共查询到20条相似文献,搜索用时 0 毫秒
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Eugene Gutkin 《Physica D: Nonlinear Phenomena》1985,16(3):398-404
We construct a large class of integrable Hamiltonian systems with n degrees of freedom. This class naturally extends the nonperiodic Hamiltonians of Toda lattice type. 相似文献
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Jiří Bičák 《General Relativity and Gravitation》1972,3(4):331-349
A recent analysis by Richard Price of spherical collapse with small nonspherical perturbations is here generalized to the case of an electrically charged collapsing star (0¦Q¦-M). The perturbations are confined to a scalar field generated by a nonspherical distribution of scalar charge in the star. As in the electrically neutral case, the scalar perturbations are probably a prototype for all others — electromagnetic, gravitational, and higherspin. The collapse is shown to produce a Reissner-Nordström black hole, and the scalar-field perturbations are shown to radiate completely away; but they die out more slowly the larger is the star's electric charge. For charge ¦Q¦M, the -pole part of the perturbation at fixedr and late times is dominated by a tail that dies out ast
–(2+ 2). But for ¦Q¦=M, the primary outgoing waves emitted from the star's surface are everywhere larger than the tail. At fixedr and late times they die as t–(+2). Also, a calculation of the redshift shows that a collapsing star becomes black more slowly the larger is the star's electric charge.Supported in part by the National Science Foundation (GP-27304, GP-28027, GP-19887). 相似文献
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With a suitable decomposition of its energy-momentum tensor into pressureless matter and a vacuum type term, we investigate the spherical gravitational collapse of a minimally coupled, self-interacting scalar field, showing that it collapses to a singularity. The formed blackhole has a mass \(M \sim 1/m\) (in Planck units), where m is the mass of the scalar field. If the latter has the axion mass, \(m \sim 10^{-5}\) eV, the former has a mass \(M \sim 10^{-5} M_{\odot }\). 相似文献
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A. A. Abrikosov Jr. 《JETP Letters》1996,63(11):869-872
Scalar matter in an instanton field in a closed volume is studied. A compact expression is found for the exact Green’s function
of massless scalar particles in the fundamental representation.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 11, 833–836 (10 June 1996) 相似文献
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A. Doicu T. Trautmann 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(1-2):146-158
We present a discrete-ordinate algorithm using the matrix-exponential solution for pseudo-spherical radiative transfer. Following the finite-element technique we introduce the concept of layer equation and formulate the discrete radiative transfer problem in terms of the level values of the radiance. The layer quantities are expressed by means of matrix exponentials, which are computed by using the matrix eigenvalue method and the Padé approximation. These solution methods lead to a compact and versatile formulation of the radiative transfer. Simulated nadir and limb radiances for an aerosol-loaded atmosphere and a cloudy atmosphere are presented along with a discussion of the model intercomparisons and timings. 相似文献
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S. I. Kruglov 《Russian Physics Journal》1991,34(2):119-122
Exact solutions are obtained for the wave equations for a scalar particle that possesses polarizability in the field of a plane electromagnetic wave of arbitrary polarization and in a constant electric field.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 40–43, February, 1991. 相似文献
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The wave function approach of Van Leeuwen and Reiner to the t-matrix is generalized to the case of a non-local potential. The transition matrix element for this potential is obtained. The results are used to compute the s-wave part of the t-matrix for a non-local square well potential combined with an outside exponential potential. 相似文献
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We study monopole perturbations of spherically symmetric scalar-vacuum and scalar-electrovacuum fields in general relativity and reduce the problem to a one-dimensional Schrödinger-like equation with a certain effective potential. Imposing certain boundary conditions, we select physically meaningful perturbations. Some of them grow exponentially and we conclude that the background system is unstable. 相似文献
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A general Lorentz-invariant scalar gravitational interaction theory with self-interaction is presented. It is shown that this theory leads to the recently proposed Higgs-field gravity and thereby provides a new approach to the Higgs potential. 相似文献
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《Chinese Journal of Physics (Taipei)》2018,56(4):1588-1598
Stochastic resonance (SR) is a vital approach to detect weak signals submerged in strong background noise, which is useful for mechanical fault diagnosis. The underdamped bistable SR (UBSR) is a kind of the most used SR, however, their potential structures are deficient to match with the complicated and diverse mechanical vibration signals and their parameters are selected subjectively which probably resulting in poor performance of UBSR. To overcome these shortcomings, this paper proposes an underdamped SR with exponential potential (UESR) which is generalized by using a harmonic model and a Gaussian potential (GP) model. The dynamics in UESR system is evaluated by the signal-to-noise ratio (SNR) which represents the effectiveness of noise utilization. Then, the effects of system parameters on system performance are investigated by output SNR versus noise intensity D for different parameters. Finally, the proposed method is used to process bearing experimental data and further perform bearing fault diagnosis. The experimental results demonstrate that a larger output SNR and higher spectrum peaks at fault characteristic frequencies can be obtained by the proposed method compared with the UBSR method, which confirm the effectiveness of the proposed method. 相似文献
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In this Letter it is shown that an i phi(3) quantum field theory is a physically acceptable model because the spectrum is positive and the theory is unitary. The demonstration rests on the perturbative construction of a linear operator C, which is needed to define the Hilbert space inner product. The C operator is a new, time-independent observable in PT-symmetric quantum field theory. 相似文献
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D. Pierotti 《Letters in Mathematical Physics》1988,15(3):219-230
The definition of the Wick exponential of the massless scalar field in two dimensions as an operator-valued distribution is discussed in the Krein space realization of the field. It is shown that the exponential Wick power series converges strongly on a suitably dense domain, provided that it is smeared with test functions which satisfy some growth conditions in configuration space. Such conditions are similar to the high energy bounds previously introduced by Jaffe for the definition of strictly localizable fields. In this case it is found that the Wick exponential is strictly localizable in momentum space. 相似文献
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The dynamics of a flat isotropic brane Universe with two-component matter source —perfect fluid with the equation of statep = (γ − 1)ρ and a scalar field with a power-law potentialV ∼ φα is investigated. We describe solutions for which the scalar field energy density scales as a power-law of the scale factor.
We also describe solutions existing in regions of the parameter space where these scaling solutions are unstable or do not
exist. 相似文献
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Antonio Zecca 《International Journal of Theoretical Physics》1997,36(6):1387-1394
The quantization of the scalar field is reconsidered in some of its basic elements in the context of the Robertson-Walker
space-time. The integration of the generalized Klein-Gordon equation is performed by preliminary separation of the equation
with the usual separation method. The orthonormal mode solutions are determined by the explicit integration of the resulting
angular and radial equations and by standard properties of the time equation. The time evolution given by the standard cosmological
model is briefly discussed. 相似文献