Evidence for collective excitations in superconducting tin whiskers

Based on the assumption that a phase-slip center in a ''clean'' quasi-one-dimensional superconductor excites a collectivve oscillation, the time-averaged value of the electrochemical potential <μ> of quasiparticles is calculated. At larger distances from the phase-slip center, <μ> ''swings'' below (or above) the electrochemical potential <μ/sub p/> of the Cooper pairs. This makes it possible to understand the unexpected results of previous measurements