QUANTUM DECAY OF ONE-DIMENSIONAL SUPERCURRENT - ROLE OF ELECTROMAGNETIC-FIELD

The quantum decay of a one-dimensional small supercurrent is a charge non-neutral process which involves an electromagnetic field. I take proper account of magnetic and electric screening, respectively, and find that the electromagnetic field contributes an exponentially small multipling factor e-A/α∼e-100 to the quantum decay rate with α the fine structure constant and A a numerical constant of order unity. This means that a circulating supercurrent lives forever. Possible relevance with several recent experiments is discussed. © 1995 The American Physical Society.