One-level density of families of elliptic curves and the Ratios Conjectures

TL;DR

This paper uses ratios conjectures to derive formulas for the one-level density of elliptic curve L-function families, revealing their symmetry types and the influence of curve rank on zero distributions.

Contribution

It provides new closed-form formulas for the one-level density of two elliptic curve L-function families using ratios conjectures, identifying their symmetry types.

Findings

First family exhibits orthogonal symmetry as predicted by Katz-Sarnak.

Second family shows a combined Dirac and even orthogonal distribution due to odd rank.

Method distinguishes distributions beyond small support Fourier transform limitations.

Abstract

Using the ratios conjectures as introduced by Conrey, Farmer and Zirnbauer, we obtain closed formulas for the one-level density for two families of L-functions attached to elliptic curves. From those closed formulas, we can determine the underlying symmetry types of the families. The one-level scaling density for the first family corresponds to the orthogonal distribution as predicted by the conjectures of Katz and Sarnak, and the one-level scaling density for the second family is the sum of the Dirac distribution and the even orthogonal distribution. This seems to be a new phenomenon, caused by the fact that the curves of the second families have odd rank. Then, there is a trivial zero at the central point which accounts for the Dirac distribution, and also affects the remaining part of the scaling density which is then (maybe surprisingly) the even orthogonal distribution. The one-level density for this second family was studied in the past for test functions with Fourier transforms of small support, but since the Fourier transforms of the even orthogonal and odd orthogonal distributions are undistinguishable for small support, it was not possible to identify the distribution with those techniques. This can be done with the ratios conjectures, and it sheds more light on "independent" and "non-independent" zeroes and the repulsion phenomenon.