arXiv subjects

Asish K. Dhara

Publications and source records attributed to Asish K. Dhara.

7 recordsLinked to original sources

arXiv2000

Coherent stochastic resonance in one dimensional diffusion with one reflecting and one absorbing boundaries

It is shown that the single-step periodic signal (periodic telegraph signal) can not produce coherent stochastic resonance for diffusion on a segment with one absorbing and one reflecting end points while the multi-step periodic signal does. The general features of this process are exihibited. The resonant frequency is found to decrease and the mean first passage time at resonant frequency increases linearly, as we increase the length of the medium. The cycle variable is shown to be the proper argument to express the first passage time density function at resonance. A formula for first passage time density function at resonance is derived in terms of two universal functions, which clearly isolates its dependence on the length of the medium.

cond-mat.stat-mech↗

arXiv2000

Features of first passage time density function for coherent stochastic resonance in the case of two absorbing boundaries

Coherent stochastic resonance is explained in terms of first passage time density functions. Scaling relation between first passage time density functions at resonance for different lengths of the medium is obtained. A formula for first passage time density function at resonance is derived in terms of two universal functions, which demonstrates the universal feature of coherent stochastic resonance. A simple approximate expression for first passage time density function at resonance is proposed which is shown to explain the behavior at resonance fairly accurately.

cond-mat.stat-mech↗

arXiv2000

Dissipative dynamics of fission in the framework of asymptotic expansion of Fokker-Planck equation

The dynamics of fission has been formulated by generalising the asymptotic expansion of the Fokker-Planck equation in terms of the strength of the fluctuations where the diffusion coefficients depend on the stochastic variables explicitly. The prescission neutron multiplicities and the mean kinetic energies of the evaporated neutrons have been calculated and compared with the respective experimental data over a wide range of excitation energy and compound nuclear mass. The mean and variance of the total kinetic energies of the fission fragments have been calculated and compared with the experimental values.

nucl-th↗

arXiv1999

Coherent stochastic resonance in the case of two absorbing boundaries

The coherent stochastic resonance is observed and studied with multi-step periodic signal in continuous medium having two absorbing boundaries. The general features of this process are exihibited. The universal features at the resonance point are demonstrated. The kinetic behaviors around the resonance point are also presented.

cond-mat↗

arXiv1999

Synchronization under periodic modulation of potential wells in a two-state stochastic system

We analyse the effect of synchronization between noise and periodic signal in a two-state spatially extended system analytically. Resonance features are demonstrated. To have the maximum cooperation between signal and noise, it is shown that noise strength at resonance should increase linearly with the frequency of the signal. The time scale of the process at resonance is also shown to increase linearly with the period of the signal.

cond-mat.stat-mech↗

arXiv1998

Asymptotic expansion in the fission process

Asymptotic expansion of the Fokker-Planck equation in terms of the strength of the fluctuation has been carried out. The mean and the variance of the total kinetic energies of the fission fragments have been calculated and compared with the experimental values.

nucl-th↗

arXiv1998

A Dynmical study of Fission Process and estimation of Prescission Neutron Multiplicity

The dynamics of fission has been studied by solving Euler-Lagrange equation with dissipation generated through one and two body nuclear friction. The average kinetic energies of the fission fragments, prescission neutron multiplicities and the mean energies of the prescission neutrons have been calculated and compared with experimental values and they agree quite well. A single value of friction coefficient has been used to reproduce the experimental data for both symmetric and asymmetric splitting of the fissioning systems over a wide range of masses and excitation energies. It has been observed that a stronger friction is required in the saddle to scission region as compared to that in the ground state to saddle region.

nucl-th↗