Speaker
Description
In this talk, I will explain how for any noncommutative smooth and proper variety X we can construct three actions of the Heisenberg algebra on the total Hochschild homology of its symmetric quotient stacks $[X^n/S_n]$. One is defined algebraically using the orbifold decomposition of Hochschild homology. One decategorifies the 2-categorical Heisenberg action of arXiv:2105.13334. One is defined representation theoretically via explicit operators intrinsic to the symmetric quotient stacks. It turns out that these three actions coincide, and thus give alternative descriptions of one natural action. For ordinary commutative varities, we give a fourth, geometrical description by correspondences similar to those used by Grojnowski and Nakajima for the Hilbert schemes of points on surfaces.