Irreducible Bases and Correlations of Spin States for Double Point Groups

In terms of the irreducible bases of the groupspace of the octahedral double group O ananalytic formula is obtained to combine the spin states|j, > into the symmetrical adapted basesbelonging to a given row of a given irreducible representationof O. This method is effective for alldouble point groups. However, for the subgroups ofO there is another way to obtain thosecombinations. As an example, the correlations of spin states for thetetrahedral double group T are calculatedexplicitly.     

Irreducible Bases in Icosahedral Group Space

The irreducible bases in the icosahedral groupspace are calculated explicitly by reducing the regularrepresentation. The symmetry-adapted bases of the systemwith I or I _h symmetry can becalculated easily and generally by applying those irreduciblebases to wavefunctions of the system, if they are notvanishing. As examples, the submatrices of the HuckelHamiltonians for carbon-60 and carbon-240 arerecalculated by the irreducible bases.     

Spin Correlations in Nonrelativistic Quantum Mechanics

Einstein—Podolsky—Rosen spin correlations in the framework of nonrelativistic quantum mechanics for moving observers are calculated. The measurements are performed in bounded regions of space (detectors), not necessarily simultaneously. The resulting correlation function depends not only on the directions of spin measurements but also on the relative velocity of the observers.     

Spin Squeezing for Superpositions of Dicke States

We investigate spin squeezing for superpositions of Dicke states. We derive the mean spin direction, the length of mean spin, the optimally squeezed angle and numerically calculate the spin squeezing parameter, which is determined by on the superposed coefficients and the relative phase. Approximate same superposed amplitude and the smaller relative phase lead to the larger the length of mean spin, the stronger spin squeezing and spin squeezing maintains in a longer time interval.     

Spin Squeezed States and Entangled States

The time evolution of spontaneous decay of a two-level atom in one dimension photonic crystals is investigated with three different methods ： （ 1 ） using the Markovian approximation, （2） using the constant approximation, and （3） without using any of the two approximations. The second and third methods are Non-Markovian, which yield similar results. The second method gives us a clear physical picture of the effect of the reflected field. The Non- Markovian processes due to the reflected field have great influence on the atomic decay mainly within one tenth of an optical cycle, and reach steady state influence fter one optical cycle. The result of Markovian approximation gives almost the same result of the other two methods after one optical cycle, but misses the details within the one optical cycle.     

Two-Photon Spin States and Entanglement States

In this paper, we have given the spin states of two-photon, which are expressed by the quadratic combination of two single-photon spin states, and given all entanglement states of two-photon from the spin states of two-photon. The new expression of two-photon entanglement states should be used in quantum computation and quantum communication.     

二十面体群拉曼和超拉曼张量的计算

本文简单介绍了计算张量的不变式－协变式方法，以及根据此原理所编程序的设计思想，并在附录中给出了二十面体群（Ⅰ群）的Ｒａｍａｎ、Ｈｙｐｅｒ Ｒａｍａｎ对称（α、β、γ）张量和非对称（α－、β－、γ－）［１］张量。     

二十面体群C-G系数计算

本文简要介绍了计算Ｃ Ｇ系数的生群元矩阵方程法，给出计算二十面体群Ｃ Ｇ系数时采用的简化计算方法，并给出了Ⅰ群Ｃ Ｇ系数的计算结果。     

Correlations in Werner States

Werner states are paradigmatic examples of quantum states and play an innovative role in quantum information theory. In investigating the correlating capability of Werner states, we find the curious phenomenon that quantum correlations, as quantified by the entanglement of formation, may exceed the total correlations, as measured by the quantum mutual information. Consequently, though the entanglement of formation is so widely used in quantifying entanglement, it cannot be interpreted as a consistent measure of quantum correlations per se if we accept the folklore that total correlations are measured （or rather upper bounded） by the quantum mutual information.     

Correlations for a Family of Two-Ququart Quantum States

In this paper, a quantum correlations analytical treatment for a family of two-ququart states are presented. For this purpose, a family of two-ququart quantum states, as well as a set of von Neumann measurements are proposed. A quantum discord analytical treatment is derived for this family of two-ququart states. Finally, the classical mutual information, the entanglement of formation and quantum discord are illustrated in this family of two-ququart quantum states.

