Effect of dimensions of Josephson junctions on their macroscopic quantum properties

The effect of the finite dimensions of a Josephson junction on the width of the lower band of its energy spectrum is analyzed. It is shown that for those relatively small junctions (dimensions a,b ≲. 10−3 cm) in which the “secondary” macroscopic quantum effects are now under study experimentally, the previously employed “lumped” (zero-dimensional) model is fully adequate. If, however, at least one of the dimensions of the junction is so large that the frequencies of the lower resonance Fiske modes lie below the “gap” frequency, the zeroth oscillations of such modes can appreciably broaden the lower band.