Towards a dephasing diode: asymmetric and geometric dephasing
Robert S Whitney1, Alexander Shnirman, Yuval Gefen
1Institut Laue-Langevin, 6 rue Jules Horowitz, B.P. 156, 38042 Grenoble, France.
Physical Review Letters
|June 4, 2008
Summary
Noisy environments create a dephasing diode in quantum wires, causing distinct spin dephasing for electrons moving in opposite directions. This effect can be controlled by wire curvature and measured using advanced spin detection methods.
Area of Science:
- Condensed Matter Physics
- Quantum Transport
Background:
- Quantum wires exhibit unique electron behavior due to confinement.
- Spin-orbit coupling, specifically Rashba coupling, influences electron spin dynamics.
- Understanding environmental noise effects is crucial for quantum device stability.
Purpose of the Study:
- Investigate the impact of environmental noise on spin and charge transport in ballistic quantum wires.
- Analyze the role of Rashba coupling in noise-induced dephasing.
- Explore geometric effects, like Berry phase, on spin dephasing.
Main Methods:
- Theoretical modeling of spin and charge transport.
- Analysis of dephasing phenomena in the presence of noise.
- Incorporation of spin-orbit coupling and geometric phase effects.
Main Results:
- A noisy quantum wire acts as a dephasing diode, leading to asymmetric spin dephasing for right- and left-moving electrons.
- Berry phase in curved wires contributes to asymmetric dephasing, alongside purely geometric dephasing.
- The study quantifies the differential dephasing rates based on electron direction.
Conclusions:
- Environmental noise can induce directional asymmetry in spin dephasing within quantum wires.
- Geometric phases offer an additional mechanism for controlling spin dephasing.
- Proposed experimental techniques can verify these dephasing phenomena.
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