Quantum tunneling of the order parameter in superconducting nanowires - art. no. 014504

Quantum tunneling of the superconducting order parameter gives rise to the phase slippage process which controls the resistance of ultrathin supercond ucting wires at sufficiently low temperatures. If the quantum phase slip ra te is high, superconductivity is completely destroyed by quantum fluctuatio ns and the wire resistance never decreases below its normal state value. We present a detailed microscopic theory of quantum phase slips in homogeneou s superconducting nanowires. Focusing our attention on relatively short wir es we evaluate the quantum tunneling rate for phase slips, both the quasicl assical exponent and the pre-exponential factor. In very thin and dirty met allic wires the effect is shown to he clearly observable even at T -->0. Ou r results are fully consistent with recent experimental findings [A. Bezrya din, C.N. Lau, and M. Tinkham, Nature (London) 404, 971 (2000)] which provi de direct evidence for the effect of quantum phase slips.