Electrostatic surface guiding of cold polar molecules with double charged wires

We propose a novel scheme to guide cold polar molecules on the surface of an insulating substrate (i.e., a chip) using a static electric field generated by the combination of a pair of parallel charged wires and a grounded metal plate. We calculate the spatial distributions of the electric fields from the above charged-wire layout and their Stark potentials for cold CO molecules, and analyze the relationships between the electric field and the parameters of the charged-wire layout. The result shows that this charged-wire scheme can be used to guide cold polar molecules in the weak-field-seeking state and to form various molecule-optical elements, even to realize a single-mode molecular waveguide on a molecule chip under certain conditions.     

Quantum Teleportation of a Three—Particle Entangled State

We present a scheme for teleporting a three-particle entangled state to three remote particles.In this scheme,three pairs of pure nonmaximally entangled states are considered as quantum channels.It is found that by means of optimal discrimination between two nonorthogonal quantum states,probabilistic teleportation of the three-particle entangled state can be achieved.     

2+1维SU(2)规范理论的胶球质量

本文对具有严格基态解的格点规范哈密顿量采用变分法,计算了2+1维SU(2)规范群的胶球质量.得到在0≤1/g²≤7范围内,标度行为是am=2.28g²,与弱耦合展开结果一致.     

2+1维SU(3)群格点规范的胶球质量

本文对具有严格基态解的Hamiltonian,采用采用变分法,计算了2+1维SU(3)规范群的C=+1.C=－1胶球质量.得到在0<1/g²≤6范围内,标度行为是am₊=36.1g²、am_－=5.98g².     

Entanglement of a two-qubit anisotropic Heisenberg XYZ chain in nonuniform magnetic fields with intrinsic decoherence

Taking the intrinsic decoherence effect into account, this paper investigates the entanglement of a two-qubit anisotropic Heisenberg XYZ model in the presence of nonuniform external magnetic fields by employing the concurrence as entanglement measure. It is found that both the intrinsic decoherence and the anisotropy of the system give a significant suppression to the entanglement. Moreover it finds that the initial state of the system plays an important role in the time evolution of the entanglement, which means that the entanglement of the system is independent of the nonuniformity and uniformity of the magnetic field when the system is in the initial state ｜ψ （0）） = ｜00） and [ψ′ （0）） = m ｜01） ＋ n ｜10）, respectively.     

Kerr介质中三能级原子与压缩光场相互作用的光子统计分布特性

本文研究了充满Ker介质的高Q腔中压缩相干态与级联三能级原子相互作用的光子统计分布特性,讨论了光场参数及Kerr介质对光子统计分布的影响.     

耦合平均影响值-连续投影算法优化种子活力近红外检测模型

目前,近红外光谱(NIRS)可以实现种子活力的快速、无损检测,但区分的活力等级一般少于3级且精度不高。建立种子活力多等级、高精度的NIRS检测模型,解决活力等级增加与预测模型精度之间的矛盾是现阶段近红外种子活力检测的主要任务。以玉米种子为研究对象,采用人工老化的方法获得5种活力等级的种子样本并采集对应的光谱数据建立反向神经网络(BP)预测模型。为了提高模型的精度和稳健性,提出一种耦合平均影响值-连续投影特征波长提取算法(MIVopt-SPAsa)。该算法针对连续投影算法(SPA)耗时过长的问题,采用平均影响值算法(MIV)对其预降维。MIV方法实现了对波长影响值的排序,但缺乏选取波长影响阈值的指标,因此引入相对距离比对MIV算法进行优化(MIV_opt),实现特征波长范围的有效分割。针对SPA提取特征变量数目确定的问题,设定了特征波长数目范围并在此范围内优中选优,实现了自适应的SPA(SPA_sa)特征提取。使用耦合MIV_opt-SPA_sa算法对具有1 845个波长的玉米种子近红外全谱数据进行特征提取,提取出特征波长37个,主要分布在玉米种子近红外光谱的7个主要吸收峰附近,表明该算法可以有效提取出与玉米种子生化物质近红外吸收特性一致的特征波长。为了测试该算法对模型性能的影响,建立了全谱BP模型、MIV-BP模型、SPA_sa-BP模型、MIV_opt-SPA_sa-BP模型和竞争自适应重加权CARS-BP模型对5个等级的玉米种子活力进行分级,MIV_opt-SPA_sa-BP模型的预测平均准确率可达99.1%,预测精度高于其他模型;其计算平均时间为14.382 s,低于MIV-BP模型的计算时间(24.523 s)、CARS-BP模型的计算时间(97.226 s)和SPA_sa-BP模型的计算时间(101.224 s),但高于全谱模型的平均计算时间(0.253 1 s);其最佳表现交叉熵为0.007 892,远远低于另外4个模型。实验结果表明：MIV_opt-SPA_sa算法可以有效地提高玉米种子活力近红外检测模型的精度,实现种子活力多等级、精确、无损检测,为种子活力检测模型的优化提供参考。     

Cavity-assisted quantum computing in a silicon nanostructure

We present a scheme of quantum computing with charge qubits corresponding to one excess electron shared between dangling-bond pairs of surface silicon atoms that couple to a microwave stripline resonator on a chip. By choosing a certain evolution time, we propose the realization of a set of universal single-and two-qubit logical gates. Due to its intrinsic stability and scalability, the silicon dangling-bond charge qubit can be regarded as one of the most promising candidates for quantum computation. Compared to the previous schemes on quantum computing with silicon bulk systems, our scheme shows such advantages as a long coherent time and direct control and readout.     

