双光腔光机械系统的动力学相变和选择性能量交换

本文探究了单腔和双腔光机械装置的动力学相变和选择性能量交换.发现系统会经历类似于Dicke-HeppLieb超辐射型的动力学相变,且两光场间的正交动量耦合出现一个新的动力学临界点.两光场间的正交动量耦合等价于单(双)模光机械系统的外场驱动.通过耦合参数的调控,系统可以实现任意两模间的选择性能量交换,且临界耦合点与选择性能量交换对应.模压缩是能量转换的标志,且任何两模的正交压缩由特定玻色模间的能量交换决定.     

Kerr介质中双模SU(1,1)相干态场与V型三能级原子的相互作用

导出了充满Kerr介质的高Q腔中V型三能级原子与双模SU（1，1）相干态场相互作用系统的态矢量，并以此计算三能级原子布居概率和辐射场统计性质随时间的演化．数值计算显示，Ker效应产生与两能级原子不同的Rabi振荡特性，而双模场的关联特性受Kerr介质的影响较小．还讨论了Ker效应对Cauchy-Schwartz不等式的影响． 关键词：     

超导电子的角动量和磁通量子化

本文指出,磁通量子化应和超导电子的角动量量子化一致。分数角动量的存在必然导致分数磁通量子化,而分数磁通量子化和超导理论以及迄今为止的实验结果不相矛盾。我们提出和分析的一个新实验可以检测任意子和分数磁通量子。 关键词：     

Adiabatic and Non-Adiabatic Berry Phases in Generalized J-C Model of Multi-Photon Process

We derive the adiabatic and non-adiabatic Berry phases in the generalized Jaynes-Cummings model of multi-photon process. The results show that the adiabatic Berry phase is kept a constant π independent of all the parameters, while the non-adiabatic approximate Berry phase is parameter-dependent, proportional to the average photon number m, and tends to be constant with the increasing detuning. In the case of exact n-photon resonance and an integer ratio of m/n, the two results coincide with each other, otherwise there appears an additional non-trivial phase factor.     

有限维希尔伯特空间含时谐振子的时间演化及Berry相位

研究了有限维希尔伯特空间含时谐振子的时间演化．通过适当的含时规范变换得到有限维含时谐振子量子态时间演化的封闭解,并给出量子态的Ｂｅｒｒｙ相位．最后讨论了驱动项对相干态压缩特性的影响 关键词：     

借助集团展开的超辐射热力学

N原子-单模辐射场相互作用系统当作相互作用准玻色子-光子系统并处理作巨正则系综.系统热力学势的明显表达式应用集团展开得到，某些热力学量按通常的热力学公式导出.数值计算和图示表明了这个超辐射系统的热力学行为，在超辐射态临界线上和其他地方出现的奇异性揭示了在此合作系统中存在第二类相变换. 关键词：     

Spin-dependent tunnelling through an indirect double-barrier structure

We use the transfer matrix method to study the quantum tunnelling through an indirect-band-gap double-barrier like the GaAs/AlAs/GaAs/AlAs/GaAs heterostructures along the [001] axis, which is described by the tight-binding model. The X-valley quasi-bound state gives rise to the Fano resonance different from the direct double-barrier transition in a resonance-tunnelling diode. The quantitative calculations demonstrate that a relatively high spin-polarization of the transmission probability can be achieved as compared with the single-barrier tunnelling ease. Moreover the extension to the multi-barrier device is provided and leads to an important observation that the spin polarization increases with the number of barriers.     

含有磁性杂质双AB环的自旋极化输运

我们研究了由电子通过含有磁性杂质双AB环结构的透射系数来表示的AB干涉振荡。在这里磁性杂质提供了自旋翻转机制。磁性杂质可以导致AB干涉的部分退相干。而且我们发现在磁通反向的情况下自旋向上和向下的透射系数关于磁通是不对称的，但反射系数和总的透射系数关于磁通却是对称的     

A drop-on-demand ink-jet printer for combinatorial libraries and functionally graded ceramics

A printer has been designed and built for the preparation of combinatorial libraries of ceramics and for solid freeforming of functionally graded ceramics with three-dimensionally programmable spatial variation in composition. Several ceramic suspensions (as inks) can be subjected to micromixing behind the nozzle and printed at precise positions. Both mixing and positioning are computer-controlled. The machine consists of an XY table to control the geometry, a set of electromagnetic valves that manage the mixing, a combined electromagnetic valve and sapphire nozzle that form the print head, and a computer that controls the whole system. The mixing valves can eject as little as 1 mg/s ink into the mixing chamber. The printer has been controlled, run, calibrated and tested; the composition and geometry of printed mixtures can be controlled precisely. This method for the controlled mixing of powders facilitates the advance of combinatorial methods within the materials sciences.     

Bifurcation of a periodic instanton and quantum－classical transition in the biaxial nano－ferromagnet with a magnetic field along hard axis

Crossover from classical to quantum regimes of the barrier transition rate in a biaxial ferromagnetic magnet with a magnetic field applied along hard anisotropy axis is investigated. We show that the type of action-temperature diagrams can he determined by counting the number of bifurcation points. The model possesses not only the known type I and Ⅱ, hut also the interesting type Ⅲ and Ⅳ of transition which do not occur in general.