On the Whittaker range of the generalized metaplectic theta lift

TL;DR

This paper investigates the behavior of the generalized theta lift in the Rallis tower, focusing on the existence and genericity of lifts across multiple orthogonal groups in higher degree metaplectic covers.

Contribution

It extends the classical theta correspondence to higher degree metaplectic covers and characterizes the Whittaker range and genericity criteria in this broader setting.

Findings

The Whittaker range consists of r+1 groups for the r-fold cover.

A period criterion for the genericity of lifts is established.

The work generalizes classical results to higher degree metaplectic covers.

Abstract

The classical theta correspondence, based on the Weil representation, allows one to lift automorphic representations on symplectic groups or their double covers to automorphic representations on special orthogonal groups. It is of interest to vary the orthogonal group and describe the behavior in this theta tower (the Rallis tower). In prior work, the authors obtained an extension of the classical theta correspondence to higher degree metaplectic covers of symplectic and special orthogonal groups that is based on the tensor product of the Weil representation with another small representation. In this work we study the existence of generic lifts in the resulting theta tower. In the classical case, there are two orthogonal groups that may support a generic lift of an irreducible cuspidal automorphic representation of a symplectic group. We show that in general the Whittaker range consists of $r+1$ groups for the lift from the $r$-fold cover of a symplectic group. We also give a period criterion for the genericity of the lift at each step of the tower.