Quantum information splitting of an arbitrary three-qubit state via the cavity input–output process

We propose a realizable quantum information splitting (QIS) scheme for an arbitrary three-qubit state via the cavity input–output process. In our scheme, a four-qubit cluster state and a three-qubit Greenberger–Horne–Zeilinge (GHZ) state are used as quantum channel. The sender and controller only need to perform Bell-state measurements and a single-qubit measurement, respectively. The receiver can reconstruct the arbitrary three-qubit state by classical communication and local operations. Compared with the scheme in Nie et al. [Optics Communications 284 (2011) 1457], the quantum resources and classical information in our scheme are decreased by 5 qubits and 1 bit, respectively. Moreover, we replace the W-state category measurement in the former with Bell-state measurements and a single-qubit measurement, which is more simple and feasible in experiment.     

Cooperative origin of low-density domains in liquid water

We study clusters formed by water molecules possessing large enough tetrahedrality with respect to their nearest neighbors. Using Monte Carlo simulation of SPC/E water and Voronoi tessellation, we find that regions of lower density than the bulk are formed by accretion of molecules into clusters exceeding a minimum size. Clusters are predominantly linear objects and become less compact as they grow until they reach a size beyond which further accretion is not accompanied by a density decrease. The results suggest that the formation of "icelike" regions in liquid water is cooperative.     

如何通过测量复摆的周期计算转动惯量

本文给出一种简约可行的方法,用来计算不规则物体绕任意轴转动时的转动惯量,同时,亦可定出质心轴位置.本文讨论的内容对教学有意义.     

电感耦合等离子体发射光谱法检测獭兔肉中的微量元素

研究了用电感耦合等离子体光谱法检测獭兔肉中多种微量元素的实验方法。实验表明,獭兔肉中多种微量元素在选定的最佳条件下能够可靠、准确测得,且精密度在0.59%—8.85%之间,回收率为96.5%—103.5%。该方法具有灵敏度高、干扰少、线性范围宽和多元素同时测定等优点,是科学工作者研究微量元素可行的方法之一;同时该方法准确、快速、简便,适用于同类样品的测定,结果令人满意。     

397 GHz斜注管互作用系统的设计模拟

斜注管是返波振荡器的一种,通过电子注的倾斜,电子距离慢波结构更近,高频场更强,耦合阻抗和互作用效率更高,显著增加输出功率。对带状注斜注管的互作用系统进行了设计,并首次将双排齿慢波结构应用于斜注管。利用电磁模拟软件和3D粒子模拟软件对设计的斜注管的色散曲线和场分布进行了分析,并对其注-波互作用进行了模拟,可以得到大于100 mW的输出功率以及50 GHz的调谐带宽。输出功率在370.5 GHz频点处处达到峰值2.3 W,电子注电压7.0 kV,注电流120 mA,聚焦磁场1.0 T。     

脉冲X射线剂量率测量不确定度分析

“强光一号”短脉冲高能X射线剂量率测量,主要包括脉冲射线总剂量与脉冲射线时间宽度的测量,前者采用热释光剂量计测量,后者采用PIN半导体探测器记录。根据不确定度传递数学模型,分析了影响X射线剂量和脉冲宽度测量结果的因素。针对“强光一号”短脉冲高能X射线测量,定量地给出了各种因素引入的测量不确定度,总剂量测量是影响剂量率测量准确性的决定性因素,其相对标准不确定度为25.1％,脉冲宽度测量不确定度为3.7％,剂量率测量扩展不确定度为50.8%,置信概率95%。     

An Overview of The Photoacoustic Phase Spectra of Rare Earth Complexes

Abstract

The photoacoustic(PA) amplitude and phase spectra of several kinds of rare earth (RE) complexes are reported and summarized briefly. It is observed that both the amplitude and phase spectra well characterize the different energy levels of the RE complexes. The phase angle of the RE complexes is associated with the relaxation time τ and the optical absorption coefficient β concerning with the π-π? transition and the f-f transitions, respectively. After individual detailed discussion of the phase spectra, a reasonable theoretical consideration is given to interpret the results.     

Plasmonic planar lens based on stack of metal–insulator–metal waveguides with height tuning

We introduce a technique capable of focusing electromagnetic (EM) waves through plasmonic nanoslits symmetrically arranged along the indented semi-circular surface in silver background. The EM transports through the tuning slits in the form of surface plasmon polaritons (SPPs), and gets the required phase retardations to focus at the focal plane. Due to the subwavelength nature of planar metallic lens, we present the rigorous electromagnetic analysis by using two dimensional (2D) finite difference time domain (FDTD) method. These height-modulated slits with uniform width are demonstrated to have unique advantages in beam manipulation. In combination with previous studies, it is expected that our structure with small number of slits could lead to realization of optimum designs of plasmonic nano-lens.     

Optical study of single crystals grown by the Czochralski method from Yb3+-doped (Gd1−x Y x )2SiO5 solid solution

Yb³⁺-doped crystals were grown by the Czochralski method from (Gd_0.5Y_0.5)₂SiO₅ melt employing seeds cut out from single crystals of Yb:Gd₂SiO₅ and Yb:Y₂SiO₅. XRD analysis revealed that the structure of the solid solution crystals grown is consistent with the structure of the seed, namely C2/c for the Yb:Y₂SiO₅ seed and P2₁/c for the Yb:Gd₂SiO₅ seed. Optical absorption spectra, emission spectra and luminescence decay curves were recorded at 10 K and 300 K. Analysis of gathered spectroscopic data made it possible to evaluate radiative transition rates for the ²F_5/2 multiplet of Yb³⁺ in the two structures and to assess crystal field splitting of multiplets involved in radiative transitions. It has been concluded that transition intensities and relaxation dynamics of Yb³⁺ in the systems studied are similar but the intensity distribution of emission and absorption bands depends significantly on the system structure. This feature, combined with inhomogeneous broadening of spectral lines, may be advantageous for the tailoring of lasers employing ytterbium-doped crystals for specific applications.     

Binary-black-hole encounters, gravitational bursts, and maximum final spin

The spin of the final black hole in the coalescence of nonspinning black holes is determined by the "residual" orbital angular momentum of the binary. This residual momentum consists of the orbital angular momentum that the binary is not able to shed in the process of merging. We study the angular momentum radiated, the spin of the final black hole, and the gravitational bursts in a sequence of equal mass encounters. The initial orbital configurations range from those producing an almost direct infall to others leading to numerous orbits before infall, with multiple bursts of radiation. Our sequence consists of orbits with fixed impact parameter. What varies is the initial linear momentum of the black holes. For this sequence, the final black hole of mass M_{h} gets a maximum spin parameter a/M_{h} approximately 0.823, with this maximum occurring for initial orbital angular momentum L/M_{h};{2} approximately 1.176.