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arXiv 0706.4466cond-mat.stat-mech
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反馈控制闪烁棘轮中时滞引起的通量增强和多稳态

Flux enhancement and multistability induced by time delays in a feedback controlled flashing ratchet

F. J. Cao, M. Feito

摘要:

反馈控制棘轮是使用系统状态信息进行操作的热整流器。我们研究了在反馈中的时间延迟的影响,在许多粒子的情况下,执行一个瞬时最大化的质心速度的协议。对于小的延迟,质心速度随着延迟的增加而减小(尽管不如在少数粒子的情况下那么快)。然而,对于大的延迟,我们发现令人惊讶的结果,延迟的存在可以提高棘轮的通量性能。事实上,最大通量获得的最佳周期协议。这意味着延迟反馈协议可以比其非延迟的对应执行更好。在大延迟的存在下观察到的通量的改善是一个新的动力学制度的出现的结果,其中延迟反馈的存在稳定的准周期解,类似于在一定的闭环协议与阈值中获得的解决方案。此外,在这个新的制度,系统呈现多稳定性,即几个准周期解可以是稳定的一个固定的时间延迟。

英文摘要:

Feedback controlled ratchets are thermal rectifiers that use information on the state of the system to operate. We study the effects of time delays in the feedback for a protocol that performs an instantaneous maximization of the center-of-mass velocity in the many particle case. For small delays the center-of-mass velocity decreases for increasing delays (although not as fast as in the few particle case). However, for large delays we find the surprising result that the presence of a delay can improve the flux performance of the ratchet. In fact, the maximum flux obtained with the optimal periodic protocol is attained. This implies that the delayed feedback protocol considered can perform better than its non-delayed counterpart. The improvement of the flux observed in the presence of large delays is the result of the emergence of a new dynamical regime where the presence of the delayed feedback stabilizes quasiperiodic solutions that resemble the solutions obtained in a certain closed-loop protocol with thresholds. In addition, in this new regime the system presents multistability, i.e. several quasiperiodic solutions can be stable for a fixed time delay.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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