Materials World Network: Investigations of Quantum Fluctuation Relations Using Superconducting Qubits

技术摘要在过去的二十年里，非平衡功涨落定理的发展为估计分子系统的自由能差提供了新的工具，揭示了微观系统如何与环境交换能量，并加深了对热力学第二定律本质的理解。然而，虽然像雅金斯基等式这样的关系已经在经典极限下得到了实验验证，但它们仍然需要在量子制度下进行测试。该项目中进行的实验得到了材料研究部门材料世界网络的奖励，将利用最先进的超导微波谐振器和超导量子比特对量子区域中的涨落定理进行首次系统研究。该项目还将提供第一批实验，以探索工作的量子力学性质，这是最近才从理论上阐明的。此外，通过与坎皮纳斯大学(巴西坎皮纳斯)和圣卡洛斯物理研究所(巴西圣卡洛斯)的理论家的密切合作，它将提供对纳米尺度耗散本质和开放量子系统建模的基本见解，最显著的是在应用非平衡涨落定理方面，这仍然是一个悬而未决的理论问题。这项研究将支持培训一名研究生和一名博士后，在纳米尺度探索量子物理的尖端技术，包括制造技术和超低温超导器件的低噪声测量；它将为学生提供量子力学和统计力学高级理论技术的培训，包括开放量子系统的建模和非平衡涨落定理；它将促进国际合作，不仅包括直接的合作研究，还包括研究型学生的交流和开发专题的、面向学生的研究教程。非技术摘要在过去的二十年里，我们在理解微米和纳米尺度的系统如何与它们不可避免地嵌入的环境交换能量方面取得了重要进展。这些进展的前沿是在某些热力学参数之间发展了一系列新的精确数学关系--例如，从系统中提取的功与同一系统的能量之间的精确数学关系。无论是从根本角度还是从应用角度来看，这些发展都是重要的。例如，这些关系加深了我们对热力学第二定律和不可逆性(即时间箭头)的理解；同时，它们使我们更深入地了解了在最小规模下对机器效率施加的限制，这是一个随着技术继续缩小规模而至关重要的问题。至关重要的是，虽然这些新的关系已经在广泛的经典微纳尺度系统中进行了测试和利用，但它们在量子系统中的实验验证仍然是一个开放的挑战。在这个国际合作项目中进行的实验将利用最先进的超导电路来进行第一次系统调查，以迎接这一挑战。这项工作的更广泛影响是多方面的：这项研究将提供对量子系统中工作和能量耗散性质的基本见解，这对于了解新兴量子技术和混合量子技术的潜力--如量子辅助传感和量子信息--具有直接重要意义；它将支持一名研究生和一名博士后在量子纳米物理尖端技术和主题方面的培训和教育；它将促进国际合作，促进研究型学生交流，并在这些先进的当代主题上对学生进行一般教育。

Technical AbstractIn the last two decades, the development of nonequilibrium work fluctuation theorems has yielded new tools for the estimation of free energy differences in molecular systems, shed light on how microscopic systems exchange energy with their environment, and provided a deeper understanding of the nature of the second law of thermodynamics. However, while relations like the Jarzynski equality have been verified experimentally in the classical limit, they remain to be tested in the quantum regime. The experiments conducted in this project, which is supported by an award from the Division of Materials Research's Materials World Network, will utilize state-of-the-art superconducting microwave resonators and superconducting qubits to perform the first systematic investigations of fluctuation theorems in the quantum regime. The project will also provide the first experiments to probe the quantum mechanical nature of work, which has only recently been elucidated theoretically. Moreover, through close collaboration with theorists from the University of Campinas (Campinas, Brazil) and The Sao Carlos Institute of Physics (Sao Carlos, Brazil), it will provide fundamental insight into the nature of dissipation at the nanoscale and the modeling of open quantum systems, most notably in application to nonequilibrium fluctuation theorems, which remains an open theoretical question. This research will support the training of one graduate student and one postdoc in cutting-edge technologies for exploring quantum physics at the nanoscale, including fabrication techniques and low-noise measurement of superconducting devices at ultra-low temperatures; it will provide training to students in advanced theoretical techniques in quantum mechanics and statistical mechanics, including the modeling of open quantum systems and nonequilibrium fluctuation theorems; and it will foster an international collaboration, consisting not only of direct collaborative research but also research student exchange and development of topical, student-oriented research tutorials.Non-Technical AbstractIn the last two decades, important advances have been made in our understanding of how systems at the micro and nanoscale exchange energy with the environment in which they are inevitably embedded. At the forefront of these advances has been the development of a new series of precise mathematical relationships between certain thermodynamic quantities - e.g. between the work that can be extracted from a system and the energy of the same system. These developments are important both from a fundamental perspective and an applied one. For example, these relations have refined our understanding of the second law of thermodynamics and irreversibility (i.e. the arrow of time); at the same time, they have provided greater insight into the limitations placed on the efficiency of machines at the smallest scale, a question of paramount importance as technology continues to be scaled down in size. Crucially, while these new relationships have been tested and utilized in a wide range of classical micro and nanoscale systems, their experimental verification in quantum systems remains an open challenge. The experiments conducted in this international collaborative project will utilize state-of-the-art superconducting circuitry to perform the first systematic investigations to meet this challenge. The broader impacts of this work are multifold: the research will provide fundamental insight into the nature of work and energy dissipation in quantum systems, which is of direct importance for understanding the potential of burgeoning quantum and hybrid-quantum technologies - such as quantum-assisted sensing and quantum information; it will support the training and education of one graduate student and one postdoc in cutting-edge techniques and topics in quantum nanoscale physics; and it will foster an international collaboration that promotes research student exchange and the general education of students in these advanced, contemporary topics.