Results 71 to 80 of about 129 (128)

Dynamics of entanglement in expanding quantum fields

open access: yesJournal of High Energy Physics, 2018
We develop a functional real-time approach to computing the entanglement between spatial regions for Gaussian states in quantum field theory. The entanglement entropy is characterized in terms of local correlation functions on space-like Cauchy ...
Jürgen Berges   +2 more
doaj   +1 more source

A tropical approach to rigidity: Counting realisations of frameworks

open access: yesJournal of the London Mathematical Society, Volume 113, Issue 2, February 2026.
Abstract A realisation of a graph in the plane as a bar‐joint framework is rigid if there are finitely many other realisations, up to isometries, with the same edge lengths. Each of these finitely many realisations can be seen as a solution to a system of quadratic equations prescribing the distances between pairs of points.
Oliver Clarke   +6 more
wiley   +1 more source

On the Work of Cartan and Münzner on Isoparametric Hypersurfaces

open access: yesAxioms
A hypersurface Mn in a real space form Rn+1, Sn+1, or Hn+1 is isoparametric if it has constant principal curvatures. This paper is a survey of the fundamental work of Cartan and Münzner on the theory of isoparametric hypersurfaces in real space forms, in
Thomas E. Cecil, Patrick J. Ryan
doaj   +1 more source

On holomorphic one-forms transverse to closed hypersurfaces

open access: yesAnais da Academia Brasileira de Ciências, 2003
In this note we announce some achievements in the study of holomorphic distributions admitting transverse closed real hypersurfaces. We consider a domain with smooth boundary in the complex affine space of dimension two or greater. Assume that the domain
Toshikazu Ito, Bruno Scárdua
doaj   +1 more source

The versal deformation of small resolutions of conic bundles over P1×P1${\mathbb {P}}^1\times {\mathbb {P}}^1$ with two sections blown down

open access: yesJournal of the London Mathematical Society, Volume 113, Issue 2, February 2026.
Abstract Twistor spaces are certain compact complex three‐folds with an additional real fibre bundle structure. We focus here on twistor spaces over P2#P2#P2${\mathbb {P}}^2\#{\mathbb {P}}^2\#{\mathbb {P}}^2$. Such spaces are either small resolutions of double solids or they can be described as modifications of conic bundles.
Bernd Kreußler, Jan Stevens
wiley   +1 more source

Isoparametric and Dupin Hypersurfaces

open access: yesSymmetry, Integrability and Geometry: Methods and Applications, 2008
A hypersurface $M^{n−1}$ in a real space-form $R^n$, $S^n$ or $H^n$ is isoparametric if it has constant principal curvatures. For $R^n$ and $H^n$, the classification of isoparametric hypersurfaces is complete and relatively simple, but as Élie Cartan ...
Thomas E. Cecil
doaj   +1 more source

Nonexistence of Homogeneous Levi-Flat Hypersurfaces in CP2

open access: yesMathematics
We investigate the longstanding question of whether compact Levi-flat hypersurfaces exist in the complex projective plane CP2. While the nonexistence of closed real-analytic Levi-flat hypersurfaces in CPn for n>2 is well known, the case n=2 remains open.
Abdel Rahman Al-Abdallah
doaj   +1 more source

The Nonimbeddability of Real Hypersurfaces in Spheres [PDF]

open access: yesProceedings of the American Mathematical Society, 1988
It is shown that there exist real analytic real hypersurfaces in C n {{\mathbf {C}}^n} which cannot be locally holomorphically imbedded in any finite dimensional sphere S 2 N
openaire   +3 more sources

What Is a Simple Liquid?

open access: yesPhysical Review X, 2012
This paper is an attempt to identify the real essence of simplicity of liquids in John Locke’s understanding of the term. Simple liquids are traditionally defined as many-body systems of classical particles interacting via radially symmetric pair ...
Trond S. Ingebrigtsen   +2 more
doaj   +1 more source

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