  We review our recent contributions to two topics that have become of interest
in the field of open, dissipative quantum systems: non-Gaussian noise and
decoherence in fermionic systems. Decoherence by non-Gaussian noise, i.e. by an
environment that cannot be approximated as a bath of harmonic oscillators, is
important in nanostructures (e.g. qubits) where there might be strong coupling
to a small number of fluctuators. We first revisit the pedagogical example of
dephasing by classical telegraph noise. Then we address two models where the
quantum nature of the noise becomes essential: "quantum telegraph noise" and
dephasing by electronic shot noise. In fermionic systems, many-body aspects and
the Pauli principle have to be taken care of when describing the loss of phase
coherence. This is relevant in electronic quantum transport through metallic
and semiconducting structures. Specifically, we recount our recent results
regarding dephasing in a chiral interacting electron liquid, as it is realized
in the electronic Mach-Zehnder interferometer. This model can be solved
employing the technique of bosonization as well as a physically transparent
semiclassical method.
