Electron Spin Dephasing due to Hyperfine Interactions with a Nuclear Spin Bath
Electron Spin Dephasing due to Hyperfine Interactions with a Nuclear Spin Bath
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DOI：
10.1103/physrevlett.102.057601
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发表时间：
2009-02-06
影响因子：
8.6
通讯作者：
Das Sarma, S.
中科院分区：
文献类型：
--
作者：
Cywinski, Lukasz;Witzel, Wayne M.;Das Sarma, S.
我们研究了自旋量子比特与核自旋浴相互作用的纯退相效应(自由感应衰变和自旋回波)。而对于无限大磁场B，唯一的退相干机制是核自旋的偶极翻转引起的光谱扩散，随着磁场B的减小，核自旋之间的超精细相互作用变得重要。我们给出了一种由于这些相互作用而产生的退相干理论，该理论利用了它们的长程性质。对于热不相关浴，我们证明了我们的理论适用于低至10mT的B，并允许与最近在GaAs量子点中的实验进行比较。
We investigate pure dephasing decoherence (free induction decay and spin echo) of a spin qubit interacting with a nuclear spin bath. While for infinite magnetic field B the only decoherence mechanism is spectral diffusion due to dipolar flip-flops of nuclear spins, with decreasing B the hyperfine-mediated interactions between the nuclear spins become important. We give a theory of decoherence due to these interactions which takes advantage of their long-range nature. For a thermal uncorrelated bath we show that our theory is applicable down to B similar to 10 mT, allowing for comparison with recent experiments in GaAs quantum dots.