Spin-current contributions to M2 excitations of 1p-shell nuclei

Microscopic analysis of spin-current contributions to magnetic quadrupole resonances in (e, e) cross sections has been performed using the particle-core coupling version of the shell model for 1p-shell nuclei. The contributions from spin-dipole and spin-octupole modes to M2 excitations of 1p-shell nuclei are traced up toq2.5 fm^–1.     

两位中国女物理学家对非平衡统计物理学的重要贡献

介绍了两位中国女物理学家王明贞和王承书在20世纪中叶对统计物理发展所作出的重要贡献，王明贞与乌伦贝克(Uhlenbeck)1945年在Review of Modem Physics上发表的有关布朗运动的综述文章。不仅详尽地分析了耦合谐振子的布朗运动特性，而且对随机过程做了完整的科学分类，至今仍被科学界采用，王承书对气体分子动理论所作的大量研究结果，特别是她与乌伦贝克提出的处理多原子分子气体输运系数的王承书-乌伦贝克方程，以及她对麦克斯韦气体的线性化玻尔兹曼方程碰撞算子本征值与本征函数的结果，已经成为现代动理学理论的经典内容，两位中国女物理学家通过她们在物理学史上留下的科学工作，为当代中国妇女攀登科学研究高峰树立了榜样。     

A unified approach to classical and quantum K.M.S. theory

We study a generalized K.M.S. condition which includes the classical and quantum mechanical K.M.S. conditions as special cases. We consider also a generalized centre of the von Neumann algebra and prove that with respect to the above K.M.S. condition it has properties analogous to the properties of the centre with respect to the quantum mechanical K.M.S. condition.     

M theory solution to the hierarchy problem

An old idea for explaining the hierarchy is strong gauge dynamics. We show that such dynamics also stabilizes the moduli in M theory compactifications on manifolds of G2 holonomy without fluxes. This gives stable vacua with softly broken supersymmetry, grand unification, and a distinctive spectrum of TeV and sub-TeV sparticle masses.     

Spin and orbital contributions to collective M1 transitions in 46,48Ti

Low- and high-lying K^π = 1⁺ states and M1 transitions in ^46,48Ti are studied. The model hamiltonian is treated in the quasi-particle particle random phase approximation (QRPA) with an exact restoration of its rotational invariance. A considerable spin contribution to the transition matrix elements is found for the low-energy (about 4 MeV) strong M1 transition (the orbital contribution being 30–70% of the spin one), although the microscopic structure of this state in ⁴⁶Ti is typical for an orbital isovector excitation. The calculated energies and B(M1) values are in good agreement with the experimental data. The results are compared to the estimates of the isovector scissor model.     

On the theory of pseudocontact N.M.R. shifts due to lanthanide complexes

The pseudocontact N.M.R. shifts due to complexes of lanthanide ions are considered in a crystal field theoretical framework including all the states J, M of an L-S manifold and an arbitrary set of crystal field parameters. Deviations from Bleaney's earlier theory are shown to be of the order of 20 per cent when the higher crystal field parameters are added.     

Early contributions to theoretical chemistry: Inga Fischer-Hjalmars,a founder of the Swedish school

ABSTRACT

Inga Fischer-Hjalmars was one of the pioneers in the creation of the Swedish school of theoretical chemistry. She started her scientific endeavours in pharmacy and biochemistry, but soon sought a deeper understanding of molecules and chemistry. With a genuine experimental background and quantum chemical skills learned from Charles Coulson in the late 1940s, Inga was well prepared to continue her research and to contribute to the establishment of theoretical chemistry as it was later defined by Coulson; the use of quantum mechanics to explain experimental phenomena in all branches of chemistry. During the 1950s and 1960s Inga made important contributions to our understanding of chemical bonding and reactivity. For example, she made key insights into the dissociation of molecular hydrogen, the influence of heteroatoms on dipole moments in organic compounds, the electronic configuration of ozone and on the validity of different approximations in molecular theory. Inga Fischer-Hjalmars and her students developed extensions of the Pariser–Parr–Pople method and during the latter part of her career, she returned to the biomolecules that once had brought her into science, now applying quantum chemical methods to understand bonding and spectral properties of these molecules at greater depth.     

Orbital pair theory of N.M.R. shielding

A simple correction accounting for the effect of truncating the atomic orbital basis on the calculation of N.M.R. shielding is proposed. This correction is obtained from the expression for the magnetic shielding as a sum of orbital pair contributions: a spurious term that vanishes only if a complete basis is used appears in this expression. It is demonstrated both theoretically and numerically (using the example of PH₃) that removing this term from the results obtained with a truncated basis improves significantly the agreement with the experimental values. As a by-product the gauge dependence of the numerical results is much reduced. The additional computing time is negligible.     

