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1.
A class of the asymptotically Euclidian space-times is shown to exist for which the Schwarzschild mass is equal to zero. The coordinate atlases of these space-times satisfy two additional conditions: k (-gg 0k )=0 and ik 0 0g ik - ik k 0g 0i =0. In aT-orthogonal metricgs 2=g 00 dt 2 -g dx dx these conditions take a simple form: 0(detg )=0 and (0 g )(0 g )=0.  相似文献   

2.
Let H be a semibounded perturbation of the Laplacian H 0 in L 2( d ). For an admissible function sufficient conditions are given for the completeness of the scattering system (H), (H 0). If is the exponential function and if eH is an integral operator we denote the kernel of the difference D = eH – eH 0 by D (x, y), > 0. The singularly continuous spectrum of H is empty ifd dx d dy |D(x,y)| (1 + |y|2)< for some > 1. This result is applied to potential perturbations and to perturbations by imposing Dirichlet boundary conditions.  相似文献   

3.
In a previous paper asymptotic creation and annhilation operatorsa ± # have been constructed by the Kato-Mugibayashi method from the creation and annihilation operatorsa # for spin 1/2 fields with an interaction Hamiltonian density which is an evendegree polynomial in the field with ultra-violet cut-off and its derivatives. For any eigenvector of the total HamiltonianH=H 0+H I partial isometries ± have been defined so thata ± # equal ± a # *± on the ranges ± of ±. Since the existence of a groundstate ofH has been proved, the existence of at least one pair ± follows. The purpose of this paper is to show that for any ± orthogonal to the distribution of spins and momenta of the interacting Schrödinger states exp[–itH]± approaches fort the distributions of spins and momenta of the free state exp[–itH 0] if a wave-amplitude renormalization is carried out in ±. This is achieved by studying the expectation values of the operators in themaximally abelian W*-algebra generated by operators of the form a*a, in terms of whichany information about spins and momenta can be expressed.Supported in part by the National Research Council of Canada.  相似文献   

4.
The quantum harmonic oscillator is described in terms of two basic sets of coordinates: linear coordinates x, px and angular coordinates ei, P (action-angle variables). The angular coordinate ei is assumed unitary, the conjugate momentum p is assumed Hermitian, and ei and p are assumed to be a canonical pair. Two transformations are defined connecting the angular coordinates to the linear coordinates. It is found that x, px can be physical, i.e., Hermitian and canonical, only under constraints on the p eigenvalue spectrum. The conclusion is that ei can be a unitary operator. A parallel analysis of the classical harmonic oscillator is done with equivalent results.  相似文献   

5.
Self-diffusion coefficients of vanadium in the FeV -phase and in the corresponding -solid solution (Fe-47 wt.% V) measured in the temperature ranges 1002–1115 °C (-phase) and 1230–1320 °C are reported. The found results differ fundamentally and significantly from the relations in ordered and disordered solid solutions [9]. The diffusivity in -phase at the transition temperature (T /=1200 °C) is cca 14 times lower than the diffusivity in the b.c.c. solid solution, the chemical composition of which is the same. The lowering is caused by the different values of frequency factors,D O=0.11 cm2/s andD O=45 cm2/s. The effect of the corresponding activation enthalpiesH =252 kJ/mole andH =293 kJ/mole is small and quite opposite. The occurence of higher activation enthalpyH in the -solid solution at temperaturesT>T / may be attributed to a certain amount of the f.c.c. phase coexisting in the b.c.c. matrix at concentrationsc v>27 wt.% at sufficiently high temperatures [7]. A comparison of vanadium self-diffusion characteristics measured in the -phase to the extrapolated values obtained on the basis of the previous measurements [1] in the Fe-V primary solid solutions 1 shows that the diffusivity ratioD 1/D (1473 K)=33 and that the activation enthalpyH is by about 3% higher than the valuesH 1 (eq. (5)) measured in the uniphase b.c.c. solid solutions.  相似文献   

6.
A study has been made of the effects of radiation corrections of order as regards the probability of lepton decay of a moving neutral vector meson V e+e and V + (V = 0, , ); -e universality has been checked by examining the effects of radiation corrections due to exchange of virtual photons between lepton and antilepton, and also to vacuum polarization by e+e electron and +muon closed loops; in addition, a study has been made of the emission of soft photons as regards the partial width for the electron and muon modes of V-meson decay. Closed expressions (1), (4), and (5) for the corrections imply that the ratio ¦Rv¦ for the probabilities of decay of a V meson to e+e and +, which are given by (11), agree well with the available evidence on 0 e+e + decays and indicates a possible deviation from -e universality in e+e+ decays.Read at the meeting on high-energy physics, Nuclear Physics Section Academy of Sciences of the USSR (Moscow, February 11–15, 1974).Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 84–89, July 1975.We are indebted to Professor A. A. Sokolov for a discussion.  相似文献   

