Abstract
We establish the first moment bound [formula presented] for triple product L-functions, where ψ is a fixed Hecke-Maass form on SL2 and ψ runs over the Hecke-Maass newforms on Γ0(p) of bounded eigenvalue. The proof is via the theta correspondence and analysis of periods of half-integral weight modular forms. This estimate is not expected to be optimal, but the exponent 5/4 is the strongest obtained to date for a moment problem of this shape. We show that the expected upper bound follows if one assumes the Ramanujan conjecture in both the integral and half-integral weight cases. Under the triple product formula, our result may be understood as a strong level aspect form of quantum ergodicity: for a large prime p, all but very few Hecke-Maass newforms on Γ0(p) of bounded eigenvalue have very uniformly distributed mass after pushforward to SL2(Z)\H. Our main result turns out to be closely related to estimates such as [formula presented] where the sum is over those n for which np is a fundamental discriminant and χnp denotes the corresponding quadratic character. Such estimates improve upon bounds of Duke-Iwaniec.
Original language | English |
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Article number | e44 |
Journal | Forum of Mathematics, Sigma |
Volume | 8 |
ISSN | 2050-5094 |
DOIs | |
Publication status | Published - Nov 2020 |
Externally published | Yes |