量子比特寄存器的近完美同时测量

Assembly and coherent control of a register of nuclear spin qubits

We introduce an optical tweezer platform for assembling and individually manipulating a two-dimensional register of nuclear spin qubits. Each nuclear spin qubit is encoded in the ground $^{1}S_{0}$ manifold of $^{87}$Sr and is individually manipulated by site-selective addressing beams. We observe that spin relaxation is negligible after 5 seconds, indicating that $T_1\gg5$ s. Furthermore, utilizing simultaneous manipulation of subsets of qubits, we demonstrate significant phase coherence over the entire register, estimating $T_2^\star = \left(21\pm7\right)$ s and measuring $T_2^\text{echo}=\l…

光学微势中原子量子比特的相干操纵

Coherent manipulation of atomic qubits in optical micropotentials

我们在实验上演示了基于二维微透镜阵列的远失谐偶极阱和偶极阱寄存器中原子态的相干操纵。通过应用Rabi，Ramsey和自旋回波技术，我们系统地研究了退相机制，并确定了相干时间。同时拉姆齐测量在多达16个偶极子陷阱，并证明了我们的方法的可扩展性。这代表了原子量子位的可缩放寄存器用于量子信息处理的应用中的重要一步。此外，该系统可以作为新的原子钟的基础，利用大量的单独的时钟的并行操作，每个保持单独寻址。

Perfect Discrimination of Non-Orthogonal Separable Pure States on Bipartite System in General Probabilistic Theory

We address perfect discrimination of two separable states. When available states are restricted to separable states, we can theoretically consider a larger class of measurements than the class of measurements allowed in quantum theory. The framework composed of the class of separable states and the above extended class of measurements is a typical example of general probabilistic theories. In this framework, we give a necessary and sufficient condition to discriminate two separable pure states perfectly. In particular, we derive measurements explicitly to discriminate two separable pure states…

通过超导耦合器量子比特在两组腔之间同时进行量子态交换或转移以及产生多个Einstein-Podolsky-Rosen对

Simultaneous quantum state exchange or transfer between two sets of cavities and generation of multiple Einstein-Podolsky-Rosen pairs via a superconducting coupler qubit

提出了一种仅用一个超导耦合器量子比特在两组含有$N$腔的腔之间同时进行量子态交换或转移的方法。被交换或转移的量子态可以是任意的纯态或混合态，可以是纠缠态或非纠缠态。操作时间不会随着腔的数量而增加，并且在整个操作期间不需要施加经典脉冲。此外，该方法还可以用于实现两组量子比特之间的量子态交换或传输，例如两个多量子比特量子寄存器之间的交换或传输。我们进一步表明，本建议可以用来同时产生多个爱因斯坦-波多尔斯基-罗森对的光子或量子比特，这是重要的量子通信。该方法可以推广到其他系统，通过使用不同类型的物理量子位作为耦合器来完成相同的任务。

用量子克隆确定互补性质

Determining complementary properties with quantum clones

在经典世界中，同时测量互补性质（例如位置和动量）给出系统的状态。在量子力学中，测量引起的扰动对于互补性质是最大的，因此限制了同时确定这些性质的精度。试图通过复制系统并在单独的副本上测量每个互补属性来避开这种干扰是很诱人的。然而，在量子力学中，完美的复制在物理上是不可能的。在这里，我们研究使用最接近这种复制策略的量子模拟，最优克隆。生成的克隆态的相干部分对应于输入系统的“孪生”。就像完美的复制品一样，这两个双胞胎都忠实地复制了输入系统的属性。与完美的复制品不同，双胞胎是纠缠在一起的。因此，对两个双胞胎的测量等同于对输入系统的同时测量。对于互补观测量，这种联合测量给出了系统的状态，就像经典情况一样。我们用偏振单光子实验证明了这一点。

泡利字符串的同时方差、加权独立数与一种新的图完美性

Simultaneous variances of Pauli strings, weighted independence numbers, and a new kind of perfection of graphs

本研究探索挫折图这一连接图论与量子信息的自然接口，提出扩展完美图与h-完美图的$\bar{h}$-完美图类，发现其在纠缠检测等多方面应用，还诱导出计算独立数的量子算法并评估其图操作行为与普遍性。

工程玻色子和费米网络中的理想态转移、有效门和纠缠产生

Perfect State Transfer, Effective Gates and Entanglement Generation in Engineered Bosonic and Fermionic Networks

我们展示了如何实现完美的量子态转移，并在工程玻色子和费米子网络中的远程站点之间构建有效的两个量子比特门。系统的哈密顿量可以通过选择满足一定条件的本征值谱来确定，这在镜像对称网络中是充分和必要的。有效的双量子比特门的性质取决于费米子和玻色子的交换对称性。对于费米子网络，门是纠缠的（因此对于量子计算是通用的）。对于玻色子网络，虽然门没有纠缠，但它们允许双向同时通信。讨论了玻色子工程网络和费米子工程网络中的纠缠产生协议。

Quantum routing in planar graph using perfect state transfer

In this article, we consider a spin-spin interaction network governed by $XX + YY$ Hamiltonian. The vertices and edges of the network represent the spin objects and their interactions, respectively. We take a privilege to switch on or off any interaction, that assists us to perform multiple perfect state transfers in a graph simultaneously. We also build up a salable network allowing quantum communication between two arbitrary vertices. Later we utilize the combinatorial characteristics of hypercube graphs to propose a static routing schema to communicate simultaneously between a set of sender…

Simultaneous multiple-users quantum communication across a spin chain channel

The time evolution of spin chains has been extensively studied for transferring quantum states between different registers of a quantum computer. Nonetheless, in most of these protocols only one pair of sender-receivers can share the channel at each time. This significantly limits the rate of communication in a network of many users as they can only communicate through their common data-bus sequentially and not all at the same time. Here, we propose a protocol in which multiple users can share a spin chain channel simultaneously without having crosstalk between different parties. This is achie…

在锗中同时操作18个量子位模块化阵列

Simultaneous operation of an 18-qubit modular array in germanium

该研究展示了基于可扩展2xN架构的锗中18个量子位阵列的同时操作，实现了高保真度的量子门操作，并构建了三量子位Greenberger-Horne-Zeilinger态。

植入团与量子对称自适应测量

Planted Cliques and Quantum Symmetry-Adapted Measurements

本文研究植入团问题的两种量子编码，证明二进制相位态检测需要大量副本，而对称自适应测量在保留标签时能保持近完美可区分性，且单个量子样本可实现高效区分，揭示量子优势潜力。