Geometry and distribution of roots of $\mu^2\equiv D\bmod m$ with $D \equiv 1 \bmod 4$

Abstract

We extend the geometric interpretation of the roots of the quadratic congruence $\mu^2 \equiv D \pmod m$ as the tops of certain geodesics in the hyperbolic plane to the case when $D$ is square-free and $D\equiv 1\pmod 4$. This allows us to establish limit laws for the fine-scale statistics of the roots using results by Marklof and the second author.