Controlled teleportation

In this article, we review the recent development of controlled teleportation which can be used for sharing quantum information and has important applications in remote quantum computation. We introduce the principles of a couple of controlled teleportation schemes with maximally entangled quantum channels and those with pure entangled quantum channels (non-maximally entangled states). The schemes based on maximally entangled states have the advantage of having maximal efficiency although there are differences in their implementations in experiment. In the controlled teleportation schemes using non-maximally entangled states as the quantum channels, the receiver can reconstruct the originally unknown state by adding an auxiliary particle and performing a unitary evolution. No matter what the unknown state is (a single qubit state or an m-qudit state), the auxiliary particle required is only a two-level quantum system.     

基于多参数测量的双向受控隐形传态

融合了双向隐形传态、受控隐形传态、概率隐形传态及多参数测量思想,提出了一个新的双向受控概率隐形传态协议。在该协议中,以五粒子非最大纠缠团簇态为信道,发送者采用多参数通用测量,接收者引入辅助粒子,并在控制者的允许下,利用测量信息施行适当酉变换,就能以一定概率同时交换他们的量子态。分析了成功概率（经典耗费）与量子纠缠参数及测量参数间的依赖关系,说明了该协议可以根据量子信道的参数来调整多参数测量的参数,达到调节成功概率或经典耗费,满足真实世界中多种不同需求的目的。此外,该协议是经典双向受控隐形传态的推广。     

量子态的概率隐形传态

利用多方控制代理的网络,提出了一个量子隐形传态多量子位的协议。协议中所使用的量子信道有别于已有协议中所使用的量子最大纠缠态。得到的研究结果是,只有在发送方和多方代理合作时,接受方才能得到概率隐形传态的量子信息。因为使用的量子信道是非最大纠缠态,所以该协议更具有实际意义。     

QKD网络量子信道管理关键技术研究

随着网络的发展,网络传播的信息日益增多,其中某些信息需要较高的安全性,因此信息加密手段的研究具有重大意义。量子密钥分发(Quantum Key Distribution,QKD)技术基于量子力学中的不可克隆定理,即不可能复制一个未知的量子态而不对其造成扰动,保证了其无条件的安全性,能够实现安全的密钥分发。但目前QKD网络规模较小,不能满足大规模组网的需求。同时,经典网络的路由技术已经不能适应QKD网络,量子信道寻径成为了一个需要解决的问题。鉴于以上问题,提出了一种能够满足较大规模QKD通信的基于光开关切换的QKD网络模型,并重点设计了其网络结构和信令体系,在此基础上设计了一个用于量子信道寻径的先导信号协议,并提出了量子信道管理机制。经实验验证,该模型的性能良好。     

受控蠕虫框架结构研究

最近几年,随着网络系统应用及复杂性的增加,网络蠕虫成为网络系统安全的重要威胁。因此研究网络蠕虫的相关技术十分重要。给出蠕虫的基本定义,介绍了蠕虫工作流程图,并在此基础上提出了一种受控蠕虫的分布式结构框架;最后从受控蠕虫功能着手描述了受控蠕虫的工作流程图。     

On the power of non-local boxes

A non-local box is a virtual device that has the following property: given that Alice inputs a bit at her end of the device and that Bob does likewise, it produces two bits, one at Alice's end and one at Bob's end, such that the XOR of the outputs is equal to the AND of the inputs. This box, inspired from the CHSH inequality, was first proposed by Popescu and Rohrlich to examine the question: given that a maximally entangled pair of qubits is non-local, why is it not maximally non-local? We believe that understanding the power of this box will yield insight into the non-locality of quantum mechanics. It was shown recently by Cerf, Gisin, Massar and Popescu, that this imaginary device is able to simulate correlations from any measurement on a singlet state. Here, we show that the non-local box can in fact do much more: through the simulation of the magic square pseudo-telepathy game and the Mermin-GHZ pseudo-telepathy game, we show that the non-local box can simulate quantum correlations that no entangled pair of qubits can, in a bipartite scenario and even in a multi-party scenario. Finally we show that a single non-local box cannot simulate all quantum correlations and propose a generalization for a multi-party non-local box. In particular, we show quantum correlations whose simulation requires an exponential amount of non-local boxes, in the number of maximally entangled qubit pairs.     

