湍流大气中随机粗糙表面激光回波空间相干性仿真

根据广义Huygens-Fresnel原理,推导了von Karman湍流谱条件下激光回波复相干度的理论解析式;基于湍流相位屏分步传输算法和随机粗糙目标表面模型,实现了激光回波光场的仿真计算.首先通过镜面反射回波光场的仿真分析,验证了算法的正确性;然后基于1.1 km的均匀传输路径,综合分析了随机粗糙目标表面特性和路径湍流强度对回波光场复相干度的影响.结果表明:回波光场的空间相干性随目标表面高度均方根的增大而降低,随目标表面相关长度的减小而降低;当表面相关长度远小于大气相干长度时,回波相干性会被严重破坏.该研究可为目标表面特性或利用已知表面获取路径湍流状态的相干探测提供有益的参考.     

Stabilizing Geometric Phase by Detuning in a Non-Markovian Dissipative Environment

The geometric phase of a two-level atom non-resonantly coupled to a non-Markovian dissipative environment is investigated. Compared to an earlier work [Chen J. J. et al. Phys. Rev. A 81 （2010）022120] in which the non-Markovian effect has a serious correction on geometric phase, we find that the geometric phase can be stabilized by detuning in non-Markovian dissipative decoherence. Moreover, the geometric phase approaches the unitary geometric phase with the increase of detuning for any initial polar angle, which shows that the geometric phase is not only resilient to the Markovian noise but is also resilient to the non-Markovian noise when a large detuning between the qubit and environment is considered. Our results may be helpful for geometric quantum computation.     

非线性多尺度建模及其应用

针对非线性时间序列数据建模问题,首先对数据进行经验模态分解(Empirical Mode Decomposition,EMD),得到一系列反映序列演化过程的本征模态函数(Intrinsic mode function,IMF),然后对IMF进行Hilbert变换,利用各分量的Hilbert变换的振幅和频率建立非线性多尺度数学模型.以黄河某水质检测站溶解氧含量为例,应用EMD分解和Hilbert变换的结果,建立两个多尺度的数学模型.经过检验,模型的拟合精度、显著性和残差均符合要求.模型模拟结果中提取溶解氧多尺度信息,并且应用该模型进行预报,预报的相对误差小在0.08%~12.8%之间.     

Distributed quantum computation with superconducting qubit via LC circuit using dressed states

A scheme is proposed where two superconducting qubits driven by a classical field interacting separately with two distant LC circuits connected by another LC circuit through mutual inductance,are used for implementing quantum gates.By using dressed states,quantum state transfer and quantum entangling gate can be implemented.With the help of the time-dependent electromagnetic field,any two dressed qubits can be selectively coupled to the data bus (the last LC circuit),then quantum state can be transferred from one dressed qubit to another and multi-mode entangled state can also be formed.As a result,the promising perspectives for quantum information processing of mesoscopic superconducting qubits are obtained and the distributed and scalable quantum computation can be implemented in this scheme.     

Generation of Wn state with three atoms trapped in two remote cavities coupled by an optical fibre

We propose two schemes for the generation of the Wn state with three atoms separately trapped in two distant cavities coupled by an optical fibre.One is implemented by controlling the interaction time,the other is implemented via the adiabatic passage.The influence of various decoherence processes,such as spontaneous emission of the atoms and photon leakages of the cavities and the optical fibre,on the fidelity is also investigated.It is found that the Wn state can be generated with high fidelity even when these decoherence processes are present.     

一类捕食——食饵模型正平衡解的整体分歧

讨论了一类改进的Leslie-Gower和Holling-Type Ⅱ型捕食-食饵模型对应的平衡态系统正解的结构.以捕食者的出生率b为分歧参数,利用局部分歧理论和整体分歧理论,得到了此平衡态系统正解的存在性与参数b的关系,即当b适当大时,该平衡态系统具有共存正解.     

Improving the teleportation of quantum Fisher information under non-Markovian environment

Quantum teleportation is designed to send an unknown quantum state between two parties. In the perspective of remote quantum metrology, one may be interested in teleporting the information that is encoded by physical parameters synthesized by quantum Fisher information (QFI). However, the teleported QFI is often destroyed by the unavoidable interaction between the system and the environment. Here, we propose two schemes to improve the teleportation of QFI in the non-Markovian environment. One is to control the quantum system through the operations of weak measurement (WM) and corresponding quantum measurement reversal (QMR). The other is to modify the quantum system based on the monitoring result of the environment (i.e., environment-assisted measurement, EAM). It is found that, in the non-Markovian environment, these two schemes can improve the teleportation of QFI. By selecting the appropriate strengths of WM and QMR, the environment noise can be completely eliminated and the initial QFI is perfectly teleported. A comprehensive comparison shows that the second scheme not only has a higher probability of success than the first one, but also has a significant improvement of the teleported QFI.     

GC–MS校准用异辛烷中八氟萘标准溶液的研制

采用重量–容量法研制了气相色谱–质谱(GC–MS)校准用100.1 pg/μL异辛烷中八氟萘溶液标准物质,分别用F检验和回归曲线法对研制的溶液标准物质进行了均匀性和稳定性检验,对定值结果的不确定度进行了评定。结果表明,研制的异辛烷中八氟萘溶液标准物质具有良好的均匀性和稳定性,定值结果的相对扩展不确定度为3%(k=2)。该标准物质可用于GC–MS联用仪的EI源及负CI源的信噪比校准。     

Mazatrol Fusion640T数控系统特点

本文主要通过作者对Mazatrol Fusion640T数控系统的使用，介绍了系统与其它控制系统不同的功能特点，包括强大的数据处理功能、PC与CNC融合技术、智能化对话式编程功能。同时，还举例说明了对话式编程与G功能代码和M功能代码编程的区别，以及对话式编程与其它编程方式相比，具有方便、快捷的优势。     

MAXIMAL ATTRACTORS OF CLASSICAL SOLUTIONS FOR REACTION DIFFUSION EQUATIONS WITH DISPERSION

The paper first deals with the existence of the maximal attractor of classical solution for reaction diffusion equation with dispersion, and gives the sup-norm estimate for the attractor. This estimate is optimal for the attractor under Neumann boundary condition. Next, the same problem is discussed for reaction diffusion system with uniformly contracting rectangle, and it reveals that the maximal attractor of classical solution for such system in the whole space is only necessary to be established in some invariant region.Finally, a few examples of application are given.