Spontaneous Localization and Superconductivity

Mariamargherita Buffa, O. Nicrosini, A. Rimini

Mariamargherita Buffa, O. Nicrosini, A. Rimini

R. P. Groff

James F. Annett, S. P. Kruchinin

Francesco Paolo Mancini, Pasquale Sodano, Andrea Trombettoni

The spontaneous emergence of enhanced responses and local orders are properties often associated with complex matter where nonlinearities and spatial inhomogeneities dominate. We discuss these phenomena in quantum devices realized with superconducting Josephson junction networks and cold atoms in optical lattices. We evidence how the pertinent engineering of the network's shape induces the enhancement of the zero-voltage Josephson critical currents in superconducting arrays as well as the emergence of spatially localized condensates for cold atoms in inhomogeneous optical lattices.

Tomo Munehisa

Spontaneous symmetry breaking is well known to be a macroscopic phenomenon in quantum physics in many body systems. The essential features of this phenomenon are the energy degeneracy and the existence of the local operator that can modify the degenerate states. Due to these properties the lowest energy state is not stable. In order to obtain the stable ground state we introduce the explicitly breaking interaction, by which it is difficult for the local operator to modify the ground state. In the superconducting qubit there exists the stable eigenstate with the definite charge number. We point out that in this system, the local operator can change this state to another state. As results the cluster property violates, which means that the events in the far distance are not irrelevant. In this paper we examine the cluster property in the superconducting qubit. Then we propose a method by cavity quantum electrodynamics with two cavities in order to observe the violation.