Persistent current noise in normal and superconducting nanorings

Abstract

We investigate fluctuations of persistent current (PC) in nanorings both with and without dissipation and decoherence. We demonstrate that such PC fluctuations may persist down to zero temperature provided there exists either interaction with an external environment or an external (periodic) potential produced, e.g., by quantum phase slips in superconducting nanorings. Provided quantum coherence is maintained in the system PC noise remains coherent and can be tuned by an external magnetic flux ${\Phi }_x$ piercing the ring. If quantum coherence gets suppressed by interactions with a dissipative bath PC noise becomes incoherent and ${\Phi }_x$-independent.

8 pages, 3 figures. Invited talk at FQMT'11

References in corpus (8)

• Quantum decoherence of interacting electrons in arrays of quantum dots and diffusive conductors
• Interference in presence of Dissipation
• Weak localization in a system with a barrier: Dephasing and weak Coulomb blockade
• Particle renormalizations in presence of dissipative environments
• Decoherence of a particle in a ring
• Persistent currents in nanorings and quantum decoherence by Coulomb interaction
• Dephasing of a particle in a dissipative environment
• Persistent current noise