摘要：At Physikalisch-Technische Bundesanstalt (PTB), superconducting 10 V circuits for the programmable josephson voltage standard (PJVS) are routinely manufactured on the basis of NbxSi1-x barrier junctions. This paper describes in detail the basic design principles for an operating frequency of 70 GHz. It starts with single junctions, discusses their insertion into microstriplines and closes with the whole microwave circuit containing 69,632 NbxSi1-x barrier junctions arranged over 128 microstriplines connected in parallel. The microwave attenuation of this junction type is a key parameter for the 10 V design and we report its experimental determination. Special attention has been devoted to subarrays with just a few josephson junctions in one of the outermost striplines. The arrangement of these subarrays determines the optimum performance of the complete 10 V series array. The high performance of programmable 10 V circuits fabricated at PTB is characterized by measured operating margins in all subarrays of more than 1 mA centered at the same dc bias current. The observed modulation of the current margins, when changing the frequency around 70 GHz, is explained by microwave reflections caused by the rf waveguide inside the cryoprobe. We determine the current margins in dependence of the output power of a microwave synthesizer and show that 60 mW is sufficient to achieve current margins larger than 1 mA.

摘要：超导量子干涉器件(superconducting quantum interference device,SQUID)是指由1个或2个约瑟夫森结(josephson junction)和超导体组成的闭合环路构成的器件,主要融合了约瑟夫森隧道效应和磁通量子化原理制作而成的高精度磁传感器。目前,量子科技发展已经成为我国未来在高技术领域发展的重要内容;作为其中重要技术之一,SQUID与应用系统技术突破将是未来我国高技术发展的重点领域;全面梳理SQUID研究方向与态势将为我国未来在相关领域的发展设计提供有力支撑。

摘要：量子力学在过去的一个世纪获得了长足的发展．其中许多反直觉的预言（如不确定性原理、叠加态和纠缠态）已经在物理学的各个分支领域被实验所证实．近年来，人们认识到有些看似荒谬的理论在许多领域也有其应用价值，如：量子密码术和量子计算等．这一认识激发了科学家对于“量子态加工技术”的兴趣，这些技术很可能在未来的量子计算中发挥作用．～般认为，量子力学主要对原子、原子核和电子等微观系统起作用，但最近的研究表明，在人工设计的超导线路（微米或毫米尺寸）中，量子力学行为也能得到控制．由超导电感和电容组成的线性谐振器是最简单的超导量子线路，它可以接受一个一个的（微波频率）光子注入并存储这些光子．另外一种超导量子线路是使用约瑟夫森（josephson）结（作为非线性电感）构成的量子比特（qubit），josephson qubit是一个双态系统，具有基态Ig）和激发态le）．