Science. 1990 Jan 12;247(4939):177-82. doi: 10.1126/science.247.4939.177.
Ideas about quantized energy levels originated in atomic physics, but research in superconductivity has led to unparalleled precision in the measurement of energy levels. A comparison of levels produced by two Josephson junctions shows that they differ by no more than 3 parts in 10(19) at an energy of 0.0003 electron volt. The fact that the myriad of interactions of 10(12) particles in a macroscopic body, a Josephson junction, can produce sharply defined energy levels suggests a dynamical state effectively divorced from the complexities of its environment. The existence of this state, the macroscopic quantum state of superconductors, is well established, but its isolation from intrinsic perturbations has recently been shown to be extraordinary. These new results, with an improved precision of about ten orders of magnitude, are discussed in the context of highly accurate results from quantum electrodynamics, atomic spectroscopy, and the standards of metrology. Further refinements in precision may be achievable at higher energy levels, about 12 electron volts, as they become available from a new series array of 18,992 Josephson junctions.
关于量子化能级的想法起源于原子物理学，但超导性的研究使得对能级的测量达到了前所未有的精度。两个约瑟夫森结产生的能级的比较表明，在 0.0003 电子伏特的能量下，它们的差异不超过 3 个部分的 10(19)。在一个约瑟夫森结这样的宏观物体中，10(12)个粒子的无数相互作用可以产生明显定义的能级，这表明存在一种与环境复杂性有效分离的动力学状态。这种状态，即超导体的宏观量子态，已经得到很好的确立，但最近表明它与内在的干扰隔离是非常特殊的。这些新的结果，精度提高了大约十个数量级，在量子电动力学、原子光谱学和计量学标准的高精度结果的背景下进行了讨论。随着新的一系列 18992 个约瑟夫森结提供的更高能量水平的结果变得可用，进一步提高精度可能是可行的。
