Dynamics of open quantum systems

Despite being an essential keyword in modern physics, "Open quantum system" is such a generic concept to signify little. Depending on what it opens into, a quantum system can be described as dissipative, or noisy, or out-of-equilibrium, or thermalized, or . . . In fact, the behaviour of an open system strongly depends on the specific characterization of its environment, as well as on the interaction with it. However, there are ultimate features which define the common ground for studying the dynamics of open quantum systems: amongst these, the time evolution of entanglement properties plays a fundamental role. In this seminar, I will first describe the essential toolbox for the study of the dynamical evolution of open quantum systems, and will then show how this is implemented in the frameworkof quantum-state transmission processes and entanglement distribution. Recent proposals for the realization of a non-dispersive quantum channel, as well as of an entangling two-qubit gate, will be finally presented.