Results 31 to 40 of about 823 (221)

Generalization of instanton-induced inflation and dynamical compactification

Journal of High Energy Physics, 2023
It was shown that Yang-Mills instantons on an internal space can trigger the expansion of our four-dimensional universe as well as the dynamical compactification of the internal space.
Jeongwon Ho, Kyung Kiu Kim, Seoktae Koh, Hyun Seok Yang   +3 more
doaj   +1 more source

η-Ricci soliton on η-Einstein-like LP-Sasakian manifolds

Annals of the West University of Timisoara: Mathematics and Computer Science, 2022
The object of the present article is to study the notion of η-Einstein-like LP-Sasakian manifolds admitting η-Ricci soliton. Furthermore, we study the η-Ricci soliton on LP-Sasakian manifolds when the potential vector field V is point-wise collinear.
Das Susanta, Biswas Ashis, Baishya Kanak Kanti   +2 more
doaj   +1 more source

Einstein almost cokähler manifolds

, 2014
We study an odd-dimensional analogue of the Goldberg conjecture for compact Einstein almost Kähler manifolds. We give an explicit non-compact example of an Einstein almost cokähler manifold that is not cokähler. We prove that compact Einstein almost cokähler manifolds with non-negative $*$-scalar curvature are cokähler (indeed, transversely Calabi-Yau);
CONTI, DIEGO, Fernández, M.
openaire   +4 more sources

Hidden Symmetries of Euclideanised Kerr-NUT-(A)dS Metrics in Certain Scaling Limits

Symmetry, Integrability and Geometry: Methods and Applications, 2012
The hidden symmetries of higher dimensional Kerr-NUT-(A)dS metrics are investigated. In certain scaling limits these metrics are related to the Einstein-Sasaki ones.
Mihai Visinescu, Eduard Vîlcu
doaj   +1 more source

$m$-quasi-$*$-Einstein contact metric manifolds

Karpatsʹkì Matematičnì Publìkacìï, 2022
The goal of this article is to introduce and study the characterstics of $m$-quasi-$*$-Einstein metric on contact Riemannian manifolds. First, we prove that if a Sasakian manifold admits a gradient $m$-quasi-$*$-Einstein metric, then $M$ is $\eta ...
H.A. Kumara, V. Venkatesha, D.M. Naik
doaj   +1 more source

On $K$-contact Einstein manifolds

Novi Sad Journal of Mathematics, 2016
In this paper, we investigate K-contact Einstein manifolds satisfying the conditions RC = Q(S,C), where C is the conformal curvature tensor and R the Riemannian curvature tensor. Next we consider K-contact Einstein manifolds satisfying the curvature condition C.S = 0, where S is the Ricci tensor.
De, U. C., Mandal, Krishanu
openaire   +2 more sources

Sasaki–Einstein Manifolds and Volume Minimisation [PDF]

Communications in Mathematical Physics, 2008
We study a variational problem whose critical point determines the Reeb vector field for a Sasaki-Einstein manifold. This extends our previous work on Sasakian geometry by lifting the condition that the manifolds are toric. We show that the Einstein-Hilbert action, restricted to a space of Sasakian metrics on a link L in a Calabi-Yau cone X, is the ...
Martelli, Dario, Sparks, James, Yau, S. T.   +2 more
openaire   +3 more sources

Organic Materials of Tomorrow: Horizons of Artificial Intelligence

Advanced Materials, EarlyView.
This review examines machine learning techniques accelerating the discovery of organic semiconductors by linking molecular structure to properties. Key methods include graph neural networks, generative models, and active learning. Applications to organic photovoltaics demonstrate practical impact.
Harold Mena, J. Terence Blaskovits, Kun‐Han Lin, Denis Andrienko   +3 more
wiley   +1 more source

The spinorial energy for asymptotically Euclidean Ricci flow

Advanced Nonlinear Studies, 2023
This article introduces a functional generalizing Perelman’s weighted Hilbert-Einstein action and the Dirichlet energy for spinors. It is well defined on a wide class of noncompact manifolds; on asymptotically Euclidean manifolds, the functional is shown
Baldauf Julius, Ozuch Tristan
doaj   +1 more source

A Note on the Geometry of Certain Classes of Lichnerowicz Laplacians and Their Applications

Mathematics, 2023
In the present paper, we prove vanishing theorems for the null space of the Lichnerowicz Laplacian acting on symmetric two tensors on complete and closed Riemannian manifolds and further estimate its lowest eigenvalue on closed Riemannian manifolds.
Vladimir Rovenski, Sergey Stepanov, Josef Mikeš   +2 more
doaj   +1 more source