Calculation of nucleon densities in calcium,nickel, and molybdenum isotopes on the basis of the dispersive optical model

The radial distributions of proton and neutron densities in the even–even isotopes ^40?70Cа and ^48?78Ni and the analogous distributions of neutron densities in the even–even isotopes ^92?138Mo were calculated on the basis of the mean-fieldmodel involving a dispersive optical potential. The respective root-mean-square radii and neutron-skin thicknesses were determined for the nuclei under study. In N > 40 calcium isotopes, the calculated neutron root-mean-square radius exhibits a fast growth with increasing N, and this is consistent with the prediction of the neutron-halo structure in calcium isotopes near the neutron drip line.     

Critical Point of the 152Sm, 154Gd,and 156Dy Isotones

Physics of Atomic Nuclei - The even—even rare-earth nuclei in U(5)—SU(3) region at neutron number (N) = 90, have been systematically studied using the Bohr—Mottelson Model (BM),...     

Spectral analysis of variations in cosmic rays,solar activity parameters,and the interplanetary medium

The periodicities of cosmic rays in the stratosphere, in the neutron component, and in different parameters of solar activity and the interplanetary medium between 1965 and 2015 are studied by means of spectral analysis. The data are analyzed separately according to cycles of solar activity. A shift of spectral components is observed in the even–odd combination of solar activity cycles.     

Gauge theories,time-dependence of the gravitational constant and antigravity in the early universe

It is shown that the interaction of the gravitational field with matter leads to a strong modification of the effective gravitational constant in the early universe. In certain cases this leads even to the change of sign of the gravitational constant, i.e. to antigravity in the early universe.     

Maxwell, Mechanism, and the Nature of Electricity

Maxwell aimed to reduce electromagnetism to the mechanics of an ether and even proposed a detailed ether model of electromagnetic phenomena that could accommodate light waves. I argue in this paper that Maxwell's undoubted successes in electromagnetism came about in spite, rather than because of his attempts to reduce electromagnetism to mechanics. By the end of the nineteenth century it had become clear that electric charge and the electromagnetic field were primitives on a par with, and not to be reduced to mechanical entities such as mass.     

Distribution of current, surface impedance, and damping in superconductor coupled microstriplines

The nonuniform current distribution in the transverse cross section of the coupled conductors of a microstripline made with superconductor films leads to a substantial dependence of the losses in the line on the relative position of the coupled strips. Analytical expressions are obtained in the static approximation for the current distribution in the coupled conductors for even and odd modes, and the current distribution in the ground plane is found. The influence of the relative position of the conductors on the impedance per unit length and on the damping of electromagnetic waves in a structure with coupled superconductor lines are investigated for excitation of even and odd modes. Pis’ma Zh. Tekh. Fiz. 67, 83–88 (February 1997)     

Electron capture of nuclides 52,53,54, 55, 56Fe in magnetars

Based on the theory of relativity in superstrong magnetic fields (SMFs), we have carried out an estimation on electron capture (EC) rates of nuclides ^{52,53,54,55,56}Fe in the SMFs in magnetars. The rates of change of electronic fraction (RCEF) in the EC process are also discussed. The results show that the EC rates increase greatly and even exceeds by 4 orders of magnitude (e.g. ⁵⁴Fe, ⁵⁵Fe and ⁵⁶Fe) in SMF. On the contrary, the RCEF decreases largely and even exceeds by 5 orders of magnitude in the SMF.     

Hysteresis, spin transitions, and magnetic ordering in the fractional quantum Hall effect

We have studied the development of metastable properties associated with a nearly spin-degenerate two-dimensional electron system. Application of large hydrostatic pressure significantly reduces the g-factor experienced by electrons in GaAs/AlGaAs heterostructure, and various fractional quantum Hall effect (FQHE) states are found to undergo transition to a spin-unpolarized ground state. In case of even numerator FQHE states, the spin transitions are accompanied by hysteresis and nonlinearity in the magnetotransport. These results strongly support a recent theory of quantum Hall magnetism in which competition between spin-polarized and spin-unpolarized ground states leads to an ordered phase that exhibits ferromagnetic correlation.     

关于自旋电子的一些为什么——浅谈与超导电性对抗的磁性元素Fe,Co,Ni为什么形成化合物就超导了?

在近20年来的凝聚态物理研究中,人们在铜基氧化物中发现了高温超导电性,在锰基钙钛矿中发现了巨磁电阻效应,以及近年来发现由铁、钴、镍等传统认为与超导对抗的元素组成化合物后可以形成超导.这些不同的体系有着迥然不同的物理行为,却具有一个共同的特征:这些铜、锰、铁、钴、镍基化合物都是3d电子材料.那么,同为3d电子,为什么在不同的环境中表现出完全不同甚至对抗的行为?文章对这些现象提出了一系列为什么,并对其进行了探讨.     

A conceptual difficulty with the distribution function for polarons,linearized in the electric field

The steady state limit of Boltzmann's equation for a polaron at weak electron-phonon coupling is studied in the ohmic regime. It is shown that the linearization of the distribution function to first order in the electric field, even at arbitrarily small field, necessarily leads to a negative distribution in some region of momentum space, if a Maxwellian distribution is assumed at zero field.     

Quantum entanglement,indistinguishability, and the absent-minded driver's problem

The absent-minded driver's problem illustrates that probabilistic strategies can give higher pay-offs than deterministic ones. We show that there are strategies using quantum entangled states that give even higher pay-offs, both for the original problem and for the generalized version with an arbitrary number of intersections and any possible set of pay-offs.     

