$\mathbb{E}_2$-algebra structures on the derived center of an algebraic scheme

Abstract

This paper provides an explicit interface between J. Lurie's work on higher centers, and the Hochschild cohomology of an algebraic $\mathbb{k}$-scheme within the framework of deformation quantization. We first recover a canonical solution to Deligne's conjecture on Hochschild cochains in the affine and global cases, even for singular schemes, by exhibiting the Hochschild complex as an $\infty$-operadic center. We then prove that this universal $\mathbb{E}_2$-algebra structure precisely agrees with the classical Gerstenhaber bracket and cup product on cohomology in the affine and smooth cases. This last statement follows from our main technical result which allows us to extract the Gerstenhaber bracket of any $\mathbb{E}_2$-algebra obtained from a 2-algebra via Lurie's Dunn Additivity Theorem.