Macroscopic quantum tunneling in multigap superconducting Josephson junctions: Escape rate enhancement via quantum fluctuations of Josephson-Leggett mode

Abstract

We theoretically study the macroscopic quantum tunneling (MQT) in a hetero Josephson junction formed by a conventional single-gap superconductor and a multi-gap one such as ${MgB}_2$ and iron-based superconductors. In such a Josephson junction more than one phase differences are defined. We clarify the quantum dynamics of the phase differences and construct a theory for the MQT in the multi-gap Josephson junctions. The dynamics of the phase differences are strongly affected by the Josephson-Leggett mode, which is the out-of-phase oscillation mode of the phase differences. The escape rate is calculated in terms of the effective action renormalized by the Josephson-Leggett mode. It is shown that the escape rate is drastically enhanced when the frequency of the Josephson-Leggett mode is less than the Josephson-plasma frequency.

4 pages, 4 figures

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Cited by in corpus (8)

• Macroscopic Quantum Tunneling Escape of Bose-Einstein Condensates
• Anomalous proximity effects at the interface of s and s+- superconductors
• Leggett modes and the Anderson-Higgs mechanism in superconductors without inversion symmetry
• Proximity fingerprint of s+- superconductivity
• Phase diagram of Josephson junction between s and s+- superconductors in dirty limit
• Theory of macroscopic quantum tunneling with Josephson-Leggett collective excitations in multi-band superconducting Josephson junctions
• Fluxon Dynamics of a Long Josephson Junction with Two-gap Superconductors
• Two-dimensional macroscopic quantum tunneling in multi-gap superconductor Josephson junctions