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     

含有Dzyaloshinskii-Moriya相互作用的自旋1键交替海森伯模型的量子相变和拓扑序标度

利用张量网络表示的无限矩阵乘积态算法研究了含有Dzyaloshinskii-Moriya (DM)相互作用的键交替海森伯模型的量子相变和临界标度行为.基于矩阵乘积态的基态波函数计算了系统的量子纠缠熵及非局域拓扑序.数据表明,随着键交替强度变化,系统从拓扑有序的Haldane相转变为局域有序的二聚化相.同时DM相互作用抑制了系统的二聚化,并最终打破系统的完全二聚化.另外,通过对相变点附近二聚化序的一阶导数和长程弦序的数值拟合,分别得到了此模型相变的特征临界指数a和b的值.结果表明,随着DM相互作用强度的增强, a逐渐减小,同时b逐渐增大. DM相互作用强度影响着此模型的临界行为.针对此模型的临界性质的研究,揭示了量子自旋相互作用的彼此竞争机制,对今后研究含有DM相互作用的自旋多体系统中拓扑量子相变临界行为提供一定的借鉴与参考.     

具有Dzyaloshinskii-Moriya相互作用的二维spin-Peierls模型的基态行为

在平均场理论基础上,研究了具有DzyaloshinskiiMoriya(缩写为DM)相互作用的二维spinPeierls模型以及DM相互作用对二聚化的影响.研究表明,随模型参量的不同,DM相互作用能加强或削弱二聚化位移.另外,发现DM相互作用对二聚化位移的依赖程度参量λ存在一个特殊点λc,当λ=λc时,DM相互作用对二聚化没有影响.随晶格弹性系数的增加,λc将增大,而链间耦合将使λc减小 关键词： 二维spinPeierls模型 DM相互作用     

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.     

氦原子基态能量的组态相互作用计算

将基态氦原子的波函数取作1s2和1s2s两个组态函数的叠加,利用组态相互作用方法解析计算了氦原子基态的非相对论能量.计算结果表明,考虑激发态1s2s与基态的相互作用,可以获得0.029 38Hartree的基态能量修正.本文的解析组态相互作用方法可作为量子力学教学的有益补充.     

两体相互作用费米系统在自旋轨道耦合和塞曼场中的基态转变

在超冷费米系统中实现人造规范势的突破,吸引了许多新问题的研究,展现了许多新奇的物理现象.本文研究了在环阱中,具有自旋轨道耦合和塞曼作用的两体相互作用费米模型.通过平面波展开的方法,解析求解了两体费米系统的本征能态.系统的总动量为守恒量,可以在不同总动量空间中研究能谱.研究发现:随着塞曼相互作用增大,在不同总动量空间,两体费米系统的本征能量均逐渐降低,系统基态从总动量为零空间转变到有限值空间.从吸引到排斥相互作用,无塞曼相互作用时,基态总动量始终为零,有塞曼相互作用时,基态总动量从零转变为有限值.通过单粒子和基态动量分布研究,本文直观地揭示了由塞曼能级劈裂引起的基态转变.     

具有Dzyaloshinskii-Moriya相互作用的三量子比特海森伯模型中的对纠缠

研究了一维三量子比特海森伯模型中的对纠缠的提高和控制问题,在该系统中引入了Dzyaloshinskii-Moriya（DM)相互作用,通过求解共生来计算两量子比特之间的热纠缠,结果表明：对于XXX模型,引入DM相互作用D,可以诱导铁磁和反铁磁自旋链产生热纠缠,尽管它们产生热纠缠所需的D值大小不同.对于XXZ模型,引入DM相互作用后,可以使原本不存在热纠缠的反铁磁自旋链产生纠缠,而且对于铁磁和反铁磁这两种XXZ自旋链,DM相互作用和各向异 关键词： 纠缠 XXX模型')" href="#">XXX模型 XXZ模型')" href="#">XXZ模型 Dzyaloshinskii-Moriya相互作用     

绿宝石晶体自旋二重态对基态能级的影响及Jahn-Teller效应

应用不可约张量方法和群的理论构造了三角对称晶场中考虑自旋 轨道相互作用,自旋 自旋相互作用和自旋 其它轨道相互作用的3d3/3d7态离子的可完全对角化的120阶微扰哈密顿矩阵.利用该矩阵计算了绿宝石晶体的基态能级、零场分裂参量,研究了自旋二重态对基态能级的贡献.理论计算值与实验值相符合,证明二重态对基态的贡献是不可忽略的.在此基础上,进一步研究了自旋 自旋相互作用、自旋 其它轨道相互作用和自旋 轨道相互作用对绿宝石晶体的光谱精细结构和零场分裂参量的影响,发现自旋 自旋和自旋 其它轨道相互作用对绿宝石晶体基态能级和零场分裂参量的影响都是不可忽略的.从而通过理论计算值和实验值的比较,证实了在绿宝石晶体中Jahn Teller效应的存在,它能够对光谱精细结构的分裂提出一些更加合理的解释.     

组态相互作用和Breit相互作用对类氖离子2p-3s碰撞激发特性的影响

基于全相对论扭曲波(RDW)电子碰撞激发计算程序REIE06,系统计算了类氖Fe~(16+)、Xe~(44+)和U~(82+)离子基态1s~22s~22p~(61)S_0到激发态1s~22s~22p~53s精细结构能级的碰撞强度,详细研究了组态相互作用和Breit相互作用对碰撞强度的影响,总结了一些有意义的结论 .在目前计算中,由于细致考虑了组态相互作用和Breit相互作用,其部分结果与已有的理论结果进行比较,对实验值的相对误差较小.     

