We propose a scheme for generating Rashba spin-orbit coupling and perpendicular Zeeman field simultaneously for cold fermionic atoms in a harmonic trap through the coupling between atoms and laser fields. The realization of Rashba spin-orbit coupling and perpendicular Zeeman field provides opportunities for exploring many topological phenomena using cold fermionic atoms. We focus on the intrinsic anomalous Hall effect and show that it may be observed through the response of atomic density to a rotation of the harmonic trap.
We study superfluid states in a two-dimensional fermionic attractive Hubbard model with Zeeman coupling to an external field. Focusing our attention on singlet pairing in both weak and strong coupling regimes, we reveal a rich phase diagram of finite momentum condensates which exhibits both Fulde-Ferrell and Larkin-Ovchinnikov orders at zero temperature. The latter are commensurate stripe states that spontaneously break a lattice symmetry; many stable ordering wavevectors are found as a function of particle density and Zeeman field. Stronger coupling significantly enhances the stability of the…
Gapless topological Fulde-Ferrell superfluidity induced by in-plane Zeeman field
拓扑超流体是最近发现的量子物质，它拥有拓扑保护的无隙边缘态，称为马约拉纳费米子-奇异的量子粒子，充当自己的反粒子，服从非阿贝尔统计。它们的实现被认为是容错量子计算等未来技术的核心。到目前为止，建立拓扑超流体和Majorana费米子的最有效方案是基于Sau-Lutchyn-Tewari-Das Sarma模型，在} \textbf{\textit{x-y}} \textbf{ plane and a large out-of-plane (perpendicular) Zeeman field along the } \textbf{\textit{z}} \textbf {-方向上具有Rashba型自旋轨道耦合。在这里，我们提出了一个替代的设置，其中的拓扑超流相驱动的应用面内塞曼场。该方案提供了许多新的特征，特别是有限质心动量下的库珀配对（即，Fulde-Ferrell配对）和大量无间隙激发。由此，出现了一种新的具有非均匀配对序参量的无隙拓扑量子物质。它的特点是在边界处的单向马约拉纳表面态，在同一方向传播，并连接两个外尔节点的散装。我们证明了这种奇异的拓扑物质和相关的马约拉纳费米子自旋轨道耦合原子费米气体的出现，并确定其参数空间。我们的计划在半导体/超导体异质结的实施进行了简要讨论。
We report on the production of a novel cold mixture of fermionic $^{53}$Cr and $^{6}$Li atoms delivered by two Zeeman-slowed atomic beams and collected within a magneto-optical trap (MOT). For lithium, we obtain clouds of up to $4 \,10^8$ atoms at temperatures of about $500\,μ$K. A gray optical molasses stage allows us to decrease the gas temperature down to $45(5)\,μ$K. For chromium, we obtain MOTs comprising up to $1.5\, 10^6$ atoms. The availability of magnetically trappable metastable $D$-states, from which $P$-state atoms can radiatively decay onto, enables to accumulate into the MOT quad…
We investigate the subradiance properties of $n\geq 2$ multilevel fermionic atoms loaded into the lowest motional level of a single trap (e.g.~a single optical lattice site or an optical tweezer). As pointed out in our previous work [arXiv:1907.05541], perfectly dark subradiant states emerge from the interplay between fermionic statistics and dipolar interactions. While in [arXiv:1907.05541] we focused on the $n=2$ case, here we provide an in-depth analysis of the single-site dark states for generic filling $n$, and show a tight connection between generic dark states and total angular momentum…
We implement a microscopic spin filter for cold fermionic atoms in a quantum point contact (QPC) and create fully spin-polarized currents while retaining conductance quantization. Key to our scheme is a near-resonant optical tweezer inducing a large effective Zeeman shift inside the QPC while its local character limits dissipation. We observe a renormalization of this shift due to interactions of a few atoms in the QPC. Our work represents the analog of an actual spintronic device and paves the way to studying the interplay between spin-splitting and interactions far from equilibrium.
