利用非线性晶体超晶格制备任意纠缠度的双光子态

Nonlinear Interference in Crystal Superlattices

Nonlinear interferometers with correlated photons hold a promise to advance optical characterization and metrology techniques by improving their performance and affordability. Nonlinear interferometers offer the sub-shot noise phase sensitivity and enable measurements in detection-challenging regions using inexpensive and efficient components. The sensitivity of such interferometers, defined by the ability to measure small shifts of interference fringes, can be significantly enhanced by using multiple nonlinear elements, or crystal superlattices. However, to date, the experiments with no more …

光晶格中原子自旋纠缠的产生与探测

Generation and Detection of Atomic Spin Entanglement in Optical Lattices

光晶格中的超冷原子由于其固有的长相干时间和对大量粒子的可控性，为产生可扩展的量子信息处理提供了巨大的希望。我们报道了光学超晶格中原子自旋纠缠的产生、操纵和探测。利用自旋相关的超晶格，在左或右位置的原子自旋可以单独寻址和相干操纵的微波脉冲与近幺正结晶。超晶格双阱中两原子的自旋纠缠是通过自旋超交换控制的动力学演化产生的。通过原位吸收成像观察碰撞原子损失，测量了双阱中原子的自旋关联，得到了纠缠保真度的下界为$0.79\pm0.06$，以及用$S=2.21\pm 0.08$破坏Bell不等式.上述结果代表了在光晶格中利用超冷原子进行可扩展量子计算的重要一步。

光学晶格中可扩展多体纠缠的功能构件

Functional building blocks for scalable multipartite entanglement in optical lattices

提出基于交叉角自旋依赖超晶格结合量子气体显微镜的新架构，实现局部原子自旋操控，构建并验证了可扩展多体纠缠的功能构件，为可扩展量子计算与模拟提供新平台。

光学和半导体超晶格中的Wannier-Stark共振

Wannier-Stark resonances in optical and semiconductor superlattices

本文讨论了量子粒子在周期势和静电力作用下的共振态。最初这个问题是制定了一个晶体电子受到静态电场和它现在被称为Wannier-Stark问题。我们描述了一种新的方法，近年来开发的Wannier-Stark问题。这种方法允许计算作为严格构造的散射矩阵的极点的Wannier-Stark系统的复能谱，并且在没有任何近似的情况下解决Wannier-Stark问题。从数值的角度来看，建议的方法是非常有效的，并已被证明是一个强大的分析工具，出现在不同的物理系统，如光晶格或半导体超晶格的Wannier-Stark共振。

莫尔TMD超晶格中Wigner分子超晶形成的晶体场效应

Crystal-field effects in the formation of Wigner-molecule supercrystals in moiré TMD superlattices

本研究通过考虑晶体场效应的全组态相互作用计算，揭示了莫尔TMD超晶格中两种Wigner分子超晶物态，解释了相关实验反常现象并指出了无约束Hartree-Fock方法的局限性。

二维光学超晶格中的孤立结构

Isolated Structures in Two-Dimensional Optical Superlattice

在相称的光晶格上叠加各种结构的超晶格，可以产生奇异的晶格拓扑结构，进而发现新的物理学。在这项研究中，通过重叠晶格的最大值，创建一个新的孤立结构，而最小值的干扰可以产生各种“子晶格”图案。三种不同类型的原始晶格被用来证明孤立的正方形，三角形，和六边形的“子晶格”结构在二维光学超晶格，其图案可以动态地操纵通过调谐偏振，频率和强度的激光束。此外，我们还提出了通过改变相对相位来调节亚晶格中隧穿振幅的方法。“我们的配置提供了独特的机会，研究粒子纠缠在交叉井形成的“晶格”，并实现特殊的量子逻辑门在异国情调的晶格几何形状。

Magnetoconductance modulations due to interlayer tunneling in radial superlattices

Radial superlattices are nanostructured materials obtained by rolling-up thin solid films into spiral-like tubular structures. The formation of these "high-order" superlattices from two-dimensional crystals or ultrathin films is expected to result in a transition of transport characteristics from two-dimensional to one-dimensional. Here, we show that a transport hallmark of radial superlattices is the appearance of magnetoconductance modulations in the presence of externally applied axial magnetic fields. This phenomenon critically relies on electronic interlayer tunneling processes that activ…

Anisotropic quantum emitter interactions in two-dimensional photonic-crystal baths

Quantum emitters interacting with two-dimensional photonic-crystal baths experience strong and anisotropic collective dissipation when they are spectrally tuned to 2D Van-Hove singularities. In this work, we show how to turn this dissipation into coherent dipole-dipole interactions with tuneable range by breaking the lattice degeneracy at the Van-Hove point with a superlattice geometry. Using a coupled-mode description, we show that the origin of these interactions stems from the emergence of a qubit-photon bound state which inherits the anisotropic properties of the original dissipation, and …

Resonantly hybridised excitons in moiré superlattices in van der Waals heterostructures

Atomically-thin layers of two-dimensional materials can be assembled in vertical stacks held together by relatively weak van der Waals forces, allowing for coupling between monolayer crystals with incommensurate lattices and arbitrary mutual rotation. A profound consequence of using these degrees of freedom is the emergence of an overarching periodicity in the local atomic registry of the constituent crystal structures, known as a moiré superlattice. Its presence in graphene/hexagonal boron nitride (hBN) structures led to the observation of electronic minibands, whereas its effect enhanced by …

耦合双阱超晶格的量子多体动力学

Quantum Many-Body Dynamics of Coupled Double-Well Superlattices

提出了一种利用光学超晶格中的旋量原子可控产生非局域纠缠对的方法。我们的方案通过控制双阱之间的耦合来迭代地增加纠缠原子之间的距离。当在2N个原子的有限线性链中实现时，它产生具有大纠缠持久性（N阶）的三重价键态。我们还研究了一维铁磁海森堡哈密顿量的非平衡动力学，并表明每个双阱上的解耦三重态的时间演化导致形成一个高度纠缠态，其中短距离反铁磁关联与长距离铁磁关联共存。我们提出了各种动态生成的状态的检测和表征的方法。这些想法是朝着使用被光捕获的原子作为量子信息处理器和量子模拟器迈出的一步。

Linear entropy fails to predict entanglement behavior in low-density fermionic systems

Entanglement is considered a fundamental ingredient for quantum technologies and condensed matter systems are among the good candidates for quantum devices. For bipartite pure states the von Neumann entropy is a proper measure of entanglement, while the linear entropy, associated to the mixedness of the reduced density matrices, is a simpler quantity to be obtained and is considered to be qualitatively equivalent to the von Neumann. Here we investigate both linear and von Neumann entropies for quantifying entanglement in homogeneous, superlattice and disordered Hubbard chains. We find regimes …