Protecting Spin Coherence in a Tunable Heisenberg Model
Protecting Spin Coherence in a Tunable Heisenberg Model
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DOI：
10.1103/physrevlett.125.060402
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发表时间：
2020-08-03
影响因子：
8.6
通讯作者：
Schleier-Smith, Monika H.
中科院分区：
文献类型：
--
作者：
Davis, Emily J.;Periwal, Avikar;Schleier-Smith, Monika H.
利用光学腔中的原子系综，我们设计了一个具有连续可调自旋-自旋耦合各向异性的非定域海森堡哈密顿量族。因此，我们获得了丰富的相图，包括顺磁性到铁磁性伊辛相变，表现为在临界点的磁化率发散。磁化率显示了Ising相互作用和XY（自旋交换）相互作用之间的对称性，这表明空间扩展的原子系统表现为单个集体自旋。磁化动力学的图像显示，自旋交换相互作用保护集体自旋的相干性，即使对非均匀场完全退相的非相互作用和伊辛系统。我们的研究结果强调利用自旋交换相互作用，以提高自旋压缩协议的鲁棒性的前景。
Using an ensemble of atoms in an optical cavity, we engineer a family of nonlocal Heisenberg Hamiltonians with continuously tunable anisotropy of the spin-spin couplings. We thus gain access to a rich phase diagram, including a paramagnetic-to-ferromagnetic Ising phase transition that manifests as a diverging magnetic susceptibility at the critical point. The susceptibility displays a symmetry between Ising interactions and XY (spin-exchange) interactions of the opposite sign, which is indicative of the spatially extended atomic system behaving as a single collective spin. Images of the magnetization dynamics show that spin-exchange interactions protect the coherence of the collective spin, even against inhomogeneous fields that completely dephase the noninteracting and Ising systems. Our results underscore prospects for harnessing spin-exchange interactions to enhance the robustness of spin squeezing protocols.