Non-Gaussian noise effects in the dynamics of a short overdamped Josephson junction

Augello, Giuseppa; Valenti, Davide; Spagnolo, Bernardo

doi:10.1140/epjb/e2010-10106-1

Cited by 94 publications

(60 citation statements)

References 81 publications

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“…As α decreases, the peaks get higher, the regions around the peak become narrower (the so-called limited space displacement [39,41]), and the tails get heavier. …”

Section: The Lévy Statisticsmentioning

confidence: 99%

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Effects of Lévy noise on the dynamics of sine-Gordon solitons in long Josephson junctions

et al. 2016

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Abstract. We numerically investigate the generation of solitons in currentbiased long Josephson junctions in relation to the superconducting lifetime and the voltage drop across the device. The dynamics of the junction is modelled with a sine-Gordon equation driven by an oscillating field and subject to an external non-Gaussian noise. A wide range of α-stable Lévy distributions is considered as a noise source, with varying stability index α and asymmetry parameter β. In junctions longer than a critical length, the mean switching time (MST) from the superconductive to the resistive state assumes a value independent of the device length. Here, we demonstrate that this value is directly related to the mean density of solitons which move into or from the washboard potential minimum corresponding to the initial superconductive state. Moreover, we observe: (i) a connection between the total mean soliton density and the mean potential dierence across the junction; (ii) an inverse behaviour of the mean voltage in comparison with the MST, with varying the junction length; (iii) evidence of non-monotonic behaviours, such as stochastic resonant activation and noise-enhanced stability, of the MST versus the driving frequency and noise intensity for dierent values of α and β; (iv) finally, these

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“…As α decreases, the peaks get higher, the regions around the peak become narrower (the so-called limited space displacement [39,41]), and the tails get heavier. …”

Section: The Lévy Statisticsmentioning

confidence: 99%

“…1 / is the Lévy noise amplitude [39]. In panels (b) and (c) of figure 3, the values of [41,89,[94][95][96][97][98][99][100][101][102], specifically stochastic resonance activation, a noise-induced phenomenon, whose signature is the appearance of a minimum in the curve of the MST versus ω.…”

Section: J Stat Mech (2016) 054012mentioning

confidence: 99%

Effects of Lévy noise on the dynamics of sine-Gordon solitons in long Josephson junctions

et al. 2016

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“…In this mesoscopic device, which can be in a resistive or superconducting state, the current and the voltage across the junction are related to the microscopic order parameter ϕ, that is the phase difference between the wave functions describing the ground state in the two superconductors [17,79,90,91]. Recently, the effects of both thermal and non-Gaussian fluctuations on the dynamics of JJs have been the focus of increasing investigations [16,17,[92][93][94][95]. Indeed, the statistical analysis of the switching from the metastable superconducting state to the resistive one of a JJ has been used as a theoretical tool to detect signals with unknown statistics [77,78,96].…”

Section: Short and Long Jjmentioning

confidence: 99%

“…Specifically, metastable states in complex systems are characterized by different time scales, the fast ones describing the dynamics inside the metastable region and the slow ones describing the dynamics between different metastable states, and often it is interesting to find long-living metastable states [5,6,13]. In particular, the stability of a metastable state can be enhanced by Gaussian and non-Gaussian noise sources [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Relaxation Phenomena in Metastable Condensed Matter Systems

Spagnolo

Guarcello

Magazzù

et al. 2016

Entropy

100

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Nonlinear relaxation phenomena in three different systems of condensed matter are investigated. (i) First, the phase dynamics in Josephson junctions is analyzed. Specifically, a superconductor-graphene-superconductor (SGS) system exhibits quantum metastable states, and the average escape time from these metastable states in the presence of Gaussian and correlated fluctuations is calculated, accounting for variations in the the noise source intensity and the bias frequency. Moreover, the transient dynamics of a long-overlap Josephson junction (JJ) subject to thermal fluctuations and non-Gaussian noise sources is investigated. Noise induced phenomena are observed, such as the noise enhanced stability and the stochastic resonant activation. (ii) Second, the electron spin relaxation process in a n-type GaAs bulk driven by a fluctuating electric field is investigated. In particular, by using a Monte Carlo approach, we study the influence of a random telegraph noise on the spin polarized transport. Our findings show the possibility to raise the spin relaxation length by increasing the amplitude of the external fluctuations. Moreover, we find that, crucially, depending on the value of the external field strength, the electron spin depolarization length versus the noise correlation time increases up to a plateau. (iii) Finally, the stabilization of quantum metastable states by dissipation is presented. Normally, quantum fluctuations enhance the escape from metastable states in the presence of dissipation. We show that dissipation can enhance the stability of a quantum metastable system, consisting of a particle moving in a strongly asymmetric double well potential, interacting with a thermal bath. 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.Keywords: metastability; nonequilibrium statistical mechanics and nonlinear relaxation time; noise enhanced stability; Josephson junction; spin polarized transport in semiconductors; open quantum systems; quantum noise enhanced stability

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“…Lévy flights have been observed in many physical, biological and social systems, where scale-invariance phenomena take place presence of Lévy noise. [26][27][28] Moreover, Lévy flights have been successfully used to describe the spatial distributions of predators or foragers in ecological systems.…”

Section: Lévy Noise In Population Dynamicsmentioning

confidence: 99%

The Bistable Potential: An Archetype for Classical and Quantum Systems

Spagnolo

Caldara

Cognata

et al. 2012

Int. J. Mod. Phys. B

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In this work we analyze the transient dynamics of three different classical and quantum systems. First, we consider a classical Brownian particle moving in an asymmetric bistable potential, subject to a multiplicative and additive noise source. We investigate the role of these two noise sources on the life time of the metastable state. A nonmonotonic behavior of the lifetime as a function of both additive and multiplicative noise intensities is found, revealing the phenomenon of noise enhanced stability. Afterward, by using a Lotka-Volterra model, the dynamics of two competing species in the presence of Lévy noise sources is analyzed. Quasiperiodic oscillations and stochastic resonance phenomenon in the dynamics of the competing species are found. Finally the dynamics of a quantum particle subject to an asymmetric bistable potential and interacting with a thermal reservoir is investigated. We use the Caldeira-Leggett model and the approach * Invited talk at the International Conference on Statistical Physics, 11-15 July 2011, Cyprus. 1241006-1 B. Spagnolo et al.of the Feynman-Vernon functional in discrete variable representation. We obtain the time evolution of the population distributions in energy eigenstates of the particle, for different values of the coupling strength with the thermal bath.

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Non-Gaussian noise effects in the dynamics of a short overdamped Josephson junction

Cited by 94 publications

References 81 publications

Effects of Lévy noise on the dynamics of sine-Gordon solitons in long Josephson junctions

Effects of Lévy noise on the dynamics of sine-Gordon solitons in long Josephson junctions

Nonlinear Relaxation Phenomena in Metastable Condensed Matter Systems

The Bistable Potential: An Archetype for Classical and Quantum Systems

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