A non-rational Verlinde formula from Virasoro TQFT

Abstract We use the Virasoro TQFT to derive an integral identity that we view as a non-rational generalization of the Verlinde formula for the Virasoro algebra with central charge c ≥ 25. The identity expresses the Virasoro fusion kernel as an integral over a ratio of modular S-kernels on the (punct...

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Main Authors: Boris Post, Ioannis Tsiares
Format: Article
Language:English
Published: SpringerOpen 2025-04-01
Series:Journal of High Energy Physics
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Online Access:https://doi.org/10.1007/JHEP04(2025)015
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author Boris Post
Ioannis Tsiares
author_facet Boris Post
Ioannis Tsiares
author_sort Boris Post
collection DOAJ
description Abstract We use the Virasoro TQFT to derive an integral identity that we view as a non-rational generalization of the Verlinde formula for the Virasoro algebra with central charge c ≥ 25. The identity expresses the Virasoro fusion kernel as an integral over a ratio of modular S-kernels on the (punctured) torus. In particular, it shows that the one-point S-kernel diagonalizes the Virasoro 6j symbol. After carefully studying the analytic properties of this ‘Virasoro-Verlinde formula’, we present three applications. In boundary Liouville CFT, the formula ensures the open-closed duality of the boundary one-point function on the annulus. In pure 3d gravity, it provides an essential step in computing the partition function on hyperbolic 3-manifolds that fiber over the circle. Lastly, in AdS3/CFT2, the formula computes a three-boundary torus wormhole, which leads to a prediction for the statistical correlation between the density of states and two OPE coefficients in the dual large-c CFT ensemble. We conclude by discussing the implications of our result for the fusion rules in generic non-rational 2d CFTs.
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spelling doaj-art-19b691e0f404425d881dfd6697ffec212025-08-20T01:49:48ZengSpringerOpenJournal of High Energy Physics1029-84792025-04-012025416110.1007/JHEP04(2025)015A non-rational Verlinde formula from Virasoro TQFTBoris Post0Ioannis Tsiares1Institute for Theoretical Physics, University of AmsterdamInstitut de Physique Théorique, Université Paris-Saclay, CNRS, CEAAbstract We use the Virasoro TQFT to derive an integral identity that we view as a non-rational generalization of the Verlinde formula for the Virasoro algebra with central charge c ≥ 25. The identity expresses the Virasoro fusion kernel as an integral over a ratio of modular S-kernels on the (punctured) torus. In particular, it shows that the one-point S-kernel diagonalizes the Virasoro 6j symbol. After carefully studying the analytic properties of this ‘Virasoro-Verlinde formula’, we present three applications. In boundary Liouville CFT, the formula ensures the open-closed duality of the boundary one-point function on the annulus. In pure 3d gravity, it provides an essential step in computing the partition function on hyperbolic 3-manifolds that fiber over the circle. Lastly, in AdS3/CFT2, the formula computes a three-boundary torus wormhole, which leads to a prediction for the statistical correlation between the density of states and two OPE coefficients in the dual large-c CFT ensemble. We conclude by discussing the implications of our result for the fusion rules in generic non-rational 2d CFTs.https://doi.org/10.1007/JHEP04(2025)015Scale and Conformal SymmetriesTopological Field TheoriesAdS-CFT CorrespondenceQuantum Groups
spellingShingle Boris Post
Ioannis Tsiares
A non-rational Verlinde formula from Virasoro TQFT
Journal of High Energy Physics
Scale and Conformal Symmetries
Topological Field Theories
AdS-CFT Correspondence
Quantum Groups
title A non-rational Verlinde formula from Virasoro TQFT
title_full A non-rational Verlinde formula from Virasoro TQFT
title_fullStr A non-rational Verlinde formula from Virasoro TQFT
title_full_unstemmed A non-rational Verlinde formula from Virasoro TQFT
title_short A non-rational Verlinde formula from Virasoro TQFT
title_sort non rational verlinde formula from virasoro tqft
topic Scale and Conformal Symmetries
Topological Field Theories
AdS-CFT Correspondence
Quantum Groups
url https://doi.org/10.1007/JHEP04(2025)015
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