Large values of quadratic Dirichlet $L$-functions over monic irreducible polynomial in $\mathbb{F}_q[t]$

Abstract

We prove an $Ω$-result for the quadratic Dirichlet $L$-function $|L(1/2, χ_P)|$ over irreducible polynomials $P$ associated with the hyperelliptic curve of genus $g$ over a fixed finite field $\mathbb{F}_q$ in the large genus limit. In particular, we showed that for any $ε\in (0, 1/2)$, \[ \max_{\substack{P\in \mathcal{P}_{2g+1}}}|L(1/2, χ_P)|\gg \exp\left(\left(\sqrt{\left(1/2-ε\right)\ln q}+o(1)\right)\sqrt{\frac{g \ln_2 g}{\ln g}}\right), \] where $\mathcal{P}_{2g+1}$ is the set of all monic irreducible polynomial of degree $2g+1$. This matches with the order of magnitude of the Bondarenko--Seip bound.