Coleman-Gross Heights and $p$-adic Néron Functions on Jacobians of Genus $2$ Curves
Francesca Bianchi, Enis Kaya, J. Steffen Müller
TL;DR
The paper develops a framework for $p$-adic Néron functions on abelian varieties and proves that global $p$-adic heights, including Mazur--Tate heights, decompose into sums of local $p$-adic Néron functions when consistent auxiliary data are used. Focusing on the Jacobian of genus $2$ curves, it establishes a direct local comparison between Coleman--Gross and Mazur--Tate heights, extending Balakrishnan–Besser’s elliptic results to genus $2$ and treating both unramified and ramified primes. In the ramified case, the authors relate $p$-adic Néron functions to Colmez Green functions and $v$-adic theta/sigma data, giving explicit descriptions via Norman’s theta function and Blakestad’s zeta functions. They also prove analyticity results for the canonical Mazur--Tate splitting in semistable ordinary genus $2$ and provide explicit descriptions of the canonical subspace $W_v$, linking to unit-root theory in good reduction and offering computational pathways for the canonical height in practice. Altogether, the work unifies several $p$-adic height frameworks in genus $2$ and furnishes concrete tools for quadratic Chabauty-type computations and explicit height decompositions.
Abstract
We develop a theory of $p$-adic Néron functions on abelian varieties, depending on various auxiliary choices, and show that the global $p$-adic height functions constructed by Mazur and Tate can be decomposed into a sum of $p$-adic Néron functions if the same auxiliary choices are made. We also consider a decomposition of the $p$-adic height constructed by Coleman and Gross for good reduction, and extended to arbitrary reduction by Colmez and Besser, into a sum of certain local height functions for Jacobians of odd degree genus~$2$ curves. We show that this local height function is equal to the $p$-adic Néron function with the same auxiliary choices, regardless of the reduction type of the curve. This extends work of Balakrishnan and Besser for elliptic curves. When the curve has semistable reduction and the reduction of the Jacobian is ordinary, we also describe the $p$-adic Néron function that arises from the canonical Mazur--Tate splitting explicitly in terms of a generalisation of the $p$-adic sigma function constructed by Blakestad.
