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Updated: May 18, 2026
12:57
Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection
Published on: October 13, 2017
Coherent two-electron spin qubits in an optically active pair of coupled InGaAs quantum dots
K M Weiss1, J M Elzerman, Y L Delley
1Institute of Quantum Electronics, ETH Zurich, Zurich, Switzerland.
Physical Review Letters
|September 26, 2012
Summary
We developed a decoherence-avoiding qubit using two exchange-coupled electron spins in semiconductors. This novel approach overcomes limitations in spin coherence time, achieving over 200 ns.
Area of Science:
- Quantum Information Science
- Semiconductor Spintronics
- Quantum Computing
Background:
- Single confined spins in semiconductors face decoherence from magnetic and charge fluctuations.
- Hyperfine and spin-orbit interactions limit the T2* coherence time of electron spins.
Purpose of the Study:
- To overcome simultaneous limitations in spin coherence time.
- To realize a single decoherence-avoiding qubit using coupled electron spins.
Main Methods:
- Utilizing two exchange-coupled electron spins to form a single qubit.
- Employing coherent population trapping.
- Generating a coherent superposition of singlet and triplet states in a quantum dot molecule.
Main Results:
- Demonstrated simultaneous overcoming of magnetic and charge fluctuation limitations.
- Achieved a T2* coherence time exceeding 200 ns for the decoherence-avoiding qubit.
Conclusions:
- Two exchange-coupled electron spins can form a robust decoherence-avoiding qubit.
- Coherent population trapping is effective for generating long-lived spin superposition states in quantum dot molecules.
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