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arXiv · 1905.08544

Quantum fluctuations and phase coherence in superconducting nanowires

Alexey Radkevich·Andrew G. Semenov·Andrei D. Zaikin
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Abstract

Quantum behavior of superconducting nanowires may essentially depend on the employed experimental setup. Here we investigate a setup that enables passing equilibrium supercurrent across an arbitrary segment of the wire without restricting fluctuations of its superconducting phase. The low temperature physics of the system is determined by a combined effect of collective sound-like plasma excitations and quantum phase slips. At $T=0$ the wire exhibits two quantum phase transitions, both being controlled by the dimensionless wire impedance $g$. While thicker wires with $g>16$ stay superconducting, in thinnest wires with $g<2$ the supercurrent is totally destroyed by quantum fluctuations. The intermediate phase with $2<g<16$ is characterized by two different correlation lengths demonstrating superconducting-like behavior at shorter scales combined with vanishing superconducting response in the long scale limit.

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Alexey Radkevich, Andrew G. Semenov, Andrei D. Zaikin. 2019-05-21. Quantum fluctuations and phase coherence in superconducting nanowires. https://doi.org/10.1103/physrevb.100.014520

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