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Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots
Published on: November 2, 2013
Double-dot charge qubit and transport via dissipative cotunneling
1Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1.
Physical Review Letters
|November 5, 2004
Summary
We found two quantum phases in a charge qubit: a Kondo phase with entanglement and a local moment phase where noise suppresses conductance. Dissipative cotunneling governs charge transfer in the Kondo phase.
Area of Science:
- Quantum physics
- Mesoscopic physics
- Quantum information science
Background:
- Exotic charge qubits are crucial for quantum computing.
- Understanding quantum dot systems requires analyzing noise effects.
Purpose of the Study:
- Investigate charge transport in a two-quantum-dot qubit system.
- Characterize quantum phases influenced by electrostatic noise.
Main Methods:
- Theoretical modeling of charge transport.
- Analysis of quantum dot systems with capacitive coupling.
- Incorporation of Johnson-Nyquist noise effects.
Main Results:
- Identified two distinct quantum phases: Kondo and local moment.
- Observed orbital-Kondo entanglement in the Kondo phase.
- Found noise-induced suppression of conductance in the local moment phase.
- Characterized charge transfer via "dissipative cotunneling" in the Kondo phase.
Conclusions:
- Quantum phase transitions are sensitive to environmental noise.
- Kondo entanglement is robust in certain regimes but susceptible to noise.
- Dissipative cotunneling is a key transport mechanism in noisy quantum dot systems.
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