Effects of massive neutrinos on the structure formation of the universe

Massive neutrinos affect the structure formation of the universe, characteristically the harmonic pattern of the cosmic microwave background (CMB) radiation and the clustering property of galaxies. Precision observations of the CMB and the power spectrum of galaxy clustering thus lead to the limit on the neutrino mass on the 1 eV scale. I address the principles and the typical results that can be derived from cosmological arguments.     

Structure study of simple fluids

The structure function of simple monatomic liquids like neon and argon is studied in an approximation scheme where intermediate functionQ(r) is extended beyond hardcore diameter rather than the direct correlation functionC(r). The calculated values show good agreement with experimental values.     

关于核多体系统的基态关联效应

对于一个原子核模型系统在不同耦合强度、不同粒子数情况下的基态关联效应进行了研究,结果表明：当具有稳定的静态形变时,基态关联基本上可用基于静态上的零点振动来解释,因此,关于静态性质的自治场计算是至关重要的. 但在开始发生单极形变的临界点附近,它随控制参量的变化显得很复杂、很敏感. 看来,在滴线附近的轻核的进一步研究中,关联效应是需要注意考虑的.     

Two-Variable Hermite Polynomial Excitation of Two-Mode Squeezed Vacuum State as Squeezed Two-Mode Number State

We find that the squeezed two-mode number state is just a two-variable Hermite polynomial excitation of the two-mode squeezed vacuum state （THPES）. We find that the Wigner function of THPES and its marginal distributions are just related to two-variable Hermite polynomials （or Laguerre polynomials） and that the tomogram of THPES can be expressed by one-mode Hermite polynomial.     

Exact results for the Potts model in two dimensions

By considering the zeros of the partition function, we establish the following results for the Potts model on the square, triangular, and honeycomb lattices: (i) We show that there exists only one phase transition; (ii) we give an exact determination of the critical point; (iii) we prove the exponential decay of the correlation functions, in one direction at least, for all temperatures above the critical point. The results are established forq 4, whereq is the number of components.Work supported by the Fond. National Suisse de la Recherche Scientifique.Work supported in part by NSF Grant No. DMR 76-20643.     

Behavior at small distances and low temperatures of the ion-ion distribution function of the two-dimensional Coulomb gas

We compute upper and lower bounds for the canonical ion-ion distribution functiong ₁₁ ^(N) (r) of the two-dimensional Coulomb gas for smallr and 1<<2, where is the plasma parameter. Both bounds are proportional tor ^2-/(-1), which proves thatg ₁₁ ^(N) (r) behaves asr ^2-, as conjectured by Hansen and Viot. We conjecture that, in the thermodynamic limit,g ₁₁(r) ~ 2(-1)^-1(r/a)^2-, wherea=(n)^–1/2 is the mean interionic distance. We also compute the canonical one-body distribution function with one pair (+,–) in a disk, for anyr and any.     

Quantum State Reconstruction of Many Body System Based on Complete Set of Quantum Correlations

We propose and study a universal approach for the reconstruction of quantum states of many body systems from symmetry analysis. The concept of minimal complete set of quantum correlation functions (MCSQCF) is introduced to describe the state reconstruction. As an experimentally feasible physical object, the MCSQCF is mathematically defined through the minimal complete subspace of observables determined by the symmetry of quantum states under consideration. An example with broken symmetry is analyzed in detail to illustrate the idea.     

Donor Properties of Ligands and the Structure and Spectra of Uranyl Halogenides in the Solid State

Complexes of uranyl halogenides with neutral organic ligands in the solid state have been obtained, the luminescence spectra at T = 77 K have been recorded, and the dependences of them on the composition of the complex have been investigated. The linear dependence of the change in the frequencies of electron and vibronic transitions on the donor number of the neutral ligands has been revealed, thus allowing us to propose a spectral method for determining the structure of the system studied. It is shown that the increased strength of the bond of some halogen ligands (in particular, fluorine) with uranyl favors the nonsaturation of their inner coordination sphere. At the same time, the most stable complexes of the substances considered are formed when two halogen ions are supplemented with three molecules of organic ligand.     

