Nonlinear Spin Waves in Magnetic Films: New Concepts and Applications

*非技术抽象*混沌和孤子是非线性科学的两个重要分支，引起了包括数学、物理、生物和工程在内的多个学科的广泛兴趣。混乱是指结果对初始条件高度敏感的想法：纽约的一只蝴蝶拍打着翅膀，东京则有一场风暴。孤子是像海啸一样的局域波，经常出现在弱非线性系统中。通常人们认为混沌和孤子是相互对立的？例如，孤立子可能会受到强烈的扰动，但仍会持续存在，使得阻止海啸变得困难。这个项目将寻求混沌和孤子之间的联系。具体地说，该项目将利用磁性薄膜系统中的自旋波(磁序中的传播扰动)来探索这些联系。在应用方面，该项目将开发一种新的安全通信方案，利用反馈环中的孤子。这是两所大学的一个实验组和一个理论组的联合项目。通过对学生进行实验和理论非线性动力学方法的培训，该项目将帮助青年科学家跨越理论领域和理论领域之间的鸿沟。和物理现实，导致更好的实验和更好的理论。教育部分还包括将非线性动力学和混沌纳入本科生和研究生课程，并接触到科罗拉多州贫困高中的学生。*技术摘要*这个项目将利用磁性薄膜系统中的自旋波来探索孤子和混沌之间可能的交叉。该项目将探索？混沌载波孤子？？具有混沌载波的孤子。磁动力学探测器将被用来研究混沌自旋波脉冲的演化以及由这样的脉冲形成包络孤子的过程。该项目还将探索？混沌孤子？？具有相干载波但在时间上表现出混沌行为的孤子。这项工作将包括研究调制不稳定性中的混沌孤子激发和磁膜反馈环中的混沌孤子。在应用方面，该项目将开发一种新的安全通信方案，该方案利用反馈环中与孤子相关的Fermi-Pasta-Ulam循环。对于所有的项目，理论建模将激励、支持和解释实验工作。教育部分的重点是通过核心课程和设计新的选修课，将非线性动力学和混沌纳入本科和研究生课程，以及培训本科生和研究生研究人员，并接触处境不利的高中的学生。

****NON-TECHNICAL ABSTRACT**** Chaos and solitons are two important branches of nonlinear science that have attracted interest over a wide range of disciplines, including mathematics, physics, biology, and engineering. Chaos is the idea that outcomes are highly sensitive to initial conditions: a butterfly flaps its wings in New York and there is a storm in Tokyo. Solitons are localized waves like tsunamis, and frequently occur in weakly nonlinear systems. Usually one believes that chaos and solitons are opposed to each other ? a soliton can be strongly perturbed and yet persists, for example, making it difficult to stop, say, a tsunami. This project will seek connections between chaos and solitons. Specifically, the project will take advantage of spin waves (a travelling disturbance in the magnetic order) in magnetic film systems to explore these connections. On the applied side, the project will develop a new secure communication scheme that exploits the solitons in feedback rings. This is a joint program between one experimental group and one theoretical group in two universities. Through the training of students in both experimental and theoretical nonlinear dynamical methods, the project will help young scientists cross the divide between ?theory land? and physical reality, leading to both better experiments and better theories. The education portion also includes the incorporation of nonlinear dynamics and chaos into undergraduate and graduate curricula and reaching out to students in disadvantaged high schools in Colorado.****TECHNICAL ABSTRACT****This project will take advantage of spin waves in magnetic film systems to explore a possible crossover between solitons and chaos. The project will explore ?chaotic carrier solitons? ? solitons with chaotic carrier waves. A magneto-dynamic probe will be used to study the evolution of a pulse of chaotic spin waves and the formation of an envelope soliton from such a pulse. The project will also explore ?chaotic solitons? ? solitons that have coherent carrier waves but exhibit chaotic behaviors in time. The work will include the study of chaotic soliton excitation through modulational instability and chaotic solitons in magnetic film feedback rings. On the applied side, the project will develop a new secure communication scheme that exploits the soliton-associated Fermi-Pasta-Ulam recurrence in feedback rings. For all the projects, theoretical modeling will inspire, support, and interpret experimental work. The education portion focuses on the incorporation of nonlinear dynamics and chaos into undergraduate and graduate curricula both through core courses and through the design of new electives, as well as training of undergraduate and graduate researchers and reaching out to students in disadvantaged high schools.