Ab initio calculations of tunneling current along a model 25-Angstrom-long
polypeptide chain, and similar extended hydrocarbon molecular wires, show t
hat in the tunneling flow there exist "topological defects,'' viz. the line
s on which the wave function of the tunneling electron is zero, and the pha
se of the wave function is not defined. As a result, the flow of quantum me
chanical probability experiences circular motions (vortices) around such no
dal lines, and the overall structure of the flow becomes remarkably complex
. The vortices in the tunneling flow are quantized, and are similar in thei
r mathematical nature to those in a quantum superfluid liquid. (C) 1999 Ame
rican Institute of Physics. [S0021-9606(99)70818-4].