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1.
We study the Sine-Gordon field theory at 2=8. We prove that the theory is renormalizable but not superrenormalizable and we show how the perturbative renormalization procedure works in this case where the interaction is not polynomial. To go beyond the perturbative results we investigate the -functional equation for this theory and discuss in what sense at 2=8 the theory is lacking the asymptotic freedom and how it is asymptotic free for 2<8 in a appropriate region of the coupling constants.  相似文献   

2.
The ultraviolet stability for the cosine interaction in two dimensions and finite volume is rederived for values 2 [4, 32/5[ and proven for the remaining 2 [4, 8[ by using renormalization group methods developed in [G, GN1] to portray renormalized effective potentials arising from a multiscale decomposition.Supported by the Studienstiftung des Deutschen VolkesSupported in part by the Schweizerischer Nationalfonds  相似文献   

3.
We study spectral properties of the discrete Laplacian H on the half space Z+ d+1 = Zd× Z+ with a boundary condition (n,-1) = tan( ... n + )(n,0), where [0,1]d. We denote by H0 the Dirichlet Laplacian on Z+ d+1. Whenever is independent over rationals (H) = R. Khoruzenko and Pastur have shown for a set of 's of Lebesgue measure 1, the spectrum of H on R\ (H0) is pure point and that corresponding eigenfunctions decay exponentially. In this Letter we show that if is independent over rationals, then the spectrum of H on the set (H0) is purely absolutely continuous.  相似文献   

4.
EC and decays of 235Am have been studied using a gas-jet coupled on-line isotope separator. Excited states in 235Pu have been established for the first time by means of -ray spectroscopy following the EC decay of 235Am. The deduced log ft value suggests that the ground state of 235Am should have the 5/2-[523] configuration. The - coincidence result has revealed that the 5/2-[523] state in 231Np populated by the favored transition of 235Am is located at < 15 keV, which allows us to precisely determine the Q value of 235Am.  相似文献   

5.
The long-wave * transitions and weak n * transitions are discussed for several compounds of practical importance. Wave functions are presented for aliphatic ketones, acids, and esters.  相似文献   

6.
We consider the quantum mechanical many-body problem of electrons and fixed nuclei interacting via Coulomb forces, but with a relativistic form for the kinetic energy, namelyp 2/2m is replaced by (p 2 c 2+m 2 c 4)1/2mc 2. The electrons are allowed to haveq spin states (q=2 in nature). For one electron and one nucleus instability occurs ifz>2/, wherez is the nuclear charge and is the fine structure constant. We prove that stability occurs in the many-body case ifz2/ and <1/(47q). For smallz, a better bound on is also given. In the other direction we show that there is a critical c (no greater than 128/15) such that if > c then instability always occurs forall positivez (not necessarily integral) when the number of nuclei is large enough. Several other results of a technical nature are also given such as localization estimates and bounds for the relativistic kinetic energy.Work partially supported by U.S. National Science Foundation grant PHY-85-15288-A02The author thanks the Institute for Advanced Study for its hospitality and the U.S. National Science Foundation for support under grant DMS-8601978  相似文献   

7.
The s-wave pion scattering amplitude is analysed with the aim to clarify the mass spectrum of scalar mesons and to find evidence of lightest glueball. The S-matrix and K¯K coupled channel formalism is used. The existence of scalar mesons S* and is implied by the data. The production K¯K and the elastic K¯KK¯K coupled amplitudes are predicted from the scattering data. The couplings c f S* to and K¯K states are determined.  相似文献   

8.
We investigate the continuum three-pion problem within a relativistic three-body model that takes into account the S andP waves. The dynamical input of the two-body subsystem is given by separable potentials, which yield a good fit to the scattering data and resonance parameters up to a two-body invariant mass of 900MeV. We introduce a parameter expressing the ambiguity in the reduction of a fully relativistic theory to a three-dimensional one. The masses and widths of the ,a 1(1260), and (1300) mesons, which decay predominantly into three pions, are reasonably well described by our model. Theh 1(1170) meson, however, which also decays into three pions, cannot be explained as a three-pion resonance. Some Argand diagrams are shown in those channels where resonances exist.  相似文献   

9.
Detailed studies have been made of elastic scattering and positronium formation in low energy collisions of positrons with lithium atoms for the two partial wavesl=0,1. For this system, as for all alkali atoms, the positronium formation channel is open even at zero positron energy. A two-channel version of the Kohn variational method is used with trial functions containing many variational parameters, and reasonably well converged results are obtained. The s-wave positronium formation cross section is infinite at zero positron energy but it then falls rapidly to become several orders of magnitude smaller than the elastic scattering cross section which has a maximum value of approximately 100 0 2 at a positron energy of 0.5 eV. For p-wave scattering the positronium formation cross section rises to a value of approximately 10 0 2 at an energy of 0.1 eV, with the elastic scattering cross section rising to a maximum of approximately 60 0 2 just below the first excitation threshold at 1.84 eV.  相似文献   

10.
Using the semiempirical method of partial neglect of differential overlap (PNDO), we have calculated the wave functions, energies, orbital configurations of electronic states, oscillator strengths of transitions, electronic density distributions, and dipole moments for the molecule of biologically active 8–azagona–12,17–dione, containing a conformationally rigid –acyl––aminovinylcarbonyl fragment. It has been established that as to their orbital nature the excited lower and higher singlet electronic states of this molecule are of the n*– and * type respectively. The results of the theoretical analysis are in good qualitative agreement with the spectral data on absorption and luminescence. The calculations of the intermolecular interaction of the compound under consideration with a medium show that the molecular systems under consideration can possess a dynamic multicenter structure.  相似文献   