Formation of intermediate coupling optical polarons and bipolarons in two-dimensional systems

The formation of the optical polaron and bipolaron in two-dimensional (2D) systems is studied in the intermediate electron–phonon coupling regime. The total energies of the 2D polaron and bipolaron are calculated by using the Buimistrov–Pekar method of canonical transformations. The obtained results are compared with other existing results obtained by using the Feynman path integral method and the modified Lee–Low–Pines unitary transformation method. It is shown that the electron–phonon correlation significantly reduces the total energy of the 2D polaron in comparison with the energy of the strong coupling (adiabatic) polaron. It is found that the polaron formation in 2D systems is possible when the electron–phonon coupling constant α is greater than the critical value ${\alpha }_c?2.94$, which is much lower than a critical value of the electron–phonon coupling constant α in three-dimensional (3D) systems. The critical values of the Fröhlich coupling constant α and the ratio $\eta ={\epsilon }_{\infty }/{\epsilon }_0$ (where ${\epsilon }_{\infty }$ and ${\epsilon }_0$ are the high frequency and static dielectric constants, respectively), which determine the bipolaron stability region in 2D systems, are calculated numerically. It is interesting for application to the layered cuprate superconductors that the (bi)polarons are formed more easily in quasi-2D regions than in the bulk. It is argued that the high-$T_c$ cuprate superconductivity can exist above the bulk superconducting transition temperature $T_c$ as the persisting superfluidity of polaronic (bosonic) Cooper pairs and large bipolarons at quasi-2D grain boundaries or in the CuO₂ layers above $T_c$.     

Gravitational critical phenomena in the realm of the galaxies and Ising magnets

In the non-relativistic and quasi-static limit, it is possible to map exactly the system of galaxies in the observable universe onto an Ising magnet. Techniques from the theory of critical phenomena as applied to magnets can then be employed to calculate rigorously the galaxy-to-galaxy correlation function, whose critical exponent is predicted to be between 1.530 to 1.862, to be compared to the empirical/observational value of 1.6 to 1.8.This essay received the fifth award from the Gravity Research Foundation, 1996—Ed.     

Letter: Hierarchy and Wave Functions in a Simple Quantum Cosmology

In a simple quantum cosmological model involving eleven dimensional space-time, an extended holographic conjecture suggests the nuclear force must be about forty orders of magnitude stronger than gravity. An interpretation of the wave function of the universe in this model is also proposed.     

30MeV/u 40Ar+ 112,124Sn反应中态布居核温度的同位旋效应

用13单元望远镜探测器阵列测量了30MeV/u ⁴⁰Ar +^112,124Sn反应中小角关联粒子,由两体符合事件提取了αα关联函数.用三体弹道理论模型MENEKA计算本底关联函数,用Monte Carlo方法计算探测效率函数,在扣除本底产额并考虑探测效率的修正后,对不同同位旋反应系统⁴⁰Ar +¹¹²Sn和⁴⁰Ar+¹²⁴Sn提取的相对态布居核温度分别是4.18±0.25 0.21MeV和4.10±0.22 0.20MeV ;考察态布居核温度和粒子能量的关系时,观察到两个系统的发射温度均随着粒子能量的增加而降低,缺中子系统⁴⁰Ar +¹¹²Sn中由低能时的5.13±0.30 0.2 6MeV降低到高能时的3.87±0.37 0.29MeV ,丰中子系统⁴⁰Ar+¹²⁴Sn中由低能时的5.39±0.30 0.26MeV降低到高能时的3.32±0.28 0.23MeV .用激发热核衰变过程的同位旋选择性对这种同位旋相关性进行了解释.     

原子相干对光缔合形成分子的影响

用量子统计方法,讨论了原子相干对超冷两态原子经光缔合形成超冷分子的影响.结果表明,在原子相干的作用下,光缔合形成的分子数随时间做近周期减幅振荡.原子相干对光缔合过程的暂态阶段影响强烈,而分子始终保持sub-Poisson统计分布.     

