In the same way that classical computer networks connect and enhance the capabilities of classical computers, quantum networks can combine the advantages of quantum information and communications. We propose a non-classical network element, a delayed commutation switch, that can solve the problem of switching time in packet switching networks. With the help of some local ancillary qubits and superdense codes we can route the information after part of it has left the network node.
Computer simulation of Wheeler's delayed choice experiment with photons
我们提出了一个惠勒延迟选择实验的计算机模拟模型，该模型是最近报道的一个实验的一对一复制（V. Jacques { \sl et al.}，Science 315，966（2007））。该模型完全基于实验事实，满足爱因斯坦的局部因果关系标准，不依赖于任何量子理论的概念。然而，模拟模型再现了惠勒延迟选择实验的量子理论描述所获得的平均值。我们的结果证明，它是可能的，以粒子的惠勒的延迟选择实验，再现从量子理论计算的平均值，这并不违背常识的描述。
This paper addresses quantum circuit mapping for Noisy Intermediate-Scale Quantum (NISQ) computers. Since NISQ computers constraint two-qubit operations on limited couplings, an input circuit must be transformed into an equivalent output circuit obeying the constraints. The transformation often requires additional gates that can affect the accuracy of running the circuit. Based upon a previous work of quantum circuit mapping that leverages gate commutation rules, this paper shows algorithms that utilize both transformation and commutation rules. Experiments on a standard benchmark dataset conf…
Wave-particle duality of quantum objects is one of the most striking features of quantum physics and has been widely studied in past decades. Developments of quantum technologies enable us to experimentally realize several quantum phenomena. Observation of wave-particle morphing behavior in the context of the quantum delayed-choice experiment (QDCE) is one of them. Adopting the scheme of QDCE, we demonstrate how the coexistence of wave and particle nature emerges as a consequence of the uncertainty in the quantum controlled experimental setup, using a five-qubit cloud-based quantum processor. …
The development of Noisy Intermediate Scale Quantum Computers (NISQC) provides for the Quantum Information community new tools to perform quantum experiences from an individual laptop. It facilitates interdisciplinary research in the sense that theoretical descriptions of properties of quantum physics can be translated to experiments easily implementable on a NISCQ. In this note I test large state-independent inequalities for quantum contextuality on finite geometric structures encoding the commutation relations of the generalized N-qubit Pauli group. The bounds predicted by Non-Contextual Hid…
Coexistence of full which-path information and interference in Wheelers delayed choice experiment with photons
我们提出了一个计算机模拟模型，它是惠勒延迟选择实验的实验实现的一对一副本，该实验采用单光子源和马赫-曾德尔干涉仪，马赫-曾德尔干涉仪由50/50输入分束器和具有可调反射系数$R$的可变输出分束器组成（V. Jacques { \sl et al.}，物理修订信函100，220402（2008））。对于$0\le R\le 0.5$，发现干涉可见度$V$和路径可扩展性$D$（量化哪个路径信息WPI的参数）的实验测量值满足互补关系$V^2+D^2\le 1$，从而允许获得部分WPI，同时保持具有有限可见度的干涉。模拟模型完全基于实验事实，满足爱因斯坦的局部因果性标准，不依赖于任何量子理论或概率论的概念，定量地再现了从量子理论计算的平均值。我们的结果证明，它是可能的，以粒子的实验，即使D=0，V=1，可以有完整的WPI，因此，关系$V^2+D^2\le 1$不能被视为量化的互补性的概念。
One-way quantum computing is a promising candidate for fault-tolerant quantum computing. Here, we propose new protocols to realize a deterministic one-way CNOT gate and one-way $X$-rotations on quantum-computing platforms. By applying a delayed-choice scheme, we overcome a limit of most currently available quantum computers, which are unable to implement further operations on measured qubits or operations conditioned on measurement results from other qubits. Moreover, we decrease the error rate of the one-way logic gates, compared to the original protocol using local operations and classical c…
Nonclassicality of a delayed remote-controlled quantum computing model
College of Computer Science and Technology, National University of Defense Technology（国防科技大学计算机学院）；College of Electronic Science and Technology, National University of Defense Technology（国防科技大学电子科学学院）
We derive a representation for a lattice U(1) gauge theory with exponential convergence in the number of states used to represent each lattice site that is applicable at all values of the coupling. At large coupling, this representation is equivalent to the Kogut-Susskind electric representation, which is known to provide a good description in this region. At small coupling, our approach adjusts the maximum magnetic field that is represented in the digitization as in this regime the low-lying eigenstates become strongly peaked around zero magnetic field. Additionally, we choose a representatio…
Users of quantum computers must be able to confirm they are indeed functioning as intended, even when the devices are remotely accessed. In particular, if the Hilbert space dimension of the components are not as advertised -- for instance if the qubits suffer leakage -- errors can ensue and protocols may be rendered insecure. We refine the method of delayed vectors, adapted from classical chaos theory to quantum systems, and apply it remotely on the IBMQ platform -- a quantum computer composed of transmon qubits. The method witnesses, in a model-independent fashion, dynamical signatures of hig…
Under suitable assumptions, the algorithms in [Lin, Tong, Quantum 2020] can estimate the ground state energy and prepare the ground state of a quantum Hamiltonian with near-optimal query complexities. However, this is based on a block encoding input model of the Hamiltonian, whose implementation is known to require a large resource overhead. We develop a tool called quantum eigenvalue transformation of unitary matrices with real polynomials (QET-U), which uses a controlled Hamiltonian evolution as the input model, a single ancilla qubit and no multi-qubit control operations, and is thus suitab…
In one-way quantum computation (1WQC) model, an initial highly entangled state called a graph state is used to perform universal quantum computations by a sequence of adaptive single-qubit measurements and post-measurement Pauli-X and Pauli-Z corrections. The needed computations are organized as measurement patterns, or simply patterns, in the 1WQC model. The entanglement operations in a pattern can be shown by a graph which together with the set of its input and output qubits is called the geometry of the pattern. Since a one-way quantum computation pattern is based on quantum measurements, w…
Grainger College of Engineering, Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校格拉inger工程学院土木与环境工程系）
