Manipulation of Quantum Nonlocality of the Single-Photon Entangled State via Beam Splitter

Quantum nonlocality of the single-photon entangled state emerging from a beam splitter with arbitrary controlling parameters is investigated by means of the parity measurement. The condition of the maximal violation of the Bell-CHSH inequality is obtained for the single-photon entangled state. Under the condition of the small coherent intensity J(J=0.1) and the phase difference γαβ of the two coherent displacements being opposite to the internal phase shift φ of the beam splitter (γαβ=-φ), we find that the quantum nonlocality depends only on the reflection coefficient R of the beam splitter, while φ plays an important role for selecting γαβ. The strongest quantum nonlocality can be observed for a 50:50 beam splitter. If R deviates from the intermediate value 0.5, the quantum nonlocality decreases gradually, even vanishes. Our results provide a method to observe and manipulate the quantum nonlocality of the single-photon entangled state by adjusting the parameters of the coherent displacements and the beam splitter.     

Entanglement Manipulation for a Two-Mode Squeezed Vacuum State

By numerically analysing the entropy of entanglement of the output state from a Mach-Zehnder interferometer for the two-mode squeezed vacuum state input, it is found that if the internal phase shift of the interferometer is adjusted to the value of 0 or 7r, the entangling characteristic of the input state is efficiently preserved at the output. If the internal phase shift is tuned to the value of Tr/2, the two-mode squeezed vacuum state is completely disentangled at the output of the setup. If the internal phase shift deviates from the above values, the input state is degraded into a partially entangled output state. Based on these results, a method for optically realizing the entanglement preservation, entanglement degradation, and disentanglement via the interferometer is obtained.     

Paul阱中囚禁离子质心运动量子态的压缩效应

文章研究Ｐａｕｌ阱中被囚禁离子才动量在奇偶相干的的压缩性质。研究结果表明，囚禁离子不仅有二阶压缩效应，而且有高阶压缩效应，本文具体给出了囚禁离子的位置和动量在奇偶相干态中的二阶和四阶压缩条件及压缩曲线。     

双模相干光场与原子依赖强度耦合双光子过程的纠缠演化

分别应用量子约化熵和量子相对熵研究了双模相干光场与原子依赖强度耦合双光子过程中原子与光场之间及光场的模之间纠缠演化.结果表明,通过选择系统初态参数、控制原子与光场的作用时间,可以调控原子与光场间的纠缠和光场的模间纠缠.可增加或减弱双模相干光场间纠缠,但无法使双模相干光场完全退纠缠.强场条件下,可周期性获得光场与原子的EPR态和可分离态.     

高效液相色谱法测定化妆品中4种硝基咪唑类药物

采用高效液相色谱法测定化妆品中的甲硝唑、替硝唑、奥硝唑和塞克硝唑。样品经甲醇和0.1mol·L-1盐酸溶液以体积比1比1组成的混合溶液超声提取15min后,以C18色谱柱为分离柱,以甲醇-乙腈-水(7+1+2)混合液为流动相,在检测波长315nm处进行测定。4种硝基咪唑类药物在一定的质量浓度范围内与峰面积呈线性关系,方法检出限(3S/N)和测定下限(10S/N)分别低于10 mg·kg-1和30 mg·kg-1。以空白样品为基体进行加标回收试验,测得回收率在93.8%~104%之间,相对标准偏差(n=6)在0.2%~4.1%之间。     

与光场依赖强度耦合下运动纠缠双原子的周期量子回声

本文将Tavis-Cummings(T-C)模型推广到同时考虑原子运动及与光场依赖强度耦合的情况.运用全量子理论,研究了与光场依赖强度耦合下运动纠缠双原子量子态保真度演化.采用数值计算的方法,探讨了双原子初始纠缠因子θ、光场平均光子数n以及场模结构参量p对双原子量子态保真度演化的影响,解析分析了双原子周期量子回声的形成规律,揭示了其物理实质.结果表明, 在场模结构参量p=1的情况下,无论光强和双原子初始纠缠因子如何取值,双原子均产生周期2π的量子回声;在强相干场n=30条件下,改变p从1到小于800时,Bell态双原子产生2π/p周期量子回声.当p≥800时,无论光场是真空场、弱相干场或强相干场,双原子量子态保真度恒为1,即第一类Bell态原子持续处于保真态;而当双原子初始纠缠因子为3π/4时,无论n、p取何值,双原子量子态保真度保持为1,双原子持续处于第二类Bell态的保真态.其结论表明, 该推广模型具有很好的双原子周期量子回声性质,为纠缠双原子信息高保真输出及噪音环境下量子信息处理的实验实现提供了理论参量和物理载体.     

海藻糖和氨基酸之间相互作用的分子动力学模拟

虽然海藻糖已经广泛用于蛋白质稳定性研究,但海藻糖稳定蛋白质的作用机理尚不清晰. 本文利用全原子分子动力学模拟研究了20种常见氨基酸和海藻糖之间的分子机理. 结果表明,所有氨基酸,尤其是极性和带电氨基酸,均优先与水分子结合. 相反,仅有疏水性氨基酸与海藻糖发生相互作用,尤其是芳香族和疏水性氨基酸的侧链更易于和海藻糖接触. 所有氨基酸的主链与水分子接触的趋势一致. 虽然氨基酸和海藻糖与水之间均形成氢键,但氨基酸和海藻糖之间的氢键相互作用要弱于氨基酸和水之间的氢键相互作用. 上述分子模拟的结果对于海藻糖稳定蛋白质作用机理的解析及高效蛋白质稳定剂的理性设计具有非常重要的理论指导意义.     

用经典混沌模拟量子不可计算态

阐明某些微扰Ｓｃｈｒ¨ｏｄｉｎｇｅｒ方程与经典混沌系统的线性化方程具有类似的数学形式,利用后者模拟前者,得到与经典混沌解相应的积分形式波函数,微扰无反射势阱的例子说明,这种波函数象经典混沌解一样不可计算,但它的量子态和能量则是可预言的．     

Preparation and control of atomic optimal entropy squeezing states for a moving two-level atom under control of the two-mode squeezing vacuum fields

From the viewpoint of quantum information,this paper studies preparation and control of atomic optimal entropy squeezing states(AOESS) for a moving two-level atom under control of the two-mode squeezing vacuum fields.Necessary conditions of preparation of the AOESS are analysed,and numerical verification of the AOESS is finished.It shows that the AOESS can be prepared by controlling the time of the atom interaction with the field,cutting the entanglement between the atom and field,and adjusting squeezing factor of the field.An atomic optimal entropy squeezing sudden generation in different components can alternately be realized by controlling the field-mode structure parameter.