CAREER: Activated Escape in Nonequilibrium Micromechanical Oscillators - Research and Education Program

非技术摘要：涨落在许多微观和纳米尺度的物理和生物现象中起着至关重要的作用。当涨落足够大时，系统可以被诱导脱离亚稳态。尽管这种转变可能很少发生，但它们在很大程度上决定了具有多个稳定状态的系统的行为。佛罗里达大学的这个教师早期职业奖的目标是研究机械设备中的波动诱导开关，其特征小到百万分之一米。当这个装置被周期性地驱动时，它以两个不同的振幅之一振荡。在存在波动的情况下，振荡幅度在两个稳定值之间切换。该研究将侧重于揭示不仅发生在我们的微尺度力学系统中，而且发生在其他非平衡系统中的一般波动现象。这些研究将回答一些悬而未决的问题，并加深对远离平衡的系统中波动的理解。尽管拟议的研究是基础性的，但这些发现可能会为使用微尺度机械设备的新检测方案和信号处理应用开辟可能性。在推广方面，该计划将为高中生提供暑期研究经验。此外，还将制作示范材料，供学生带回学校，以进一步加强教育影响。微机械设备也将用于提高教学的介绍mechanics course.Technical摘要：这个教师早期职业奖在佛罗里达大学的目标是研究激活的切换共存的稳定状态系统远离热平衡。实验研究将使用欠阻尼非线性微机械扭转振荡器进行。在足够强的周期驱动场作用下，该振子在一定的驱动频率范围内具有两个振幅不同的稳定动力学态。该研究将侧重于揭示不同的系统参数和波动的参数范围内的稳定状态的固定人口是彼此接近的一般特征的激活势垒的标度行为。这些研究将允许验证现有的预测，回答关于非平衡系统波动的开放性问题，并激发新的理论研究。尽管所提出的研究是基础性的，但这些发现可能为使用微机械设备的新型传感方案和信号处理应用开辟了可能性。在推广方面，该计划将为高中生提供暑期研究经验。此外，还将制作示范材料，供学生带回学校，以进一步加强教育影响。微机械装置也将用于加强力学入门课程的教学。

Non-Technical Abstract: Fluctuations play a crucial role in many physical and biological phenomena at the micro- and nanoscale. A system can be induced to switch out of a metastable state when fluctuations are sufficiently large. Even though such transitions may occur infrequently, they largely determine the behavior of systems with multiple stable states. The goal of this Faculty Early Career Award at the University of Florida is to study fluctuation-induced switching in a mechanical device with features as small as a millionth of a meter. When this device is periodically driven, it oscillates with one of two distinct amplitudes. In the presence of fluctuations, the oscillation amplitude switches between the two stable values. The research will focus on revealing generic fluctuation phenomena that occur not only in our micro-scale mechanical system but also in other nonequilibrium systems. Such studies will answer open questions and enhance the understanding of fluctuations in systems that are far from equilibrium. Even though the proposed research is of fundamental nature, the findings could open possibilities for new detection schemes and signal-processing applications using micro-scale mechanical devices. In terms of outreach, the program will provide summer research experiences for high school students. Furthermore, demonstration materials will be developed for the students to bring back to their schools to further enhance the educational impact. Micromechanical devices will also be used to enhance teaching in an introductory mechanics course.Technical Abstract: The goal of this Faculty Early Career Award at the University of Florida is to study activated switching between coexisting stable states in systems far from thermal equilibrium. Experimental studies will be carried out using an underdamped nonlinear micromechanical torsional oscillator. Under a sufficiently strong periodic driving field, the oscillator possesses two stable dynamical states with different oscillation amplitudes within a certain range of driving frequencies. The research will focus on revealing the scaling behaviors of the activation barrier with varying system parameters and generic features of fluctuations in the parameter range where stationary populations of the stable states are close to each other. Such studies will allow verification of the existing predictions, answer open questions on fluctuations in nonequilibrium systems and stimulate new theoretical research. Even though the proposed research is of fundamental nature, the findings could open possibilities for novel sensing schemes and signal-processing applications using micromechanical devices. In terms of outreach, the program will provide summer research experiences for high school students. Furthermore, demonstration materials will be developed for the students to bring back to their schools to further enhance the educational impact. Micromechanical devices will also be used to enhance teaching in an introductory mechanics course.