Final dt stickingω s using the “survived moun method”

A new direct measurement of the final dt sticking probability _s using a special data analysis called the survived muon method is presented. The data were obtained at PSI using a high pressure ionization chamber with H/D/T gas mixtures. The method can provide information on final sticking dt +n independent of theoretical models of stripping and initial sticking. It was found: _s=(0.57±0.07±0.02)%. The experiment and the analysis method are discussed in detail.     

НИЗКОЧАСТОТНЫЕ КОЛЕ БАНИЯ ПРЯМОУГОЛЬНЫХ ПЛАСТИНОК ADP

- — . , - NH₄H₂PO₄,- ADP. ; - .     

Asymptotically abelian systems

We study pairs { , } for which is aC*-algebra and is a homomorphism of a locally compact, non-compact groupG into the group of *-automorphisms of . We examine, especially, those systems { , } which are (weakly) asymptotically abelian with respect to their invariant states (i.e. |A _g (B) — _g (B)A 0 asg for those states such that ( _g (A)) = (A) for allg inG andA in ). For concrete systems (those with -acting on a Hilbert space andg _g implemented by a unitary representationg U _g on this space) we prove, among other results, that the operators commuting with and {U _g } form a commuting family when there is a vector cyclic under and invariant under {U _g }. We characterize the extremal invariant states, in this case, in terms of weak clustering properties and also in terms of factor and irreducibility properties of { ,U _g }. Specializing to amenable groups, we describe operator means arising from invariant group means; and we study systems which are asymptotically abelian in mean. Our interest in these structures resides in their appearance in the infinite system approach to quantum statistical mechanics.     

Between Equilibrium Fluctuations and Eulerian Scaling: Perturbation of Equilibrium for a Class of Deposition Models

We investigate propagation of perturbations of equilibrium states for a wide class of 1D interacting particle systems. The class of systems considered incorporates zero range, K-exclusion, misanthropic, bricklayers models, and much more. We do not assume attractivity of the interactions. We apply Yau's relative entropy method rather than coupling arguments. The result is partial extension of T. Seppäläinen's recent paper. For 0<<1/5 fixed, we prove that, rescaling microscopic space and time by N, respectively N ¹⁺ , the macroscopic evolution of perturbations of microscopic order N ^– of the equilibrium states is governed by Burgers' equation. The same statement should hold for 0<<1/2 as in Seppäläinen's cited paper, but our method does not seem to work for 1/5.     

Positivity of entropy production in nonequilibrium statistical mechanics

We analyze different mechanisms of entropy production in statistical mechanics, and propose formulas for the entropy production ratee() in a state . When is steady state describing the long term behavior of a system we show thate()0, and sometimes we can provee()>0.     

Approximate calculation of frequencies of localized vibrations

An exact calculation of the frequencies of localized vibrations in a crystal with defects meets with considerable difficulties and therefore only the simplest cases have been calculated [9, 10]. An approximate calculation is confined to computing the frequencies of a system composed of several atoms in the neighbourhood of the defect. The interaction between this system and the other atoms of the lattice, which however are immobile in this approximation, is taken into consideration. Since the analytical estimate of the approximation is very rough, the approximate and exact calculations have been compared for some concrete cases (Fig. 1, 2). It is clear from these calculations that the use of the proposed approximation leads to good results.

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, [9, 10]. , . , , . , (. 1, 2). , .

     

Is the “missing mass” really missing?

We have no experimental evidence for the validity of the inverse square law for gravitation at distances significantly larger than the diameter of the solar system. This raises the very real possibility that the missing mass (dark matter) may not exist. Instead, the inverse square law may be breaking down at distances of the order of tens of kiloparsecs. I discuss this possibility within the framework of Scalar-Vector-Tensor (SVT) theories of gravity. It appears to be relatively easy to account for up to approximately 10% of the galactic halo dark matter via SVT theories of gravity. With some fine-tuning of parameters, it is conceivable that all of the dark matter can be accounted for in this way.This essay received an honorable mention from the Gravity Research Foundation for the year 1987.Supported by the U.S. Department of Energy under grant #DE-FG03-84ER-40168.     

The rate of growth of the magnetic energy density during a gravitational collapse

It is shown that during an isotropic gravitational collapse of a fluid with infinite electrical conductivity, the magnetic energy density cannot grow faster than ^4/3 no matter the equation of state, where is the total proper energy density. If the equation of state is=c ², where 01, then the rate of growth of the magnetic energy density in such a collapse is proportional to ^4/3(1+). If an isotropic collapse is also locally adiabatic, it is shown, independently of any equation of state, that the rate of increase of the magnetic energy density is proportional tor ^4/3, wherer is the proper material density. If the collapse is nonisotropic, shear can modify these results. Numerical estimates of the magnetic field strength at various stages in the collapse of a magnetic star are given.     

