Weight 2 CM newforms as p-adic limits

Abstract

Previous works have shown that certain weight $2$ newforms are $p$-adic limits of weakly holomorphic modular forms under repeated application of the $U$-operator. The proofs of these theorems originally relied on the theory of harmonic Maass forms. Ahlgren and Samart obtained strengthened versions of these results using the theory of holomorphic modular forms. Here, we use such techniques to express all weight $2$ CM newforms which are eta quotients as $p$-adic limits. In particular, we show that these forms are $p$-adic limits of the derivatives of the Weierstrass mock modular forms associated to their elliptic curves.