Quantum mechanics of superconducting nanowires
  In a short superconducting nanowire connected to bulk superconducting leads, quantum phase slips behave as a system of linearly (as opposed to logarithmically) interacting charges. This system maps onto quantum mechanics of a particle in a periodic potential. We show that, while the state with a high density of phase slips is not a true insulator (a consequence of Josephson tunneling between the leads), for a range of parameters it behaves as such down to unobservably small temperatures. We also show that quantum phase slips give rise to multiple branches (bands) in the energy-current relation and to an interband ("exciton") mode. 
S. Khlebnikov