Hannover 2020 – scientific programme

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PV: Plenarvorträge

PV VII

PV VII: Plenary Talk

Wednesday, March 11, 2020, 09:45–10:30, e415

Quantum fluctuation mesoscopic approach to Josephson junctions — •Fabio Benatti — Department of Physics, University of Trieste, Strada Costiera 11, I-34151 Trieste, Italy

The quantum features of Josephson circuits are usually studied by modelling them as non-linear quantum oscillators. It will be discussed how such phenomenological approaches can be accounted for by means of the theory of quantum fluctuations applied to the so-called strong-coupling quasi-spin version of the BCS Hamiltonian.

Within this formulation suitable quantum fluctuations, namely sums of microscopic quantum degrees of freedom scaling differently from the classical mean-field limits, provide mesoscopic degrees of freedom. These latter are at the same time macroscopic and behave quantumly; moreover, they evolve in time according to a Hamiltonian able to support a Josephson current.