Probabilistic conformal blocks for Liouville CFT on the torus

Liouville theory is a fundamental example of a conformal field theory (CFT) first introduced by Polyakov in the context of string theory. Conformal blocks are objects underlying the integrable structure of CFT via the conformal bootstrap equation. The present work provides a probabilistic construction of the 1-point toric conformal block of Liouville theory in terms of a Gaussian multiplicative chaos measure corresponding to a one-dimensional log-correlated field. We prove that our probabilistic conformal block satisfies Zamolodchikov's recursion, and we relate it to the instanton part of Nekrasov's partition function by the Alday-Gaiotto-Tachikawa correspondence. Our proof rests upon an analysis of Belavin-Polyakov-Zamolodchikov differential equations, operator product expansions, and Dotsenko-Fateev type integrals.