English

Signed $p$-adic $L$-functions of Bianchi modular forms

Number Theory 2025-12-11 v4

Abstract

Let p3p\geq 3 be a prime number and KK be a quadratic imaginary field in which pp splits as pp\mathfrak{p}\overline{\mathfrak{p}}. Let F\mathcal{F} be a cuspidal Bianchi eigenform over KK of weight (k,k)(k,k), where k0k\geq 0 is an integer, level m\mathfrak{m} coprime to pp, and non-ordinary at both of the primes above pp. We assume F\mathcal{F} has trivial nebentypus. For q{p,p}\mathfrak{q}\in\{\mathfrak{p}, \overline{\mathfrak{p}}\}, let aqa_{\mathfrak{q}} be the TqT_{\mathfrak{q}} Hecke eigenvalue of F\mathcal{F} and let αq,βq\alpha_{\mathfrak{q}},\beta_{\mathfrak{q}} be the roots of polynomial X2aqX+pk+1X^{2} -a_{\mathfrak{q}}X+ p^{k+1}. Then we have four pp-stabilizations of F\mathcal{F}: Fαp,αp,Fαp,βp,Fβp,αp,\mathcal{F}^{\alpha_{\mathfrak{p}},\alpha_{\overline{\mathfrak{p}}}}, \mathcal{F}^{\alpha_{\mathfrak{p}},\beta_{\overline{\mathfrak{p}}}}, \mathcal{F}^{\beta_{\mathfrak{p}},\alpha_{\overline{\mathfrak{p}}}}, and Fβp,βp \mathcal{F}^{\beta_{\mathfrak{p}},\beta_{\overline{\mathfrak{p}}}} which are Bianchi cuspforms of level pmp\mathfrak{m}. By the works of Williams, to each pp-stabilization F,\mathcal{F}^{*,\dagger}, we can attach a locally analytic distribution Lp(F,)L_{p}(\mathcal{F}^{*,\dagger}) over the ray class group Cl(K,p)\text{Cl}(K,p^{\infty}). On viewing Lp(F,)L_{p}(\mathcal{F}^{*,\dagger}) as a two-variable power series with coefficients in some pp-adic field having unbounded denominators satisfying certain growth conditions, we decompose this power series into a linear combination of power series with bounded coefficients in the spirit of Pollack, Sprung, and Lei--Loeffler--Zerbes.

Keywords

Cite

@article{arxiv.2401.15881,
  title  = {Signed $p$-adic $L$-functions of Bianchi modular forms},
  author = {Mihir Deo},
  journal= {arXiv preprint arXiv:2401.15881},
  year   = {2025}
}

Comments

Minor changes. Accepted for publication in Research in Number Theory

R2 v1 2026-06-28T14:29:43.204Z