  On a microscopic scale, resistivity during electric conduction is caused by
collisions of the free conduction electrons with the obstructing atoms or
molecules of the conductor material, resulting in heat production. Based on
this fundamental understanding, a hypothesis concerning a physical requirement
of the superconductor material is proposed, which suggests that for
superconductivity (i.e., with zero resistivity) to occur, the conductor
material must have nano-sized, continuous and straight vacuum tunnels inside
with effective radius size large enough to allow collision-free conduction of
free electrons. Besides, some of the composite atoms of the conductor should be
able to readily release electrons to form the conduction band; in fact, this
basic requirement is for all forms of electrical conductors, not just for
superconductors. The proposed hypothesis is supported by experimental
observations in the literature, and also offers a plausible explanation for
some of the poorly-understood experimental phenomena observed in the past. In
addition, the hypothesis offers practical strategies for the rational design of
electrical conductors with (quasi-)superconductivity. Lastly, the proposed new
hypothesis also suggests a novel mechanism for neural microtubule-mediated
electrical quasi-superconductance in the nervous system.
