二维势场中弹性耦合粒子的定向输运研究

摘要

A transport model of elastically coupled particles in a two-dimensional potential is investigated. Here, we propose that one dimension of the model is exerted by an AC drive and an external noise, and the other dimension by neither AC drive nor external noise. The effects of system and external parameters on the directed current under an overdamped case are discussed. The studies show that particles can transfer energy from one direction to its perpendicular direction through coupling, thereby producing a directed current. There is an optimal value of the spring free length or the coupling intensity at which the directed current can reach a maximum. For a fixed coupling intensity or noise intensity, the directed current will oscillate as the free length of spring varies, that is, multiple peaks appear. Moreover, a stochastic resonance appears in the directed current as noise intensity varies. Finally, when the degree of asymmetry of the ratchet potential achieves a maximum value, the current reversion takes place.%建立了二维势场中弹性耦合粒子的输运模型，其中一维上加交流驱动及噪声，另一维上不加驱动及噪声，分析讨论了过阻尼情形下系统和外部参量对定向流的影响。结果表明，粒子可以通过相互耦合使一个方向上输入的驱动能量转化到垂直方向上，从而使无能量输入的方向产生定向流。适当的弹簧自由长度及耦合强度可以使定向流达到极值，特别是当耦合强度及噪声强度固定时，定向流会随弹簧自由长度的变化而振荡，出现多峰现象。研究还发现，定向流随噪声强度的变化出现随机共振现象。当产生定向流方向上的势的不对称度达到一定程度时会出现流反转现象。