Hyperkähler varieties as Brill-Noether loci on curves

Abstract

Consider the moduli space $M_C(r;K_C)$ of stable rank r vector bundles on a curve $C$ with canonical determinant, and let $h$ be the maximum number of linearly independent global sections of these bundles. If $C$ embeds in a K3 surface $X$ as a generator of $Pic(X)$ and the genus $g$ of $C$ is sufficiently high, we show the Brill-Noether locus $B{N}_C\subset M_C(r;K_C)$ of bundles with $h$ global sections is a smooth projective Hyperkähler manifold of dimension $2g-2r\lfloor \frac{g}{r}\rfloor$, isomorphic to a moduli space of stable vector bundles on $X$.

arXiv comment27 pages, 8 figures