高激发态原子间的范德瓦尔斯相互作用

与基态原子相比,高激发态原子(主量子数n15)具有很强的长程范德瓦尔斯(Van der Waals)相互作用,这种强相互作用可以阻止相邻原子的进一步激发,产生激发阻塞效应.本文从理论上利用微扰方法计算碱金属原子Rb和Cs激发态nS,nD原子对态的相互作用,获得原子相互作用的色散系数并分析了原子间的长程相互作用特性.结果表明,Rb和Cs原子的nS态表现为排斥相互作用,而nD态原子L=0时,Rb原子表现为吸引作用,Cs原子表现为排斥作用.     

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.     

Dzyaloshinskii-Moriya相互作用对量子XY链中热纠缠的影响

研究了Dzyaloshinskii-Moriya(DM)相互作用对混合自旋(1/2,3/2)XY链以及自旋为1的XY链热纠缠的影响.通过计算两粒子之间的纠缠,发现它不仅能够增强纠缠,而且能使两粒子之间的纠缠度达到一稳定值;当温度较高时,要使热纠缠达到稳定值需要更强的这种相互作用.在相同的条件下,自旋s=1的两粒子之间的纠缠要小于混合自旋两粒子之间的纠缠.粒子之间的交换耦合相互作用有助于加强粒子之间的热纠缠,因此可以与DM相互作用一起调节纠缠度.当交换耦合相互作用比 关键词： 量子纠缠 XY 模型')" href="#">XY 模型 negativity Dzyaloshinskii-Moriya相互作用     

带有Dzyaloshinski-Mariya相互作用的两比特纠缠量子Otto热机和量子Stirling热机

研究了以带有Dzyaloshinski-Mariya(DM)相互作用的两比特自旋体系为工质的量子纠缠Otto热机和量子Stirling热机.两种不同热机在各自的循环过程中,通过保持其他参量不变,只有DM相互作用发生改变,从而分析热机循环中DM相互作用与热传递、做功以及效率等热力学量之间的关系.研究结果表明:DM相互作用对两种热机的基本量子热力学量都具有重要的影响,但量子Stirling热机由于回热器的使用,其循环效率会大于量子Otto纠缠热机的效率,甚至会超过Carnot效率;得到了量子Otto纠缠热机和量子Stirling热机做正功的条件.因此,在这两个纠缠体系中,热力学第二定律都依然成立.     

RKKY interaction in the zigzag-edge silicene-like nanoflake

By considering the Kane-Mele-Hubbard approximation on the honeycomb lattice, we investigate the spin-spin correlation for two magnetic impurities in zigzag edge silicene-like nanoflake (ZSiLF). The dependence of the spatial behaviors of RKKY interaction on the electron-electron (e-e), intrinsic spin-orbit interactions (ISOI) and, electric field are systematically investigated. Generally, the spatial behaviors of the RKKY interaction sensitively change by changing e-e interaction and electric field strengths in the presence of ISOI. The ISOI in a ZSiLF result in long-range in-plane and Ising interactions. Moreover, e-e interaction induces non-zero Dzyaloshinsky-Moriya (DM) term and nearly distance-independent Ising interaction (similar to graphene nanoflake) in the presence of ISOI. Furthermore, with considering e-e interaction, the in-plane DM interaction increases by increasing the strengths of the electric field and ISOI.     

高分子中电子相互作用矩阵元

高分子中二聚化的增强或减弱决定于电子相互作用的力程。为了阐明这个事实的物理原因,本文计算了屏蔽库仑势的对角和非对角相互作用矩阵元。定量地证明了,当力程减小时,非对角相互作用愈来愈重要,它与对角相互作用的竞争使二聚化从增强而变为减弱。 关键词：     

Transferring information through a mixed-five-spin chain channel

We initially introduce one-dimensional mixed-five-spin chain with Ising-XY model which includes mixture of spins-1/2 and spins-1. Here, it is considered that nearest spins(1, 1/2) have Ising-type interaction and nearest spins(1/2, 1/2)have both XY-type and Dzyaloshinskii–Moriya(DM) interactions together. Nearest spins(1, 1) have X X Heisenberg interaction. This system is in the vicinity of an external homogeneous magnetic field B in thermal equilibrium state. We promote the quantum information transmitting protocol verified for a normal spin chain with simple model(refer to Rossini D, Giovannetti V and Fazio R 2007 Int. J. Quantum Infor. 5 439)(widely in reference: Giovannetti V and Fazio R 2005 Phys. Rev. A 71 032314) by means of considering the suggested mixed-five-spin chain as a quantum communication channel for transmitting both qubits and qutrits ideally. Hence, we investigate some useful quantities such as quantum capacity and quantum information transmission rate for the system. Finally, we conclude that, when the DM interaction between spins(1/2, 1/2) increases the system is a more ideal channel for transmitting information.     

Density of states and phase diagram of the antiferromagnetic spin chain with Dzyaloshinsky–Moriya interaction and spin-phonon coupling

The effects of DM interaction on the density-of-states, the dimerization and the phase diagram in the antiferromagnetic Heisenberg chain coupled with quantum phonons have been studied by a nonadiabatic analytical approach. The results show that the effect of the DM interaction is to increase the staggered antisymmetric spin exchange interaction order but to decrease the spin dimerization and their competitions result in the lattice dimerization ordering parameter to increase for large staggered DM interaction parameter β and decrease for small β. A crossover of β exists in which the dimerization ordering parameter changes non-monotonously. As the DM interaction parameter D increases, depending on the appropriate values of spin-phonon coupling, phonon frequency and β, the system undergoes phase transition from spin gapless state to gapped state or reversely and can even reenter between the two states. The relation between the phonon-staggered ordering parameter, the spin-dimer order parameter and the staggered DM interaction order parameter gives clearly their contributing weights to the lattice dimerization.