论文标题
与耦合自旋浴的扩展中央自旋模型的连贯性
Coherence of an extended central spin model with a coupled spin bath
论文作者
论文摘要
我们研究了一种延伸的中央自旋模型，该模型具有淋浴之间的各向同性近端自旋交流。该系统可通过分别施加在中央自旋和浴缸上的外部磁场来控制。我们构建了Hilbert空间的基础集，并将扩展模型的Hamiltonian表达为一系列$ 2 \ times2 $块矩阵，以成功地获得该模型的精确解决方案。从中研究了中央自旋的连贯性和自旋极化。我们发现，如果浴缸之间的耦合是抗磁磁性的，则中央自旋在低温下具有良好的连贯性和极化。此外，在中央和浴场磁场的强度采用相同值的临界点上大大抑制了变质。当中央自旋的初始状态不偏振时，确定了一种脱落现象。
We study an extended central spin model with an isotropic nearest-neighbour spin-exchange interaction among the bath spins. The system is controllable by external magnetic fields applied on the central spin and the bath, respectively. We construct a basis set of the Hilbert space and express the Hamiltonian of the extended model into a series of $2\times2$ block matrices to obtain the exact solution of the model successfully. Therefrom, the coherence and the spin polarization of the central spin are investigated. We find that if the couplings among the bath spins are antiferromagnetic, the central spin has good coherence and polarization at low temperatures. Moreover, the decoherence is greatly suppressed at the critical point where the strengthes of the central and the bath magnetic field take the same value. A dephasing phenomenon is identified when the initial state of the central spin is unpolarized.
