  We present extensive \textit{ab initio} path integral Monte Carlo (PIMC)
simulations of two-dimensional quantum dipole systems in a harmonic
confinement, taking into account both Bose- and Fermi-statistics. This allows
us to study the nonclassical rotational inertia, which can lead to a negative
superfluid fraction in the case of fermions [Phys. Rev. Lett. \textbf{112},
235301 (2014)]. Moreover, we study in detail the structural characteristics of
such systems, and are able to clearly resolve the impact of quantum statistics
on density profiles and the respective shell structure. Further, we present
results for a more advanced center-two particle correlation function [Phys.
Rev. E \textbf{91}, 043104 (2015)], which allows to detect differences between
Fermi- and Bose-systems that do not manifest in other observables like the
density. Overall, we find that bosonic systems sensitively react to even small
values of the dipole--dipole coupling strength, whereas such a weak interaction
is effectively masked for fermions by the Pauli exclusion principle. In
addition, the abnormal superfluid fraction for fermions is not reflected by the
structural properties of the system, which are equal to the bosonic case even
though the moments of inertia diverge from each other. Lastly, we have
demonstrated that fermionic PIMC simulations of quantum dipole systems are
feasible despite the notorious fermion sign problem, which opens up new avenues
for future investigations in this field.
