On higher Brézin-Gross-Witten tau-functions
Alexander Alexandrov, Saswati Dhara
TL;DR
The paper builds a comprehensive framework for higher BGW tau-functions within the KP hierarchy by constructing canonical KS operators and quantum spectral curves and proving W^{(3)}-constraints for both the original and generalized models. It demonstrates that higher BGW tau-functions are KP tau-functions corresponding to the (m+1)-reduction and provides an algebraic topological recursion via cut-and-join operators, giving explicit recursion relations for the topological expansion. A one-parameter deformation with N leads to generalized higher BGW tau-functions τ^{(m,N)}, with deformed KS algebras, quantum curves, and W-constraints, enriching the geometric interpretation through irregular spectral curves. Collectively, the results connect matrix models, Sato Grassmannian data, and enumerative geometry through explicit operator algebras and recursive structures, applicable to non-semi-simple cohomological field theories and related topological recursion frameworks.
Abstract
In this paper, we consider the higher Brézin--Gross--Witten tau-functions, given by the matrix integrals. For these tau-functions we construct the canonical Kac--Schwarz operators, quantum spectral curves, and $W^{(3)}$-constraints. For the simplest representative we construct the cut-and-join operators, which describe the algebraic version of the topological recursion. We also investigate a one-parametric generalization of the higher Brézin--Gross--Witten tau-functions.
