Spin-orbit-coupled fermions in an optical lattice clock
Spin-orbit-coupled fermions in an optical lattice clock
复制标题
DOI：
10.1038/nature20811
复制
发表时间：
2017-02-02
期刊：
影响因子：
64.8
通讯作者：
Ye, J.
中科院分区：
文献类型：
--
作者：
Kolkowitz, S.;Bromley, S. L.;Ye, J.
冷原子系统中的工程自旋轨道耦合（SOC）可以使新合成材料和复杂凝聚态现象的研究成为可能1 - 8。然而，碱原子自旋轨道耦合系统中的自发辐射受到加热的阻碍，限制了对多体效应的观察（1，2，5），并激发了对潜在替代方案的研究（9 - 11）。在这里，我们证明了自旋轨道耦合费米子可以被设计成在一维光学晶格时钟中自然发生（12）。与先前的SOC实验（1 - 11）相比，在这里，使用Sr-87原子中的两个电子轨道状态之间的直接超窄光学时钟跃迁来生成和探测SOC。我们使用时钟光谱来准备晶格带的人口，内部电子状态和准动量，并产生自旋轨道耦合动力学。激发时钟态的超长寿命（160秒）消除了所有相关实验时间尺度下自发辐射的退相干和原子损失，从而允许随后对SOC能带结构和本征态进行动量和自旋分辨的原位探测。我们利用这些能力来研究布洛赫振荡，自旋动量锁定和货车霍韦奇异性的过渡态密度。我们的研究结果奠定了基础，利用费米光学晶格时钟探测新的相位的物质。
Engineered spin-orbit coupling (SOC) in cold-atom systems can enable the study of new synthetic materials and complex condensed matter phenomena1-8. However, spontaneous emission in alkali-atom spin-orbit-coupled systems is hindered by heating, limiting the observation of many-body effects(1,2,5) and motivating research into potential alternatives(9-11). Here we demonstrate that spin-orbit-coupled fermions can be engineered to occur naturally in a one-dimensional optical lattice clock(12). In contrast to previous SOC experiments(1-11), here the SOC is both generated and probed using a direct ultra-narrow optical clock transition between two electronic orbital states in Sr-87 atoms. We use clock spectroscopy to prepare lattice band populations, internal electronic states and quasi-momenta, and to produce spin-orbit-coupled dynamics. The exceptionally long lifetime of the excited clock state (160 seconds) eliminates decoherence and atom loss from spontaneous emission at all relevant experimental timescales, allowing subsequent momentum-and spin-resolved in situ probing of the SOC band structure and eigenstates. We use these capabilities to study Bloch oscillations, spin-momentum locking and Van Hove singularities in the transition density of states. Our results lay the groundwork for using fermionic optical lattice clocks to probe new phases of matter.