Quantum Interference and Critical Currents of Superconduct- ive Microcircuits Without Josephson Junctions

虽然大多数用于小规模应用的超导电路都使用约瑟夫森结作为有源或开关元件，但在一些重要的情况下，约瑟夫森结应该用简单的细导线代替，其尺寸与温度相关的相干长度E(T)相同。研究人员正在从理论上研究一种微电路的可行性，这种微电路在许多方面可能像SQUID（超导量子干涉器件）电路一样，而不使用约瑟夫森结。该装置可以通过直径为相干长度数量级的超导环路制造，并在超导导线的两侧连接，以注入外部控制电流。磁通B垂直于环。磁通密度产生循环电流。将研究各种注入控制电流的循环电流密度作为磁通量的函数，并将这些结果推广到更复杂的电路，如有限和无限阶梯电路和阵列。

Although most superconducting circuits employed for small-scale applications use Josephson conjunctions as an active or switching element, in some important instances Josephson junctions should be replaceable by simple thin wires whose dimensions are of the size of the temperature-dependent coherence length, E(T). The researchers are studying theoretically the feasibility of a microcircuit which may behave in many respects like a SQUID (superconducting quantum interference device) circuit without the use of Josephson junctions. This device may be fabricated by means of a superconducting loop whose diameter is of the order of magnitude of the coherence length and has connected to it on opposite sides superconducting wires for the purpose of injecting an external control current. Magnetic flux B is applied perpendicular to the ring. The flux density gives rise to a circulating current. The circulating current density will be studied as a function of magnetic flux for various injected control currents, and these results will be extended to more complicated circuits such as finite and infinite ladder circuits and arrays.