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Updated: Jun 26, 2026
06:42
Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Coherent control of quantum-dot spins with cyclic optical transitions
Zhe Xian Koong1, Urs Haeusler2, Jan M Kaspari3
1Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom. zxk22@cam.ac.uk.
Nature Communications
|June 24, 2026
Summary
Researchers developed a new method for controlling electron-spin qubits in quantum dots. This breakthrough enables simultaneous optical spin control and single-shot readout, crucial for quantum communication technologies like quantum repeaters.
Area of Science:
- Quantum Information Science
- Solid-State Physics
- Quantum Optics
Background:
- Solid-state spins in quantum dots are promising for quantum communication.
- Challenges exist in simultaneously performing optical spin control and single-shot readout.
Purpose of the Study:
- To overcome the limitations of simultaneous optical spin control and single-shot readout in solid-state emitters.
- To enable efficient quantum control and photon emission for quantum technologies.
Main Methods:
- Leveraging light-hole mixing to create an asymmetric lambda system in a negatively charged heavy-hole exciton.
- Compensating GHz-scale differential Stark shifts and performing nuclear-spin cooling.
- Demonstrating the scheme in both GaAs and InGaAs quantum dots.
Main Results:
- Achieved quantum control of an electron-spin qubit with 97.4% π-pulse contrast.
- Preserved spin-selective optical transitions with a cyclicity of 471(50).
- Demonstrated compatibility with nuclear quantum memory operation.
Conclusions:
- The developed scheme enables repeated emission of indistinguishable photons alongside qubit control.
- This is essential for single-shot readout, photonic cluster-state generation, and quantum repeater technologies.
- The approach is applicable to both GaAs and InGaAs quantum dots.
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