Four-Electron Quantum Ring in a Magnetic Field

We study a quantum ring （QR） with four electrons in a perpendicular external magnetic field B by exact diagonalization. The low-lying spectra of the QR as a function orb are obtained. A phase diagram is presented indicating that the angular momentum and the spin of the ground state of the QR may jump when B and/or the radius of the QR vary, and a corresponding analysis is performed. By plotting the density functions of the QR, the ground-state configuration is found to be a regular quadrangle. Furthermore, the features of the ground-state persistent current are revealed.     

子孔径光学检测拼接准确度实验研究

实验研究了子孔径光学检测的拼接准确度.实验选取9个子孔径进行拼接,同时利用ZYGO干涉仪来测量子孔径和整个被检面的表面面形.实验发现,测量基准子孔径和整个被检面的时间间隔对子孔径拼接准确度的评价存在严重影响.为此,重点研究了产生影响的原因并提出了消除测量基准子孔径和整个被测面时间间隙影响的方法.最后,利用该方法研究了子孔径重叠面积对拼接准确度的影响.结果显示,当重叠面积比为7%时,PV和RMS的拼接误差分别为0.03λ(λ=632.8 nm) 和 0.01λ,并且重叠面积比和拼接准确度呈近似线性关系.     

Soliton squeezing generated in an all-fiber configuration

We experimentally demonstrate amplitude squeezed soliton utilizing intensity-dependent self-phase modulation in an asymmetric Sagnac interferometer. The system, whose components are connected via ferrule connector/physical connection （FC/PC） fiber connectors, constitutes all-fiber configuration to generate squeezed soliton. Soliton amplitude reduction measured by homodyne detection is near 4.0 dB below the shot-noise level. Optimal squeezing fields in both simple and compact all-fiber configuration are obtained.     

对高频声子的探测

晶体中的原子在其平衡点附近的摇晃会产生振动波,即声子．声子能在固体中传播声、热能和其他形式的能量,测量声子的性质可以提供有关晶体的结构以及原子间相互作用的各种信息．声子的性质一般是利用与光子的声一光相互作用来测定的．但当声波的波长小到只有原子间距的大小时,就很难利用声一光作用来探测声子了．因此,尽管有许多科学家都认为,在固体中已激发出了高频声子,但却无法用直接或间接的方法来精确地测定它们．     

Band gap control of phononic beam with negative capacitance piezoelectric shunt

Periodic arrays of negative capacitance shunted piezoelectric patches are employed to control the band gaps of phononic beams. The location and the extent of induced band gap depend on the mismatch in impedance generated by each patch. The total impedance mismatch is determined by the added mass and stiffness of each patch as well as the shunting electrical impedance. Therefore, the band gap of the shunted phononic beam can be actively tuned by appropriately selecting the value of negative capacitance. The control of the band gap of phononic beam with negative capacitive shunt is demonstrated numerically by employing transfer matrix method. The result reveals that using negative capacitive shunt to tune the band gap is effective.     

Effects of the δ meson on the direct Urca processes in neutron stars

In the framework of the relativistic mean field theory, the effects of the δ meson on the direct Urca (DURCA) processes are investigated. In a neutron star, the DURCA processes involving nucleons, Λ and Ξ^- can take place while the process involving the Ξ⁰ can not. With the inclusion of the δ meson, the threshold densities for the DURCA processes become lower. With the δ included, the threshold neutron star mass for the DURCA process among nucleons and electrons becomes smaller while the threshold masses for the processes involving hyperons become larger. When the δ meson is included, the total neutrino emissivity remarkably increases in the density range of 0.32--0.41 fm^-3. The total neutrino luminosity increases with the neutron star mass first and then decreases. The neutrino luminosity gets larger with the inclusion of the δ meson. The cooling of the EXO0748-676 is sensitive to the isovector scalar interaction.     

水基切伦科夫μ子探测器的研究

利用高速带电粒子在透明介质中产生切伦科夫辐射的特性,以蒸馏水作为辐射介质,搭建了一个小尺寸(π×22.52cm2×45 cm)的切伦科夫探测器,对能量在GeV量级的μ子进行了相应的测量,考虑其他能量损耗、光传输和收集效率、阴极量子效率后,实验结果与理论估计值有比较高的相符度,可以初步断定仪器具备探测GeV量级μ子的能力.     

一类子转移的拓扑强混合性

对一类子转移的拓扑强混合性进行研究,给出了一个子转移是拓扑强混合的一个必要条件和两个充分条件。     

一族Liouville可积的有限维Hamilton系统

本文生成了一族Liouville可积的Hamilton相流彼此可交换的有限维Hamilton系统,并且给出了一串对合的显式公共运动积分及其一组对合的显式生成元.