7.
A cluster of two atoms described by thes-f model with Coulomb repulsion has been considered. The interaction between localized 4f electrons (S=1/2) is taken in the molecular field approximation. The thermodynamic quantities like magnetization, specific heat and correlation functions n , n , S z n , S z n , S z (n n ), n n and S + a + a as functions of temperature are presented for different band fillingN=0, 0.5, 1, 1.5, 2. The dependence of Curie temperature onN is calculated. The phase diagram forN=1 (T=0K) shows the possibility of existence of two phases: paramagnetic and ferromagnetic.The Curie temperature and the specific heat as functions ofN exhibit similar trends as found in experiments on doped magnetic semiconductors.  相似文献   

8.
We study the change of an quasienergy spectrum upon variation of the weight of a perturbation in the Floquet operatorF=F 0e–iV . Employing ideas from level dynamics and random matrix-theory we show that the distribution of nearest-neighbor spacings can display effectively irreversible behavior. Small deviations from equilibrium relax in a certain collision time which scales with the numberN of levels as collN –3/2.  相似文献   

9.
We study the spectral properties of the Floquet operator for the periodically kicked HamiltonianH(t) =H 0+ + (tnT),H 0 being self-adjoint and pure point. We show that the Floquet operator is pure point for almost every , if is cyclic forH 0 and has absolutely convergent expansion in the basis of eigenstates ofH 0. When this last condition is not satisfied, the Floquet operator can have a continuous spectrum, as we show by an example.  相似文献   

10.
An analytic gravitational fieldZ (Z y ) is shown to include electromagnetic phenomena. In an almost flat and almost static complex geometryds 2 =zdzdz of four complex variables z=t, x, y, x the field equationsR Rz = –(U U Z ) imply the conventional equations of motion and the conventional electromagnetic field equations to first order if =(Z v) and =(z ) are expressed in terms of the conventional mass density function , the conventional charge density function , and a pressurep as follows: v=const=p/c 2–10–29 gm/cm3.  相似文献   

11.
Our most complete results concern the Ising spin system with purely ferromagnetic interactions in a magnetic fieldH (or the corresponding lattice gas model with fugacityz=const. exp(–2mH) wherem is the magnetic moment of each spin). We show that, in the limit of an infinite lattice, (i) the free energy per site and the distribution functionsn s (x 1, ...,x s ; ,z) are analytic in the two variables andH if the reciprocal temperature >0 and the complex numberH is not a limit point of zeros of the grand partition function , and (ii) the Ursell functionsu s (x 1, ...,x s ; ,z) tend to 0 as s Max i, j |x i x j | if >0 and ReH0; in particular, if the interaction potential vanishes for separations exceeding some fixed cutoff value , then |u s |<C exp [(–2 m |ReH|+) s /] where is any small positive number andC is independent of s . One consequence of the result (i) is that a phase transition can occur as is varied at constantH only ifH is a limit point of zeros of (which can happen only if ReH=0); this supplements Lee and Yang's result that the same condition is necessary for a phase transition whenH is varied at constant .For a lattice or continuum gas with non-negative interaction potential (corresponding, in the lattice case, to an Ising antiferromagnet), similar results are shown to hold provided >0 and the complex fugacityz is less than the radius of convergence of the Mayerz expansion; for the continuum gas, however,n s andu s must be replaced by their values integrated over small volumes surrounding each of the pointsx 2, ...,x s .It is shown that the pressurep is analytic in both andz, if it is analytic inz at fixed over a suitable range of values of andz, and further that, except for continuum systems without hard cores,p,n s andu s have convergent Maclaurin expansions in for small enoughz.Supported by the U.S. Air Force Office of Scientific Research under grant no. AF 68-1416.  相似文献   

12.
Let t be an analytic solution of the Schrödinger equation with the initial condition . Let t be the solution of the Schrödinger equation with the initial condition =, where is an analytic function. When 0, then t (x) t (x)1 ( t (x)), where t (x) trajectory starting from x. We relate this result to Feynman's sum over trajectories and complex stochastic differential equations.  相似文献   

13.
We assume that the electron (e ), neutrino (v e), and gauge bosons (W ±,Z 0) are composed of only two kinds of particles, an ultimate particleu at an infinite sublayer quark level and a chargeless fermiont, such thate =(u cp u cp l),V e =(u u cp l,W +=(u u ),W =(u cp u cp andZ 0=(u u cp . It is then shown thatCP is violated in weak interactions associated with these electron, neutrino, and gauge bosons.  相似文献   

