  Ab initio calculations of bulk nuclear properties (ground-state energies,
root mean square charge radii and charge density distributions) are presented
for seven complete isotopic chains around calcium, from argon to chromium.
Calculations are performed within the Gorkov self-consistent Green's function
approach at second order and make use of two state-of-the-art two- plus
three-nucleon Hamiltonians, $NN$+$3N\text{(lnl)}$ and NNLO$_{\text{sat}}$. An
overall good agreement with available experimental data is found, in particular
for differential energies (charge radii) when the former (latter) interaction
is employed. Remarkably, neutron magic numbers $N=28,32,34$ emerge and evolve
following experimental trends. In contrast, pairing gaps are systematically
underestimated. General features of the isotopic dependence of charge radii are
also reproduced, as well as charge density distributions. A deterioration of
the theoretical description is observed for certain nuclei and ascribed to the
inefficient account of (static) quadrupole correlation in the present many-body
truncation scheme. In order to resolve these limitations, we advocate the
extension of the formalism towards incorporating breaking of rotational
symmetry or, alternatively, performing a stochastic sampling of the
self-energy.
