Quantum-mechanical calculation of the van der Waals interaction between small metallic spheres

We give the first microscopic calculation of the leading terms in the van der Waals interaction energy between two very small metallic particles, treating their electronic excitations in the quantum-mechanical Infinite Barrier Model and the Random Phase Approximation. The results are very close to those obtained for the corresponding classical spheres, provided that we describe them by their effective radii calculated to satisfy the electrostatic zero-force sum-rule. We examine the higher order terms and the exact results at short distances in the plasmon-pole approximation, and discuss the convergence of the multipole expansions.     

The interaction between zonal flow and Rossby waves with scalar nonlinearity

The nonlinear interactions between zonal flow and Rossby waves are studied by numerical simulations with focus on the effects of scalar nonlinearity. The numerical results show that the scalar nonlinearity has an appreciable influence on the Rossby dipole evolution and can reduce the threshold of the disturbance energy increase.     

Klein's paradox and the relativistic point interaction

We discuss a short-range approximation for relativistic delta-function potentials.On leave of absence from the Nuclear Centre, Faculty of Mathematics and Physics, V. Holesovickach 2 Prague 8 Czechoslovakia     

Linear AAD interaction and the relativistic rotator

It is shown that the weak-potential limit allows us to reveal quite naturally the presence of the relativistic rotator in linear AAD interaction. In the language of extended constraint dynamics it is able to give all required rotator generators including the evolution equation of the Hamilton-Jacobi type suitable for rigorous quantization.Dedicated to Academician Václav Votruba on the occasion of his eightieth birthday.     

Masses of light tetraquarks and scalar mesons in the relativistic quark model

Masses of the ground-state light tetraquarks are dynamically calculated in the framework of the relativistic diquark–antidiquark picture. The internal structure of the diquark is taken into account by calculating the form factor of the diquark–gluon interaction in terms of the overlap integral of the diquark wave functions. It is found that scalar mesons with masses below 1 GeV, f ₀(600) (σ), K ₀^*(800) (κ), f ₀(980) and a ₀(980), agree well with the light-tetraquark interpretation.     

All-electron exact exchange treatment of semiconductors: effect of core-valence interaction on band-gap and d-band position

We present the first all-electron full-potential exact exchange (EXX) Kohn-Sham density functional calculations on a range of semiconductors and insulators (Ge, GaAs, CdS, Si, ZnS, C, BN, Ne, Ar, Kr, and Xe). We remove one of the main computational obstacles of such calculations by the use of a highly efficient basis for inversion of the response function. We find that the band gaps are not as close to experiment as those obtained from previous pseudopotential EXX calculations. The locations of d bands, determined using the full-potential EXX method, are in excellent agreement with experiment, irrespective of whether these are core, semicore, or valence states. We conclude that the inclusion of the core-valence interaction is necessary for accurate determination of EXX Kohn-Sham band structures and that EXX alone is not a complete answer to the band-gap problem in semiconductors.     

同轴膜片加载圆波导相对论行波管注-波互作用线性理论研究

 从改善圆盘加载波导作为相对论行波管慢波结构的特性入手,加入同轴内导体,着重研究其小信号理论。利用场匹配法导出了“热”色散方程并计算求解,具体分析了系统的电子注参量及慢波结构几何尺寸对小信号增益及慢波相速的影响,为同轴圆盘加载相对论行波管的设计提供了理论基础。     

New limit on the scalar P,T-odd electron-nucleus interaction

The EDM of an atom with closed shells, caused by the scalar P,T-odd interaction and the hyperfine interaction is calculated. From the experiment of Lamoreaux et al. ¹⁹⁹Hg the most stringent limit on the constant of the scalar P,T-odd interaction is obtained: C_s=−0.8±1.7)×10⁻⁵.     

The mixing of scalar mesons and the baryon-baryon interaction

By introducing the mixing of scalar mesons in the chiral SU(3) quark model, we dynamically investigate the baryon-baryon interaction. The hyperon-nucleon and nucleon-nucleon interactions are studied by solving the resonating group method (RGM) equation in a coupled-channel calculation. In our present work, the experimental lightest pseudoscalar p \pi, K,h \eta,h^￠ \eta^{{\prime}}_{} mesons correspond exactly to the chiral nonet pseudoscalar fields p \pi, K,h \eta,h^￠ \eta^{{\prime}}_{} in the chiral SU(3) quark model. The h \eta,h^￠ \eta^{{\prime}}_{} mesons are considered as the mixing of singlet and octet mesons, and the mixing angle q_ps \theta_{{ps}}^{} is taken to be -23^° . For scalar nonet mesons, we suppose that there exists a correspondence between the experimental lightest scalar f ₀(600) , k \kappa , a ₀(980) , f ₀(980) mesons and the theoretical scalar nonet s \sigma , k \kappa , s^￠ \sigma^{{\prime}}_{} , e \epsilon fields in the chiral SU(3) quark model. For scalar mesons, we consider two different mixing cases: one is the ideal mixing and another is the q_s \theta_{s}^{} = 19^° mixing. The masses of the s^￠ \sigma^{{\prime}}_{} and e \epsilon mesons are taken to be 980MeV, which are just the masses of the experimental a ₀(980) , f ₀(980) mesons. The mass of the s \sigma meson is an adjustable parameter and is decided by fitting the binding energy of the deuteron, the masses of 560MeV and 644MeV are obtained for the ideal mixing and the q_s \theta_{s}^{} = 19^° mixing, respectively. We find that, in order to reasonably describe the YN interactions, the mass of the k \kappa meson is near 780MeV for the ideal mixing. However, we must enhance the mass of the k \kappa meson for the q_s \theta_{s}^{} = 19^° mixing, the 1050MeV is favorably used in the present work. The experimental s \sigma and k \kappa scalar mesons are very strange, both have larger widths. Hence, no matter what kind of mixing is considered, all the masses of scalar mesons we used in the present work seem to be consistent with the present PDG information.     

