Search results for "statistical"
showing 10 items of 4960 documents
JOSEPHSON MESOJUNCTIONS AS DETECTORS OF LOW-INTENSITY QUANTIZED COHERENT FAR-INFRARED FIELDS
2000
We show that the quantum nature of a mesoscopic Josephson junction may be exploited for detecting low-intensity electromagnetic quantized fields. In particular we prove that intensity and phase of single-mode quantized coherent field may be reconstructed measuring amplitude and quantum noise of the first quantum Shapiro step occurring in the I-V characteristic of the ultrasmall Josephson junction.
Voltage drop across Josephson junctions for L\'evy noise detection
2020
We propose to characterize L\'evy-distributed stochastic fluctuations through the measurement of the average voltage drop across a current-biased Josephson junction. We show that the noise induced switching process in the Josephson washboard potential can be exploited to reveal and characterize L\'evy fluctuations, also if embedded in a thermal noisy background. The measurement of the average voltage drop as a function of the noise intensity allows to infer the value of the stability index that characterizes L\'evy-distributed fluctuations. An analytical estimate of the average velocity in the case of a L\'evy-driven escape process from a metastable state well agrees with the numerical calc…
Enhancement of stability in systems with metastable states
2007
The investigation of noise‐induced phenomena in far from equilibrium systems is one of the approach used to understand the behaviour of physical and biological complex systems. Metastability is a generic feature of many nonlinear systems, and the problem of the lifetime of metastable states involves fundamental aspects of nonequilibrium statistical mechanics. The enhancement of the life‐time of metastable states through the noise enhanced stability effect and the role played by the resonant activation phenomenon will be discussed in models of interdisciplinary physics: (i) Ising model (ii) Josephson junction; (iii) stochastic FitzHugh‐Nagumo model; (iv) a population dynamics model, and (v) …
Noise stabilization effects in models of interdisciplinary physics
2009
Metastability is a generic feature of many nonlinear systems, and the problem of the lifetime of metastable states involves fundamental aspects of nonequilibrium statistical mechanics. The investigation of noise-induced phenomena in far from equilibrium systems is one of the approaches used to understand the behaviour of physical and biological complex systems. The enhancement of the lifetime of metastable states through the noise enhanced stability effect and the role played by the resonant activation phenomenon will be discussed in models of interdisciplinary physics: (i) polymer translocation dynamics; (ii) transient regime of FitzHugh-Nagumo model; (iii) market stability in a nonlinear …
Flux flow effects in very long Josephson junctions
2000
We report on measurements on very long, L ≃ 30λj, NbAlOxNb underdamped in-line junctions, on which we observed displaced linear slope (DLS) generated by the application of an external magnetic field. We study the behaviour of the branches as a function of the applied magnetic field in terms of both current amplitude and voltage position. The DLS is seen to shift rigidly towards higher voltages when increasing the field, spanning a region roughly centred around the Josephson plasma frequency. We discuss the behaviour of linear branches in terms of one dimensional flux-flow along the extended side of the junction, comparing our data with the results of numerical modeling; from these calculat…
Nonlinear relaxation phenomena in metastable condensed matter systems
2016
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 s…
Stabilization Effects of Dichotomous Noise on the Lifetime of theSuperconducting State in a Long Josephson Junction
2015
We investigate the superconducting lifetime of a long overdamped current-biased Josephson junction, in the presence of telegraph noise sources. The analysis is performed by randomly choosing the initial condition for the noise source. However, in order to investigate how the initial value of the dichotomous noise affects the phase dynamics, we extend our analysis using two different fixed initial values for the source of random fluctuations. In our study, the phase dynamics of the Josephson junction is analyzed as a function of the noise signal intensity, for different values of the parameters of the system and external driving currents. We find that the mean lifetime of the superconductive…
The efficacy of two rotary NiTi instruments and H-files to remove gutta-percha from root canals
2011
WOS: 000304343300026
Nonequilibrium Green's function approach to strongly correlated few-electron quantum dots
2009
The effect of electron-electron scattering on the equilibrium properties of few-electron quantum dots is investigated by means of nonequilibrium Green's function theory. The ground and equilibrium states are self-consistently computed from the Matsubara (imaginary time) Green's function for the spatially inhomogeneous quantum dot system whose constituent charge carriers are treated as spin-polarized. To include correlations, the Dyson equation is solved, starting from a Hartree-Fock reference state, within a conserving (second-order) self-energy approximation where direct and exchange contributions to the electron-electron interaction are included on the same footing. We present results for…
Are Ocular Response Analyzer useful to measure corneal hysteresis in patients with intracorneal rings?
2008
Purpose Corneal hysteresis is a viscoelastic property characterized by the difference in behavior under loading and unloading. The aim of the study was to determine corneal hysteresis in different eyes: healthy eyes, keratoconic eyes and keratoconic eyes after intracorneal ring implants. Methods This study comprised 95 eyes of 59 patients. The study population was divided into 3 groups. We analyze 30 healthy human eyes, 35 keratoconic eyes (Amsler grade II-III) and 30 keratoconic eyes after intracorneal rings implantation. Corneal biomechanical properties of these eyes were measured with the Ocular Response Analyser (ORA-Reichert) according to two parameters: corneal hysteresis (CH) and cor…