A Chebotarev variant of the Brun-Titchmarsh theorem and bounds for the Lang-Trotter conjectures

Abstract

We improve the Chebotarev variant of the Brun-Titchmarsh theorem proven by Lagarias, Montgomery, and Odlyzko using the log-free zero density estimate and zero repulsion phenomenon for Hecke L-functions that were recently proved by the authors. Our result produces an improvement for the best unconditional bounds toward two conjectures of Lang and Trotter regarding the distribution of traces of Frobenius for elliptic curves and holomorphic cuspidal modular forms. We also obtain new results on the distribution of primes represented by positive-definite integral binary quadratic forms.Comment: 26 pages; v2 several typographical and minor errors are fixed, some of which had a small impact on the quality of the exponents in Thm 1.1, Thm 1.2, and Cor 1.