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The dynamics of homogeneous Robertson–Walker cosmological models with a self-interacting scalar field source is examined here
in full generality, requiring only the scalar field potential to be bounded from below and divergent when the field diverges.
In this way we are able to give a unified treatment of all the already studied cases—such as positive potentials which exhibit
asymptotically polynomial or exponential behaviors—together with its extension to a much wider set of physically sensible
potentials. Since the set includes potentials with negative inferior bound, we are able to give, in particular, the analysis
of the asymptotically anti De Sitter states for such cosmologies. 相似文献
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G. Ooms C. Poelma P. Poesio MJ.B.M. Pourquie J. Westerweel 《International Journal of Multiphase Flow》2008
In an earlier publication some of the authors presented a theoretical model for the calculation of the influence of particle inertia and gravity on the turbulence in a stationary particle-laden flow. In the present publication the model is extended for application to a decaying suspension. Also a comparison is given between predictions made with the model and experimental data (own data and data reported in the literature) on a decaying turbulent flow with particles in a water tunnel or in a wind tunnel. For most of the experiments a prediction with reasonable accuracy and an interpretation is possible by means of the model. 相似文献
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Fabio Giannoni Antonio Masiello Paolo Piccione 《Communications in Mathematical Physics》1997,187(2):375-415
This paper is dedicated to the study of light rays joining an event p with a timelike curve γ in a light–convex subset &\Lambda; of a stably causal Lorentzian manifold . We set up a functional framework, defined intrinsically, consisting of a family of manifolds and a positive functional Q defined on them. The critical points of Q on approach, as , the lightlike, future pointing geodesics joining p and γ. We prove some regularity results, including the C
1–regularity of , the C
2–regularity of Q on and the C
2–regularity of its critical points. Using them, we develop a Ljusternik–Schnirelman theory for light rays, obtaining some
multiplicity results, depending on the topology of the space of all lightlike curves joining p and γ.
Received: 9 April 1996 / Accepted: 27 December 1996 相似文献
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Summary We describe the geometrical properties of some ordinary nonlinear differential equations, and we obtain multiplicity results of solutions by the study of the behaviour of our operator near certain singular points.Work supported by M.P.I. and G.N.A.F.A. 相似文献
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