Search results for "Colors of noise"

showing 10 items of 26 documents

Dynamics of a FitzHugh-Nagumo system subjected to autocorrelated noise

2008

We analyze the dynamics of the FitzHugh-Nagumo (FHN) model in the presence of colored noise and a periodic signal. Two cases are considered: (i) the dynamics of the membrane potential is affected by the noise, (ii) the slow dynamics of the recovery variable is subject to noise. We investigate the role of the colored noise on the neuron dynamics by the mean response time (MRT) of the neuron. We find meaningful modifications of the resonant activation (RA) and noise enhanced stability (NES) phenomena due to the correlation time of the noise. For strongly correlated noise we observe suppression of NES effect and persistence of RA phenomenon, with an efficiency enhancement of the neuronal respo…

PhysicsFluctuation phenomena random processes noise and Brownian motionSettore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciAutocorrelationDynamics (mechanics)Mean and predicted responseModels of single neurons and networks; Noise in the nervous system; Fluctuation phenomena random processes noise and Brownian motion; Nonlinear dynamics and chaosFOS: Physical sciencesNoise in the nervous systemModels of single neurons and networkCondensed Matter PhysicsFitzhugh nagumoNonlinear dynamics and chaosStability (probability)Electronic Optical and Magnetic MaterialsPeriodic functionNoiseColors of noiseBiological Physics (physics.bio-ph)Statistical physicsPhysics - Biological Physics
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EFFECTS OF COLORED NOISE IN SHORT OVERDAMPED JOSEPHSON JUNCTION

2008

We investigate the transient dynamics of a short overdamped Josephson junction with a periodic driving signal in the presence of colored noise. We analyze noise induced henomena, specifically resonant activation and noise enhanced stability. We find that the positions both of the minimum of RA and maximum of NES depend on the value of the noise correlation time tau_c. Moreover, in the range where RA is observed, we find a non-monotonic behavior of the mean switching time as a function of the correlation time tau_c.

PhysicsJosephson effectPhysics and Astronomy (miscellaneous)Condensed matter physicsCondensed Matter - SuperconductivityFOS: Physical sciencesResonant activationJosephson junction; Colored noise; Resonant activation; Noise enhanced stabilityColored noiseStability (probability)SignalSettore FIS/03 - Fisica Della MateriaSuperconductivity (cond-mat.supr-con)Switching timeColors of noiseJosephson junctionRange (statistics)Transient (oscillation)Noise enhanced stabilityNoise (radio)International Journal of Quantum Information
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Noise induced effects in overdamped Josephson junction in the presence of colored noise

2007

We analyze the role of the correlated fluctuations, with a correlation time τc, in the dynamics of an overdamped Josephson junction in the presence of a periodic driving signal.

PhysicsJosephson effectmean switching timeJosephson phaseCondensed matter physicsNoise inducedJosephson junction; mean switching time; colored noiseNoise (electronics)SignalSettore FIS/03 - Fisica Della MateriaPi Josephson junctioncolored noiseColors of noiseCondensed Matter::SuperconductivityJosephson junctionElectronic engineeringSuperconducting tunnel junction
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Harmonic Coupling of the Red Noise in X‐Ray Pulsars

1997

The power spectra of X-ray pulsars often show the presence of a red-noise component. This noise is produced by aperiodic variability believed to be associated with instabilities that seem to occur in accretion flows onto compact objects. In this paper we discuss how, independently of the details of the physical processes that generate these instabilities, a careful analysis of the power spectra can furnish some constraints on the distance from the stellar surface at which the sudden energy release associated with the instabilities occurs. In particular, any aperiodic variability coming from the accretion flow funneled toward the magnetic poles should be modulated at the pulsar spin period (…

PhysicsPulsarSpace and Planetary ScienceColors of noiseAperiodic graphHarmonicsX-rayAstronomy and AstrophysicsAstrophysicsLight curveAccretion (astrophysics)Spectral lineThe Astrophysical Journal
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Magnetostochastic resonance under colored noise condition

2012

Stochastic resonance (SR) is an amplification of the system output in correspondence of well-defined finite values of the noise strength that is injected into the system [Gammaitoni et al., Rev. Mod. Phys. 70, 223 (1998), Grigorenko et al., IEEE Trans. Magn. 31, 2491 (1995), Mantegna et al., J. Appl. Phys. 97, 10E519 (2005)]. In order to clarify the influence of a colored noise, in this paper magnetostochastic resonance (MSR) in magnetic systems described by the dynamic Preisach model is numerically investigated in the presence of colored noise. In this paper it is shown that: a) noise spectrum affects MSR; b) white noise, 1/f and 1/f(2) noise induce in magnetic systems described by the dyn…

PhysicsStochastic resonanceSTOCHASTIC RESONANCEPREISACH MODELNoise spectral densityGeneral Physics and AstronomyResonanceWhite noiseSettore ING-IND/32 - Convertitori Macchine E Azionamenti ElettriciMagnetic hysteresisNuclear magnetic resonanceColors of noiseQuantum mechanicsHYSTERESISNoise (radio)Noise strengthJournal of Applied Physics
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How does environmental variation translate into biological processes?

