In mesoscopic systems, such as those encountered in nanotechnology, the physical dimensions are comparable to the phase coherence length of the electrons. This means that quantum interference effects cannot be ignored. The Landauer formula is used to express the conductance in terms of the transmission probabilities of electronic channels. For a single-channel conductor, the conductance \( G \) is given by:
\[ G = \frac{2e^2}{h} T \]
where \( e \) is the electron charge, \( h \) is Planck's constant, and \( T \) is the transmission probability.
