Search results for "RESONANT ACTIVATION"
showing 6 items of 16 documents
Coexistence of resonant activation and noise enhanced stability in a model of tumor-host interaction: Statistics of extinction times
2006
We study a Langevin equation derived from the Michaelis-Menten (MM) phenomenological scheme for catalysis accompanying a spontaneous replication of molecules, which may serve as a simple model of cell-mediated immune surveillance against cancer. We examine how two different and statistically independent sources of noise - dichotomous multiplicative noise and additive Gaussian white noise - influence the population's extinction time. This quantity is identified as the mean first passage time of the system across the zero population state. We observe the effects of resonant activation (RA) and noise-enhanced stability (NES) and we report the evidence for competitive co-occurrence of both phen…
Stabilization by dissipation and stochastic resonant activation in quantum metastable systems
2018
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, produci…
Analysis of soliton dynamics and noise induced effects on the superconductive lifetime in long Josephson junctions.
2013
The influence of various noise sources on the transient dynamics of long Josephson junctions (LJJ) is investigated in the presence of an oscillating bias current signal and a noise source with Gaussian or non-Gaussian (i.e. Cauchy-Lorentz or Lévy-Smirnov) probability distributions. These systems are computationally analyzed integrating the perturbed Sine-Gordon equation describing the phase evolution. We found evidence of noise induced effects on trends of the mean escape time (MET) from the superconductive metastable state, varying different system parameters, as the bias frequency, noise intensity and junction length. In particular, we find resonant activation (RA) and noise enhanced stab…
Transient dynamics in driven long Josephson junctions.
2013
The switching time from the superconductive metastable state of a long Josephson junction (LJJ)[1] is computationally analyzed in the framework of the perturbed sine-Gordon equation. The model includes an external bias current term and a stochastic noise source, i.e. a Lévy noise term. The effects of this noise on the mean escape time (MET) from the superconductive state are analyzed. The investigation is performed by considering a wide range of values of system parameters and different noise statistics: Gaussian, Cauchy-Lorentz and Lévy-Smirnov[2]. We found evidence of well known noise induced phenomena on the MET behavior, that is the noise enhanced stability (NES) and resonant activation…
Noise phenomena and soliton dynamics in long Josephson junctions
2013
In this work we computationally explore the transient dynamics of a noisy Josephson junction (JJ). Principal purpose is to investigate the behavior of the lifetime of the superconductive state as a function of the system and noise source parameters. The relations between the emerging phenomena and the evolution of the JJ order parameter φ, that is the phase difference between the macroscopic wave functions describing the superconducting condensate in the two electrodes, is deeply investigated. We focus our interest on the switching events from the superconducting metastable state, and in particular on the mean escape time (MET). In the used model, a long JJ can be represented by a string co…
Lifetime of the superconductive state in long Josephson junctions in presence of non-Gaussian noise sources
2012
The effects of Lévy noise sources on the transient dynamics of long Josephson junctions (LJJ) are investigated in the presence of both a periodical current signal and a noise source with Gaussian, Cauchy-Lorentz or Levy-Smirnov probability distributions. In particular, by numerically integrating the Sine-Gordon equation, the mean escape time (MET) from the superconductive metastable state is obtained as a function both of the frequency of the periodical force and amplitude of the noise signal. We find resonant activation (RA) and noise enhanced stability (NES). Significative changes in RA and NES are observed by using Lévy noise sources with different statistics. MET is also studied as a fu…