Deformed Mirror Symmetry for Punctured Surfaces

Abstract

Mirror symmetry originally envisions a correspondence between deformations of the A-side and deformations of the B-side. In this paper, we achieve an explicit correspondence in the case of punctured surfaces. The starting point is the noncommutative mirror equivalence $ \operatorname{Gtl} Q \cong \operatorname{mf} (\operatorname{Jac} \check{Q}, \ell) $ for a punctured surface $ Q $. We pick a deformation $ \operatorname{Gtl}_q Q $ which captures a large part of the deformation theory and includes the relative Fukaya category. To find the corresponding deformation of $ \operatorname{mf} (\operatorname{Jac} \check{Q}, \ell) $, we deform work of Cho-Hong-Lau which interprets mirror symmetry as Koszul duality. As result we explicitly obtain the corresponding deformation $ \operatorname{mf} (\operatorname{Jac}_q \check{Q}, \ell_q) $ together with a deformed mirror functor $ \operatorname{Gtl}_q Q \xrightarrow{\sim} \operatorname{mf} (\operatorname{Jac}_q \check{Q}, \ell_q) $. The bottleneck is to verify that the algebra $ \operatorname{Jac}_q \check{Q} $ is indeed a (flat) deformation of $ \operatorname{Jac} \check{Q} $. We achieve this by deploying a result of Berger-Ginzburg-Taillefer on deformations of CY3 algebras, which however requires the relations to be homogeneous. We show how to replace this homogeneity requirement by a simple boundedness condition and obtain flatness of $ \operatorname{Jac}_q \check{Q} $ for almost all $ Q $. We finish the paper with examples, including a full treatment of the 3-punctured sphere and 4-punctured torus. With the help of our computations in arXiv:2305.09112, we describe $ \operatorname{Jac}_q \check{Q} $ explicitly. It turns out that the deformed potential $ \ell_q $ is still central in $ \operatorname{Jac}_q \check{Q} $, in contrast to the popular slogan that central elements do not survive under deformation.