Persistent currents in nanorings and quantum decoherence by Coulomb interaction

Abstract

Employing instanton technique we evaluate equilibrium persistent current (PC) produced by a quantum particle moving in a periodic potential on a ring and interacting with a dissipative environment formed by diffusive electron gas. The model allows for detailed non-perturbative analysis of interaction effects and -- depending on the system parameters -- yields a rich structure of different regimes. We demonstrate that at low temperatures PC is exponentially suppressed at sufficiently large ring perimeters $2\pi R>L_{\phi }$ where the dephasing length $L_{\phi }$ is set by interactions and does not depend on temperature. This behavior represents a clear example of quantum decoherence by electron-electron interactions at $T\to 0$.

13 pages, 4 figures

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Cited by in corpus (4)

• Persistent current noise and electron-electron interactions
• Fluctuations of persistent current
• Persistent current noise
• Persistent current noise in normal and superconducting nanorings