arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1002.3104cond-mat.mes-hall
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持续电流波动

Fluctuations of persistent current

Andrew G. Semenov, Andrei D. Zaikin

摘要:

从理论上分析了纳米环中持续电流的平衡涨落。我们证明,这些波动持续到零温度提供当前运营商不与系统的总哈密顿量交换。对于环上的量子粒子模型,我们明确评估PC噪声功率,其具有由相应的能级间距离设置的频率处的尖峰的形式。在具有许多传导通道的环中,预期PC噪声谱更平滑和更宽。PC噪声的一个特殊特征是它的频谱可以被外部磁通量调谐,这表明系统中存在量子相干性。

英文摘要:

We theoretically analyze equilibrium fluctuations of persistent current (PC) in nanorings. We demonstrate that these fluctuations persist down to zero temperature provided the current operator does not commute with the total Hamiltonian of the system. For a model of a quantum particle on a ring we explicitly evaluate PC noise power which has the form of sharp peaks at frequencies set by the corresponding interlevel distances. In rings with many conducting channels a much smoother and broader PC noise spectrum is expected. A specific feature of PC noise is that its spectrum can be tuned by an external magnetic flux indicating the presence of quantum coherence in the system.

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