BGU Physics Department

Colloquium, Oct. 28, 2010


Superconductivity-superinsulation duality


Valerii Vinokur, Argonne National Lab

 

Superconductivity rests on two cornerstones: (i) all electrons in a superconductor are described by a unique macroscopic wave function and (ii) the phase of this wave function is well-defined over the whole superconducting system, i.e. superconductivity is a quantum macroscopic state maintaining the global phase coherence. The phase and the absolute value of the wave function are canonically conjugated quantum variables, thus uncertainties in the phase Dφ and in the condensed particle number, DN, are coupled by the Heisenberg relation DφD ~ 1.  This implies the existence of the superinsulating state dual to superconducting one and possessing zero conductivity at finite temperatures. We review realizations of the superinsulating state in two-dimensional disordered superconducting films and Josephson junction arrays and discuss microscopic mechanism that ensures superinsulating behavior: the cascade relaxation.