نتایج جستجو برای: curvature field
تعداد نتایج: 823080 فیلتر نتایج به سال:
Abstract. The magnetic moment of an electron gas on the surface of constant negative curvature is investigated. It is shown that the surface curvature leads to the appearance of the region of the monotonic dependence M(B) at low magnetic fields. At high magnetic fields, the dependence of the magnetic moment on a magnetic field is the oscillating one. The effect of the surface curvature is to in...
In this paper, we study the curvature of a semi-Riemannian manifold M̃ of quasi-constant curvature admits some half lightlike submanifolds M . The main result is two characterization theorems for M̃ admits extended screen homothetic and statical half lightlike submanifolds M such that the curvature vector field of M̃ is tangent to M .
Suppose that Σ = ∂M is the n-dimensional boundary of a connected compact Riemannian spin manifold (M, 〈 , 〉) with nonnegative scalar curvature, and that the (inward) mean curvature H of Σ is positive. We show that the first eigenvalue of the Dirac operator of the boundary corresponding to the conformal metric 〈 , 〉H = H 〈 , 〉 is at least n/2 and equality holds if and only if there exists a non-...
A pp-wave is a Lorentzian manifold with a parallel light-like vector field satisfying a certain curvature condition. We introduce generalisations of pp-waves, on one hand by allowing the vector field to be recurrent and on the other hand by weakening the curvature condition. These generalisations are related to the screen holonomy of the Lorentzian manifold. While pp-waves have a trivial screen...
By attaching five (complex) anticommuting property coordinates to the four (real) commuting space-time ones, it is possible to accommodate all the known fundamental particles in their three generations. A general relativistic extension to space-time-property can be carried out such that the gauge fields find their place in the space-property sector and the Higgs scalars in the property-property...
By attaching five (complex) anticommuting property coordinates to the four (real) commuting space-time ones, it is possible to accommodate all the known fundamental particles in their three generations. A general relativistic extension to space-time-property can be carried out such that the gauge fields find their place in the space-property sector and the Higgs scalars in the property-property...
A phase field model for dealing with shape instabilities in fluid membrane vesicles is presented. This model takes into account the Canham-Helfrich bending energy with spontaneous curvature. A dynamic equation for the phase-field is also derived. With this model it is possible to see the vesicle shape deformation dynamically, when some external agent instabilizes the membrane, for instance, ind...
The aim of the present paper is to study properties of Quasi conformally flat LP-Sasakian manifolds with a coefficient α. In this paper, we prove that a Quasi conformally flat LP-Sasakian manifold M (n > 3) with a constant coefficient α is an η−Einstein and in a quasi conformally flat LP-Sasakian manifold M (n > 3) with a constant coefficient α if the scalar curvature tensor is constant then M ...
While a radar target is illuminated under the condition of spherical wave, two-dimensional ISAR image can be obtained in near field, and the wavefront curvature must be compensated. A novel two-dimensional mathematical model is set up, and a 2DESPRIT super-resolution algorithm based on matrix pencil is applied to estimate the accurate locations of the scattering centers in near field. Numerical...
Cosmological perturbation theory fails in the new ekpyrotic and cyclic ekpyrotic scenarios, before the scale factor of the Universe reaches zero. As a result, these scenarios do not provide a mechanism for generating the observed curvature perturbation at the bounce. Introduction It is now clear that the dominant cause of large-scale structure in the Universe is a perturbation in the spatial cu...
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