Infinitely many hyperelliptic curves of small genus and small fixed rank, and of any genus and rank two

Abstract

We prove that for any number field $K$ and any fixed genus $g\ge 2$, there are infinitely many non-isomorphic hyperelliptic curves of genus $g$ over $K$ whose Jacobians have rank over $K$ equal to each of 0, 1, or 2. As an example of our method, over $\mathbb{Q}$, we prove that there exist infinitely many non-isomorphic hyperelliptic curves of genus two, whose Jacobians have rank equal to a fixed number between $1$ and $11$, genus three and four curves with rank between $1$ and $4$, and genus five and six with rank between $1$ and $3$.

18 pages, fourth version, minor updates in exposition. Comments welcome