Fri - 07/18/25

There is no new related paper today

There is no new related paper today

  1. [] - Title: Space-based mm/mg-scale Laser Interferometer for Quantum Gravity - Nobuyuki Matsumoto, Katsuta Sakai, Kosei Hatakeyama, Kiwamu Izumi, Daisuke Miki, Satoshi Iso, Akira Matsumura, Kazuhiro Yamamoto

Thu - 07/17/25

**Title:

      Conformal Turaev-Viro Theory**  - **Authors:** Thomas Hartman  - **Subjects:** Subjects: High Energy Physics - Theory (hep-th)  - **Arxiv link:** [https://arxiv.org/abs/](https://arxiv.org/abs/)  - **Abstract**  We define and study Conformal Turaev-Viro (CTV) theory, a dual formulation of Virasoro TQFT based on triangulating 3-manifolds with tetrahedra. Edges of the triangulation are labeled by continuous conformal weights, and tetrahedra are glued together weighted by the Cardy density of states. We demonstrate that the CTV partition function is equal to the modular S-transform of the Virasoro TQFT amplitude-squared, $|Z_{Vir}|^2$. This is analogous to a known result for discrete spin networks. The derivation uses a variant of the chain-mail formalism, adapted to the Virasoro context. As a CFT application, we derive formulae for the S-transforms of the squared Virasoro crossing kernels. These results lay the topological foundation to study the exact path integral of pure AdS$_3$ quantum gravity by triangulations.

There is no new related paper today

  1. [] - Title: Testing the effective action approach to bubble nucleation in holography - Oscar Henriksson, Niko Jokela, Xin Li

Wed - 07/16/25

There is no new related paper today

There is no new related paper today

  1. [] - Title: Causal structure and topology change in (2+1)-dimensional simplicial gravity - Seth K. Asante, Björn Borgolte

Tue - 07/15/25

**Title:

      Singularities in loop quantum cosmology**  - **Authors:** Martin Bojowald, Manuel Diaz, Erick I. Duque  - **Subjects:** Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)  - **Arxiv link:** [https://arxiv.org/abs/](https://arxiv.org/abs/)  - **Abstract**  Quantum effects are expected to modify the cosmological dynamics of the early universe while maintaining some (potentially discrete) notion of space-time structure. In one approach, loop quantum cosmology, current models are shown here to either be incompatible with a consistent space-time structure, or to have physical singularities. The latter happens in spite of a non-zero scale factor in the isotropic background dynamics. A new effective Friedmann equation shows that a bounce is obtained at sub-Planckian densities, preceded by a physical singularity at infinite scale factor that resembles a time-reversed big rip. The entire phase is accompanied by rapid changes of the Hubble radius. In addition, a new version of perturbative inhomogeneity in loop quantum cosmology is introduced that maintains a consistent space-time structure and has a non-singular background dynamics.

There is no new related paper today

Mon - 07/14/25

**Title:

      Singularities in loop quantum cosmology**  - **Authors:** Martin Bojowald, Manuel Diaz, Erick I. Duque  - **Subjects:** Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)  - **Arxiv link:** [https://arxiv.org/abs/](https://arxiv.org/abs/)  - **Abstract**  Quantum effects are expected to modify the cosmological dynamics of the early universe while maintaining some (potentially discrete) notion of space-time structure. In one approach, loop quantum cosmology, current models are shown here to either be incompatible with a consistent space-time structure, or to have physical singularities. The latter happens in spite of a non-zero scale factor in the isotropic background dynamics. A new effective Friedmann equation shows that a bounce is obtained at sub-Planckian densities, preceded by a physical singularity at infinite scale factor that resembles a time-reversed big rip. The entire phase is accompanied by rapid changes of the Hubble radius. In addition, a new version of perturbative inhomogeneity in loop quantum cosmology is introduced that maintains a consistent space-time structure and has a non-singular background dynamics.

There is no new related paper today

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