基于量子高维Bell态纠缠交换的分发式投票方案

利用了高维Bell态,设计一种新的量子投票方案.方案分为4个阶段:首先,高维Bell纠缠态粒子被作为投票信息载体被分发给投票者;然后投票者利用最小复杂度搜索寻找竞选者,并用相移操作投出选票;接着代理人收到选票后,运用纠缠交换过程来检测窃听,通过检查粒子的测量结果来发现是否非法攻击;最后代理人利用计票算子统计票数并公布.所有人都只知道总的投票结果,单个投票者的投票信息是保密的.协议分析了各种攻击下的抵抗,证明了这是一个合理,安全,高效的量子投票方素.     

基于纠缠转换秘密共享一个任意两原子纠缠态

提出一个利用纠缠转换在腔QED中来实现秘密共享一个任意两原子纠缠态的方案.结果表明,随着控制者数量的增加,窃听者的成功机率降低.     

纠缠双原子与压缩相干态光场相互作用系统的量子纠缠

利用全量子理论,研究了双原子与压缩相干态光场相互作用系统的量子纠缠特性,分别讨论了相干态振幅参量、光场压缩参量和耦合系数比值对系统场熵和原子相对熵演化的影响.结果表明： 当相干态振幅参量为零或很小时,两原子间纠缠度随时间演化规律和场-原子纠缠度随时间演化规律几乎相反,场-原子间的纠缠削弱了两原子间的纠缠.随着相干态振幅参量增大或光场压缩参量减小,在一定时域内,两原子处于稳定的纠缠态,并且这个时域逐渐变长,同时原子-原子平均纠缠度值增大,而场-原子平均纠缠度值减小.耦合系数比值（原子之间偶极-偶极相互作用）的增大会减弱原子与场之间的作用,使两原子始终处于最大纠缠态.     

振动剪切作用下聚合物熔体的非仿射网络结构模型 I.动态速率方程

对Liu( 1 981 )提出的动态速率方程加以修正 ,用修正的速率方程来研究振动剪切场下缠结密度的变化情况 ,给出其理论分析 ,同时也分析了缠结密度对熔体粘度的影响     

Nonlinear Response and Observable Signatures of Equilibrium Entanglement

We investigate how equilibrium entanglement is manifested in the nonlinear response of an N-qubit system. We show that in the thermodynamic limit the irreducible part of the nth-order nonlinear susceptibility indicates that the eigenstates of the system contain entangled (n + 1)-qubit clusters. This opens the way to a directly observable multiqubit entanglement signature. We show that the irreducible part of the static cubic susceptibility of a system of four flux qubits, as a function of external parameters, behaves as a global 4-qubit entanglement measure introduced in Ref. (20). We discuss the possibility of extracting purely-entanglement-generated contribution from the general multipoint correlators in a multiqubit system.      

双腔光力学系统的稳态纠缠

为了提高耦合腔光力学系统的稳态纠缠,将光学参量放大器放置到光学腔中并研究了其纠缠状.首先利用量子朗之万方程和线性化处理,求出系统的稳态解; 然后将纠缠负对数作为纠缠判据,对系统的量子纠缠进行数值模拟.研究结果表明,含有光学参量放大器的系统不但可以显著增强稳态力学纠缠,而且可使纠缠不受热库环境温度的影响; 因此,本文方案可为操控力学系统间的量子纠缠提供参考.     

利用受激拉曼跃迁制备原子－光子的杂化纠缠态

提出了一种利用玻色-爱因斯坦凝聚体中三能级原子与一束较弱的相干态探测光和一束较强的经典耦合光相互作用产生受激拉曼跃迁制备原子－光子杂化纠缠态的理论方案。研究了探测光场与原子间的相互作用强度、双光子失谐量和处在基态的原子间的相互作用强度对制备杂化纠缠态的影响。结果表明,通过增加探测光场与原子间的相互作用强度或减小双光子失谐量,能够更快地制备纠缠程度更高的原子－光子杂化纠缠态。     

Adhesive Failure and Deformation Behaviour of Polymers

An instrument has been developed to determine the adhesive fracture energy as a function of the most important parameters such as temperature, contact time etc. and to study the stress-strain behaviour during bond separation. Additionally, the deformation processes during debonding were observed by high speed photography. Investigations of two high molecular weight polymers, polyisobutylene (PIB) and polyethylhexylacrylate (PEHA), showed two different types of bond separation: “brittle” behaviour with low adhesive failure energy for PIB and the formation and deformation of fibrillar structures for PEHA leading to much higher strains at break and adhesive failure energies. It follows from mechanical measurements that both polymers differ mainly by their entanglement networks. The much longer entanglement spacing for PEHA leads to the formation of fibrillar structures which, in accordance with a theory of Good, seem to be the reason for strong adhesion.     

Yang–Baxterizations,Universal Quantum Gates and Hamiltonians

The unitary braiding operators describing topological entanglements can be viewed as universal quantum gates for quantum computation. With the help of the Brylinski’s theorem, the unitary solutions of the quantum Yang–Baxter equation can be also related to universal quantum gates. This paper derives the unitary solutions of the quantum Yang–Baxter equation via Yang–Baxterization from the solutions of the braid relation. We study Yang–Baxterizations of the non-standard and standard representations of the six-vertex model and the complete solutions of the non-vanishing eight-vertex model. We construct Hamiltonians responsible for the time-evolution of the unitary braiding operators which lead to the Schrödinger equations.     

Unambiguous State Discrimination in Quantum Key Distribution

The quantum circuit and design are presented for an optimized entangling probe attacking the BB84 Protocol of quantum key distribution (QKD) and yielding maximum information to the probe. Probe photon polarization states become optimally entangled with the signal states on their way between the legitimate transmitter and receiver. Although standard von-Neumann projective measurements of the probe yield maximum information on the pre-privacy amplified key, if instead the probe measurements are performed with a certain positive operator valued measure (POVM), then the measurement results are unambiguous, at least some of the time. It follows that the BB84 (Bennett–Brassard 1984) protocol of quantum key distribution has a vulnerability similar to the well-known vulnerability of the B92 (Bennett 1992) protocol Pacs: 03.67.Dd, 03.67.Hk, 03.65.Ta