CAREER: Quantum Phase Transitions and Dissipation in Superconducting Nanowires

约翰霍普金斯大学的这个教师早期职业发展项目的目标是研究超导纳米线中的量子相变和耗散。当系统的某些关键参数发生变化时，如导线的直径或施加的磁场，可以在接近绝对零度的温度下观察到量子相变。跃迁的性质通常取决于纳米线的结构和来自环境的不需要的噪声。一种新的制造技术将被开发，以实现纳米线的微观结构的精确控制。为了研究其对纳米线量子特性的影响，将有目的地以可控和可调的方式引入与环境的耦合。这些纳米线将代表一个模型系统的实验实现，用于研究量子系统与环境相互作用的一般行为。除了推进我们对介观超导体和量子系统的基本物理学的理解外，该项目还将为研究生和本科生的科学生涯做好准备，开发新的基于网络的教学工具，为高中学生和教师提供研究机会，并为未来的研究奠定坚实的基础。技术摘要约翰霍普金斯大学教师早期职业发展项目的目标是研究超导纳米线中的量子相变和耗散。量子相变发生在温度的绝对零度，并由某些参数的量子涨落驱动，例如导线的直径或磁场。将开发一种新的制造技术，以实现纳米线的物理特性的精确控制，并将特别注意调查施加的磁场的影响，以及在非超导制度的运输细节。将使用带有稀释制冷机和适当过滤装置的低温恒温器，以最大限度地减少来自环境的不必要噪音。然后将以可控和可调的方式引入与环境的耦合，以研究其对纳米线中量子效应的影响。实现可调谐耗散并将其耦合到超导纳米线中将为研究量子系统与环境相互作用的一般行为提供重要的模型系统。除了推进我们对介观超导体和量子系统的基本物理学的理解外，该项目还将为研究生和本科生的科学生涯做好准备，开发新的基于网络的教学工具，为高中学生和教师提供研究机会，并为未来的研究奠定坚实的基础。

Non-technical AbstractThe goal of this Faculty Early Career Development project at Johns Hopkins University is to investigate the quantum phase transitions and dissipation in superconducting nanowires. A quantum phase transition can be observed close to absolute zero temperature when some critical parameter of the system is varied, such as the diameter of the wire or an applied magnetic field. The nature of the transition generally depends on the structure of the nanowire and the unwanted noise from the environment. A new fabrication technique will be developed in order to achieve precise control of the microstructure of the nanowires. The coupling with the environment will be purposely introduced in a controlled and tunable way in order to study its effect on the quantum properties of the nanowires. These nanowires will represent an experimental realization of a model system for investigating the general behavior of quantum systems interacting with the environment. Besides advancing our understanding of the fundamental physics of mesoscopic superconductors and quantum systems in general, this project will serve to prepare graduate and undergraduate students for scientific careers, develop new web-based teaching tools, provide research opportunities to high school students and teachers, and build a solid basis for future research. Technical AbstractThe goal of this Faculty Early Career Development project at Johns Hopkins University is to investigate the quantum phase transitions and dissipation in superconducting nanowires. Quantum phase transitions occur at the absolute zero of temperature and are driven by quantum fluctuations of some parameter, such as the diameter of the wire or a magnetic field. A new fabrication technique will be developed in order to achieve a precise control of the physical properties of the nanowires and special attention will be paid to investigating the effects of an applied magnetic field, and the details of transport in the non-superconducting regime. A cryostat with a dilution refrigerator and the appropriate filtering arrangements will be used to minimize the unwanted noise from the environment. The coupling with the environment will then be introduced in a controlled and tunable way, in order to study its impact on the quantum effects in the nanowires. Realizing tunable dissipation and coupling it into a superconducting nanowire will provide an important model system for investigating the general behavior of quantum systems interacting with the environment. Besides advancing our understanding of the fundamental physics of mesoscopic superconductors and quantum systems in general, this project will serve to prepare graduate and undergraduate students for scientific careers, develop new web-based teaching tools, provide research opportunities to high school students and teachers, and build a solid basis for future research.