arXiv subjects

Mousumi Biswas

Publications and source records attributed to Mousumi Biswas.

3 recordsLinked to original sources

arXiv2022

A shortcut way to the Fokker-Planck equation for the non-Markovian dynamics

Using a shortcut way we have derived the Fokker-Planck equation for the Langevin dynamics with a generalized frictional memory kernel and time-dependent force field. Then we have shown that this method is applicable for the non-Markovian dynamics with additional force from harmonic potential or magnetic field or both of them. The simplicity of the method in these complex cases is highly noticeable and it is applicable to derive the Fokker-Planck equation for any kind of linear Langevin equation of motion which describes additive colored noise driven non Markovian dynamics with or without frictional memory kernel. For example, one may apply the method even for the linear system with an additional colored Gaussian noise which is not related to the damping strength. With these the present study may get strong attention in the field of stochastic thermodynamics which is now at early stage to consider the non-Markovian dynamics.

cond-mat.stat-mech↗

arXiv2022

Magnetic field induced anomalous distribution of particles

It seems that a stochastic system must be a nonlinear one to observe the phenomenon, noise induced transition. But in the present paper, we have demonstrated that the phenomenon may be observed even in a linear stochastic process where both deterministic and stochastic parts are linear functions of the relevant phase space variables. The shape of the stationary distribution of particles (which are confined in a harmonic potential) may change on increasing the strength of the applied fluctuating magnetic field. The probability density may vary non monotonically with an increase in the coordinate of a Brownian particle. Thus the distribution of particles may deviate strongly from the Boltzmann one and it is a unique signature of the fluctuating magnetic field. Then we are motivated strongly to study the distribution of particles in a nonlinear stochastic system where the Brownian particles are confined in a bi-stable potential energy field in the presence of the fluctuating magnetic field. With a relatively large strength of the fluctuating field, the distribution of particles may be a strange one where many islands may appear which are not expected from the given potential energy field. It may offer an explanation to describe the phenomenon, the reduction of the current in a semiconductor in the presence of a time dependent magnetic field.

cond-mat.stat-mech↗

arXiv2021

Mechanism of barrier crossing dynamics in the presence of both time dependent and independent magnetic fields

In this paper we have presented the mechanism of the barrier crossing dynamics of a Brownian particle which is coupled to a thermal bath in the presence of both time independent and fluctuating magnetic fields. Here the following three aspects are important in addition to the role of the thermal bath on the barrier crossing dynamics. Magnetic field induced coupling may introduce a resonance like effect. Another role of the field is that enhancement of its strength reduces the frequency factor of the barrier crossing rate constant. Finally, the fluctuating magnetic field introduces an induced electric field which activates the Brownian particle to cross the energy barrier. As a result of interplay among these aspects versatile non-monotonic behavior may appear in the variation of the rate constant as a function of the strength of the time independent magnetic field.

cond-mat.stat-mech↗