Quantum Phase Transitions And Many-Body Localization In Unconventional 1D Josephson Arrays

我们生活在建立在量子力学基础上的经典世界。经典行为令人着迷的复杂性是如何从我们世界的量子本质中显现出来的？这项研究项目通过设计由超导体(所谓的约瑟夫森结阵列)组成的复杂量子系统，并使用为表征量子比特而开发的方法来探索它们在超低温下的行为，从而解决了这一基本问题。该研究计划的实现对量子超导电子学的新兴领域非常重要：约瑟夫森阵列为构建具有更高相干性的量子比特提供了新的令人兴奋的机会。该项目支持研究生的教育，这些研究生广泛接触到现代固态研究的最先进工具。多组分教育和推广计划是该项目的重要组成部分，旨在开发创新的纳米科学课程。技术摘要该奖项支持对相互作用量子系统的两个基本量子力学问题的实验研究：一维量子相变，以及与环境隔离的复杂量子系统中的多体局部化。为了解决这些现象，设计了新型的纳米级约瑟夫森结阵列来模拟各种量子模型。该研究计划的目标是利用为表征超低温超导量子比特而开发的微波光谱和时间域技术来探索量子临界点附近新对称性的出现和这些新系统的动力学。这一研究计划的实现对量子超导电子学的广阔领域具有重要意义。特别是，具有大动态电感和最小损耗的约瑟夫森阵列的发展提供了新的功能，例如容错量子比特和量子电路的高阻抗隔离。该项目支持研究生的教育，这些研究生广泛接触到现代固态研究的最先进工具。由多个组成部分组成的教育和推广方案是该项目的重要组成部分，旨在开发创新的纳米科学课程。

NON-TECHNICAL ABSTRACTWe live in the classical world which is built upon quantum mechanics. How does the fascinating complexity of classical behaviors emerge from the underlying quantum nature of our world? This research project addresses this fundamental question by designing the complex quantum systems made of superconductors (the so-called arrays of Josephson junctions) and exploring their behavior at ultra-low temperatures using the methods developed for the characterization of quantum bits. Realization of the research program is important for the nascent field of quantum superconducting electronics: the Josephson arrays offer novel exciting opportunities for building quantum bits with improved coherence. The project supports the education of graduate students who enjoy broad exposure to the state-of-the-art tools of modern solid state research. The multi-component Educational and Outreach Program, an essential part of the project, is designed to develop innovative nanoscience curricula.TECHNICAL ABSTRACTThis award supports experimental research on two fundamental problems of quantum mechanics of interacting quantum systems: the quantum phase transitions in one dimension, and the many-body localization in complex quantum systems isolated from the environment. To address these phenomena, novel arrays of nanoscale Josephson junctions are designed to emulate the range of quantum models. The objectives of the research program are to explore the emergence of novel symmetries near the quantum critical point and the dynamics of these novel systems using the microwave spectroscopic and time-domain techniques developed for the characterization of superconducting qubits at ultra-low temperatures. Realization of the research program is important for the broad field of quantum superconducting electronics. In particular, the development of Josephson arrays with large kinetic inductance and minimal losses offers new functionality, such as fault-tolerant qubits and high-impedance isolation of quantum circuits. The project supports the education of graduate students who enjoy broad exposure to the state-of-the-art tools of modern solid state research. The multi-component Educational and Outreach Program, an essential part of the project, is designed to develop innovative nanoscience curricula.