Nonperturbative Master Equation Solution of Central Spin Dephasing Dynamics
Nonperturbative Master Equation Solution of Central Spin Dephasing Dynamics
复制标题
DOI：
10.1103/physrevlett.109.140403
复制
发表时间：
2012-10-05
影响因子：
8.6
通讯作者：
Das Sarma, S.
中科院分区：
文献类型：
--
作者：
Barnes, Edwin;Cywinski, Lukasz;Das Sarma, S.
我们解决了一组一般的非均匀浴耦合和一大类初始浴状态的长期存在的中心自旋问题。我们通过恢复时间无卷积主方程的所有阶数来计算与旋转浴耦合的中心自旋的相干性的时间演化，从而避免了假设与旋转浴的弱耦合的需要。全量子非马尔可夫解是在大浴极限下获得的，并且在最大耦合常数设置的时间尺度内有效。我们的结果捕获了与 GaAs 量子点中的核自旋浴耦合的电子自旋量子位的完全退相干，以获得实验相关参数。此外，我们的解决方案非常紧凑，可以轻松用于对退相干过程进行定量预测并指导核态制备协议的设计。
We solve the long-standing central spin problem for a general set of inhomogeneous bath couplings and a large class of initial bath states. We compute the time evolution of the coherence of a central spin coupled to a spin bath by resumming all orders of the time-convolutionless master equation, thus avoiding the need to assume weak coupling to the bath. The fully quantum, non-Markovian solution is obtained in the large-bath limit and is valid up to a time scale set by the largest coupling constant. Our result captures the full decoherence of an electron spin qubit coupled to a nuclear spin bath in a GaAs quantum dot for experimentally relevant parameters. In addition, our solution is quite compact and can readily be used to make quantitative predictions for the decoherence process and to guide the design of nuclear state preparation protocols.