热镀铜层冷凝过程的分子动力学模拟

采用常温、常压分子动力学模拟方法和FS(Finnis Sinclair)势 ,研究了在周期性边界条件下由 5 0 0个原子构成的液态Cu模型系统的凝固过程 ,考察了不同降温速率下Cu的凝固行为 ,得到了不同温度、不同冷却速率下Cu的双体分布函数 ;采用HA键型指数法统计了各种小原子团在不同温度下所占比例 ,采用键取向序分析了体系降温全过程的局域取向对称性 ,得到原子体系微观结构组态变化的重要信息 ;最后 ,利用能量分析的方法对体系微观结构的变化进行了说明 ,给出了液态Cu冷凝过程中微观结构转变的重要信息 .     

关联函数在耗散反应激发函数涨落中的应用

应用关联函数方法,分析耗散反应激发函数中的涨落.通过推导出能量自关联函数、角度互关联函数、反应产物元素之间的互关联函数、反应产物同位素之间的互关联函数,来分析在耗散反应这一由非平衡向平衡演化的系统中,核反应体系演化过程的特点,说明关联函数在研究耗散反应激发函数涨落中的特殊作用.用推导出的函数分析了实验4.5MeV/u ²⁷Al+²⁷Al和102.5MeV ¹⁹F+⁵¹V的数据,并且指出了用这种方法可以提取的耗散反应体系的信息.     

基态UC2分子的结构和势能函数

采用密度泛函理论 (DFT)的B3LYP方法和相对论有效原子实势理论模型 (RECP) ,对UC2 分子可能的结构进行优化计算 ,得到UC2 分子稳定构型为角形C -U -C(C2v) ;由微观可逆性原理 ,判断了UC2 分子的离解极限 ;并且导出了基态UC2 分子 (X 5B1)的多体项展式势能函数 ,其势能面等值图展现了C -U -C(C2v)稳定结构 ;根据势能面等值图 ,讨论了C +UC(X 3 П)反应和U +C2 (X 1∑+ g)反应的势能面静态特征     

Sub-wavelength interference in the field assisted by surface plasmons

We present a theoretical study of the optical transmission from a thin metallic double slit. The second-order correlation function as a function of the displacement of the detectors for different values of slit separation is studied. It is shown that surface plasmons excited at one slit and propagating to the other slit modulate the coincidence counts with the variation of slit separation. Sub-wavelength interference effect has also been observed for the field assisted by surface plasmons. It is also shown that the second order interference-diffraction pattern changes with slit separation and at some particular value of slit separation it changes into the Hanbury Brown and Twiss (HBT) effect.     

Critical behavior of the correlation function of a coulombic fluid

An extension of the Ornstein-Zernike theory of critical scattering by a simple fluid to include a type of coulombic system is suggested. The relation between the oscillations of the charge distribution predicted by the second moment condition of Stillinger and Lovett in the restricted primitive model and the critical behavior of the correlation function is also discussed.This work was supported in part by a grant from the National Institutes of Health, GM 20800-03.Contribution No. 3100 from the Department of Chemistry, Indiana University.Supported by CONACYT (Mexico) and on leave from Universidad Autónoma de Puebla, Puebla, Mexico.     

散斑自相关分辨率测量和修正

散斑相关是许多基于散斑的光学测量和成像技术的基础,决定了光学系统的分辨率。当前散斑尺寸（颗粒度或分辨率）的理论描述不够精确,也缺乏实验验证。探究了散斑图样自相关尺寸的影响因素,与相同数值孔径物镜聚焦进行比对,揭示薄散射介质的“散射透镜”性质。通过散斑自相关和透镜聚焦尺寸的多组测量,结果表明,截趾函数会影响其分辨率,需要根据具体光路对阿贝判据做修正。对基于散斑的测量和成像技术具有一定的参考价值。