Gurupada Goswami

Coloured thermal noise-driven dynamical system: upper bound of time derivative of information entropy

In this paper we have studied the upper bound of the time derivative of information entropy for non-Markovian and thermodynamically closed system(s) using reduced model theory (RMT). The upper bound is calculated on the basis of the Fokker–Planck equation and the Schwartz inequality principle. Our calculation shows that the upper bound exhibits extremal nature in the variation of system parameters such as noise correlation time, dissipation strength. The present calculation also considers how the upper bound does change if we increase the number of auxiliary variables involved in the RMT.

ESCAPE THROUGH A FLUCTUATING ENERGY BARRIER IN THE PRESENCE OF NON-GAUSSIAN NOISE

In this paper we have studied how barrier crossing dynamics is affected by colored additive non-Gaussian noise if the barrier fluctuates deterministically. Our investigation indicates that resonant activation(RA) is either enhanced or it becomes robust if noise characteristic is deviated from the Gaussian behavior. We find that additive colored non Gaussian noise can induce the RA-like phenomenon. Another interesting observation is that the turnover behavior persists even in presence of barrier fluctuations at finite rate. Finally, it is observed that mean first passage time(MFPT) decreases with increase of non-Gaussian characteristic of the additive colored noise for a given noise strength and noise correlation time and ultimately reaches to a limiting value. The limiting value remains almost the same if the barrier fluctuating frequency is zero or far from the resonant condition. But near the resonant condition the mean first passage time initially decreases and then increases passing through a minimum as the non Gaussian parameter grows.

Entropy evolution of a harmonic oscillator driven by broadband noise

We discuss the time evolution of the entropy (S) of a harmonic oscillator driven by colored noise. Our analysis is based on the Fokker–Planck description of the stochastic process. For all noise colors, the rate dS/dt, and its upper bound UB, monotonically decay to zero with time. The decay is determined by the rate of phase space contraction, which in turn depends on the noise spectrum. The dependence of dS/dt and UB on the damping strength for various noise colors is studied in detail. The role of the noise correlation time in the present context has been studied for different colored noises.

A UNIFIED DESCRIPTION OF TIME DEPENDENCE OF INFORMATION ENTROPY PRODUCTION AND FLUX IN THERMAL BROADBAND NOISE-DRIVEN DYNAMICAL SYSTEMS

In this paper we have studied the dynamics of thermal broadband noise-driven dynamical system in terms of information entropy at both the nonstationary and stationary states. Here, a unified description of fluctuating force is considered in a thermodynamically closed system. Based on the Fokker–Planck description of stochastic processes and the entropy balance equation, we have calculated the time-dependence of the information entropy production and entropy flux in the presence and absence of nonequilibrium constraint. Our calculation considers how the time evolution of these quantities is affected if the characteristic of noise changes from white to red or green and red to green in a unified scheme.