I E Tamm Department of Theoretical Physics, P N Lebedev Physics Institute, Moscow, Russia.
J Phys Condens Matter. 2010 Dec 8;22(48):485302. doi: 10.1088/0953-8984/22/48/485302. Epub 2010 Nov 12.
We theoretically analyze equilibrium fluctuations of the 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.
我们从理论上分析了纳米环中持续电流（PC）的平衡涨落。我们证明，只要电流算符与系统的总哈密顿量不对易，这些涨落就会一直持续到零温度。对于一个在环上运动的量子粒子模型，我们明确地计算了 PC 噪声功率，它在由相应能级差决定的频率处具有尖锐的峰值。在具有多个传导通道的环中，预期会有更平滑和更宽的 PC 噪声谱。PC 噪声的一个特定特征是，其谱可以通过外部磁通进行调节，这表明系统中存在量子相干。
