The symmetric and antisymmetric superexchange interactions in spin-Peierls system

The influences of Dzyaloshinskii Moriya （DM） interaction and Kaplan-Shekhtman-Entinwohlman-Aharony （KSEA） interaction on the dimerization of a spin-Peierls system are investigated theoretically by using the Lanczos numerical method. The ground state of the spin-Peierls system is still dimerized phase when both of the DM and the KSEA interactions have the same value with Heisenberg interaction. It is found that the KSEA interaction and uniform DM interaction are always against systemic dimerization, but the staggered DM interaction acts in favour of dimerization. Furthermore, the influences of the DM and the KSEA interactions are also studied in terms of the ground state index rate and the energy gap index rate of the dimerized Heisenberg system. The results show that the DM interaction makes the index rates larger, while the KSEA interaction makes them smaller.     

钆钪铝石榴石单晶缺陷的微观形貌与成因研究

采用提拉法生长了2%Dy³⁺和1%Tb³⁺(原子数分数)共掺的钆钪铝石榴石激光晶体(Gd₃Sc₂Al₃O₁₂, GSAG)。研究了晶体(111)晶面的腐蚀缺陷形貌并对缺陷形成机理进行了解释,讨论了晶体缺陷的特征形貌与晶体结构之间的关系。表征并计算了晶体(111)晶面的维氏硬度和莫氏硬度,在0.2 kgf载荷和10 s保荷时间条件下,晶体(111)面的维氏硬度为1 267 kg/mm²,对应的莫氏硬度为7.3。研究结果对揭示混晶石榴石晶体中缺陷的成因和探索高品质晶体生长与加工工艺具有一定的参考价值。     

Spontaneous emission from an atom in a photonic crystal with two coherent bands

The dynamic and the radiative properties of an excited three-level atom embedded in an anisotropic photonic crystal with two coherent bands are investigated.The relative position of the atom in a Wigner-Seitz cell is described with a position-dependent parameter θ(r0),which is used as the coherent parameter for the two bands.The result shows that the dynamic properties of the atomic system are not only determined by atomic transition frequencies,but also affected by the gap width and the coherence of the two bands.In addition,the spontaneous emission spectrum of the atomic transition in free space is discussed.The center and the intensity of the spectrum can be obviously manipulated via the coherent parameter.     

链间超交换相互作用下spin-Peierls梯子模型的基态行为

采用Lanczos数值计算方法研究了具有链间海森堡相互作用和链间Dzyaloshinskii-Moriya(DM)相互作用spin-Peierls梯子模型的基态行为.分析了链间海森堡相互作用和链间DM相互作用对系统二聚化的影响.结果发现，这两种链间作用都不利于系统的二聚化，会造成系统基态二聚化的减小，这说明随着系统维度的增大，系统的各向相互作用会限制系统的二聚化，甚至会破坏系统的二聚化相. 关键词： spin-Peierls模型 海森堡相互作用 DM相互作用 二聚化     

运用动态Lorentz库实现对激发态原子动力学特性的调控

从理论上讨论了运用动态的Lorentz库环境实现对处于激发态的两能级原子演化过程的调控.研究发现,Lorentz库环境的变化导致腔内电磁模式与腔外电磁模式之间相互作用,从而产生电磁模式密度重新分配;当库环境的变化频率和原子与环境之间交换能量的过程保持一致时可以实现相对稳定的相干性演化,衰减效应得到明显的抑制. 关键词： 动态库 激发态原子 量子调控     

运用动态腔环境实现对原子自发辐射过程的调控

本文从理论上讨论了运用动态的腔环境实现对处于激发态的两能级原子自发辐射过程的调控.研究发现,周期性地改变与原子相互作用的腔环境导致电磁模式之间相互作用,产生电磁模式密度重新分配,并使得原子与腔环境之间的能量交换的频率以及能量耗散的速度发生改变;当腔环境的变化频率和原子、环境之间交换能量的过程保持相对一致时可以实现稳定的相干性演化,衰减效应受到显著的抑制,进而可以通过环境变化操纵相干态的演化. 关键词： 自发辐射 动态环境 量子调控     

具有对称和反对称超交换相互作用的一维spin-Peierls系统的基态行为

采用Lanczos数值计算方法研究了具有Dzyaloshinskii-Moriya（DM）相互作用和Kaplan-She khtman-Entin-Wohlman-Aharony（KSEA）相互作用的一维spin-Peierls（s-P）系统的基态 行为.计算结果发现KSEA相互作用总是不利于系统二聚化，并且它还影响DM相互作用对系统 二聚化的贡献，甚至可以抵消其作用；在某些特定条件下, KSEA和DM的共同作用可以破坏系 统的二聚化基态而转化为均匀基态. 关键词： DM相互作用 KSEA相互作用 二聚化     

Influence of Dzyaloshinskii-Moriya and Kaplan-Shekhtman-Entinwohlman-Aharony superexchange interactions on ground state properties of the one-dimensional spin-Peilers model in open chain

The effects of the Dzyaloshinskii-Moriya (DM) and the Kaplan-Shekhtman-Entinwohlman-Aharony (KSEA) superexchange interactions on the ground state properties of the one-dimensional spin-Peilers system in open chain are studied by using the Lanczos numerical method.The study concentrates mainly on the influence of systemic dimerisation in open chain.The results show that systemic ground state energy density varies with dimerisation parameter δ in different DM interactions,and there exists a special point δ c where the DM interaction has no influence on the systemic dimerisation,no matter whether the DM interaction is relative or irrelative to systemic dimerisation (η=1 or η=0).The KSEA interaction has no fixed special point,but the points of intersection are dense relatively in a certain numberical value range,and sparse in other numberical value ranges.So we can conclude that the antisymmetric anisotropy DM interaction differs from the symmetric anisotropy KSEA interaction,but they are analogous in the sense of the influence of systemic dimerisation in open chain.