Results 61 to 70 of about 693,970 (340)
Certain aspects of regularity in scalar field cosmological dynamics
, 2007 We consider dynamics of the FRW Universe with a scalar field. Using Maupertuis principle we find a curvature of geodesics flow and show that zones of positive curvature exist for all considered types of scalar field potential.
A. Toporensky +19 more
core +1 more source
Intrinsic problems of the gravitational baryogenesis
Physics Letters B, 2017 Modification of gravity due to the curvature dependent term in the gravitational baryogenesis scenario is considered. It is shown that this term leads to the fourth order differential equation of motion for the curvature scalar instead of the algebraic ...
E.V. Arbuzova, A.D. Dolgov
doaj +1 more source
Bures distance between two displaced thermal states
, 1999 The Bures distance between two displaced thermal states and the corresponding geometric quantities (statistical metric, volume element, scalar curvature) are computed.
C. W. Gardiner +17 more
core +1 more source
Scalar Curvature via Local Extent
Analysis and Geometry in Metric Spaces, 2018 We give a metric characterization of the scalar curvature of a smooth Riemannian manifold, analyzing the maximal distance between (n + 1) points in infinitesimally small neighborhoods of a point.
Veronelli Giona
doaj +1 more source
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
doaj +1 more source
Infinite loop spaces and positive scalar curvature in the presence of a fundamental group [PDF]
Geometry and Topology, 2017 This is a continuation of our previous work with Botvinnik on the nontriviality of the secondary index invariant on spaces of metrics of positive scalar curvature, in which we take the fundamental group of the manifolds into account.
Johannes Ebert, O. Randal-Williams
semanticscholar +1 more source
Curvature operators and scalar curvature invariants [PDF]
Classical and Quantum Gravity, 2010 We continue the study of the question of when a pseudo-Riemannain manifold can be locally characterised by its scalar polynomial curvature invariants (constructed from the Riemann tensor and its covariant derivatives). We make further use of alignment theory and the bivector form of the Weyl operator in higher dimensions, and introduce the important ...
Hervik, Sigbjørn, Coley, Alan
openaire +3 more sources
Schwinger Pair Production in dS_2 and AdS_2
, 2009 We study Schwinger pair production in scalar QED from a uniform electric field in dS_2 with scalar curvature R_{dS} = 2 H^2 and in AdS_2 with R_{AdS} = - 2 K^2. With suitable boundary conditions, we find that the pair-production rate is the same analytic
A. D. Polyanin +15 more
core +1 more source
Scalar curvature and singular metrics [PDF]
, 2016 Let $M^n$, $n\ge3$, be a compact differentiable manifold with nonpositive Yamabe invariant $\sigma(M)$. Suppose $g_0$ is a continuous metric with $V(M, g_0)=1$, smooth outside a compact set $\Sigma$, and is in $W^{1,p}_{loc}$ for some $p>n$.
Yuguang Shi, Luen-Fai Tam
semanticscholar +1 more source
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
core +1 more source