Soliton ratchets in homogeneous nonlinear Klein-Gordon systems.
Soliton ratchets in homogeneous nonlinear Klein-Gordon systems.
复制标题
齐次非线性克莱因-戈登系统中的孤子棘轮。
作者：
L. Morales;N. Quintero;A. Sánchez;F. Mertens
详细研究了双谐力驱动下齐次非线性Klein-Gordon系统中拓扑孤子的棘轮动力学。通过使用具有两个自由度的集体坐标方法，即孤立子的中心X（t）和其宽度l（t），我们表明，首先，能量被不均匀地泵入系统，从而产生定向运动;第二，时移对称性的破缺引起共振机制，每当宽度l（t）以外部AC力的至少一个频率振荡。此外，我们还证明了孤子棘齿的出现也需要打破时间反演对称性。我们详细分析了系统中耗散的影响，计算了孤子的平均速度作为交流力和阻尼的函数。我们发现电流反转现象取决于参数的选择，并讨论了交流力的相位所发挥的重要作用。我们的分析计算证实了全偏微分方程的sine-Gordon和phi 4系统，这被认为是表现出相同的定性行为的数值模拟。我们的研究结果表明，在最近的实验工作中获得的耗散诱导对称性破缺类似的功能。
We study in detail the ratchetlike dynamics of topological solitons in homogeneous nonlinear Klein-Gordon systems driven by a biharmonic force. By using a collective coordinate approach with two degrees of freedom, namely the center of the soliton, X(t), and its width, l(t), we show, first, that energy is inhomogeneously pumped into the system, generating as result a directed motion; and, second, that the breaking of the time shift symmetry gives rise to a resonance mechanism that takes place whenever the width l(t) oscillates with at least one frequency of the external ac force. In addition, we show that for the appearance of soliton ratchets, it is also necessary to break the time-reversal symmetry. We analyze in detail the effects of dissipation in the system, calculating the average velocity of the soliton as a function of the ac force and the damping. We find current reversal phenomena depending on the parameter choice and discuss the important role played by the phases of the ac force. Our analytical calculations are confirmed by numerical simulations of the full partial differential equations of the sine-Gordon and phi4 systems, which are seen to exhibit the same qualitative behavior. Our results show features similar to those obtained in recent experimental work on dissipation induced symmetry breaking.