共查询到20条相似文献,搜索用时 15 毫秒
1.
The screening of an external color field in an instanton liquid is studied. Effective Lagrangians are derived for a weak field and for a strong field in the long-wave approximation. The coupling-constant dependence of the feedback of the field on the instanton liquid is estimated by considering the model problem of a Euclidean pointlike charged color source. 相似文献
2.
We develop a technique for the reconstruction of the potential for a scalar field or a tachyon field, reproducing a given cosmological evolution in a closed and open isotropic cosmological models. Such potentials are explicitly written down for the cases of the evolutions driven by a generic barotropic fluid and by radiation plus a cosmological constant, for the case of a scalar field. For tachyon and pseudo-tachyon fields the potentials are reconstructed for some special cases, corresponding to particular values of the barotropic index. 相似文献
3.
Kh. Huleihil 《Physics letters. [Part B]》1984,138(4):287-288
Wong's and Drechsler and Rosenblum's equations for a particle moving in the Yang-Mills field are solved for motion in the instanton field. Particular cases of motion are considered and expressed in terms of the total angular momentum. 相似文献
4.
Exact propagator for an electron in a quadratic saddle-point potential and a magnetic field 下载免费PDF全文
We study the propagator for an electron moving in a two-dimensional (2D) quadratic saddle-point potential,in the presence of a perpendicular uniform magnetic field. A closed-form expression for the propagator is derived using the Feynmann path integrals. 相似文献
5.
Soumya Chakrabarti 《General Relativity and Gravitation》2017,49(2):24
An analogue of the Oppenheimer–Synder collapsing model is treated analytically, where the matter source is a scalar field with an exponential potential. An exact solution is derived followed by matching to a suitable exterior geometry, and an analysis of the visibility of the singularity. In some situations, the collapse indeed leads to a finite time curvature singularity, which is always hidden from the exterior by an apparent horizon. 相似文献
6.
R. G. Shulyakovskii 《Physics of Particles and Nuclei Letters》2008,5(5):417-419
Two-dimensional scalar field models with nontrivial potential determined in bounded spatial regions are considered. Exact analytic instanton solutions for these models and soliton solutions for similar three-dimensional systems are obtained. 相似文献
7.
The quark propagator in the presence of an arbitrary gluon field is calculated gauge and Lorentz covariantly order by order
in terms of powers of the gluon field and its derivatives. The result is independent of the path connecting the ends of the
propagator, and the leading order result coincides with the exact propagator in the trivial case of a vanishing gluon field.
Received: 5 February 2003 / Published online: 23 May 2003 相似文献
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9.
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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11.
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
12.
A. S. Schwarz 《Communications in Mathematical Physics》1979,64(3):233-268
The number of instantons and the number of zero fermion modes in the field of instanton are calculated. The quantum fluctuations of instantons are studied. 相似文献
13.
A.E. Dorokhov S.V. Esaibegyan A.E. Maximov S.V. Mikhailov 《The European Physical Journal C - Particles and Fields》2000,13(2):331-345
We suggest a constrained instanton (CI) solution in the physical QCD vacuum which is described by large-scale vacuum field
fluctuations. This solution decays exponentially at large distances. It is stable only if the interaction of the instanton
with the background vacuum field is small and additional constraints are introduced. The CI solution is explicitly constructed
in the ansatz form, and the two-point vacuum correlator of the gluon field strengths is calculated in the framework of the
effective instanton vacuum model. At small distances the results are qualitatively similar to the single instanton case; in
particular, the invariant structure is small, which is in agreement with the lattice calculations.
Received: 18 June 1999 / Revised version: 21 July 1999 / Published online: 17 February 2000 相似文献
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15.
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
16.
We investigate the distribution of instanton sizes in the framework of a simplified model for ensembles of instantons. This
model takes into account the non-diluteness of instantons. The infrared problem for the integration over instanton sizes is
dealt with in a self-consistent manner by approximating instanton interactions by a repulsive hard core potential. This leads
to a dynamical suppression of large instantons. The characteristic features of the instanton size distribution are studied
by means of analytic and Monte Carlo methods. In one dimension exact results can be derived. In any dimension we find a power
law behaviour for small sizes, consistent with the semi-classical results. At large instanton sizes the distribution decays
exponentially. The results are compared with those from lattice simulations.
Received: 15 May 2000 / Revised version: 17 July 2000 / Published online: 25 September 2000 相似文献
17.
T. Harkó 《Acta Physica Hungarica A》1996,3(1-2):115-129
The dynamics of a homogeneous, anisotropic, spatially flat Bianchi type I universe filled with a scalar field is studied. Using the usual synchronous form of the line element, general exact solutions for the Einstein field equations are obtained in the case of the exponential-potential scalar field (V=Λexp(k?)) and in the case of the Barrow-Saich potential ( $V \sim \dot \varphi ^2 $ ). Conditions under which inflation can occur are discussed and the late-time behaviour of the models is also considered. 相似文献
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19.
Richard Montgomery 《Communications in Mathematical Physics》1986,107(3):515-533
We consider the scattering of a classical colored particle off an instanton. That is, we investigate Wong's equations (or equivalently, the Kaluza-Klein geodesic equations) for a colorSU(2) particle under the influence of a Euclidean instanton. We solve the equations in the limit in which the instanton becomes singular. Our main result is that particles with head-on trajectories scatter off the instanton with a scattering angle of π/3. This angle is independent of the magnitude of the color charge and velocity of the particle as long as both are nonzero. The plane in which the scattering takes place is determined by the particle's initial position and color charge. We also solve for the geodesics for the corresponding (singular) Kaluza-Klein metric onS 7. 相似文献