Hybrid bounds for ${\rm{GL}}(4)\times {\rm{GL}}(1)$ twisted $L$-functions
Fei Hou
Abstract
Let $P,M$ be a two primes such that $(P,M)=1$. Let $Π$ be a normalized Hecke-Maaß form on ${\rm{GL}}(4)$ of level $P$, and $χ$ a primitive Dirichlet character modulo $M$. In this paper, we study the hybrid subconvexity problem for $L(s, Π\otimes χ)$ simultaneously in the level and conductor aspects. Among other things, we prove a hybrid subconvex bound, so long as $M^{1/5}<P<M^{2/5}$.
