Ceresa Cycles of $X_{0}(N)$
Elvira Lupoian, James Rawson
TL;DR
The paper analyzes the Ceresa cycle on Jacobians of modular curves, focusing on $X_0(N)$. It establishes that for prime level $p$, the Ceresa cycle $ ext{Cer}(p)$ is non-torsion precisely when $X_0(p)$ is non-hyperelliptic, yielding concrete non-vanishing results for many primes; it also proves that only finitely many levels $N$ yield a torsion Ceresa cycle. The core method links vanishing of the Ceresa cycle to Chow-Heegner points (via GK-S cycles and shadow points) and leverages the endomorphism action of the modular Jacobians (notably Hecke operators) to produce infinite-order points. The results connect to triple product $L$-functions through height pairings and offer explicit computations (and computational criteria) for many levels, while detailing limitations when $J_0(N)(Q)$ has rank zero. Overall, the work combines modular-curve geometry, CM points, and endomorphism-technology to advance understanding of algebraic nontriviality of Ceresa cycles in a central arithmetic setting.
Abstract
The Ceresa cycle is an algebraic 1-cycle on the Jacobian of an algebraic curve. Although it is homologically trivial, Ceresa famously proved that for a very general complex curve of genus at least 3, it is non-trivial in the Chow group. In this paper we study the Ceresa cycle attached to the complete modular curve $X_{0}(N)$ modulo rational equivalence. For prime level $p$ we give a complete description, namely we prove that if $X_{0}(p)$ is not hyperelliptic, then its Ceresa cycle is non-torsion. For general level $N$, we prove that there are finitely many $X_{0}(N)$ with torsion Ceresa cycle. Our method relies on the relationship between the vanishing of the Ceresa cycle and Chow-Heegner points on the Jacobian. We use the geometry and arithmetic of modular Jacobians to prove that such points are of infinite order and therefore deduce non-vanishing of the Ceresa cycle.
