Results 71 to 80 of about 1,202,632 (386)

Gödel metrics with chronology protection in Horndeski gravities

Physics Letters B, 2018
Gödel universe, one of the most interesting exact solutions predicted by General Relativity, describes a homogeneous rotating universe containing naked closed time-like curves (CTCs).
Wei-Jian Geng, Shou-Long Li, H. Lü, Hao Wei   +3 more
doaj   +1 more source

Homogeneous Einstein metrics on Stiefel manifolds [PDF]

, 1996
summary:A Stiefel manifold $V_k\bold R^n$ is the set of orthonormal $k$-frames in $\bold R^n$, and it is diffeomorphic to the homogeneous space $SO(n)/SO(n-k)$. We study $SO(n)$-invariant Einstein metrics on this space.
Arvanitoyeorgos, Andreas
core  

Poincaré–Einstein metrics and the Schouten tensor [PDF]

Pacific Journal of Mathematics, 2003
We examine here the space of conformally compact metrics $g$ on the interior of a compact manifold with boundary which have the property that the $k^{th}$ elementary symmetric function of the Schouten tensor $A_g$ is constant. When $k=1$ this is equivalent to the familiar Yamabe problem, and the corresponding metrics are complete with constant negative
Mazzeo, Rafe, Pacard, Frank
openaire   +3 more sources

Molecular Dynamics Studies of Shape Memory Polymers: From Bead–Spring Models to Atomistic Simulations

Advanced Engineering Materials, EarlyView.
Coarse‐grained (left) and atomistic (right) models of the shape memory polymer ESTANE ETE 75DT3 are shown schematically. The two representations bridge molecular detail and mesoscopic description. Both models capture shape memory behavior, linking segmental mobility and conformational relaxation of anisotropic chains to macroscopic recovery, and ...
Fathollah Varnik
wiley   +1 more source

A Note on Discrete Einstein Metrics

Journal of Mathematical Study, 2019
8 ...
Ge, Huabin, Mei, Jinlong, Zhou, Da
openaire   +2 more sources

On Einstein–Kropina metrics

, 2013
In this paper, a characteristic condition of Einstein–Kropina metrics is given. By the characteristic condition, we prove that a non-Riemannian Kropina metric F=α2β with constant Killing form β on an n-dimensional manifold M, n⩾2, is an Einstein metric ...
Shen, Yi-Bing, Zhang, Xiaoling
core   +1 more source

Ultrasensitive Anti‐Stokes Luminescence Thermometry in Transition Metal Dichalcogenide Monolayers

Advanced Functional Materials, EarlyView.
We demonstrate a highly sensitive nanothermometer using anti‐Stokes photoluminescence, also known as photoluminescence upconversion (UPL), in monolayer tungsten disulfide. A strong resonantly enhanced UPL is observed, confirming the central role of optical phonons in the PL upconversion mechanism.
Sharada Nagarkar, Fahrettin Sarcan, Elanur Hut, Emiliano R. Martins, Stuart A. Cavill, Thomas F. Krauss, Yue Wang   +6 more
wiley   +1 more source

8D conformal gravity with Einstein sector, and its relation to the Q-curvature

Journal of High Energy Physics
We first streamline the construction of the unique six-dimensional conformal gravity action found by Lü, Pang and Pope, that admits Einstein metrics as solutions to the field equations. We then prove that there exists a unique eight-dimensional conformal
Nicolas Boulanger, Davide Rovere
doaj   +1 more source

New Examples of Einstein Metrics in Dimension Four

International Journal of Mathematics and Mathematical Sciences, 2010
We construct new examples of four-dimensional Einstein metrics with neutral signature and two-dimensional holonomy Lie algebra.
Ryad Ghanam
doaj   +1 more source

New Einstein metrics on E7

Differential Geometry and its Applications, 2017
The authors obtain some new naturally reductive and non naturally reductive left-invarant Einsein metrics on the exceptional Lie group \(E_7\). To this end, they consider a decomposition of the Lie algebra \(\mathfrak{g}=\mathfrak{e}_7\) by using the generalized Wallach space \(G/H=E_7/\mathrm{Spin}(8)\).
Zhang, Lei, Chen, Zhiqi, Deng, Shaoqiang
openaire   +1 more source