紧致空间中辐射场的统计性质

通过对有限紧致空间中辐射场的研究来讨论腔中的原子-辐射场耦合系统. 利用T(1)×SO(4)群的表示, 给出了辐射场的单粒子波函数以及相应的色散关系. 由此详细讨论了紧致空间中辐射场的玻色-爱因斯坦统计. 发现其性质与空间的几何性质(曲率半径)有显著的依赖关系, 并表现与通常黑体辐射系统的显著差异.     

Quadrupole-octopole alignment of CMB related to the primordial power spectrum with dipolar modulation in anisotropic spacetime

The WMAP and Planck observations show that the quadrupole and octopole orientations of the CMB might align with each other. We reveal that the quadrupole-octopole alignment is a natural implication of the primordial power spectrum in an anisotropic spacetime. The primordial power spectrum is presented with a dipolar modulation. We obtain the privileged plane by employing the “power tensor” technique. At this plane, there is maximum correlation between quadrupole and octopole. The probability for the alignment is much larger than that in the isotropic universe. We find that this model would lead to deviations from the statistical isotropy only for low-l multipoles.     

基于简单MOPA结构实现3.08 kW全光纤窄线宽线偏振激光输出

基于简单的主振荡功率放大结构,演示了一种高功率窄线宽线性偏振全光纤激光器,其最大输出功率为3.08 kW,3 dB线宽为0.2 nm。在整个功率缩放过程中,偏振消光比约为94%,光束质量M 2约为1.4。这是国内外首次实现3 kW全保偏光纤激光输出,与基于相位调制的窄线宽激光器相比,该激光器可实现近似的线宽,同时具有受激布里渊散射阈值高、系统结构简单、成本低等特点。     

Ultra-high energy cosmic rays threshold in Randers-Finsler space

Kinematics in Finsler space is used to study the propagation of ultra high energy cosmic rays particles through the cosmic microwave background radiation. We find that the GZK threshold is lifted dramatically in Randers-Finsler space. A tiny deformation of spacetime from Minkowskian to Finslerian allows more ultra-high energy cosmic rays particles to arrive at the earth. It is suggested that the lower bound of particle mass is related with the negative second invariant speed in Randers-Finsler space.     

Finslerian Perturbation for the ACDM Model

We present Finslerian perturbation for the ∧CDM model, which breaks the isotropic symmetry of the universe. The analysis on the Killing vectors shows that the Randers-Finsler spacetime breaks the isotropic symmetry even ff the scalar perturbations of the FRW metric vanish. In Randers-Finsler spacetime, the modified geodesic equation deduces a modified Boltzmann equation. We propose a perturbational version of the gravitational field equation in Randers-Finsler spacetime, where we have omitted the curvature tensor that does not belong to the base space of the tangent bundle. The gravitational field equations for the gravitational wave are also presented. The primordial power spectrum of the gravitational wave is investigated. We show that the primordial power spectrum for super-horizon perturbations is unchanged. For sub-horizon perturbations, however, the power spectrum is modified.     

A Matter Dominated Navigation Universe in Accordance with the Type Ia Supernova Data

We investigate a matter dominated navigation cosmological model.The influence of a possible drift(wind) in the navigation cosmological model makes the spacetime geometry change from Riemannian to Finslerian.The evolution of the Finslerian Universe is governed by the same gravitational field equation with the familiar Friedmann-Robertson-Walker one.However,the change of space geometry from Riemannian to Finslerian supplies us a new relation between the luminosity distant and redshift.It is shown that the Hubble diagram based on this new relation could account for the observations on distant Type Ia supernovae.     

Constraints from Type Ia supernovae on the Λ-CDM model in Randers-Finsler space

Gravitational field equations in Randers-Finsler space of approximate Berwald type are investigated. A modified Friedmann equation and a new luminosity distance-redshift relation is proposed. A best-fit to the Type Ia supernovae (SNe) observations yields that the Ω_Λ in the Λ-CDM model is suppressed to almost zero. This fact indicates that the astronomical observations on the Type Ia SNe can be described well without invoking any form of dark energy. The best-fit age of the universe is given. It is in agreement with the age of our galaxy.     

经典q变形谐振子及其h量子化

通常所谓的量子包络代数可以在经典Poisson括号的意义下实现,以谐振子系统为例,给出U_q(SU(2))的这种经典实现,指出这种q变形伴随着相空间复坐标的Beltrami变形。并讨论了这种经典q变形谐振子系统的量子化,得到在Lie括号意义下的U_q(SU(2))代数。     

镍促进电化学还原交叉偶联合成偕二氟烯烃（英文）

偕二氟烯烃是一类重要的含氟有机化合物,在有机合成化学和药物化学研究领域展现出独特的结构优势.例如,偕二氟烯基可以便利地转化为单氟烯基、二氟烷基、三氟甲基以及其他多种含氟结构.偕二氟烯基结构作为羰基理想的电子等排体在药物设计研究中也有广泛的应用.报道了一种镍促进的电化学还原交叉偶联反应合成功能化的偕二氟烯烃.该反应在非分隔电解槽中进行,在温和的电化学还原条件下,实现了三氟甲基烯烃烯丙基脱氟、氧化还原活性羧酸酯脱羧或者烷基卤化物脱卤素的有机结合.反应可有效避免使用化学计量的金属粉末或有机还原剂.该反应为含偕二氟烯基功能结构的生物活性分子提供了有效的合成途径.