论文标题
在可调的海森堡模型中保护自旋连贯性
Protecting Spin Coherence in a Tunable Heisenberg Model
论文作者
论文摘要
我们在光学腔中使用了一组原子，我们设计了一个非局部海森伯格汉密尔顿家族的家族，并具有连续可调的自旋旋转耦合的各向异性。因此，我们可以访问丰富的相图，包括顺磁到有铁磁性的相变，该相位表现为在临界点处的磁敏感性。敏感性显示了相反符号之间的Ising相互作用与XY相互作用（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旋转。磁化动力学的图像表明，自旋交换相互作用可以保护集体自旋的连贯性，即使是完全消除非相互作用和iSing系统的不均匀场。我们的结果强调了利用自旋交换相互作用的前景，以增强自旋挤压方案的鲁棒性。
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 non-interacting and Ising systems. Our results underscore prospects for harnessing spin-exchange interactions to enhance the robustness of spin squeezing protocols.
