Quantum impurities in channel mixing baths

Decoherence by engineered quantum baths

Davide Rossini, Tommaso Calarco, 3 Vittorio Giovannetti, Simone Montangero, 4 and Rosario Fazio 1 NEST-CNR-INFM & Scuola Normale Superiore, piazza dei Cavalieri 7, I-56126 Pisa, Italy Dipartimento di Fisica, Università di Trento and BEC-CNR-INFM, I-38050 Povo, Italy ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA Institut für Theoretische Festkörperphysik, Universit...

Quantum pairing of impurities in quantum crystals.

Nonequilibrium quantum chains under multisite Lindblad baths.

We study a quantum XX chain coupled to two heat reservoirs that act on multiple sites and are kept at different temperatures and chemical potentials. The baths are described by Lindblad dissipators, which are constructed by direct coupling to the fermionic normal modes of the chain. Using a perturbative method, we are able to find analytical formulas for all steady-state properties of the syste...

Thermalization of quantum systems by finite baths

– We consider a discrete quantum system coupled to a finite bath, which may consist of only one particle, in contrast to the standard baths which usually consist of continua of oscillators, spins, etc. We find that such finite baths may nevertheless equilibrate the system though not necessarily in the way predicted by standard open system techniques. This behavior results regardless of the init...

Mixing doubly stochastic quantum channels with the completely depolarizing channel

It is proved that every doubly stochastic quantum channel that is properly averaged with the completely depolarizing channel can be written as a convex combination of unitary channels. As a consequence, we find that the collection of channels expressible as convex combinations of unitary channels has non-zero Borel measure within the space of doubly stochastic channels.