QUROPE Quantum Information Processing and Communication in Europe

Macroscopic quantum dynamics of Josephson tunnel junctions is analogous to a motion of fictitious particle in an adiabatic Josephson potential. This analogy relies upon equilibrium state of quasiparticles, protected by a wide superconducting energy gap. In junctions containing low energy quasiparticles, the physical picture drastically differs due to a non-­‐adiabatic current component generated by quasiparticles driven far away from equilibrium by the Josephson oscillation. We discuss the implications of this physical picture for artificial grain boundary junctions of high temperature superconductors, where generic zero energy superconducting bound states exist due to d-­‐wave symmetry of the order parameter.