Results 51 to 60 of about 298,518 (247)
Derivative couplings in gravitational production in the early universe
Journal of High Energy Physics, 2020 Gravitational particle production in the early universe is due to the coupling of matter fields to curvature. This coupling may include derivative terms that modify the kinetic term.
Daniel E. Borrajo Gutiérrez +3 more
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Dynamical Analysis of Scalar Field Cosmologies with Spatial Curvature
The Open Journal of Astrophysics, 2016 We explore the dynamical behaviour of cosmological models involving a scalar field (with an exponential potential and a canonical kinetic term) and a matter fluid with spatial curvature included in the equations of motion.
Mateja Gosenca, Peter Coles
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Integrable scalar cosmologies with matter and curvature [PDF]
Nuclear Physics B, 2020 We show that several integrable (i.e., exactly solvable) scalar cosmologies considered by Fré, Sagnotti and Sorin (Nuclear Physics \textbf{B 877}(3) (2013), 1028--1106) can be generalized to include cases where the spatial curvature is not zero and, besides a scalar field, matter or radiation are present with an equation of state $p^{(m)} = w\, ρ^{(m)}$
Massimo Gengo +4 more
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Rigidity of noncompact complete Bach-flat manifolds
, 2010 Let $(M,g)$ be a noncompact complete Bach-flat manifold with positive Yamabe constant. We prove that $(M,g)$ is flat if $(M, g)$ has zero scalar curvature and sufficiently small $L_{2}$ bound of curvature tensor.
Anderson +15 more
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Disformal transformation of cosmological perturbations
Physics Letters B, 2014 We investigate the gauge-invariant cosmological perturbations in the gravity and matter frames in the general scalar–tensor theory where two frames are related by the disformal transformation.
Masato Minamitsuji
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Circle actions and scalar curvature [PDF]
Transactions of the American Mathematical Society, 2015 25 pages; several changes according to comments of a referee made; to appear in Trans. Am.
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Erratum to: Total Scalar Curvature and Harmonic Curvature [PDF]
Taiwanese Journal of Mathematics, 2016 It has been realized that the proof of Theorem 5.1 in Section 5 is imcomplete. It was pointed out by Professor Jongsu Kim and Israel Evangelista.
Yun, Gabjin +2 more
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Generalized Wintgen inequality for BI-SLANT submanifolds in conformal Sasakian space form with quarter-symmetric connection [PDF]
Arab Journal of Mathematical SciencesPurpose – In 1979, P. Wintgen obtained a basic relationship between the extrinsic normal curvature the intrinsic Gauss curvature, and squared mean curvature of any surface in a Euclidean 4-space with the equality holding if and only if the curvature ...
Mohd Aslam +2 more
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Thermodynamic Geometry and Phase Transitions in Kerr-Newman-AdS Black Holes
, 2010 We investigate phase transitions and critical phenomena in Kerr-Newman-Anti de Sitter black holes in the framework of the geometry of their equilibrium thermodynamic state space. The scalar curvature of these state space Riemannian geometries is computed
A Chamblin +44 more
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Scalar curvature of Lie groups [PDF]
Proceedings of the American Mathematical Society, 1981 In this paper, we prove the following theorem: If G G is a connected Lie group, then G G admits left invariant metric of positive scalar curvature if and only if the universal covering space G ~ \tilde G of G G is not homeomorphic to the ...
Huei Shyong Lue, Hêng Lung Lai
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