Calculation of the interaction force between a relativistic electron beam and an Ohmic plasma channel

A formula for calculating the interaction force between a relativistic electron beam and a preformed Ohmic plasma channel with an arbitrary offset of the channel axis from the beam axis is obtained in the case of complete charge neutralization. It is shown that this force is repulsive for radial profiles of the conductivity with a peak on the channel axis. Zh. Tekh. Fiz. 67, 69–76 (June 1997)     

Leading relativistic correction to the interaction coefficients between atoms and molecules using Borel integral II

Lower and upper bounds to the leading relativistic correction to the interaction coefficients between H, He, Ne, Kr, and Xe atoms, and H₂ and N₂ molecules have been evaluated by using Borel integral for the dynamic dipole polarizability. Our results for these bounds are in agreement with others.     

Controlling the interaction between light and gold nanoparticles: selective suppression of extinction

The interaction of visible light with the particle-plasmon resonance of metallic nanoparticles can be controlled by geometrical arrangement of nanoparticle arrays. These arrays are placed on a substrate that supports guided modes in the wavelength range of the particle plasmon. Coupling of this particle-plasmon resonance to the directly incident light and to the waveguide modes results in almost complete suppression of light extinction within narrow spectral bands due to destructive interference. Variation of the structure parameters allows continuous tuning of these high-transmission bands across the particle-plasmon resonance.     

Optical interaction between one-dimensional fiber photonic crystal microcavity and gold nanorod

Localized surface plasmon resonance(LSPR) has demonstrated its promising capability for biochemical sensing and surface-enhanced spectroscopy applications. However, harnessing LSPR for remote sensing and spectroscopy applications remains a challenge due to the difficulty in realizing a configuration compatible with the current optical communication system. Here, we propose and theoretically investigate a hybrid plasmonic-photonic device comprised of a single gold nanorod and an optical fiber-based one-dimensional photonic crystal microcavity, which can be integrated with the optical communication system without insertion loss. The line width of the LSPR, as a crucial indicator that determines the performances for various applications, is narrowed by the cavity-plasmon coupling in our device. Our device provides a promising alternative to exploit the LSPR for high-performance remote sensing and spectroscopy applications.     

Improved limit on the induced scalar interaction in nuclearβ-decay

The cross sections, the angular distributions and the ranges of the target fragmentation products formed by the reaction of 84 MeV/A¹²c with natural silver and tin have been evaluated. Their identification has been made by offline gamma ray decay measurements.     

Relativistic calculation of the two photon coupling of scalar and tensor mesons

The decay rates of scalar and tensor mesons into two photons are calculated in the Bethe-Salpeter bound state formalism. The suppression of the non-relativistic estimates due to relativistic kinematics is found to be substantial. Production crosssections in colliding beam experiments are estimated to be in the picobarn range. Also in the relativistic case the helicity 0 production cross-section of tensor mesons is found to be negligible.     

Form factor of a relativistic two-particle system within the relativistic quasipotential approach: Case of an arbitrary masses and a scalar current

A new relativistic form factor for a bound two-particle system was obtained for the case of a scalar current. The respective analysis was performed within the relativistic quasipotential approach based on a covariant Hamiltonian formulation of quantum field theory by going over to a three-dimensional relativistic configuration representation for the case of the interaction of two relativistic spinless particles that have arbitrary masses.     

Prediction of interaction between small molecule and enzyme using AdaBoost

The knowledge of whether one enzyme can interact with a small molecule is essential for understanding the molecular and cellular functions of organisms. In this paper, we introduce a classifier to predict the small molecule– enzyme interaction, i.e., whether they can interact with each other. Small molecules are represented by their chemical functional groups, and enzymes are represented by their biochemical and physicochemical properties, resulting in a total of 160 features. These features are input into the AdaBoost classifier, which is known to have good generalization ability to predict interaction. As a result, the overall prediction accuracy, tested by tenfold cross-validation and independent sets, is 81.76% and 83.35%, respectively, suggesting that this strategy is effective. In this research, we typically choose interactions between small molecules and enzymes involved in metabolism to ultimately improve further understanding of metabolic pathways. An online predictor developed by this research is available at . Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.