Nuclear spin dynamics and Zeno effect in quantum dots and defect centers

被引:35
作者
Klauser, D. [1 ]
Coish, W. A. [1 ,2 ,3 ]
Loss, Daniel [1 ]
机构
[1] Univ Basel, Dept Phys, CH-4056 Basel, Switzerland
[2] Univ Waterloo, Inst Quantum Comp, Waterloo, ON N2L 3G1, Canada
[3] Univ Waterloo, Dept Phys & Astron, Waterloo, ON N2L 3G1, Canada
关键词
D O I
10.1103/PhysRevB.78.205301
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We analyze nuclear-spin dynamics in quantum dots and defect centers with a bound electron under electron-mediated coupling between nuclear spins due to the hyperfine interaction ("J coupling" in NMR). Our analysis shows that the Overhauser field generated by the nuclei at the position of the electron has short-time dynamics quadratic in time for an initial nuclear-spin state without transverse coherence. The quadratic short-time behavior allows for an extension of the Overhauser-field lifetime through a sequence of projective measurements (quantum Zeno effect). We analyze the requirements on the repetition rate of measurements and the measurement accuracy to achieve such an effect. Further, we calculate the long-time behavior of the Overhauser field for effective electron Zeeman splittings larger than the hyperfine coupling strength and find, both in a Dyson-series expansion and a generalized master-equation approach, that for a nuclear-spin system with a sufficiently smooth polarization the electron-mediated interaction alone leads only to a partial decay of the Overhauser field by an amount of the order of the inverse number of nuclear spins interacting with the electron.
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页数:11
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