Current Transport And Mass Separation Of Underdamped Particles Under Noise Excitation

The directional transport phenomenon of nonlinear systems has become a very attractive research field in physics,biology,chemistry and other fields,it is widely concerned by scholars.The ratchet system can convert non-directional external driving force and noise energy into system directed transport energy that effectively utilize the system's ratchet effect.And studies have shown that it is possible to separate fine particles by directional transport phenomena,in addition,it also has a wide range of application prospects in controlling transport and realizing certain biological functions.Therefore,it is worthwhile to study the nonlinear systems and directional transport phenomena.As we all know,noise is widespread in nature.A large number of studies and experiments have proved that noise does not always have a negative impact on the system.In some cases,noise also has some positive and creative effects.Therefore,it is very necessary to study the influence of noise on the directional transport of nonlinear systems.The following is the research contents and conclusions of this paper:1.The current transport of underdamped particles under the influence of cor-related white noises and external fluctuation force are analyzed.By using numerical simulation,the effects of the system parameters on the current directional transport are discussed.Get the following conclusion through analysing:The current is posi-tive when ?<0,and when ?>0,the current is negative.The ext,ernal fluct,uation force and correlated noises may effect,the direction of the current.When the asym-metric parameter of the external fluctuation force is negative,the correlated noises intensity can cause the current reversal.Besides,we have noticed an interesting phenomenon that the.smaller the particle mass,the greater the current generated,and when the external force and correlated noises intensity are the same sign,it may even cause a reversal of the current.Therefore,the Brownian particles can be effectively separated according to their masses.2.For the transport of underdamped particles driven by color noise and external forces in the periodic potential,a corresponding mathematical model is established and its transport phenomena are studied.The results show:The greater the asym-metry parameter of the periodic potential ?,the greater the corresponding current.When the external force is non-zero,the current monotonously decreases with the increase of the intensity of the additive noise a,and the variation of the current with the multiplicative noise intensity D is asymmetrical.When the correlation time ?16,?2 are shorter and the particle mass is smaller,it will have a greater impact on the current.Finally,the greater the external force,the greater the corresponding current or the absolute value.