Recent progress in open quantum systems: Non-Gaussian noise and decoherence in fermionic systems

摘要

We review our recent contributions to two topics that have be-come of interest in the field of open, dissipative quantum sys-tems: non-Gaussian noise and decoherence in fermionic sys-tems. Decoherence by non-Gaussian noise, i.e. by an environ-ment that cannot be approximated as a bath of harmonic oscil-lators, is important in nanostructures (e.g. qubits) where theremight be strong coupling to a small number of fluctuators. Wefirst revisit the pedagogical example of dephasing by classicaltelegraph noise. Then we address two models where the quan-tum nature of the noise becomes essential: "quantum telegraph noise" and dephasing by electronic shot noise. In fermionicsystems, many-body aspects and the Pauli principle have to betaken care of when describing the loss of phase coherence. Thisis relevant in electronic quantum transport through metallic andsemiconducting structures. Specifically, we recount our recentresults regarding dephasing in a chiral interacting electron liq-uid, as it is realized in the electronic Mach— Zehnder-interfer-ometer. This model can be solved employing the technique ofbosonization as well as a physically transparent semiclassicalmethod.