Model for γγ→VV reactions near threshold

We propose a Veneziano-like model for VV reactions near threshold involving exchanges of 0^– trajectories int- andu-channels. The model is applied to , , , and processes. The model in its simplest form cannot account for the disparities in the cross sections for andK ^*+ K ^*– and for ⁰⁰ and ^+–. Further refinements of the model are suggested.     

The basic equations of the dynamics of the continuous distribution of dislocations III. special problems

The basic equations of the dynamics of the continuous distribution of dislocations analogical to Maxwell equations are derived in a series of papers [I, II, III]. The analogy of the elastic and electromagnetic fields is analyzed. In part [III] some special problems are discussed, such as the density of the forces acting on the dislocations, the energy dissipation during the movement of dislocations, which is expressed by an equation analogical to Ohm's law. The equations derived in the previous parts in four-dimensional symbolics are considered in the three-dimensional differential and integral form. It is found that in special cases the relations become the known ones of elastodynamics, hydrodynamics and the static theory of the continuous distribution of dislocations. It is found that Kröner's method of integrating the equations of the dislocation field by means of so-called incompatibility tensors is analogical to the integration of the Maxwell equations by means of Hertz vectors. The analogy between the elastic dislocation field and the electromagnetic field is discussed in detail.

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III.

, . . : , , , , . , , . , , . , . .

     

Nonsingular cosmological model with matter creation and entropy production

The study of nonsingular cosmological models [4] based on a theory of gravitation in flat space-times [1] is continued. For a radiation free universe the solution of the model is given analytically. Under the assumption that entropy cannot decrease the cosmological constant must be zero. At the beginning of the universe all energy is in the form of gravitation. The universe contracts. Matter and radiation are created out of gravitational energy and entropy is produced. The contraction stops and then the universe expands without limit. The creation of matter continues producing entropy but today the production of matter and entropy is negligible. The density parameter ₀ 1, i.e. there must be missing mass in the universe. The flatness and the homogeneity problem are solved.     

Mild Inflation and Modified General Relativity in the Early Universe

This article deals with particle creation andthe production of specific entropy per baryon in theearly universe, which is regarded as a thermodynamicallyopen system in the sense of Prigogine. The modified general relativity (MGR) theory of Rastall,Al-Rawaf, and Taha is employed. It contains an extraindependent constant which is peculiar to thenon-Newtonian regime, besides the usual gravitationalconstant. Usual general relativity (GR) appears here asa special case for = 1. With a modifiedthermodynamic energy conservation law, it is possible toobtain an equation for the expansion scalar byincorporating the epoch dependence of elementary particlemasses. The epoch dependence of particle masses for theRobertson-Walker (RW) universe appears as a consequenceof hadronic matter extension in a microlocal space-time regarded as anisotropic and Finslerian. Thegoverning equations in the present formalism specify theequation of state and give a solution for the expansionscalar. This solution represents a mild inflationary phase in the very early universe. It is alsoshown that there are no 'turn-on' and'turn-off' problems for this mild inflation.It can account for particle creation and production ofspecific entropy per baryon consistent with the observation. Theproduction of specific entropy per baryon is alsoconsidered here in the MGR framework with theintroduction of viscous pressure; the calculated valueis in good agreement with observation for the GR case, butfor the MGR case, in order to have its value withinobservational limits, must lie in the range 0.75 1. It is also argued that this formalismdoes not have horizon and flatnessproblems.     

Parameterization of the energy spectrum of an impurity ion in a perturbing field

The method of parameterizing the energy spectrum for systems with symmetries of the simplest point groups (SR groups) in an external stationary perturbing field has been generalized to the third approximation. The sums over intermediate states are partially convolved in 3n coefficients. We retain sums of derivatives of the given matrix elements which refer to states of all possible energy levels which enter into the external parameters which represent the minimal set of parameters describing the corrections to the energy. We give formulas for calculating the external parameters and establish the connection with the internal parameters in the usual version of the stationary theory of perturbations. In determining the parameters from experimental data the advantage of our method is found in those cases where the number of external parameters is less than the number of internal ones, which is the usual case. The method is illustrated using the Zeeman and Stark effects for energy levels of the T_2g type for an impurity ion having O_h site symmetry, as an example.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 61–67, March, 1995.     

