no new related paper today

  1. [] - Title: Huge BPS Operators and Fluid Dynamics in $\mathcal{N}=4$ SYM - Vladimir Kazakov, Harish Murali, Pedro Vieira

Tue - 06/04/24

There is no new related paper today

There is no new related paper today

  1. [] - Title: Should we necessarily treat masses as localized when analysing tests of quantum gravity? - Adrian Kent (Centre for Quantum Information and Foundations, DAMTP, University of Cambridge and Perimeter Institute)

Mon - 06/03/24

There is no new related paper today

There is no new related paper today

  1. [] - Title: Should we necessarily treat masses as localized when analysing tests of quantum gravity? - Adrian Kent (Centre for Quantum Information and Foundations, DAMTP, University of Cambridge and Perimeter Institute)

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