玉米秸秆纤维素和半纤维素NIRS特征波长优选

预处理是提高玉米秸秆生物转化利用效率的有效途径。玉米秸秆经生物炼制转化为生物燃料时,转化率与其原料内的纤维素和半纤维素含量直接相关。为了实现对预处理后玉米秸秆的生物炼制过程的有效调控,提出使用近红外光谱(NIRS)对玉米秸秆的纤维素和半纤维素含量进行快速检测,解决传统化学方法测试速度慢、成本高的问题。为了提高NIRS检测的效率和精度,将遗传算法与模拟退火算法相结合构建遗传模拟退火算法(GSA)用于预处理后玉米秸秆纤维素和半纤维素含量NIRS特征波长优选。GSA算法以NIRS波长点数为码长进行二进制编码,以偏最小二乘法(PLS)回归模型的交叉验证均方根误差为目标函数,结合温度参数设计适应度函数,基于Metropolis判别准则实现扰动解的选择复制,能够在避免早熟的同时有效提高进化后期的搜索效率。采用碱预处理、生物预处理及其相结合的方法对采集的玉米秸秆进行预处理后制备样品120个,并测定其纤维素和半纤维素含量及NIRS。使用7点Savitzky-Golay平滑结合多元散射校正和标准正则变换对光谱进行预处理后,利用Kennard-Stone法按3∶1比例划分校正集和验证集。然后,使用GSA算法对NIRS全谱进行特征波长优选(记为Full-GSA)、对协同区间偏最小二乘法(SiPLS)优选后谱区进行特征波长优选(记为SiPLS-GSA)、对反向区间偏最小二乘法(BiPLS)优选后谱区进行特征波长优选(记为BiPLS-GSA),并使用PLS回归模型和验证集对特征波长优选结果进行评测。Full-GSA以全谱1 557个波长点为基因,执行16次算法,优选出118个纤维素特征波长点和164个半纤维素特征波长点。SiPLS-GSA经SiPLS优选的纤维素和半纤维素谱区波长点数分别为388个和160个,再经GSA进一步优选后得到157个纤维素特征波长点和148个半纤维素特征波长点。BiPLS-GSA经BiPLS优选的纤维素和半纤维素谱区波长点数分别为358个和180个,再经GSA进一步优选后得到130个纤维素特征波长点和153个半纤维素特征波长点。结果表明,通过波长优选,不仅参与建模的波长点数量显著减少,而且回归模型的性能显著优于全谱建模。其中,采用Full-GSA优选的纤维素特征光谱回归性能最佳,采用SiPLS-GSA优选的半纤维素特征光谱回归性能最佳。回归模型验证集的平均相对误差(MRE)分别为1.752 4%和2.020 8%,较全谱建模分别降低了13.636 6%和25.368 4%。基于结合温度参数设计适应度函数的策略构建的GSA具有良好的全局搜索性能,适用于玉米秸秆纤维素和半纤维素含量NIRS特征波长优选。GSA以全谱每个波长点为染色体基因的编码方案适用于NIRS全谱的特征波长优选。GSA同样适用于SiPLS和BiPLS优选后谱区的特征波长优选,能够有效实现优选后谱区的波长点优选。     

Deterministic joint remote preparation of an arbitrary two-qubit state in the presence of noise

Using two tripartite Greenberger-Horne-Zeilinger （GHZ） states as the shared channels, we investigate the noise effects on the deterministic joint remote preparation of an arbitrary two-qubit state. By unitary matrix decomposition procedure, we first construct the quantum logic circuit of the deterministic joint remote state preparation protocol. Then, we analytically derive the fidelity and the average fidelity for the deterministic joint remote preparation of an arbitrary two- qubit state and of four types of special two-qubit states under the influence of the Pauli noises. It is found that the fidelity depends on the noise types, the qubit-environment coupling strength, and the state to be remotely prepared. Moreover, even if the two GHZ channels are subject to the same environmental noises, the average fidelities for remotely preparing different two-qubit states display different time evolution behaviors. The remote preparation of the identical two-qubit states also shows that the average fidelities affected by different noisy environments exhibit different evolution actions.