Quantum systems are a natural choice for generating probability distributions due to the phenomena of quantum measurements. The data that we observe in nature from various physical phenomena can be modelled using quantum circuits. To load this data, which is mostly in the form of a probability distribution, we present a hybrid classical-quantum approach. The classical pre-processing step is based on the concept of deconvolution of discrete signals. We use the Jensen-Shannon distance as the cost function to quantify the closeness of the outcome from the classical step and the target distribution. The chosen cost function is symmetric and allows us to perform the deconvolution step using any appropriate optimization algorithm. The output from the deconvolution step is used to construct the quantum circuit required to load the given probability distribution, leading to an overall reduction in circuit depth. The deconvolution step splits a bell-shaped probability mass function into smaller probability mass functions, and this paves the way for parallel data processing in quantum hardware, which consists of a quantum adder circuit as the penultimate step before measurement. We tested the algorithm on IBM Quantum simulators and on the IBMQ Kolkata quantum computer, having a 27-qubit quantum processor. We validated the hybrid Classical-Quantum algorithm by loading two different distributions of bell shape. Specifically, we loaded 7 and 15-element PMF for (i) Standard Normal distribution and (ii) Laplace distribution.
Bell State Preparation using Pulsed Non-Degenerate Two-Photon Entanglement
报道了一个新颖的贝尔态制备实验。利用飞秒脉冲泵浦的\emph{nondegenerate}共线自发参量下转换制备了高纯度的Bell态。飞秒泵浦脉冲的使用{ \em does not}导致我们方案中量子干涉可见度的降低,其中不使用振幅的后选择和其他传统机制,例如使用薄的非线性晶体或窄带光谱滤波器。该方案的另一个显著特点是泵浦、信号和空闲波长都是可区分的,这对于量子通信非常有用。
Bell-state preparation for fullerene based electron spins in distant peapod nanotubes
我们提出了一个潜在的实用方案,结合贝尔状态分析器[Zhang et al.,Phys.Rev.A73,014301(2006)],以产生分别被限制在两个遥远的富勒烯中的两个电子自旋的Bell态。为此,我们考虑了单壁碳纳米管(SWCNTs)中的内嵌富勒烯,并采用辅助移动电子和选择性微波脉冲。讨论了该方案的应用和实验可行性。
Sharing non-locality and non-trivial preparation contextuality using same family of Bell expressions
在[Phys. Rev. Lett. 114,250401(2015)]通过Clauser-Horne-Shimony-Halt不等式的量子破坏证明了多个观察者共享非定域性。在本文中,我们提供了一个方案,通过量子破坏一族贝尔不等式,其中爱丽丝和鲍勃执行$2^{n-1}$和$n$数量的测量二分法观测值,共享非局域性和非平凡的准备上下文顺序。对于这一点,我们认为,爱丽丝总是执行投影测量和多个鲍勃顺序执行unsharp测量。我们表明,当鲍勃的测量设置的选择是无偏的,最大的两个鲍勃可以通过违反我们的不等式顺序共享非局部性。此外,我们表明,上述家庭的不平等的本地界得到减少,如果非平凡的准备非上下文的假设进一步施加。然后,有机会分享更多的鲍勃比非局部性的非平凡的准备上下文。我们证明,非平凡的准备上下文可以顺序共享任意数量的鲍勃无偏选择他的测量设置。
Entanglement boosting: Low-volume logical Bell pair preparation for distributed fault-tolerant quantum computation
Nanofiber Quantum Technologies, Inc. (NanoQT)(纳米纤维量子技术有限公司);Clarendon Laboratory, University of Oxford(牛津大学克拉伦登实验室);Department of Computer Science, Graduate School of Information Science and Technology, The University of Tokyo(东京大学大学院信息理工学研究系计算机科学专业)
Generation of Bell, W and GHZ states via exceptional points in non-Hermitian quantum spin systems
研究了非厄米XY自旋链和横场伊辛自旋链中的量子相变,其中非厄米性由虚磁场引起。分析和数值计算结果表明,在特殊情况下,这些模型中的合并本征态靠近W态,远离Bell态和GHZ态,它们在T. D. Lee et.等(Phys. Rev. Lett. 113,250401(2014))。通过选取合适的初始状态,数值模拟显示了系统到目标状态的时间演化过程。
An Optimized Bidirectional Quantum Teleportation Scheme with the use of Bell states
双向量子隐形传态方案是一种双方同时接收对方信息的双向量子通信过程。最近,在文献[1](Zhou et al.,IEEE Access,7,44269(2019)),六量子比特簇态已被用于双向传送三量子比特纠缠态(Alice)和任意单量子比特未知量子态(Bob)。从实验的角度来看,团簇型纠缠态的制备和维持是非常困难和昂贵的。因此,在本文中,我们设计了一个双向量子隐形传态方案的最佳方案,并表明所提出的方案需要优化的量子资源量。
Fidelity of remote state preparation can be enhanced by local operation
远程态制备(Remote State Preparation,RSP)是一种量子信息协议,它允许在一个预先共享的非经典资源态和一个经典信道的帮助下,在一个遥远的位置制备一个量子态。成功完成此任务的效率可以通过资源状态的RSP-fidelity来表示。在本文中,我们研究的影响,通过施加一定的本地操作的资源状态上的RSP-fidelity。我们证明了对任何单位局部操作,RSP保真度都不会增加。然而,对于非单位的本地操作,如本地振幅阻尼信道,我们发现,一些资源状态可以被增强,以增加的RSP保真度。给出了对称局部幅度阻尼信道增强贝尔对角资源状态的最佳参数。此外,我们还证明了在局域退相干的情况下,响应面保真度会突然变化甚至瞬间消失。
Robust Preparation of Bell States by Time Boundary Effect
School of Physics, Beijing Institute of Technology(北京理工大学物理学院);School of Physics Science and Technology, Kunming University(昆明大学物理科学与技术学院);National Laboratory of Solid State Microstructures, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University(南京大学固体微结构物理国家重点实验室、物理系和先进微结构协同创新中心)
Distribution of Bell State Entanglement in Qubit Networks via Collision Models
Turkish-German University(土耳其-德国大学);Koç University(科奇大学);Freie Universität Berlin(柏林自由大学);TÜBİTAK Research Institute for Fundamental Sciences (TBEA)(土耳其科学技术研究协会基础科学研究所(TBEA))