2001

Birth and death rates, as so many other biological processes, are usually not linearly related to environmental variation. Common examples of non-linear response forms include unimodal ‘‘optimum-type’’ responses and various saturating responses. These responses filter the signal coming from the environment to a corresponding biological process. We explored how different types of environmental signal may be transformed to a biological process. We were interested in the effect of the filter on modulation of (1) the variance of the signal, on (2) the variance-covariance structure between the signal and the filtered signal, and on (3) the match between the power spectra of the signal and the fi…

Physicseducation.field_of_studyColors of noiseModulationPopulationSpectral densityFilter (signal processing)Biological systemeducationSignalEcology Evolution Behavior and SystematicsBirth–death processPower (physics)Oikos
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Nonmonotonic Pattern Formation in Three Species Lotka-Volterra System with Colored Noise

2005

A coupled map lattice of generalized Lotka-Volterra equations in the presence of colored multiplicative noise is used to analyze the spatiotemporal evolution of three interacting species: one predator and two preys symmetrically competing each other. The correlation of the species concentration over the grid as a function of time and of the noise intensity is investigated. The presence of noise induces pattern formation, whose dimensions show a nonmonotonic behavior as a function of the noise intensity. The colored noise induces a greater dimension of the patterns with respect to the white noise case and a shift of the maximum of its area towards higher values of the noise intensity.

Population DynamicSettore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciStatistical Mechanics (cond-mat.stat-mech)General MathematicsLotka–Volterra equationsStatistical MechanicGeneral Physics and AstronomyPattern formationFOS: Physical sciencesStatistical Mechanics; Population Dynamics; Noise induced effects; Lotka-Volterra equationsWhite noiseMultiplicative noiseNoiseColoredColors of noiseControl theoryNoise induced effectQuantitative Biology::Populations and EvolutionLotka-Volterra equationsStatistical physicsCondensed Matter - Statistical MechanicsCoupled map latticeMathematics
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Design of a Lambda system for population transfer in superconducting nanocircuits

2013

The implementation of a Lambda scheme in superconducting artificial atoms could allow detec- tion of stimulated Raman adiabatic passage (STIRAP) and other quantum manipulations in the microwave regime. However symmetries which on one hand protect the system against decoherence, yield selection rules which may cancel coupling to the pump external drive. The tradeoff between efficient coupling and decoherence due to broad-band colored Noise (BBCN), which is often the main source of decoherence is addressed, in the class of nanodevices based on the Cooper pair box (CPB) design. We study transfer efficiency by STIRAP, showing that substantial efficiency is achieved for off-symmetric bias only i…

Quantum decoherenceStimulated Raman adiabatic passageFOS: Physical sciencesSINGLE COOPER PAIR ADIABATIC PASSAGE QUANTUM STATES FLUX QUBIT SPECTROSCOPY MOLECULES CIRCUIT ATOMS NOISE BOX01 natural sciencesNoise (electronics)Settore FIS/03 - Fisica Della Materia010305 fluids & plasmasSuperconductivity (cond-mat.supr-con)Quantum mechanics0103 physical sciencesMesoscale and Nanoscale Physics (cond-mat.mes-hall)010306 general physicsQuantumQuantum computerPhysicsCouplingQuantum PhysicsCondensed Matter - Mesoscale and Nanoscale PhysicsCondensed Matter - SuperconductivityCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsColors of noiseCooper pairQuantum Physics (quant-ph)
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Role of the Colored Noise in Spatio-Temporal Behavior of Two Competing Species

2005

We study the spatial distributions of two randomly interacting species, in the presence of an external multiplicative colored noise. The dynamics of the ecosystem is described by a coupled map lattice model. We find a nonmonotonic behavior in the formation of large scale spatial correlations as a function of the multiplicative colored noise intensity. This behavior is shifted towards higher values of the noise intensity for increasing correlation time of the noise.

Settore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciStatistical Mechanics (cond-mat.stat-mech)Scale (ratio)General MathematicsLotka–Volterra equationsMultiplicative functionStatistical MechanicSpatio-temporal patternsFOS: Physical sciencesGeneral Physics and AstronomyStatistical mechanicsFunction (mathematics)NoiseLotka-Volterra equationColors of noiseStatistical Mechanics; Noise induced effects; Lotka-Volterra equations; Spatio-temporal patternsStatisticsNoise induced effectStatistical physicsCondensed Matter - Statistical MechanicsMathematicsCoupled map lattice
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Role of the colored noise in a FitzHugh-Nagumo system driven by a periodic signal

2007

During these last years the interest in neuronal dynamics increased. The study of this kind of system has been carried out by using the FitzHugh-Nagumo (FHN) model that is a simplified modification of the Hodgkin-Huxley model. Many interesting phenomena can be observed in the presence of fluctuations: modification of detection threshold by manipulation of noisy parameters (FHN model), noise-induced activation and coeherence resonance for suitable noise amplitude (absence of periodic signal), resonant activation for high periodic signals and noise reduction, intrinsic stochastic resonance (ISR) in Hodgkin-Huxley neuron and the enhancement of a weak signal by tuning the subthreshold intrinsic…

Settore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciStochastic resonanceNoise (signal processing)Mathematical analysisShot noiseWhite noiseNoise Enhanced StabilityColored NoiseNeuronal modelsymbols.namesakeColors of noiseControl theoryGaussian noisePhase noisesymbolsBrownian noiseResonant ActivationNeuronal models; Resonant Activation; Noise Enhanced Stability; Colored NoiseMathematics
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