Quantum Dynamics and Fluctuations in Nonlinear Nanomechanical Systems

非线性纳米机械系统中的量子动力学和涨落

基本信息

批准号：
1806473
负责人：
Mark Dykman
金额：
$ 60万
依托单位：
Michigan State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-01 至 2023-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1806473&HistoricalAwards=false
关键词：
Quantum Dynamics Fluctuations Nonlinear Nanomechanical

项目摘要

Nanomechanical systems are of significant fundamental interest and are also playing an increasingly important role in various applications - including biosensing, mass spectrometry, force detection at the atomic scale, and realization of stable frequency sources. The unique and advantageous feature of such systems is that they are sufficiently large that the vibrations can be studied in an individual system while, at the same time, they are sufficiently small as to provide that exceptional detection sensitivity enabling their novel applications. Because of the smallness of nanomechanical systems, a fundamentally important role in their dynamics is played by quantum fluctuations, which are unavoidable even for low temperatures. Also fundamental is that vibrations have a relatively large amplitude compared to the system size; as a consequence, they can become strongly nonlinear. Although substantial progress has been made over the last few years, major questions remain concerning the fluctuations of nanomechanical systems and their various consequences. Addressing these questions requires new characterization tools and new theoretical techniques. Poorly understood fluctuations and energy dissipation currently limit the performance of nanomechanical systems in applications. The proposed research is motivated by the largely untapped richness of this field. It has the dual aims of studying the underlying physics of nanoscale vibrational systems and using these systems to explore nonequilibrium phenomena in a uniquely well-controlled and highly-sensitive setting. The combined expertise of the principal investigators in theoretical and experimental physics should facilitate significant and rapid progress in these studies. The project should also provide an excellent platform for cross-disciplinary training of graduate and undergraduate students in theoretical and experimental physics.The major emphases of the proposed research are: (i) To develop new theoretical and experimental means and to study, using these means, both the spectra and the statistics of eigenfrequency fluctuations. This should reveal the physical mechanisms underlying these fluctuations. (ii) To explore Floquet dynamics of periodically-driven nonlinear quantum dissipative modes. Here, of particular interest is the spontaneous breaking of the discrete time-translation symmetry in the quantum-coherent regime. Also of interest are new types of quantum-coherent and dissipative states with a period, which is a multiple of the period of the driving, as well as the transitions between these states, and (iii) To explore interaction-induced symmetry-breaking for coupled, periodically-modulated nonlinear modes that is mediated by quantum and classical fluctuations. This symmetry breaking should sensitively depend on the connectivity of the nanomechanical modes - which the investigators can precisely engineer - and should encompass phenomena such as frustration and quantum phase transitions in the time domain, as well as the occurrence of microscopic currents in the stationary state of quantum systems far from thermal equilibrium.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

纳米力学系统具有重要的基本兴趣，并且在各种应用中也起着越来越重要的作用，包括生物传感，质谱，原子量表的力检测以及稳定频率源的实现。这种系统的独特和有利的特征是它们足够大，可以在单个系统中研究振动，同时它们足够小，以至于提供了具有出色的检测敏感性以实现其新颖的应用。由于纳米力学系统的较小程度，量子波动在动力学中的根本重要作用是从量子波动发挥的，即使对于低温也是不可避免的。同样基本的是，与系统尺寸相比，振动具有相对较大的振幅。结果，它们可能会变得强烈非线性。尽管在过去几年中取得了重大进展，但关于纳米力学系统及其各种后果的波动仍然存在的重大问题。解决这些问题需要新的特征工具和新的理论技术。目前，知识较低的波动和耗散限制了应用在应用中的纳米力学系统的性能。拟议的研究是由该领域未开发的丰富性的动机。它具有研究纳米级振动系统的潜在物理学的双重目的，并使用这些系统在独特的良好控制和高度敏感的环境中探索非平衡现象。主要研究者在理论和实验物理学方面的专业知识的综合知识应促进这些研究的重大和快速进步。该项目还应为研究生和实验物理学的研究生和本科生的跨学科培训提供一个绝佳的平台。拟议的研究的主要重点是：（i）开发新的理论和实验手段，并使用这些手段进行研究，并使用这些手段进行研究，特征频率波动的光谱和统计数字。这应该揭示这些波动的物理机制。（ii）探索定期驱动的非线性量子耗散模式的浮动动力学。在这里，特别感兴趣的是量子固定方案中离散时间翻译对称性的自发断裂。同样令人感兴趣的是带有一个时期的新型量子增生和耗散状态，这是驾驶时期的倍数，以及这些状态之间的过渡，以及（iii）探索相互作用引起的对称性的破坏由量子和经典波动介导的耦合，定期调制的非线性模式。这种对称破裂应敏感地取决于纳米力学模式的连通性 - 研究人员可以精确地工程师 - 并应包含时间域中的挫败感和量子相变的现象，以及在固定状态下显微镜的发生。量子系统远非热平衡。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评论标准来评估值得支持的。