哈密顿SQUID超材料中的异步呼吸子
Asynchronous Breathers in Hamiltonian SQUID Metamaterials
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中文总结 AI 辅助
本文数值研究一维SQUID超材料的非线性局域特性，发现新型异步离散呼吸子，明确了局域与离域模式的转变规律，填补了相关研究空白。
中文摘要 AI 辅助
本文通过数值方法研究了一维SQUID（超导量子干涉器件）阵列/超材料在无耗散、无周期驱动条件下由非线性导致的局域化特性。该系统具有一个代表其能量的守恒哈密顿函数，即便在中等偏高的直流磁通偏置下，也能支持离散呼吸子类型的局域模式，而这类系统中离散呼吸子的存在此前在文献中很大程度上被忽视了。我们发现了一种新型的异步离散呼吸子，即呼吸子中心位点处SQUID的振荡频率与超材料其他位点处SQUID的振荡频率不同。我们通过在固定耦合系数下以给定振幅（初始振幅）的单格点激发初始化系统，研究非线性局域化特性，其中直流磁通偏置、单格点初始激发振幅和/或SQUID等参数可独立变化。我们以能量参与比作为局域化程度的度量，识别出了异步高度局域模式的存在，以及离域（扩展）模式与局域模式之间的转变。
英文摘要
A one-dimensional SQUID (superconducting quantum interference device) array/metamaterial is investigated numerically with respect to its localization properties due to nonlinearity in the absence of dissipation and periodic driving. The system possesses a conserved Hamiltonian function representing its energy, and supports localized modes of the discrete breather type even in the presence of a moderately high dc flux bias. The appearance of discrete breathers in that system has been largely overlooked in literature. We find a new type of discrete breather that is asynchronous, meaning that the frequency of oscillation of the SQUID at the central breather site is different than that of the SQUIDs at the other sites of the metamaterial. Nonlinear localization is investigated by initializing the system with a single-site excitation of given amplitude (initial amplitude) for a fixed value of the coupling coefficient, while parameters such as the dc flux bias, the single-site initial excitation amplitude, and/or the SQUID can vary independently. Using the energetic participation ratio as a measure of the degree of localization, the existence of asynchronous highly localized modes and transitions between delocalized (extended) and localized modes re identified.
