Results 91 to 100 of about 75,961 (279)

Optical Skyrmions with Tunable or Reconfigurable Topology Using Spin‐Decoupled Metaoptics

open access: yesLaser &Photonics Reviews, EarlyView.
The work introduces advanced optical elements capable of generating and dynamically reconfiguring complex light patterns known as optical skyrmions. By precisely shaping light polarization at the nanoscale, a single engineered metasurface can generate and manipulate robust and tunable polarization textures in an efficient and scalable way.
Andrea Vogliardi   +5 more
wiley   +1 more source

Sphere Theorems for σk-Einstein Manifolds

open access: yesAxioms
A problem that geometers have always been concerned with is when a closed manifold is isometric to a round sphere. A classical result shows that a closed locally conformally flat Einstein manifold is always isometric to a quotient of a round sphere.
Jingyang Zhong, Xinran Mu
doaj   +1 more source

Unveiling New Perspectives on the Hirota–Maccari System With Multiplicative White Noise

open access: yesMathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT In this study, we delve into the stochastic Hirota–Maccari system, which is subjected to multiplicative noise according to the Itô sense. The stochastic Hirota–Maccari system is significant for its ability to accurately model how stochastic affects nonlinear wave propagation, providing valuable insights into complex systems like fluid dynamics
Mohamed E. M. Alngar   +3 more
wiley   +1 more source

Super Quasi-Einstein Warped Products Manifolds with Respect to Affine Connections

open access: yesAxioms
In this paper, we investigate warped products on super quasi-Einstein manifolds under affine connections. We explore their fundamental properties, establish conditions for their existence, and prove that these manifolds can also be nearly quasi-Einstein ...
Mohd Vasiulla   +3 more
doaj   +1 more source

Complex manifolds and Einstein’s equations

open access: yes, 1982
We present a generalization of Penrose’s twistor theory based on the geometry of rational curves in complex manifolds. The analytical counterpart of this complex geometry consists, in the three simplest cases, of a system of differential equations closely connected with Einstein’s equations.
openaire   +2 more sources

On Einstein, Hermitian 4-manifolds

open access: yesJournal of Differential Geometry, 2012
Let (M,h) be a compact 4-dimensional Einstein manifold, and suppose that h is Hermitian with respect to some complex structure J on M. Then either (M,J,h) is Kaehler-Einstein, or else, up to rescaling and isometry, it is one of the following two exceptions: the Page metric on CP2 # (-CP2), or the Einstein metric on CP2 # 2 (-CP2) constructed in Chen ...
openaire   +3 more sources

Shape Derivatives of the Eigenvalues of the de Rham Complex for Lipschitz Deformations and Variable Coefficients: Part II

open access: yesMathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT In this second part of our series of papers, we develop an abstract framework suitable for de Rham complexes that depend on a parameter belonging to an arbitrary Banach space. Our primary focus is on spectral perturbation problems and the differentiability of eigenvalues with respect to perturbations of the involved parameters. As a byproduct,
Pier Domenico Lamberti   +2 more
wiley   +1 more source

There Are No Conformal Einstein Rescalings of Pseudo-Riemannian Einstein Spaces with n Complete Light-Like Geodesics

open access: yesMathematics, 2019
In the present paper, we study conformal mappings between a connected n-dimension pseudo-Riemannian Einstein manifolds. Let g be a pseudo-Riemannian Einstein metric of indefinite signature on a connected n-dimensional manifold M.
Josef Mikeš   +2 more
doaj   +1 more source

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