Coherent transfer of Cooper pairs by a movable grain
  A coherent hybrid of states with different number of Cooper pairs can be built in a superconductor grain as a result of periodically repeated discrete encounters with bulk superconductor leads. As a direct manifestation of such states a non-dissipative current depending on the phase difference between the leads can be measured. 
L. Y. Gorelik, A. Isacsson, Y. M. Galperin, R. I. Shekhter, M. Jonson