Synthesis and Structure of Paramagnetic β-Octamolybdate Complex,[Fe(2,2''-bipy)3]2[Mo8O26]·6H2O

A novel octamolybdate complex, [Fe(2,2-bipy)3]2[Mo8O26]·6H2Ohas been synthesized via the hydrothermal technique, and it crystallizes in monoclinic, space group P21/c with two molecules in a unit cell: a = 1.2 1 512(5), b = 1.36840(5), c = 2.18823(9) nm, β = 90.515( 1 )°, Mr = 2340.42, Z = 2, V = 3.6384(2) nm3, Dc = 2.136 g/cm3, F(000) = 2296, λ,(MoKα) = 0.071073 nm, μ = 1.813 mm 1, R =0.0719 and wR = 0.1093 for 4058 observed reflections with I≥2σ(I). The structure is characterized by the co-existence of octahedral [Fe(2,2′-bipy)3]2+ cations and β-octamolybdate [Mo8O26]4- anions. The magnetic susceptibility data show a Curie-Weiss paramagnetic behavior (θ = -5.201 K) in accordance with the spin-only ground state of Fe11 ions. IR, UV-Vis, and EPR spectra are also briefly noted in this paper.     

量子混沌系统中的自旋压缩性质

量子信息是21世纪的一门新兴交叉学科,现已经成为世界关注的热门研究领域.近年来,量子计算机的研究正成为大家十分感兴趣的课题.在寻找量子计算的实现方案过程中,量子混沌引起了研究人员的极大关注,因为在量子计算机执行一些量子运算法则的过程中可能产生量子混沌,并可能破坏量子计算机的运算操作条件.近期有关量子纠缠与量子混沌之间的关系已经有所报道,而自旋压缩作为另外一种典型的纯量子效应,是否也与量子混沌之间存在一定关系呢?讨论了量子混沌研究中一个非常典型的QKT模型,研究了量子混沌系统中自旋压缩的性质.通过数值模拟计算,给出了两种不同定义的自旋压缩系数与混沌系数κ之间的变化关系,结果发现在经典相空间中,如果在规则区域占优势的情况下,当初始自旋相干态波包位于椭圆形中心时,随着时间的演化,系统压缩行为表现得非常强;而对于经典相空间中混沌区域占优势的情况下,初始自旋相干态波包同样位于椭圆形中心,则系统的压缩行为表现得非常弱,说明自旋压缩对相应的经典混沌非常敏感.通过比较还发现,采用Wineland等定义的自旋压缩系数比采用Kitagawa和Ueda等定义的自旋压缩系数对经典混沌更敏感一些,从而得出用自旋压缩可以刻画量子混沌的结论.     

Dynamics of Quantum Fisher Information in Homodyne-Mediated Feedback Control

We investigate the quantum Fisher information(QFI) dynamics of a dissipative two-level system in homodynemediated quantum feedback control. The analytical results demonstrate that the maximum values and stable values of the QFI can be greatly enhanced via feedback control. The quantum feedback plays a more evident role in the improvement of classical Fisher information. The classical part can reach a high stable value, while the quantum part eventually decays to zero whatever the feedback parameter is.     

积极开展第二课堂活动,促进学生知识,能力,素质的全面提高

本文通过开展第二课堂活动的介绍和分析，提出了在工科大学物理课程教学过程中进行了教学改革的一种方法。     

Bipartite Entanglement in the Two-Mode Quantum Kicked Top

We show that the bipartite entanglement in the two-mode quantum kicked top can reveal the underlying chaotic and regular structures in phase space： namely, the entanglement displays a rapid rise after a very short time for an initial spin coherent state centred in a chaotic region of the phase space, whereas the entanglement displays a periodic modulation for the coherent state centred at an elliptic fixed point. The quantum-classical correspondence is investigated by studying the mean and maximal linear entropy.