Rate enhancement of gated drift-diffusion process by optimal resetting.

"Gating" is a widely observed phenomenon in biochemistry that describes the transition between the activated (or open) and deactivated (or closed) states of an ion-channel, which makes transport through that channel highly selective. In general, gating is a mechanism that imposes an additional restriction on a transport, as the process ends only when the "gate" is open and continues otherwise. When diffusion occurs in the presence of a constant bias to a gated target, i.

Expediting Feller process with stochastic resetting.

We explore the effect of stochastic resetting on the first-passage properties of the Feller process. The Feller process can be envisioned as space-dependent diffusion, with diffusion coefficient D(x)=x, in a potential U(x)=x(x/2-θ) that owns a minimum at θ. This restricts the process to the positive side of the origin and therefore, Feller diffusion can successfully model a vast array of phenomena in biological and social sciences, where realization of negative values is forbidden.

Resetting transition is governed by an interplay between thermal and potential energy.

A dynamical process that takes a random time to complete, e.g., a chemical reaction, may either be accelerated or hindered due to resetting.

Space-dependent diffusion with stochastic resetting: A first-passage study.

We explore the effect of stochastic resetting on the first-passage properties of space-dependent diffusion in the presence of a constant bias. In our analytically tractable model system, a particle diffusing in a linear potential U(x) ∝ μ|x| with a spatially varying diffusion coefficient D(x) = D|x| undergoes stochastic resetting, i.e.

Diffusion with resetting in a logarithmic potential.

We study the effect of resetting on diffusion in a logarithmic potential. In this model, a particle diffusing in a potential U(x) = U log |x| is reset, i.e.

Stochastic thermodynamics of periodically driven systems: Fluctuation theorem for currents and unification of two classes.

Periodic driving is used to operate machines that go from standard macroscopic engines to small nonequilibrium microsized systems. Two classes of such systems are small heat engines driven by periodic temperature variations, and molecular pumps driven by external stimuli. Well-known results that are valid for nonequilibrium steady states of systems driven by fixed thermodynamic forces, instead of an external periodic driving, have been generalized to periodically driven heat engines only recently.

Microscopic theory of heat transfer between two fermionic thermal baths mediated by a spin system.

In this paper we have presented the heat exchange between the two fermionic thermal reservoirs which are connected by a fermionic system. We have calculated the heat flux using solution of the c-number Langevin equation for the system. Assuming small temperature difference between the baths we have defined the thermal conductivity for the process.

Resonance behavior of a charged particle in presence of a time dependent magnetic field.

In this article, we have explored the resonance behavior of a particle in the presence of a time dependent magnetic field (TDMF). The particle is bound in a harmonic potential well. Based on the Hamiltonian description of the system in terms of action and angle variables, we have derived the resonance condition for the applied TDMF along z-direction which is valid for arbitrary frequencies along x and y directions of the two dimensional harmonic oscillator.

Shannon entropic temperature and its lower and upper bounds for non-Markovian stochastic dynamics.

In this article we have studied Shannon entropic nonequilibrium temperature (NET) extensively for a system which is coupled to a thermal bath that may be Markovian or non-Markovian in nature. Using the phase-space distribution function, i.e.

Resonant activation in a colored multiplicative thermal noise driven closed system.

In this paper, we have demonstrated that resonant activation (RA) is possible even in a thermodynamically closed system where the particle experiences a random force and a spatio-temporal frictional coefficient from the thermal bath. For this stochastic process, we have observed a hallmark of RA phenomena in terms of a turnover behavior of the barrier-crossing rate as a function of noise correlation time at a fixed noise variance. Variance can be fixed either by changing temperature or damping strength as a function of noise correlation time.

Nonequilibrium entropic temperature and its lower bound for quantum stochastic processes.

In this paper, we have studied the Shannon "entropic" nonequilibrium temperature (NET) of quantum Brownian systems. The Brownian particle is attached to either a bosonic or fermionic bath. Based on the Fokker-Planck description of the c-number quantum Langevin equation, we have calculated entropy production, NET, and their bounds.

Magnetic field induced dynamical chaos.

In this article, we have studied the dynamics of a particle having charge in the presence of a magnetic field. The motion of the particle is confined in the x-y plane under a two dimensional nonlinear potential. We have shown that constant magnetic field induced dynamical chaos is possible even for a force which is derived from a simple potential.

Tuning of barrier crossing time of a particle by time dependent magnetic field.

We have studied the effect of time dependent magnetic field on the barrier crossing dynamics of a charged particle. An interplay of the magnetic field induced electric field and the applied field reveals several interesting features. For slowly oscillating field the barrier crossing rate increases remarkably particularly at large amplitude of the field.

Ab initio calculations on the excited states of Na3 cluster to explore beyond Born-Oppenheimer theories: adiabatic to diabatic potential energy surfaces and nuclear dynamics.

We perform ab initio calculation using quantum chemistry package (MOLPRO) on the excited states of Na(3) cluster and present the adiabatic PESs for the electronic states 2(2)E' and 1(2)A(1)', and the non-adiabatic coupling (NAC) terms among those states. Since the ab initio calculated NAC elements for the states 2(2)E' and 1(2)A(1)' demonstrate the numerical validity of so called "Curl Condition," such states closely form a sub-Hilbert space. For this subspace, we employ the NAC terms to solve the "adiabatic-diabatic transformation (ADT)" equations to obtain the functional form of the transformation angles and pave the way to construct the continuous and single valued diabatic potential energy surface matrix by exploiting the existing first principle based theoretical means on beyond Born-Oppenheimer treatment.