A moduli space of stable sheaves on a cubic threefold

Abstract

In this paper, we prove that the moduli space $\overline{M}_{X}(\nu)$ of $H$-Gieseker semistable sheaves on a smooth cubic threefold $X$ with Chern character $\nu=(4,-H,-\frac{5}{6}H^{2},\frac{1}{6}H^{3})$ is non-empty, smooth and irreducible of dimension $8$. Moreover, we give a set-theoretic description of the moduli space $\overline{M}_{X}(\nu)$, which also yields that $\overline{M}_{X}(\nu)$ is a birational model of the moduli space of smooth quartic rational curves in $X$.