On the microscopic theory of electronic contributions to lattice dynamics of anharmonic crystals

A formalism is set up to study the electronic contribution to the phonon dynamics in an arbitrary crystal, conducting or insulating, without assuming small ionic oscillations. Therefore, in contrast to a harmonic Born-Oppenheimer approximation, such an approach allows for renormalization effects due to phonon-phonon interaction over the complete temperature range of the solid phase. The “weak coupling” approximation between nuclei and electrons is shown to be sufficient in order to obtain the dynamical matrix microscopically in terms of the complete inverse dielectric function of the electrons.     

Fourth-order contributions to μμ elastic scattering in the gauge theory of weak interactions

The fourth-order contributions of WW, Z? and ZZ intermediate states to the S-matrix elements of μμ elastic scattering have been calculated by dispersion theoretic techniques in the U-gauge. It is shown that the contributions are finite and very small compared to the low-order contributions. It is also shown that the main part of these finite contributions comes from the WW intermediate state.     

From simplified BLG action to the first-quantized M theory

A concise summary of recent progress in the search for the world-volume action for multiple M2 branes is provided. After the recent discovery of a simplified version of the BLG action, which is based on the ordinary Lie-algebra structure and that does not have coupling constants or extra dynamical fields, attention should be switched to the study of M2 brane dynamics. A viable brane analog of the Polyakov formalism and the Belavin-Knizhnik theorem for strings can probably be provided by the Palatini formalism for a 3d (super-) gravity. The text was submitted by the author in English.     

Some theoretical investigations in crystal field theory

General expressions for the crystal field parameters are established by the introduction of an electronic charge density which depends on the operator Ô(n) = |ψ _n >< ψ _n |, where |ψ _n > is an eigenstate of the system (central ion + ligands). The connection with molecular orbital theory is discussed as well as the expected behaviour of the crystal field parameters with the eigenstates |ψ _n > for the case of both weak and strong field. Especially in the former case, simple expressions are obtained for the correlation crystal field parameters.     

Introduction to M(atrix) theory and noncommutative geometry

Noncommutative geometry is based on an idea that an associative algebra can be regarded as “an algebra of functions on a noncommutative space”. The major contribution to noncommutative geometry was made by A. Connes, who, in particular, analyzed Yang–Mills theories on noncommutative spaces, using important notions that were introduced in his papers (connection, Chern character, etc). It was found recently that Yang–Mills theories on noncommutative spaces appear naturally in string/M-theory; the notions and results of noncommutative geometry were applied very successfully to the problems of physics.

In this paper we give a mostly self-contained review of some aspects of M(atrix) theory, of Connes’ noncommutative geometry and of applications of noncommutative geometry to M(atrix) theory. The topics include introduction to BFSS and IKKT matrix models, compactifications on noncommutative tori, a review of basic notions of noncommutative geometry with a detailed discussion of noncommutative tori, Morita equivalence and -duality, an elementary discussion of noncommutative orbifolds, noncommutative solitons and instantons. The review is primarily intended for physicists who would like to learn some basic techniques of noncommutative geometry and how they can be applied in string theory and to mathematicians who would like to learn about some new problems arising in theoretical physics.

The second part of the review (Sections 10–12) devoted to solitons and instantons on noncommutative Euclidean space is almost independent of the first part.     

On Møller's tetrad theory of gravitation. Gravitational radiation

In the background of Møller's theory, two energy-momentum complexest andP, are defined. From them, the losses of energy and angular momentum of a nongravitationally bound system due to the radiation of gravitational waves are evaluated. To solve the field equations some approximation procedures are used. The post-Newtonian limit is studied. When the modulus of the coupling constant of the theory is smaller than 10³ and some reasonable conditions are assumed, the results here obtained appear to be identical to those of general relativity. The work performed here would be basic when dealing with some important questions in generalizing Møller's theory.     

Experimental and theoretical N.M.R. studies of the coupling constants in seven isotopic ethyl fluorides

The N.M.R. spin-spin coupling constants and chemical shifts are reported for seven isotopically substituted ethyl fluorides. ¹H, ²H and ¹⁹F spectra have been observed and a consistent set of data obtained. Isotope effects are reported in ¹H and ¹⁹F spectra due to replacement of ¹H by ²H and ¹²C by ¹³C.

Using an accurate microwave structure of ethyl fluoride, CNDO and INDO calculations have been carried out, including dipolar and orbital terms. As independent options, configuration interaction between all single-excited states, variable radial electron distribution <r ^-3> and variable electron density at the site of nuclei, <s(0)²>, are included. Calculated values for all combinations of the options are given and a discussion of the results presented.