English

Short-interval sector problems for CM elliptic curves

Number Theory 2023-05-03 v2

Abstract

Let E/QE/\mathbb{Q} be an elliptic curve that has complex multiplication (CM) by an imaginary quadratic field KK. For a prime pp, there exists θp[0,π]\theta_p \in [0, \pi] such that p+1#E(Fp)=2pcosθpp+1-\#E(\mathbb{F}_p) = 2\sqrt{p} \cos \theta_p. Let x>0x>0 be large, and let I[0,π]I\subseteq[0,\pi] be a subinterval. We prove that if δ>0\delta>0 and θ>0\theta>0 are fixed numbers such that δ+θ<524\delta+\theta<\frac{5}{24}, x1δhxx^{1-\delta}\leq h\leq x, and Ixθ|I|\geq x^{-\theta}, then 1hx<px+hθpIlogp121π2I+I2π, \frac{1}{h}\sum_{\substack{x < p \le x+h \\ \theta_p \in I}}\log{p}\sim \frac{1}{2}\mathbf{1}_{\frac{\pi}{2}\in I}+\frac{|I|}{2\pi}, where 1π2I\mathbf{1}_{\frac{\pi}{2}\in I} equals 1 if π2I\frac{\pi}{2}\in I and 00 otherwise. We also discuss an extension of this result to the distribution of the Fourier coefficients of holomorphic cuspidal CM newforms.

Keywords

Cite

@article{arxiv.2105.11093,
  title  = {Short-interval sector problems for CM elliptic curves},
  author = {Apoorva Panidapu and Jesse Thorner},
  journal= {arXiv preprint arXiv:2105.11093},
  year   = {2023}
}

Comments

10 pages, significant revision after referee comments

R2 v1 2026-06-24T02:23:42.832Z