arXiv subjects

Matteo Selle

Publications and source records attributed to Matteo Selle.

3 recordsLinked to original sources

arXiv2026

Brane effective actions and their island rule from $T\overline T$ flows

We derive a $2d$ effective action for semi-classical AdS$_3$ gravity with an EOW brane of arbitrary tension by solving the radial Hamiltonian flow in a derivative expansion. Interpreting the radial flow as an RG flow, the effective theory is identified with a $T\bar T$-like deformed CFT. This leads us to propose that the holographic dual for semi-classical AdS$_3$ gravity with Neumann or conformal boundary conditions is obtained by setting the $T\bar T$-like deformed CFT free. We verify our proposal explicitly for saddles corresponding to $(A)dS_2$ branes in empty AdS$_3$. We discuss three useful ways to decompose the effective brane theory into a matter sector ($T\bar T$-deformed, $T\bar T$-like deformed, and undeformed CFT, respectively) and a corresponding braneworld gravity sector. In particular, the split into $T\bar T$-deformed CFT coupled to $T\bar T$-like deformed Liouville gravity directly extends the Liouville description of the integrated Weyl anomaly into the bulk. The effective action is then used to perform an island-rule calculation for a non-asymptotic brane in an AdS/bCFT set-up, finding exact agreement with the Ryu-Takayanagi result. This extends previous holographic checks on the island rule to non-asymptotic regimes of application, as well as provides a Wald entropy interpretation for $T\bar T$ entanglement. Finally, we relate our effective theory and its higher derivative corrections to AdS$_3$ gravity with a fluctuating radial cutoff by explicit calculation of the on-shell action.

hep-th↗

arXiv2025

Deforming and dissecting AdS$_3$ with matter

We study deformations of the model by Henneaux, Mart\'inez, Troncoso and Zanelli [arXiv:hep-th/0201170] which features asymptotically AdS$_3$ black hole solutions that incorporate the exact backreaction of a scalar field. The presence of bulk matter causes the $T \overline T$ deformation of the (putative) dual CFT$_2$ to differ from the deformation defined in the bulk by imposing Dirichlet boundary conditions at finite radius. We work out both of these deformations explicitly and verify that $T \overline T$-deforming the boundary theory corresponds to imposing mixed boundary conditions on the metric at the conformal boundary, whereas the bulk "Dirichlet deformation" gives rise to a field theory deforming operator that includes $T \overline T$ as well as other irrelevant terms. We check our results by calculating the deformed energy spectrum for either case using both the bulk and boundary prescriptions, finding agreement after taking into account additional terms coming from the flow of the scalar source. We interpret our explicit results and compare them with the predictions of similar proposals in the literature.

hep-th↗

arXiv2025

Setting $T^2$ free for braneworld holography

We identify what has been referred to as 'cut-off CFT' in holographic braneworld with $T^2$ or $T\bar T$ theory (depending on the dimension of the bulk), so that the holographic dual of AdS-gravity with Neumann boundary conditions is a $T^2$-deformed CFT that is set free. After making statements that apply for general dimensions higher than three, we focus on the case of a three-dimensional bulk. We find from bulk arguments that the effective theory on the brane is governed by a $T\bar T$-like flow equation, such that under certain assumptions the effective gravity theory on the brane is given by a $T\bar T$-like deformed timelike Liouville theory, which limits to the description of the holographic Weyl anomaly for branes that approach the asymptotic boundary.

hep-th↗