Quantum superposition of distinct macroscopic states
Quantum superposition of distinct macroscopic states
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DOI：
10.1038/35017505
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发表时间：
2000-07-06
期刊：
影响因子：
64.8
通讯作者：
Lukens, JE
中科院分区：
文献类型：
--
作者：
Friedman, JR;Patel, V;Lukens, JE
1935年，薛定谔（1）试图通过一个思想实验来证明量子力学的局限性，在这个实验中，一只猫被置于活态和死态的量子叠加态中。直到20世纪80年代，这个想法一直是学术界的好奇心，当时有人提出（2-4），在适当的条件下，具有许多微观自由度的宏观物体可以表现出量子力学行为，只要它与环境充分解耦。虽然在证明各种系统的宏观量子行为方面已经取得了很大进展，例如超导体（5-9），纳米级磁体（10-12），激光冷却捕获离子（13），微波腔中的光子（14）和C-60分子（15），但还没有实验证明真正宏观不同状态的量子叠加。在这里，我们提出的实验证据表明，超导量子干涉仪（SQUID）可以放入两个磁通量状态的叠加：一个对应于几微安的电流顺时针流动，另一个对应于相同数量的电流逆时针流动。
In 1935, Schrodinger(1) attempted to demonstrate the limitations of quantum mechanics using a thought experiment in which a cat is put in a quantum superposition of alive and dead states. The idea remained an academic curiosity until the 1980s when it was proposed(2-4) that, under suitable conditions, a macroscopic object with many microscopic degrees of freedom could behave quantum mechanically, provided that it was sufficiently decoupled from its environment. Although much progress has been made in demonstrating the macroscopic quantum behaviour of various systems such as superconductors(5-9), nanoscale magnets(10-12), laser-cooled trapped ions(13), photons in a microwave cavity(14) and C-60 molecules(15), there has been no experimental demonstration of a quantum superposition of truly macroscopically distinct states. Here we present experimental evidence that a superconducting quantum interference device (SQUID) can be put into a superposition of two magnetic-flux states: one corresponding to a few microamperes of current flowing clockwise, the other corresponding to the same amount of current flowing anticlockwise.