CRITICAL-CURRENT OF A ONE-DIMENSIONAL SUPERCONDUCTOR

We solve the Bogoliubov-de Gennes equations for a clean, one-dimensional superconductor in the presence of superfluid flow. The maximum electrical current occurs when the superfluid velocity v(s) equals the Landau depairing velocity DELTA/p(F), where DELTA is the pairing potential of the superconductor and p(F) is the Fermi momentum. The resulting critical current is approximately 2/pi times than the value eDELTA/HBAR recently predicted for a superconducting point contact. The ''discretized'' critical current of (2/pi)(eDELTA/HBAR) arises when all the conducting electrons are forced to drift at the Landau depairing velocity.