Effects of W~(6+) occupying Sc~(3+) on the structure,vibration, and thermal expansion properties of scandium tungstate

We experimentally investigate effects of W~(6+)occupying the sites of Sc~(3+)in the unit cell of Sc_2 W_3 O_(12)(Sc_8 W_(12) O_(48))on the structure, vibration and thermal expansion. The composition and structure of the doped sample(Sc_6 W_2)W_(12) O_(48±δ)(with two W~(6+)occupying two sites of Sc~(3+)in the unit cell of Sc_8 W_(12) O_(48)) are analyzed and identified by combining the x-ray photoelectron spectroscopy and the synchronous x-ray diffraction with first-principles calculations based on density functional theory. Results show that the crystal with even W~(6+)occupying even Sc~(3+)in the unit cell is stable and maintains the orthorhombic structure at room temperature. The structure of the doped sample is similar to that of Sc_2 W_3 O_(12), and with even W occupying even positions of Sc in the unit cell and constituting the WO_6 octahedra. Raman analyses show that the doped sample possesses stronger W–O bonds and wider Raman linewidths than those of Sc_2 W_3 O_(12). The sample doped with W also exhibits intrinsic negative thermal expansion in the measured range of 150 K–650 K.     

Irreversibility,organization, and self-organization in quantum electrodynamics

QED is a fundamental microscopic theory satisfying all the conservation laws and discrete symmetries C, P, T. Yet, dissipative phenomena, organization, and self-organization occur even at this basic microscopic two-body level. How these processes come about and how they are described in QED is discussed. A possible new phase of QED due to self-energy effects leading to self-organization is predicted.     

Relevance of the slowly varying electron gas to atoms, molecules, and solids

We present a Thomas-Fermi-inspired density scaling under which electron densities of atomic, molecular, or condensed matter become both large and slowly varying, so that semiclassical approximations and second-order density gradient expansions are asymptotically exact for the kinetic and exchange energies. Thus, even for atoms and molecules, density-functional approximations should recover the universal second-order gradient expansions in this limit. We also explain why common generalized gradient approximations for exchange do not.     

Stationary,cylindrically symmetric sources in the linearized limit of topologically massive gravity

In the linearized theory of topologically massive gravitation, we consider the spacetime describing a stationary, cylindrically symmetric source. We calculate the asymptotic form of the corresponding metric. We find an off-diagonal component even if the source has a vanishing angular momentum. Moreover, we determine the component representing the Newtonian potential. The non-spinning point source is obtained as a limit case within the framework of the Abelian Higgs model.     

Connecting the Dots: Mott for Emulsions,Collapse Models,Colored Noise,Frame Dependence of Measurements,Evasion of the “Free Will Theorem”

We review the argument that latent image formation is a measurement in which the state vector collapses, requiring an enhanced noise parameter in objective reduction models. Tentative observation of a residual noise at this level, plus several experimental bounds, imply that the noise must be colored (i.e., non-white), and hence frame dependent and non-relativistic. Thus a relativistic objective reduction model, even if achievable in principle, would be incompatible with experiment; the best one can do is the non-relativistic CSL model. This negative conclusion has a positive aspect, in that the non-relativistic CSL reduction model evades the argument leading to the Conway–Kochen “Free Will Theorem”.     

Kolmogorov scaling of turbulent flow in the vicinity of the wall

How to scale even the simplest of turbulent flows continues to be a cause for considerable controversy. In the present research, a data base compiling results from channel flow direct numerical simulations and turbulent boundary layer experiments is employed to investigate the properties of shear and normal Reynolds stresses very close to the wall. Two types of scaling based on Kolmogorov length and velocity scales are analyzed. It is shown that it is highly likely that large length scales of the order of the channel half-width or the boundary layer thickness play an important role even in the innermost regions of wall-bounded turbulent flows, which hints at the persistence of Reynolds number effects in even high Reynolds number flows.     

Accuracy, latency, and listener-search behavior in localization in the horizontal and vertical planes

Thirty-six listeners localized continuous filtered noise bursts centered on 2.3 or 8.3 kHz under normal listening conditions or while wearing earmuffs. The noise bursts were from any one of 20 loudspeakers, 18 degrees apart, visible to the listeners, and arranged in the horizontal and vertical planes. Listeners were free to move, while remaining seated, throughout all trials. The noise bursts were terminated by the listeners. Measures of accuracy and latency showed that earmuff listening had a significant effect whereas, overall, signal frequency had no significant effect. There was, however, an apparent downward shift of the 2.3-kHz signals presented above the midline in the vertical plane. Analysis of video records of listeners' behavior revealed a strong tendency for initial orientation by head or eye movement to correlate with final response, even when both were inaccurate. The paradigm adopted in this latter aspect of the study illustrates an "ecological" approach to the study of auditory phenomena.     

Sm(Co,Cu,Fe,Zr)z反磁化过程的微磁学分析

通过微磁学有限元方法研究了微结构对各向异性的Sm(Co,Cu,Fe,Zr)z磁性能的影响， 并 对不同温度下的退磁曲线进行了计算.计算结果表明，矫顽力随着2∶17相晶粒尺寸的增大 而增大，随1∶5晶界相厚度的增大而减小；通过减小晶界相厚度或增大晶粒尺寸可以有效提 高 磁能积.反磁化的物理机制主要为形核机制，主要表现为首先在晶界相形成反磁化核，随 着 磁场的增大反磁化核不断长大，最后导致整个磁体的磁化反转；而当温度升高时，晶界相逐 渐变成非磁性相，使得反磁化核难以形成，因此出现了反常的矫顽力温度依赖关系. 关键词： 微磁学 有限元 微结构 磁性能