Tamagawa number conjecture for CM modular forms and Rankin--Selberg convolutions
Francesc Castella
TL;DR
This work proves the $p$-part of the Birch–Swinnerton-Dyer formula for CM elliptic curves $E/F$ under precise CM and abelian-torsion hypotheses, and extends the framework to CM abelian varieties and CM modular forms. It builds an anticyclotomic Iwasawa Main Conjecture for self-dual pairs $(g,\chi)$ via square-root $p$-adic $L$-functions and Katz two-variable $L$-functions, hinges on generalized Heegner cycles, and leverages explicit reciprocity laws to connect $p$-adic invariants with central $L$-values. The approach yields a Gross–Zagier–Kolyvagin-type p-converse in this CM setting and provides a pathway to the equivariant Tamagawa number conjecture in analytic rank 1 for CM motives. By specializing to weight 2, it derives the $p$-part BSD for CM abelian varieties, supported by period comparisons and Néron–Tate height pairings, with broader implications for higher-weight CM modular forms. Overall, the paper integrates Iwasawa theory, $p$-adic $L$-functions, and Euler systems to establish precise arithmetic–analytic correspondences in the CM context and beyond.
Abstract
Let $E/F$ be an elliptic curve defined over a number field $F$ with complex multiplication by the ring of integers of an imaginary quadratic field $K$ such that the torsion points of $E$ generate over $F$ an abelian extension of $K$. In this paper we prove the $p$-part of the Birch--Swinnerton-Dyer formula for $E/F$ in analytic rank $1$ for primes $p>3$ split in $K$. This was previously known for $F=\mathbb{Q}$ by work of Rubin as a consequence of his proof of Mazur's Main Conjecture for rational CM elliptic curves, but the problem for $[F:\mathbb{Q}]>1$ remained wide open. The approach introduced in this paper also yields a proof of similar results for CM abelian varieties $A/K$ and for CM modular forms, as well as an analogue in this setting of Skinner's $p$-converse to the theorem of Gross--Zagier and Kolyvagin.
