On the repulsion of beam electrons

The results showing the difficulty of measurement of the current amplitude of subnanosecond electron beams are presented. It was found that the transverse velocity due to electron repulsion results in an electron fraction removal beyond a collector.     

On Einstein four-manifolds

In this paper we obtain obstructions to the existence of Einstein metrics satisfying auxiliary sectional curvature bounds. In particular, we give sufficient conditions for a compact-oriented Einstein four-manifold M to be isometric to either the sphere S⁴ or the complex projective space CP². Also, we improve the Hitchin–Thorpe’s inequality which relates the Euler characteristic of M and its signature.     

On the universality of Einstein equations

It is proved that a Lagrangian field theory based on a linear connection in space-time is equivalent to Einstein's general relativity interacting with additional matter fields.     

On the exchange repulsion between beryllium atoms

Assuming the wave functions for free atoms in the form of the closed-shell SCF determinants, the first-order interaction energy for a system of three ground-state beryllium atoms has been computed. The decomposition of two and three-body interaction energies into individual, intershell contributions has been proposed. The results show that only the electrostatic energy is well approximated by the interaction of outer shells. For the two and three-body exchange energies this approximation is reliable only in the region of small orbital overlap. It has also been found that the three-body contribution to the interaction energy is considerably greater than in the case of the interaction of helium atoms.     

On the consequences of Einstein locality

After some considerations about the equivalence of the objective local theories to the deterministic theories of Bell's type, a simple and systematic way to deduce inequalities from Einstein locality is introduced: All the inequalities deduced by Bell and by other authors, as well as several new ones, are so obtained. Some theorems are proven which show how striking the difference is at small angles between a correlation function satisfying Einstein locality and the quantum mechanical one. Experiments at small angles involve weaker additional assumptions than those used up to now in experimental research on Bell's inequality.     

Einstein equations and inertial forces in axially symmetric stationary spacetimes

We investigate the relations between the inertial forces and the Einstein equations in axially symmetric stationary spacetimes. For the vacuum stationary axially symmetric spacetimes, we use the Geroch formalism to express the Einstein equations in terms of inertial forces. For the spacetimes with the perfect fluid sources, we use the formalism developed by Hansen and Winicour for establishing the relations. As expected intuitively, the gradients of inertial forces represent the field equations.     

On the definition of the repulsion energy between unlike particles

An equation for the repulsion energy between unlike molecules, which is independent of the form of potential, is obtained from the data on the repulsion energy for like molecules. The equation is based on the model of deformable atoms and on the theoretically substantiated assumption concerning the relation between the closest approach distance and the coordinate of the energy distribution peak for the pair interaction. The applicability of the resultant relation for the known forms of the repulsion potential is considered.     

On the fifth forces

We discuss the possibility of fifth forces in relativistic gravitation theories of fourth order. The fifth force may be an analog to the weak forces in the theories of electroweak interactions.     

On Chelnokov-Zeitlin solutions to the vacuum Einstein equations

The equivalence of the Chelnokov-Zeitlin solutions to the vacuum Einstein equations with a special class of Lewis solutions is established in a direct way. Also, an oversight on the signature of the solutions is pointed out and corrected.     

On the Energy-Momentum Problem in Static Einstein Universe

The energy-momentum distributions of Einstein＇s simplest static geometrical model for an isotropic and homogeneous universe are evaluated. For this purpose, Einstein, Bergmann-Thomson, Landau-Lifshitz （LL）, Moller and Papapetrou energy-momentum complexes are used in general relativity. While Einstein and Bergmann-Thomson complexes give exactly the same results, LL and Papapetrou energy-momentum complexes do not provide the same energy densities. The Moller energy-momentum density is found to be zero everywhere in Einstein＇s universe. Also, several spacetimes are the limiting cases considered here.     

On a static axisymmetric solution of the Einstein equations

A family of static, axisymmetric, asymptotically flat solutions of the Einstein equations is discussed. A source with an exterior described by a member of this family initially could have an area smaller than that of a n appropriately defined Schwarzchild surface. Intuition does not suggest the fate of the collapsing source.     

On the nonexistence of Einstein metrics on 4-manifolds

By using the gluing formulae of the Seiberg–Witten invariant, we show the nonexistence of Einstein metrics on manifolds obtained from a 4-manifold with a nontrivial Seiberg–Witten invariant by performing sufficiently many connected sums or appropriate surgeries along circles or homologically trivial 2-spheres with closed oriented 4-manifolds with negative-definite intersection form.     

论广义力的涨落

应用系统理论和准热力学方法，计算了气体压强和电介质极化强度的涨落。结果表明，这两个量在正则系统和巨正则系统的涨落均在数值上的差异，准热力学方法对气体压强的涨落给出的结果和巨正则系综相同，对电介质极化强度的涨落所得结果则和正则系缩相同，文中阐明了这些结果异同的原因。     

On a remarkable electromagnetic field in the Einstein Universe

We present a time-dependent solution of the Maxwell equations in the Einstein universe, whose electric and magnetic fields, as seen by the stationary observers, are aligned with the Clifford parallels of the 3-sphere \(S^3\). The conformal equivalence between Minkowski’s spacetime and (a region of) the Einstein cylinder is then exploited in order to obtain a knotted, finite energy, radiating solution of the Maxwell equations in flat spacetime. We also discuss similar electromagnetic fields in expanding closed Friedmann models, and compute the matter content of such configurations.     

On an exact classical wave solution of the Einstein equations

The J. Scherk and J. H. Schwarz generalization of a Peres solution is shown to be the Peres solution in a different system of coordinates.     

On the possibility of pair condensation in the Hubbard model with strong repulsion

The phonon-free mechanism of superconductivity at infinite Hubbard energy is discussed. The temperature of superconducting transition (T_c) depending on the rate of non-fulfilling (x) of the lower Hubbard subband has been calculated.     

On the type N twisting vacuum solution of the Einstein equations

One of the problems in the catalogue of solutions to the vacuum solutions of the Einstein equations is the dearth of solutions to what is known as the type N twisting metric. Were it to be found in its general form it would then, according to the Peeling theorem of Sachs (Proc R Soc Lond A270:103, 1962), describe the asymptotic gravitational field of an isolated source. The only known mathematical solution was found by Hauser (Phys Rev Lett 33:1112, 1974) and (Phys Rev Lett 33:1525, 1974). In this article the general equations are reduced to one third order complex equation for one complex variable plus one simple condition.