11.
We study ergodic Jacobi matrices onl 2(Z), and prove a general theorem relating their a.c. spectrum to the spectra of periodic Jacobi matrices, that are obtained by cutting finite pieces from the ergodic potential and then repeating them. We apply this theorem to the almost Mathieu operator: (H , , u)(n)=u(n+1)+u(n–1)+ cos(2n+)u(n), and prove the existence of a.c. spectrum for sufficiently small , all irrational 's, and a.e. . Moreover, for 0<2 and (Lebesgue) a.e. pair , , we prove the explicit equality of measures: |ac|=||=4 –2.Work partially supported by the US-Israel BSF  相似文献   

12.
Using the approximative expression for the elastic energy density of the antiferroelectric (AF) liquid crystal the elastic self-energy of (, b)-wedge-screw dispiration is estimated. Then the elastic interaction between (, b)-wedge-screw dispiration and (2)-wedge dischnation in AF liquid crystals is investigated. The attraction of dislocation part of dispiration with (2)-wedge disclination can lead to the formation of (3)-wedge-screw dispiration. When (2)-wedge disclination is trapped by (2d)-screw dislocation the resulting (2, 2d)-dispiration can dissociate into a pair of two (, d)-dispirations.The authors express their thanks to Professors A. Fukuda, H. Takezoe, Dr. Y. Takanishi and to Dr. K. Miyachi for discussions concerning their experimental observations of (3, d)-wedge-screw dispirations and (, d)-twist-edge dispirations in AF structures. This work was supported by the grant No. 19062 from Acad. Sci. Cz. R. and also benefited by the grant No.: 202/93/155 from the Grant Agency of the Czech Republic.  相似文献   

13.
The solvent and temperature effect of fluorescence and phosphorescence and its polarization characteristics for -carboline-3-carboxylic acid N-methylamide were studied. From the results obtained it is concluded that the first excited singlet state changes from the * type in a polar solvent (EPA) to the n* type in a nonpolar solvent (MC) and that the lowest singlet excited states (* type and n* type) interact by vibronic coupling. In the nonpolar solvent (MC) the lowest singlet excited states are very close in energy and consequently the vibronic coupling is stronger. It has been found that the 0–0 band of the phosphorescence emission in EPA is polarized out of plane, using the excitations corresponding to absorptions into the first and second excited * singlet states. This fact and the order of lifetime measured indicate an emitting triplet that is *. The origin of this polarization is very likely mixing as a result of spin–orbit coupling. However, the vibrational structures and changing polarization outside the 0–0 band indicate that second-order effects involving spin–orbit coupling and vibronic interactions are important and the mixing scheme appears to be and . The proximity effect can qualitatively explain the absence of phosphorescence and the stronger vibronic interaction between the n* and the * states of -carboline-3-carboxylic acid .N-methylamide in a hydrocarbon solvent (MC).  相似文献   

14.
The possible ways of drawing of the intensity of the S0 T* transition in the chlorobenzene molecule are investigated. The effective spin-orbit coupling of either S* or S* states with the T* state leads to the out-of-plane polarized component of phosphorescence in the chlorobenzene. The in-plane polarized component cannot be explained by the mechanism under consideration — by drawing of intensity of the S0 S0* transitions through spin-orbit coupling of first order.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 134–138, August, 1974.  相似文献   

15.
Let us consider a Lie (super)algebra G spanned by T where T are quantum observables in BV formalism. It is proved that for every tensor c... that determines a homology class of the Lie algebra G the expression c...T...T is again a quantum observable. This theorem is used to construct quantum observables in the BV sigma model. We apply this construction to explain Kontsevich's results about the relation between homology of the Lie algebra of Hamiltonian vector fields and topological invariants of manifolds.  相似文献   

16.
Let i (x),i=1,...,d,xZ d , satisfy i (x)>0, and 1(x)+...+ d (x)=1. Define a Markov chain onZ d by specifying that a particle atx takes a jump of +1 in thei th direction with probability 1/2 i (x) and a jump of –1 in thei th direction with probability 1/2 i (x). If the i (x) are chosen from a stationary, ergodic distribution, then for almost all the corresponding chain converges weakly to a Brownian motion.  相似文献   

17.
We extend the theorem of Balslev and Combes on the absence of singular continuous spectrum to a class of interactions includingr (3/2<2) local potentials. In addition, we note that the theory of sectorial operators allows a simplification of their proof and allows one to push the cuts through angles larger than the /2 restriction employed by Balslev-Combes.A. Sloan Foundation Fellow.  相似文献   

18.
The paper considers the processes of formation of pseudoscalar mesons by the interaction of an antineutrino with a leptonv ll K, , K.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 139–143, August, 1974.  相似文献   

19.
The scattering cross section of the reaction + N N + , + N N + is calculated by the semiclassical method. It is predicted that the latter reaction occurs through N** resonance. The mass of this resonance, the spin, and isospin are found. The zero approximation with respect to the coupling constant between the - and -mesons is considered.  相似文献   

20.
We study the almost Mathieu operator: (H , , u)(n)=u(n+1)+u(n-1)+ cos (2n+)u(n), onl 2 (Z), and show that for all ,, and (Lebesgue) a.e. , the Lebesgue measure of its spectrum is precisely |4–2|. In particular, for ||=2 the spectrum is a zero measure cantor set. Moreover, for a large set of irrational 's (and ||=2) we show that the Hausdorff dimension of the spectrum is smaller than or equal to 1/2.Work partially supported by the GIF  相似文献   

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