14.
We show that ifb andb are two boundary conditions (b.c.) for general spin systems on d such that the difference in the energies of a spin configuration in d is uniformly bounded, |H ,b ()–H ,b()|C < , then any infinite-volume Gibbs states and obtained with these b.c. have the same measure-zero sets. This implies that the decompositions of and into extremal Gibbs states are equivalent (mutually absolutely continuous). In particular, if is extremal,=. Application of this observation yields in an easy way (among other things) (a) the uniqueness of the Gibbs states for one-dimensional systems with forces that are not too long-range; (b) the fact that various b.c. that are natural candidates for producing non-translation-invariant Gibbs states cannot lead to such an extremal Gibbs state in two dimensions.Supported in part by NSF Grant PHY 78–15920 and by the Swiss National Foundation For Scientific Research.  相似文献   

15.
The applicability of (K ,) - and (K , N)-reactions on13,14C and14,15N nuclei to the study of -transitions in primary and daughter -hypernuclei is discussed. The intensity of -deexcitation of 13C state |S 12C(15·11 MeV; 1+1): 1/2+ has been shown to be comparable with the intensity of baryon decay. Isospin selection rules are used to distinguish excitation energy ranges of primary hypernuclei, where the identification of the secondary -lines is probable.Presented at the symposium Mesons and Light Nuclei, Bechyn, Czechoslovakia, May 27–June 1, 1985.  相似文献   

16.
Integration of the cross section of the process+(Ze)(Ze)+1+e+e+ over the angles of emission of the electron and positron was carried out, and the angular, energy, and spin dependences of the cross section were obtained. The cross section for photoproduction of a lepton-antilepton pair and a quantum on nuclei in the case where the emitted photon moves in the same direction as the incident quantum can exceed the Bethe-Heitler cross section for ordinary photoproduction of an ee+ pair. The probabilities of some electron and positron spin states are analyzed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 106–110, June, 1972.In conclusion I express my thanks to A. A. Sokolov and A. I. lViukhtarov for valuable advice.  相似文献   

17.
The dynamics of ann-component vector spin glass with infinite range interactions are investigated near and above the Gabay-Toulouse (GT) line. The local transverse susceptibility T for 0 varies along the whole GT lineT c1 (H) as v , with a field and temperature independent critical exponentv=1/2. The longitudinal susceptibility L () remains analytic for all (T, H)T c1 (H), except for a cross-over fromv=1 tov=1/2 forH0 at the freezing temperatureT=T f . The dynamic susceptibilities T () and L () are already coupled above the GT line via self-energy terms. BelowT c1 (H), this coupling is strongly enhanced by other mechanisms.  相似文献   

18.
The phenomenological approach to investigating the decay of the vacuum energy density is generalized in the spirit of Dirac's large number hypothesis. Different arguments are outlined to justify an universal dependence of the type =H 2 ( is a pure number andH is the Hubble parameter). Such time-varying A does change the predictions of the earlier Dirac's cosmology. The deceleration parameter (q 0=(2–)/(1+)) and the age parameter (H 0t0=(1+)/3) are now compatible with the observations. The model also allows a power-law inflationary phase and a rate of matter creation smaller than the one present in the steady state universe.  相似文献   

19.
Let U(a, ) be a representation of the Poincaré group with mass and helicity zero, realized in the space of C -functions with compact support on 3, without the origin. Let U (2)(a, ) denote the tensorial product of U(a, ) by itself. We explicitly determine the cocycles of extension of U(a, ) by U (2)(a, ) and we prove that the nontrivial cohomology is indexed by (u(),),u()D 1 ]0,3\,.  相似文献   

20.
The (non-Lorentz covariant) system consisting of a relativistic scalar Boson field interacting with a single spinless particle (relativistic polaron) with kinetic energy function (m 2+|p|2)1/2 is studied ind space demensions, whered3. The interaction Hamiltonian is taken to be (x)* (x) (x)dx where has a momentum cutoff. The physical one polaron Hilbert space ph for this model, corresponding to no cutoff on , is constructed. The total renormalized HamiltonianH without cutoff is constructed as a semibounded self-adjoint operator on pH . The time zero physical Boson field is also constructed. First order estimates are established for the local (in momentum space) number operators in terms ofH.This research was partially supported by N.S.F. grants GP 28109 and GP 28443 and U.S.A.F. grant AF-AFOSR 743-67.  相似文献   

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