Collaborative Research: Investigation of Superconducting Nanowires and Graphene Junctions Using a Coplanar Fabry-Perot Microwave Resonator as a Qubit Device

****非技术摘要****最近，人们清楚地认识到，传统上用于描述单个和小群基本粒子（例如，电子和原子）的量子力学也可以预测所谓的“介观”物体的行为，即包含大量原子的系统，如大分子或纳米器件。该项目的目标是研究量子力学定律如何应用于纳米线。这些纳米线是金属圆柱体，直径只有几十亿分之一米。该项目将探索由超导金属制成的纳米线。要解决的科学问题是海森堡测不准原理在涉及纳米线的纳米器件中的电流和电荷的适用性。最先进的纳米科学和纳米技术将用于制造这种电线。纳米线的测量将采用一种新颖的实验方法，即将纳米线插入一种称为微波超导法布里-珀罗谐振器的特殊类型的微波谐振器中。该项目将探索使用混合纳米线谐振器设备作为量子比特的可能性，量子比特是在计算机中存储信息的经典“比特”的量子力学模拟。该项目将支持这些先进技术的研究生教育，这将为他们在学术界和我们最先进的技术行业的科学事业做好准备。本科生也将参与该项目，在最先进的科学研究中获得培训和实践经验。该项目还将为博士后提供培训。本研究项目得到材料研究部和物理部的支持。****技术摘要****最近，人们清楚地认识到，宏观自由度，如电流，可以用所谓介观系统的量子力学定律来描述：例如，量子力学对于描述涉及大分子、纳米粒子或超导纳米器件的系统中的输运测量结果很重要。该项目的目标是研究宏观量子力学定律如何应用于超导纳米线。特别是，量子相滑移将被研究。将采用一种新颖的实验方法，即将纳米线耦合到超导微波法布里-珀罗谐振器上。与传统的直流电输运测量相比，这种混合装置将提供互补的实验信息。纳米线有望作为非线性动力学电感。该项目将探索使用混合纳米线谐振器器件作为量子比特的可能性。这种纳米线-量子比特应该不存在影响超导量子比特所使用的约瑟夫森隧道结的退相干机制。纳米线将由最先进的纳米技术制造和成像。测量将使用超低温冰箱和超低噪声微波测量进行。该项目将支持这些先进技术的研究生教育，这将为他们在学术界和我们最先进的技术行业的科学事业做好准备。本科生也将参与该项目，在最先进的科学研究中获得培训和实践经验。该项目还将为博士后提供培训。本研究项目得到材料研究部和物理部的支持。

****NON-TECHNICAL ABSTRACT****Recently, it became clear that quantum mechanics, which is traditionally used to describe individual and small groups of elementary particles (e.g., electrons and atoms), can also predict the behavior of the so-called "mesoscopic" objects, i.e. systems containing a large number of atoms like large molecules or nanodevices. The goal of this project is to investigate how the laws of quantum mechanics apply to nanowires. These nanowires are metallic cylinders having a diameter of a few billionth of a meter. The project will explore nanowires made out of superconducting metals. The scientific question to be addressed is the applicability of the Heisenberg uncertainty principle to the electrical current and electrical charge in nanodevices involving nanowires. The most advanced nanoscience and nanotechnology will be used to fabricate such wires. The measurements on nanowires will be done using a novel experimental approach, namely a nanowire will be inserted into a special type of microwave resonator called a microwave superconducting Fabry-Perot resonator. This project will explore the possibility of using the hybrid nanowire-resonator devices as qubits, the quantum mechanical analog of the classical "bit" that stores information in a computer. This project will support the education of graduate students in these advanced technologies, which will prepare them for scientific careers in academia and in our most advanced technology industries. Undergraduate students will also participate in the project, gaining training and hands-on experience in the most advanced scientific research. The project will also provide training to a postdoc. This research project receives support from the Division of Materials Research and the Physics Division.****TECHNICAL ABSTRACT****Recently, it became clear that macroscopic degrees of freedom, such as electrical current, can be described by laws of quantum mechanics for so-called mesoscopic systems: for example quantum mechanics is important for describing results of transport measurements in systems involving large molecules, nanoparticles, or superconducting nanodevices. The goal of this project is to investigate how the laws of macroscopic quantum mechanics apply to superconducting nanowires. In particular, quantum phase slips will be investigated. A novel experimental approach will be used, namely the nanowires will be coupled to a superconducting microwave Fabry-Perot resonator. Such a hybrid device will provide complementary experimental information when compared with traditional dc electrical transport measurements. The nanowires are expected to act as nonlinear kinetic inductors. This project will explore the possibility of using the hybrid nanowire-resonator devices as qubits. Such nanowire-qubits should be free of the decoherence mechanisms affecting Josephson tunnel junction so far employed for superconducting qubits. The nanowires will be fabricated and imaged by the most advanced nanotechnology. The measurements will be carried out using ultra-low-temperature refrigerators and ultra-low-noise microwave measurements. This project will support the education of graduate students in these advanced technologies, which will prepare them for scientific careers in academia and in our most advanced technology industries. Undergraduate students will also participate in the project, gaining training and hands-on experience in the most advanced scientific research. The project will also provide training to a postdoc. This research project receives support from the Division of Materials Research and the Physics Division.