Entanglement assisted classical capacity of a class of quantum channels with long-term memory

In this paper we evaluate the entanglement assisted classical capacity of a class of quantum channels with long-term memory, which are convex combinations of memoryless channels. The memory of such channels can be considered to be given by a Markov chain which is aperiodic but not irreducible. This class of channels was introduced by Datta and Dorlas in (J. Phys. A, Math. Theor. 40:8147–8164, 2007), where its product state capacity was evaluated.      

多体非对称纠缠信道的量子受控密集编码

利用多粒子非对称量子纠缠态,提出一种多体高维非对称量子信道的量子受控密集编码方案。采用量子测量的方法控制纠缠量子信道和密集编码经典信息的传送,通过构造幺正变换矩阵和正交量子测量,纯化量子信道,以一定的概率实现量子受控密集编码,解决了实际量子信道退相干影响下最大纠缠态提取的问题,实现了N方发送方和1方接收方之间密集编码传送信息量的控制,提高了密集编码可调控传送信息量,扩大了调控范围。     

信道噪声对量子信息分离的影响

文献[7]给出了一个三者之间利用四粒子团簇态作为量子信道实现单粒子量子态的量子信息分离的方案。在此方案的基础上,分析了经典噪声信道对这个量子信息分离方案的影响。通过利用二元对称信道以及二元删除信道,得到了信息分离成功概率与经典信道噪声系数之间的关系。除此之外,还研究了量子噪声信道对此方案的影响。在振幅阻尼信道或者去极化信道上进行量子信息分离的过程中,量子纠缠信道将会发生退相干,从而导致量子信息分离质量的下降。文中给出了量子信息分离保真度与噪声系数以及所传送量子态系数之间的关系刻画。     

Remotely Prepared Entanglement: a Quantum Web Page

Abstract. In quantum teleportation, an unknown quantum state is transmitted from one party to another using only local operations and classical communication, at the cost of shared entanglement. Is it possible similarly, using an N party entangled state, to have the state retrievable by any of the N-1 possible receivers? If the receivers cooperate, and share a suitable state, this can be done reliably. The N party GHZ is one such state; I derive a large class of such states, and show that they are in general not equivalent to the GHZ. I also briefly discuss the problem where the parties do not cooperate, and the relationship to multipartite entanglement quantification. I define a new set of entanglement monotones, the entanglements of preparation.     

SuperDense Quantum Teleportation

Recent advances in experimental technique make SuperDense Teleportation (SDT) possible only now, ten years after my first proposal at an ISI Torino summer conference on Quantum Computing. The effect uses remote state preparation to send more state-specifying parameters per bit than ordinary quantum teleportation (QT) can transmit. The SDT uses a maximally entangled state to teleport the relative phases of an n-dimensional state with equal amplitudes on every standard basis vector. For n greater than or equal to 3, the SDT sends more of these state-specifying parameters than QT. In the limit of large n the ratio is 2 to 1, hence the nomenclature by analogy with Super Dense Coding. Alice’s measurements and Bob’s transformations are far simpler than their corresponding operations in QT. The roles of Charles who chooses the state and Diana who deploys it are different than in QT. My discussion includes a brief review of the progress and possibilities of realization for several different experimental approaches around the world. This paper is the write-up of my remarks at the Festschrift conference for Anton Zeilinger, for many years a close collaborator in the Hampshire College NSF grant continuing our work with Mike Horne and Danny Greenberger started under Cliff Shull at MIT in the late 20th century.     

电流控制传送器研究进展

本文在简要介绍电流传送器特性后,对基于BJT的电流控制传送器电路进行了推导。在对MOS电路亚阈值模型进行分析的基础上,阐述了基于CMOS的电流控制传送器的设计原理和方法,并对基于BiCMOS的电流控制传送器的原理进行了介绍。     

控制对象仿真系统的研究

用系统工程的分析方法建立了一系列常见的动态仿真模型。模型包括动态画面制作、对象参数的设定、脚本程序的编制、通信程序的编写及参数设置等内容,达到了动态模拟真实被控对象的效果。该仿真系统用VB语言开发并在Windows环境下运行,它为可编程序控制器的教学与培训提供了一套较为丰富、灵活的虚拟被控对象,利用它可以设置一些异常情况,以训练和提高操作员的编程技能和解决突发事故的能力。此外,该模型作为一种有效的训练手段可以大大节省培训设备的投资。     

Controlled composition and abstraction for bottom-up integration and verification of abstract components

This work proposes a method for improving the scalability of model-checking compositions in the bottom-up construction of abstract components. The approach uses model checking in the model construction process for testing the composite behaviors of components, including process deadlock and inconsistency in inter-component call sequences. Assuming a single processor model, the scalability issue is addressed by introducing operational models for synchronous/asynchronous inter-component message passing, which are designed to reduce spurious behaviors caused by typical parallel compositions. Together with two abstraction techniques, synchronized abstraction and projection abstraction, that hide verified internal communication behavior, this operational model helps to reduce the complexity of composition and verification.The approach is supported by the Marmot development framework, where the soundness of the approach is assured through horizontal verification as well as vertical verification. Application of the approach on a wireless sensor network application shows promising performance improvement with linear growth in memory usage for the vertically incremental verification of abstract components.     

