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arXiv 0812.2394cond-mat.supr-con
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0 π约瑟夫森结中单个半流激子的量子隧穿

Quantum tunneling of a single semifluxon in a 0-pi Josephson junction

E. Goldobin, K. Vogel, W. P. Schleich, D. Koelle, R. Kleiner

摘要:

我们考虑一个长度为$L$的对称0 π约瑟夫森结,它可以处于两个简并基态之一,对应于围绕0 π边界顺时针或逆时针循环的超电流。当结的长度$L$变得小于约瑟夫森穿透深度$λ_J$时,系统可以由于热波动或量子隧穿而从一种状态切换到另一种状态。我们将这个问题映射到周期性双势阱中单个粒子的动力学,并估计宏观量子相干性可能被观察到的参数。我们得出结论,这个系统不太有希望构建量子位,因为(a)它需要非常低的温度才能达到量子状态,(b)它的微小通量很难读出,(c)它对结的0和π部分之间的不对称非常敏感。

英文摘要:

We consider a symmetric 0-pi Josephson junction of length $L$, which classically can be in one of two degenerate ground states up or down, corresponding to supercurrents circulating clockwise or counterclockwise around the 0-pi boundary. When the length $L$ of the junction becomes smaller than the Josephson penetration depth $λ_J$, the system can switch from one state to the other due to thermal fluctuations or quantum tunneling. We map this problem to the dynamics of a single particle in a periodic double well potential and estimate parameters for which macroscopic quantum coherence may be observed. We conclude that this system is not very promising to build a qubit because (a) it requires very low temperatures to reach the quantum regime, (b) its tiny flux is hard to read out and (c) it is very sensitive to the asymmetries between the 0 and pi parts of the junction.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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