On Diophantine properties for values of Dedekind zeta functions
Jerson Caro, Fabien Pazuki, Riccardo Pengo
TL;DR
The article investigates when the Dedekind zeta-height $h_s([K]) = |\zeta_K^*(s)|$ has Northcott or Bogomolov properties across real and complex values of $s$. It establishes Bogomolov failure for all $\sigma \ge \tfrac{1}{2}$ using a combination of Soundararajan’s resonance method and random Euler product models, alongside explicit field-construction arguments to treat $\sigma>1$. For $\mathrm{Re}(s)<0$, it proves a Northcott property for the pair $(|\zeta_K^*(s)|,[K:\mathbb{Q}])$, showing that height control combined with degree bounds yields finiteness. The work unifies resonator techniques, probabilistic models, and explicit arithmetic constructions to map the Diophantine behavior of Dedekind zeta-values across the half-plane, including the critical line and its right side.
Abstract
We study the Northcott and Bogomolov property for special values of Dedekind $ζ$-functions at real values $σ\in \mathbb{R}$. We prove, in particular, that the Bogomolov property is not satisfied when $σ\geq \frac{1}{2}$. If $σ> 1$, we produce certain families of number fields having arbitrarily large degrees, whose Dedekind $ζ$-functions $ζ_K(s)$ attain arbitrarily small values at $s = σ$. On the other hand, if $\frac{1}{2} \leq σ\leq 1$, we construct suitable families of quadratic number fields, employing either Soundararajan's resonance method, which works when $\frac{1}{2} \leq σ< 1$, or results on random Euler products by Granville and Soundararajan, and by Lamzouri, which work when $\frac{1}{2} < σ\leq 1$. We complete the study by proving that the Dedekind $ζ$ function together with the degree satisfies the Northcott property for every complex $s\in{\mathbb{C}}$ such that $\mathrm{Re}(s) <0$, generalizing previous work of Généreux and Lalín.
