Metastability and bifurcation in superconducting nanorings

Khlebnikov, Sergei

doi:10.1103/physrevb.95.174507

Cited by 5 publications

(4 citation statements)

References 22 publications

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“…We start by discussing the behavior of the supercurrent at zero applied magnetic field by varying the amplitude of the electrostatic field and the temperature. The evolution of I C as a function of temperature follows the conventional Bardeen's profile [30][31][32] [33][34][35], and it disappears when T > 400 mK, which is consistent with an enhanced thermalization mediated by phonon coupling.…”

Section: A Electric Field Vs In-and Out-of-plane Magnetic Fieldsupporting

confidence: 61%

Unveiling mechanisms of electric field effects on superconductors by a magnetic field response

Bours

Mercaldo

Cuoco

et al. 2020

Phys. Rev. Research

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We demonstrate that superconducting aluminium nanobridges can be driven into a state with complete suppression of the critical supercurrent via electrostatic gating. Probing both in-and out-of-plane magnetic field responses in the presence of electrostatic gating can unveil the mechanisms that primarily cause the superconducting electric field effects. Remarkably, we find that a magnetic field, independently of its orientation, has only a weak influence on the critical electric field that identifies the transition from the superconducting state to a phase with vanishing critical supercurrent. This observation points to the absence of a direct coupling between the electric field and the amplitude of the superconducting order parameter or 2π-phase slips via vortex generation. The magnetic field effect observed in the presence of electrostatic gating is described within a microscopic model where a spatially uniform interband π phase is stabilized by the electric field. Such an intrinsic superconducting phase rearrangement can account for the suppression of the supercurrent, as well as for the weak dependence of the critical magnetic fields on the electric field.

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Section: A Electric Field Vs In-and Out-of-plane Magnetic Fieldsupporting

confidence: 61%

Unveiling mechanisms of electric field effects on superconductors by a magnetic field response

Bours

Mercaldo

Cuoco

et al. 2020

Phys. Rev. Research

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show abstract

“…At the base temperature of 50 mK, the critical current I C ≈ 12.8 µA. The evolution of I C as a function of temperature follows the conventional Bardeen's profile [24][25][26]…”

mentioning

confidence: 89%

Unveiling Mechanisms of Electric Field Effects on Superconductors by Magnetic Field Response

Bours,

Mercaldo,

Cuoco

et al. 2020

Preprint

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We demonstrate that superconducting aluminium nano-bridges can be driven into a state with complete suppression of the critical supercurrent via electrostatic gating. Probing both in-and out-of-plane magnetic field responses in the presence of electrostatic gating can unveil the mechanisms that primarily cause the superconducting electric field effects. Remarkably, we find that a magnetic field, independently of its orientation, has only a weak influence on the critical electric field that identifies the transition from the superconducting state to a phase with vanishing critical supercurrent. This observation points to the absence of a direct coupling between the electric field and the amplitude of the superconducting order parameter or 2π-phase slips via vortex generation. The magnetic field effect observed in the presence of electrostatic gating is well described within a microscopic scenario where a spatially uniform inter-band π-phase is stabilized by the electric field. Such an intrinsic superconducting phase rearrangement can account for the suppression of the supercurrent, as well as for the weak dependence of the critical magnetic fields on the electric field.

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“…This relaxation process proceeds through metastable states with different time scales, often characterized by long lifetimes [17,33,34]. Metastability in open quantum systems and relaxation processes from metastable states are a fundamental issue in many branches of physics, chemistry and biology, and recently have been subject of increasing interest in superconducting phase transitions and also in topological condensed matter structures [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50].…”

Section: Introductionmentioning

confidence: 99%

Stabilization by dissipation and stochastic resonant activation in quantum metastable systems

Spagnolo

Carollo

Valenti

2018

Eur. Phys. J. Spec. Top.

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In this tutorial paper we present a comprehensive review of the escape dynamics from quantum metastable states in dissipative systems and related noise-induced effects. We analyze the role of dissipation and driving in the escape process from quantum metastable states with and without an external driving force, starting from a nonequilibrium initial condition. We use the Caldeira-Leggett model and a non-perturbative theoretical technique within the Feynman-Vernon influence functional approach in strong dissipation regime. In the absence of driving, we find that the escape time from the metastable region has a nonmonotonic behavior versus the system-bath coupling and the temperature, producing a stabilizing effect in the quantum metastable system. In the presence of an external driving, the escape time from the metastable region has a nonmonotonic behavior as a function of the frequency of the driving, the thermal-bath coupling and the temperature. The quantum noise enhanced stability phenomenon is observed in both systems investigated. Finally, we analyze the resonantly activated escape from a quantum metastable state in the spin-boson model. We find quantum stochastic resonant activation, that is the presence of a minimum in the escape time as a function of the driving frequency. Background and introductory material has been added in the first three sections of the paper to make this tutorial review reasonably self-contained and readable for graduate students and non-specialists from related areas.

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Metastability and bifurcation in superconducting nanorings

Cited by 5 publications

References 22 publications

Unveiling mechanisms of electric field effects on superconductors by a magnetic field response

Unveiling mechanisms of electric field effects on superconductors by a magnetic field response

Unveiling Mechanisms of Electric Field Effects on Superconductors by Magnetic Field Response

Stabilization by dissipation and stochastic resonant activation in quantum metastable systems

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