نتایج جستجو برای: quasi conformal curvature tensor

تعداد نتایج: 185289  

2000
H. Salehi

We present a model in which the breackdown of conformal symmetry of a quantum stress-tensor due to the trace anomaly is related to a cosmological effect in a gravitational model. This is done by characterizing the traceless part of the quantum stress-tensor in terms of the stress-tensor of a conformal invariant classical scalar field. We introduce a conformal frame in which the anomalous trace ...

2009
A. A. Saharian A. L. Mkhitaryan

We investigate the Wightman function, the vacuum expectation values of the field squared and the energy-momentum tensor for a massless scalar field with general curvature coupling parameter in spatially flat Friedmann-Robertson-Walker universes with an arbitrary number of toroidally compactified dimensions. The topological parts in the expectation values are explicitly extracted and in this way...

2010
Bandana Das Arindam Bhattacharyya

In this paper we consider pseudo projectively flat Riemannian manifold whose Ricci tensor S satisfies the condition S(X,Y ) = rT (X)T (Y ), where r is the scalar curvature, T is a non-zero 1-form defined by g(X, ξ) = T (X), ξ is a unit vector field and prove that the manifold is of pseudo quasi constant curvature, integral curves of the vector field ξ are geodesic and ξ is a proper concircular ...

Journal: :Physics Letters B 2022

We generalize the Quantum Geometric Tensor by replacing a Hamiltonian with modular Hamiltonian. The symmetric part of provides Fubini-Study metric, and its anti-symmetric sector gives Berry curvature. Our generalization dubbed Modular metric curvature Kinematic Space. also use result identity Virasoro block to relate connected correlator two Wilson lines two-point function This relation realize...

1993
H Osborn

Recently obtained results for two and three point functions for quasi-primary operators in conformally invariant theories in arbitrary dimensions d are described. As a consequence the three point function for the energy momentum tensor has three linearly independent forms for general d compatible with conformal invariance. The corresponding coefficients may be regarded as possible generalisatio...

Journal: :Journal of Nonlinear Mathematical Physics 2022

Abstract We study conformal $$\eta$$ ? -Einstein solitons on the framework of trans-Sasakian manifold in dimension three. Existence is discussed. Then we find some results which are where Ricci tensor cyclic parallel and Codazzi type. also consider curvature conditions with addition to manifold. use torse-for...

Journal: :Proceedings of the National Academy of Sciences 1934

Journal: :Physical review letters 2014
Paolo Creminelli Jérôme Gleyzes Jorge Noreña Filippo Vernizzi

We show that the prediction for the primordial tensor power spectrum cannot be modified at leading order in derivatives. Indeed, one can always set to unity the speed of propagation of gravitational waves during inflation by a suitable disformal transformation of the metric, while a conformal one can make the Planck mass time independent. Therefore, the tensor amplitude unambiguously fixes the ...

Journal: :Proceedings of the American Mathematical Society 2021

In this paper, we prove that a compact quasi-Einstein manifold $(M^n,\,g,\,u)$ of dimension $n\geq 4$ with boundary $\partial M,$ nonnegative sectional curvature and zero radial Weyl tensor is either isometric, up to scaling, the standard hemisphere $\Bbb {S}^n_+,$ or $g=dt^{2}+\psi ^{2}(t)g_{L}$ $u=u(t),$ where $g_{L}$ Einstein Ricci curvature. A similar classification result obtained by assum...

Journal: :فیزیک زمین و فضا 0
علیرضا آزموده اردلان استاد، گروه مهندسی نقشه برداری، قطب علمی مهندسی نقشه برداری در مقابله با سوانح طبیعی، پردیس دانشکده های فنی، دانشگاه تهران، بهزاد وثوقی دانشیار، دانشکده مهندسی نقشه برداری، دانشگاه صنعتی خواجه نصیرالدین طوسی، مهدی روفیان نایینی دانشجوی دکترای ژئودزی، گروه مهندسی نقشه برداری، قطب علمی مهندسی نقشه برداری در مقابله با سوانح طبیعی، پردیس دانشکده های فنی، دانشگاه تهران

unlike the classical deformation analysis of the earth crust, which derives the planar and vertical strains separately, in this study, we have offered a method for 3-d deformation study based on intrinsic geometry of the manifolds on the topographic surface of the earth. in this way, our method would be based on the 2-d metric tensor of horizontal deformation and 2-d curvature tensor of vertica...

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