Near-threshold-energy conductance of a thin wire

We show (1) that a single impurity can have an extremely strong impact on the conductance of a thin wire; (2) that in such a thin wire a couple of two-dimensional impurities may be responsible to strong resonances. (3) Further, we study rough wire transmission in the low-energy regime. We obtain strong localization behavior T congruent to exp(-L/xi) [L is the wire length and xi(omega --> omega th) similar to 1/ln(omega - omega(th)), omega is the particle energy and omega(th) equivalent to ((h) over bar pi/d)(2)/2m is the threshold energy of a similar wire but without the roughness]. We also show that for very long wires the difference between the threshold energy for transmission (omega(TH)) and omega(th) increases logarithmically with the wire length omega(TH) - omega(th) similar to ln L. [S0163-1829(99)09639-3].