Parallelization of entanglement-resistant multi-prover interactive proofs

Multi-prover interactive proof systems are said to be entanglement-resistant if the soundness holds even when provers are allowed to share an arbitrary quantum state before the interaction starts. This letter proves that every entanglement-resistant multi-prover interactive proof system can be parallelized to two rounds without ruining its entanglement resistance at the expense of adding one prover.     

连续变量系统中的纠缠与非局域性

通过场(原子)约化熵、量子相对熵研究了各种双模非经典光场(包括纠缠相干态、对相干态、双模压缩真空态)与三型三能级原子作用时的纠缠特性,讨论了原子初态和光场参数的影响,并与赝自旋算符构造的贝尔算符期待值进行了对比.结果表明:熵与贝尔算符期待值具有相似的演化趋势;相对于贝尔算符期待值,熵更易受原子相干性的影响;纠缠最大时非局域性也最大,纠缠最小时贝尔算符期待值并不是最小.在贝尔算符期待值较小时纠缠仍可能较大,这说明纠缠和非局域是量子世界中既相互关联又独立的2个不同属性.     

Theoretical study of dark solitons in media with competing nonlocal nonlinearities and local quintic nonlinearity

Dark solitons, in a medium with competing nonlocal nonlinearities and local quintic nonlinearity, have been studied analytically in this paper. The phenomenological rectangular profile model for nonlocal response function is considered. The exact conditions for the existence of analytical dark soliton solutions are presented using variational principle. The influence of strengths and degrees of competing nonlocality as well as the strength of quintic locality, on the properties of dark solitons, are discussed.     

Nonlocality for continuous variable system with local symplectic operation

We study Bell's theorem for two-mode squeezed state with realizable operations in experiment. For the purpose, we suggest the Bell–CHSH operator with photon presence measurement using symplectic operation and displacement. The symplectic operation can be decomposed into phase shifter and squeezing operation in single mode. These operations are realizable experimentally in quantum optics. As a result, we obtain a larger degree of quantum nonlocality by local symplectic operation and displacement.     

Cheating on Complementarity and Interference by Translational – Internal Entanglement

We show that if internal and momentum states of an interfering particle are entangled, then by measuring its internal state we may infer both path (corpuscular) and phase (wavelike) information with practically any precision, without the complementarity constraints of which-path detection. This holds also for multipath–multistate configurations, allowing large amounts of information to be stored in a single particle. We further show that highly complex particles (e.g., molecules or macroscopic bodies) subject to fields that couple (entangle) their internal and translational (momentum) states may undergo an irresversible randomization (diffusion), manifest by the disappearance of the interference pattern, as if they are subject to decoherence. Thus, translational-internal entanglement can give rise to anomalies in quantum wavepacket propagation.     

基于量子非定域性的时间同步方案

给出了一种基于非定域性(量子纠缠)的对钟协议.证明了空间分离的两体可以利用预先共有的量子纠缠和经典通讯去建立一对同步化的原子钟.跟经典的对钟方法不同的是,这里展现的方法或者说协议的准确性不依赖于对钟的两体间的相对位置和他们之间传播媒质的性质.     

关于量子非局域逻辑门的研究

对几种类型的量子非局域逻辑门进行了讨论,并且研究了信道为非最大纠缠态的情况,此时量子非局域控制-非门只能概率性实现.     

The Multifarious Quantum Information

This paper considers the scope and possibilities of quantum information within the consensus interpretation of the theory. It is pointed out that a prepared quantum state offers a multitude of answers determined by the query directed to it. It predicts the outcome of measurements of alternative observations or allows the performance of a selection of quantum information processes. Knowing the state does not determine which observables can be assigned values, but defining a point of view of the observer allows him to derive outcomes of measurements. However, all predictions are in the form of statistical distributions or correlations between observations. Thus they are intrinsically independent of separations in space and time: like all statistical knowledge they have to be reassessed when new infomation imposes a new initial state. Many properties determined by quantum observations must be assigned to the results of the measurements and not to the physical system itself. Thus the property of nonlocality is a consequence of the probabilistic interpretation only, and it corresponds to no feature assigned to the physical reality.     

A Spatially Nonlocal Model for Polymer Desorption

In order to describe diffusion of a penetrant in a polymer entanglement network, one must incorporate nonlocal effects. Most previous models have included nonlocality in time only; however, by exploiting the disparate length scales in such systems, one can model these effects by a partial integrodifferential equation which is nonlocal in space. When considering the case of diffusion near the glass-rubber transition, a moving boundary separates the polymer into two regions, each governed by a different set of PDEs. The desorption of a semi-infinite polymer is studied using singular perturbation methods. Layers arise at the exposed surface, at the moving boundary, and initially. Analytical and phase-plane solutions are obtained for the solution, which exhibits physically realistic forms of desorption overshoot. Thus, spatially nonlocal models have the potential to replicate experimental systems, and should be considered in concert with other viscoelastic models of polymer-penetrant systems.     

Transmitting boundary conditions for 1D peridynamics

The peridynamic theory reformulates the equations of continuum mechanics in terms of integro‐differential equations instead of partial differential equations. It is not straightforward to apply the available artificial boundary conditions for continua to peridynamic modeling. We therefore develop peridynamic transmitting boundary conditions (PTBCs) for 1D wave propagation. Differently from the previous method where the matching boundary condition is constructed for only one boundary material point, the PTBCs are established by considering the interaction and exchange of information between a group of boundary material points and another group of inner material points. The motion of the boundary material points is recursively constructed in terms of their locations and is determined through matching the peridynamic dispersion relation. The effectiveness of the PTBCs is examined by reflection analyses, numerical tests, and numerical convergent conditions. Furthermore, two‐way interfacial conditions are proposed. The PTBCs are then applied to simulations of wave propagation in a bar with a defect, a composite bar with interfaces, and a domain with a seismic source. All the analyses and applications demonstrate that the PTBCs can effectively remove undesired numerical reflections at artificial boundaries. The methodology may be applied to modeling of wave propagation by other nonlocal theories. Copyright © 2016 John Wiley & Sons, Ltd.