We study a large ensemble of nuclear spins interacting with a single electron spin in a quantum dot under optical excitation and photon detection. At the two-photon resonance between the two electron-spin states, the detection of light scattering from the intermediate exciton state acts as a weak quantum measurement of the effective magnetic (Overhauser) field due to the nuclear spins. In a coherent population trapping state without light scattering, the nuclear state is projected into an eigenstate of the Overhauser field operator, and electron decoherence due to nuclear spins is suppressed: We show that this limit can be approached by adapting the driving frequencies when a photon is detected. We use a Lindblad equation to describe the driven system under photon emission and detection. Numerically, we find an increase of the electron coherence time from 5 to 500 ns after a preparation time of 10 micros.
Enhancement of electron spin coherence by optical preparation of nuclear spins.
D. Stepanenko,G. Burkard,G. Giedke,A. Imamoğlu
Published 2005 in Physical Review Letters
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- Publication year
2005
- Venue
Physical Review Letters
- Publication date
2005-12-15
- Fields of study
Medicine, Physics
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Semantic Scholar, PubMed
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