Quantum Fluctuations and Resistivity of Thin Superconducting Wires
  We present a microscopic study of the quantum fluctuations of the superconducting order parameter in thin homogeneous superconducting wires at all temperatures below $T_C$. The rate of quantum phase slip processes determines the resistance $R(T)$ of the wire, which is observable in very thin wires, even at low temperature. Furthermore, we predict a new low temperature metallic phase below a critical wire-thickness in the 10nm range, in which quantum phase slips proliferate. 
Andrei D. Zaikin, Dmitrii S. Golubev, Anne van Otterlo, and Gergely T.   Zimanyi