Temperature in Friedmann thermodynamics and its generalization to arbitrary space-times

In recent articles we have introduced Friedmann thermodynamics, where certain geometric parameters in Friedmann models were treated like their thermodynamic counterparts (temperature, entropy, Gibbs potential, etc.). This model has the advantage of allowing us to determine the geometry of the universe by thermodynamic stability arguments. In this paper, in search for evidence for the definition of gravitational temperature, we will investigate a massless conformal scalar field in an Einstein universe in detail. We will argue that the gravitational temperature of the Einstein universe is given asT _g=1/2) (c/k) (1/R ₀), where R₀ is the radius of the Einstein universe. This is in accord with our definition of gravitational temperature in Friedmann thermodynamics and determines the dimensionless constant as 1/2. We discuss the limitations of the model we are using. We also suggest a method to generalize our gravitational temperature to arbitrary space-times granted that they are sufficiently smooth.Based on three essays awarded honorable mention in the years 1987, 1988 and 1989 by the Gravity Research Foundation—Ed.     

ВЛИЯНИЕ ПОЛНОГО ОТРА ЖЕНИЯ НА ДИАФРАГМЕ СОЛЛЕРА НА РАЗРЕШАЮШ УЮ СИЛУ РЕНТГЕНОВСКО ГО СПЕКТРОГРАФА

- - , , , . - , -.     

Problems in the interpretation of cosmic ray nuclear interactions

Difficulties in the interpretation of high-energy nuclear interactions are discussed and explanations suggested on the basis of successive or composite nucleon-nucleus collisions, the first predominant below a few 10 ¹¹ eV,the second for higher energies. In the energy region up to about 10 ¹¹ eVsome discrepancies in the frequency of production of strange particles, the small interaction cross-section of iron etc. are explained, taking into account secondary intranuclear collisions. The tunnel model of Heitler and McCusker is replaced by assuming a cone-shaped interaction volume (funnel) even at the highest primary energies. A number of consequences concerning the energies of the primary particles, the multiplicity and asymmetry in the angular distribution of secondaries, coefficient of inelasticity etc. are discussed.

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, , 10¹¹ eV, — . 10¹¹ eV , ., , . () . , , , .

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This paper contains a condensed summary of some of the material presented in a series of lectures given by the author on the occasion of his visit to Prague in December 1957/January 1958. Its publication in this form is intended as an expression of thanks to the Czechoslovak Academy of Sciences and its leading Officers, in particular Prof. V. Procházka, Prof. J. Novák, and Prof. V. Petrílka, whose kind invitation made this visit possible.     

Absence of symmetry breakdown and uniqueness of the vacuum for multicomponent field theories

Correlation inequalities are used to show that the two component (²)² model (with HD, D, HP, P boundary conditions) has a unique vacuum if the field does not develop a non-zero expectation value. It follows by a generalized Coleman theorem that in two space-time dimensions the vacuum is unique for all values of the coupling constant. In three space-time dimensions the vacuum is unique below the critical coupling constant.For then-componentP(||²)₂+₁ model, absence of continuous symmetry breaking, as goes to zero, is proven for all states which are translation invariant, satisfy the spectral condition, and are weak* limit points of finite volume states satisfyingN _loc and higher order estimates.     

Random surfaces with two-sided constraints: An application of the theory of dominant ground states

We consider some models of classical statistical mechanics which admit an investigation by means of the theory of dominant ground states. Our models are related to the Gibbs ensemble for the multidimensional SOS model with symmetric constraints _x m/2. The main result is that for ₀, where ₀ does not depend onm, the structure of thermodynamic phases in the model is determined by dominant ground states: for an evenm a Gibbs state is unique and for an oddm the number of space-periodic pure Gibbs states is two.     

ИЗЛУЧЕНИЕ ЧЕРЕНКОВА ПРОСТРАНСТВЕННОГО З АРЯДА В ВОЛНОВОДАХ И В НЕОГР АНИЧЕННОЙ СРЕДЕ

, - e . -. , .     

Remarks on a quantum state extension problem

The problem is considered of finding, for a given pair of states on C ^*-algebras A ₁ A ₂ and A ₂ A ₃, a joint extension to A ₁ A ₂ A ₃. The fact that, in contrast to classical probability, such an extension may fail to exist, is related to the fact that different convex decompositions of the same quantum state need not have a common refinement. Improved necessary criteria for extensibility in terms of Bell's inequalities are derived, and are compared to the necessary and sufficient criteria, as well as to entropic bounds in the simplest case.