各向异性磁电介质量子真空水平上的动量转移

通过计算各向异性磁电材料内电磁场模式的本征方程研究了任意方向量子真空模式对磁电材料动量转移总贡献，并指出介质由真空动量转移所获得速度可以由目前发展起来的光纤光学传感器(能测量纳米量级速度)所探测.对该量子真空宏观力学效应的物理机理与潜在应用也做了讨论.     

中尺度地形对热带气旋边界层的影响

基于梯度风动量近似理论,考虑气压梯度力、科氏力、湍流摩擦力、离心力和惯性偏差力5力平衡,得到了柱坐标系下具有热带气旋边界层特征的解析解.并着重讨论了三维钟型孤立地形及二维钟型地形对径向速度、垂直水平流场及垂直速度场的影响.对于数值解的再现表明,热带气旋内边界层的运动同时受到湍流摩擦作用与地形作用的共同影响,二维钟型地形比三维钟型孤立地形对于垂直速度场、径向速度场及流场有更明显的影响.而热带气旋中心与地形中心的不重合会产生风场的不对称结构,且会在地形西北侧形成"偶极型"的垂直速度.     

Carbonyl sulphide under strong laser field: Time-dependent density functional theory

The first 52 fs of a time evolution of the electron density in OCS after an interaction with an intense sub 10 fs laser pulse are studied using the time-dependent density functional theory. The nuclear motion in this linear trimer is simulated by the classical molecular dynamics method. Laser fields of intensity 10¹³ W/cm² and 10¹⁵ W/cm² are used. Details of the laser induced changes of the structure, as well as the ionization rate are sensitive to the applied field intensity and its polarization. It is found that under suitable conditions the OCS molecule bends soon after an interaction with a laser pulse. A deviation from the linear geometry of up to 23.6° and charged ions of up to +3 are observed. The time evolution of electric dipole moments and the time-dependent electron localization function (ELF) are also studied.     

Recent Advances in Rare Earth Doped Inorganic Crystalline Materials for Quantum Information Processing

Since quantum information technologies are expected to offer communication security and high computational capacities, research in the field is currently attracting a lot of attention. Among the materials studied so far, rare earth doped inorganic insulators are one of the most promising. With the different available trivalent rare earth ions, the visible and the IR range including the telecom wavelength at 1.5 μm can be covered. Transitions are usually narrow, and at low temperatures, long optical and spin coherence times can often be observed. Investigations using bulk single crystals have already led to many promising results. Recently, spectroscopic studies have been extended to other forms of inorganic materials, such as transparent ceramics, thin films, and nanoparticles for single rare‐earth qubits. Progress in these areas is expected to offer many new possibilities for the design of quantum light‐matter interfaces and scalable quantum memories and processors.     

电磁场角动量守恒定律的简明推导

对电磁场角动量守恒定律作了一种简明的推导。     

Low–energy photodisintegration of 9Be and α+α+n→9Be +γ reactions at astrophysical conditions

A semi–microscopic model for the low–energy photodisintegration of the ⁹Be nucleus is constructed, and the experimental data are analyzed with its help. The older radioactive isotope data are supported by this analysis. The theoretical photodisintegration cross section is derived. The astrophysical rates for the reaction α+α+n→⁹Be+γ and the reverse photodisintegration of ⁹Be are calculated. The new reaction rate for α+α+n→⁹Be+γ is compared with previous estimations. Received: 19 January 1998     

爆炸载荷作用下离散平板运动速度的工程计算

选择轴对称结构作为研究对象,在合理的假设条件下,导出了离散平板运动速度的解析表达式。该式不仅可用于进行离散平板运动速度的工程计算,也可用于进行类似结构破片速度的工程估算。同时结合牛顿切应力公式,导出了整体平板的临界断裂厚度估算式。     

一维无限深势阱定态波函数动量展开讨论

一维无限深势阱定态的动量概率分布存在两种"互相矛盾"的结论.为帮助学生理解两种结论的异同,锻炼严谨的科学作风和解决复杂问题的能力,笔者在量子力学理论教学中指导学生利用Python等现代科学计算工具,将一维无限深势阱定态波函数动量展开的讨论进行数值求解与可视化,绘制了不同观点以及不同情形下粒子的动量概率分布图.以此为基础讨论了不同计算结果的物理含义,揭示了两种结论的内在联系.此创新性的举措不仅有效加深了学生对于该重要问题的理解,还促进了学生专业知识、科学能力和综合素质的全面培养.     

Transmissive 2-bit anisotropic coding metasurface

Coding metasurfaces have attracted tremendous interests due to unique capabilities of manipulating electromagnetic wave. However, archiving transmissive coding metasurface is still challenging. Here we propose a transmissive anisotropic coding metasurface that enables the independent control of two orthogonal polarizations. The polarization beam splitter and the orbital angular momentum (OAM) generator have been studied as typical applications of the anisotropic 2-bit coding metasurface. The simulated far field patterns illustrate that the x and y polarized electromagnetic waves are deflected into two different directions, respectively. The anisotropic coding metasurface has been experimentally verified to realize an OAM beam with l = 2 of right-handed polarized wave, resulting from both contributions from linear-to-circular polarization conversion and the phase profile modulation. This work is beneficial to enrich the polarization manipulation field and develop transmissive coding metasurfaces.     

Controlling acoustic orbital angular momentum with artificial structures: From physics to application

Acoustic orbital angular momentum (OAM) associated with helicoidal wavefront recently attracts rapidly-growing attentions, offering a new degree of freedom for acoustic manipulation. Due to the unique dynamical behavior and inherent mode orthogonality of acoustic OAM, its harnessing is of fundamental interests for wave physics, with great potential in a plethora of applications. The recent advance in materials physics further boosts efforts into controlling OAM-carrying acoustic vortices, especially acoustic metasurfaces with planar profile and subwavelength thickness. Thanks to their unconventional acoustic properties beyond attainable in the nature, acoustic artificial structures provide a powerful platform for new research paradigm for efficient generation and diverse manipulation of OAM in ways not possible before, enabling novel applications in diverse scenarios ranging from underwater communication to object manipulation. In this article, we present a comprehensive view of this emerging field by delineating the fundamental physics of OAM-metasurface interaction and recent advances in the generation, manipulation, and application of acoustic OAM based on artificial structures, followed by an outlook for promising future directions and potential practical applications.