Quantum dynamics of a single vortex
Quantum dynamics of a single vortex
复制标题
单涡旋的量子动力学
DOI：
10.1038/nature01826
复制
发表时间：
2003
期刊：
影响因子：
64.8
通讯作者：
A. V. Ustinov
中科院分区：
文献类型：
--
作者：
A. Wallraff;A. Lukashenko;J. Lisenfeld;A. Kemp;M. Fistul;Y. Koval’;A. V. Ustinov
涡旋自然地出现在从宏观到微观的各种气体和流体中。在稀薄原子气体、超流氦和超导体的玻色-爱因斯坦凝聚体中，涡旋的存在是系统量子性质的结果。超导电流的量子化涡旋是由磁通穿透材料产生的，在决定材料性质和超导体器件性能方面起着关键作用。在高温下，这种涡旋的动力学本质上是经典的，而在低温下，以前的实验已经提出了集体量子动力学。然而，关于涡旋隧道是否在低温下发生的问题只在大量涡旋集合中得到了解决。这里我们研究了超导约瑟夫森结中单个涡旋的量子动力学。通过测量涡旋从可控钉扎势中逃逸的统计性质，我们证明了捕获势垒内涡旋能量的量子化能级的存在以及涡旋通过钉扎势垒的量子隧穿。
Vortices occur naturally in a wide range of gases and fluids, from macroscopic to microscopic scales. In Bose–Einstein condensates of dilute atomic gases, superfluid helium and superconductors, the existence of vortices is a consequence of the quantum nature of the system. Quantized vortices of supercurrent are generated by magnetic flux penetrating the material, and play a key role in determining the material properties and the performance of superconductor-based devices. At high temperatures the dynamics of such vortices are essentially classical, while at low temperatures previous experiments have suggested collective quantum dynamics. However, the question of whether vortex tunnelling occurs at low temperatures has been addressed only for large collections of vortices. Here we study the quantum dynamics of an individual vortex in a superconducting Josephson junction. By measuring the statistics of the vortex escape from a controllable pinning potential, we demonstrate the existence of quantized levels of the vortex energy within the trapping potential well and quantum tunnelling of the vortex through the pinning barrier.