     

Pairwise Quantum Correlations for Superpositions of Dicke States

Pairwise correlation is really an important property for multi-qubit states. For the two-qubit X states extracted from Dicke states and their superposition states, we obtain a compact expression of the quantum discord by numerical check. We then apply the expression to discuss the quantum correlation of the reduced two-qubit states of Dicke states and their superpositions, and the results are compared with those obtained by entanglement of formation, which is a quantum entanglement measure.     

MC-Simulation of the Transverse Double Spin Asymmetry for RHIC

We give a leading order estimate of the hadronic transverse double spin asymmetry in the Drell-Yan process at RHIC using Sphinx tt,anew polarized version ofthe Monte Carlo Pythia 5.6. We also calculate the statistical error to next to leading order with Pythia 5.7. Both quantities are of the same order if one assumes that the transversity weighted parton distributions equal the helicity weighted ones at some low perturbative scale Q ₀ ² .     

Coset Structure of Spin Group

This article considers the coset structure of spin group via analyzing the expression of its representation.One example is also given to take a closer look at what the coset and the subgroup are.     

Wigner Functions and Spin Tomograms for Qubit States

We establish the relation of the spin tomogram to the Wigner function on a discrete phase space of qubits. We use the quantizers and dequantizers of the spin tomographic star-product scheme for qubits to derive the expression for the kernel connecting Wigner symbols on the discrete phase space with the tomographic symbols.     

高温超导体中的短程反铁磁自旋关联

传统超导体具有大的相干长度 ,借助于由隧穿测量给出的电流 -电压关系 ,可以反演出电声子相互作用的谱密度α2 Ｆ(ω) .对于高温超导体来说 ,情况完全不同 ,它的相干长度很短 ,为要研究其中的相互作用谱密度 ,最好的办法是采用红外光反射率测量或进行中子非弹性散射实验 .最近 ,美国橡树岭 (ＯａｋＲｉｄｇｅ)国家实验室的Ｐ .Ｃ .Ｄａｉ等 ,对ＹＢａ2 Ｃｕ3Ｏ6 ｘ(ＹＢＣＯ)系列样品 ,给出了中子非弹性散射研究的新数据 .结果表明 ,短程反铁磁自旋关联 ,在超导形成中起着重要的作用 .中子散射与Ｘ射线散射的区别主要在于 :Ｘ射线散射的强…     

Study on High Spin States

The high spin states of ⁸⁵Zr were populated by using fusion evaporation 60Ni (²⁸Si,2pn)⁸⁵Zr reaction. The r-r coincidence and DCO ratios were measured with 10 HPGe-BGO detectors at beam energy 102 MeV. A level scheme with 43 levels and 75 r-transitions are proposed. About 25 levels and 36 r-transitions are added to the previous work. The spin is up to 49/2+ for the yrast band. The first and second bank bandings, are observed with configurations vg9/2 π(g/2) and (vg9/2) π(g9/2) . A △I= 1 Ml band built on the 17/2- is conformed. The level structure is compared with its isotones nuclei and discussed.     

85Zr核的高自旋态研究

利用102MeV的28Si束流,通过60Ni(28Si,2pn)熔合蒸发反应布居了85Zr核的高自旋态,测量了γ-γ符合及DCO比值,建立了一个有43条能级,75条γ跃迁的能级纲图,新增加了36条γ跃迁,25条能级.将能级自旋推高到(49/2+),首次观察到了转晕带的第二回弯.并确认了一条建立在17/2-负宇称带上的磁转动带.     

On Decay of Correlations for Unbounded Spin Systems with Arbitrary Boundary Conditions

We propose a method based on cluster expansion to study the truncated correlations of unbounded spin systems uniformly in the boundary condition and in a possible external field. By this method we study the spin–spin truncated correlations of various systems, including the case of infinite range simply integrable interactions, and we show how suitable boundary conditions and/or external fields may improve the decay of the correlations.     

Representation of Spin Group Spin（p, q）

The representation η（P, q） of spin group Spin（p, q） in any dimensional space is given by induction, and the relation between two representations, which are obtained in two kinds of inductions from Spin（p, q） to Spin（p ＋ 1, q ＋ 1） are studied.