Controlled experimentation on adaptations of pair programming

The use of agile methods is growing in industrial practice due to the documented benefits of increased software quality, shared programmer expertise, and user satisfaction. These methods include pair programming (two programmers working side-by-side producing the code) and test-driven approaches (test cases written first to prepare for coding). In practice, software development organizations adapt agile methods to their environment. The purpose of this research is to understand better the impacts of adapting these methods. We perform a set of controlled experiments to investigate how adaptations, or variations, to the pair programming method impact programming performance and user satisfaction. We find that method variations do influence programming results. In particular, better performance and satisfaction outcomes are achieved when the pair programming is performed in face-to-face versus virtual settings, in combination with the test-driven approach, and with more experienced programmers. We also find that limiting the extent of collaboration can be effective, especially when programmers are more experienced. These experimental results provide a rigorous foundation for deciding how to adapt pair programming methods into specific project contexts.     

混合跨导线性回路在电流控制传送器的运用

本文在简要介绍电流控制传送器特性后,电流控制传送器的理想模型。阐述了跨导线性回路的原理,分析了混合跨导线性回路以及混合跨导线性回路的工作原理,并对电流控制传送器以及负寄生电阻电流控制传送器的电路原理进行了推导。     

Controlled accurate searches with balloons

In this paper, we propose a system that can perform controlled, accurate search for fuzzy boundaries in noisy images. Since our system is based on the balloon model (L.D. Cohen, I. Cohen, IEEE Trans. Pattern Mach. Intell. 15 (11) (1993) 1131-1147), we propose using an adaptive inflating force instead of a constant one to make the parameters physically meaningful and easy to set. A traditional constant inflating force serves to overcome both the image forces and the intrinsic contracting force of the internal energy model. Therefore, choosing an appropriate magnitude for the inflating force is very difficult. Moreover, a chosen inflating force is not physically meaningful. The adaptive inflating force we use is controlled by two parameters, one controlling the strength of edges that a balloon is allowed to overcome and the other controlling the inflation level of the balloon. The adaptive forces are thus physically meaningful, and they can be computed systematically. Used along with a pre-processing module that we developed, our improved balloons can be controlled to extract contours with a specified strength, a property that is quite desirable.     

任意二粒子纠缠态的受控量子通信

为了解决任意二量子通信问题,首先给出了五粒子和七粒子纠缠态的构造方法,并提供了它们的量子线路图。其次,以该五粒子纠缠态为量子信道,提出一个任意二粒子未知量子态的受控隐形传态协议。该协议在监察者Charlie的控制下,Alice进行四粒子投影测量和经典通信,Bob采用简单酉变换就能以100%的概率成功重构一个任意二粒子纠缠态。最后,利用七粒子纠缠态为量子信道,提出了任意二粒子纠缠态的联合受控远程制备方案。在此方案中,发送者Alice用自己掌握被制备态的部分信息构造测量基,发送者Bob采用前馈测量策略,接收者Diana在监控者Charlie的帮助下,通过简单幺正变换就能确定性地恢复原始态。     

Controlled terminology for clinically-relevant indexing and selective retrieval of biomedical images

Received: 5 April 1997 / Revised: 10 July 1997 / Accepted: 5 August 1997     

GHZ态的多参数测量控制概率隐形传态

量子隐形传态大多都使用最大化纠缠态作为量子信道,但最大化纠缠资源只存在于理想情况下。研究了非最大化纠缠信道的量子隐形传态,基于非最大化纠缠GHZ态提出了一个新型的概率控制隐形传态方案。通过引入多参数通用测量,可以根据量子信道参数调整测量基参数,进而实现最佳的成功概率。加入了量子控制者,使方案具有更高的灵活性。该方案可以被扩展到接收者没有足够量子能力的半量子通信情况,进一步扩大了概率隐形传态的应用范围。