摘要:In superconductors the zero-resistance current-flow is protected from dissipation at finite temperatures ( T ) by virtue of the short-circuit condition maintained by the electrons that remain in the condensed state. The recently suggested finite- T insulator and the “superinsulating” phase are different because any residual mechanism of conduction will eventually become dominant as the finite- T insulator sets-in. If the residual conduction is small it may be possible to observe the transition to these intriguing states. We show that the conductivity of the high magnetic-field insulator terminating superconductivity in amorphous indium-oxide exhibits an abrupt drop, and seem to approach a zero conductance at T T insulator.