1,273 results for geometry · 0.100s

arxiv.org/abs/1508.01896v2

On the geometry and topology of initial data sets with horizons

We study the relationship between initial data sets with horizons and the existence of metrics of positive scalar curvature. We define a Cauchy Domain of Outer Communications (CDOC) to be an asymptotically flat initial set $(M, g, K)$ such that the b...

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arxiv.org/abs/2404.02019v2

Aspects of the geometry and topology of expanding horizons

The aim of this paper is to extend some basic results about marginally outer trapped surfaces to the context of surfaces having general null expansion. Motivated in part by recent work of Chai-Wan, we introduce the notion of $\mathfrak{g}$-stability...

arxiv.org/abs/2408.00155v1

Space Station Rotational Stability

Designing for rotational stability can dramatically affect the geometry of a space station. If improperly designed, the rotating station could end up catastrophically tumbling end-over-end. Active stabilization can address this problem; however, desi...

arxiv.org/abs/2206.14178v1

The gauging procedure and carrollian gravity

We discuss a gauging procedure that allows us to construct lagrangians that dictate the dynamics of an underlying Cartan geometry. In a sense to be made precise in the paper, the starting datum in the gauging procedure is a Klein pair corresponding t...

arxiv.org/abs/2112.03319v3

Carrollian and celestial spaces at infinity

We show that the geometry of the asymptotic infinities of Minkowski spacetime (in $d+1$ dimensions) is captured by homogeneous spaces of the Poincaré group: the blow-ups of spatial (Spi) and timelike (Ti) infinities in the sense of Ashtekar--Hansen...

arxiv.org/abs/2008.07285v1

The geometry of quadrangular convex pyramids

A convex quadrangular pyramid $ABCDE$, where $ABCD$ is the base and $E$ -- the apex, is called \emph{strongly flexible}, if it belongs to a continuous family of pairwise non-congruent quadrangular pyramids that have the same lengths of corresponding...

arxiv.org/abs/2105.11404v2

Infinite flags and Schubert polynomials

We study Schubert polynomials using geometry of infinite-dimensional flag varieties and degeneracy loci. Applications include Graham-positivity of coefficients appearing in equivariant coproduct formulas and expansions of back-stable and enriched Sch...

arxiv.org/abs/0807.2747v1

Observation of new quantum interference effect in solids

In order to achieve quantum interference of free electrons inside a solid, we have modified the geometry of the solid so that de Broglie waves interfere destructively inside the solid. Quantum interference of de Broglie waves leads to a reduction i...

arxiv.org/abs/0807.0889v5

Possible mechanism of Cooper pairing in HTS cuprates

In this study, the possible pairing mechanism based on attraction between electrons from adjacent CuO2 layers is proposed. Initially, each CuO2 layer was found to expand the Fermi sphere owing to ridged geometry. When the two layers are close enough...

arxiv.org/abs/0807.2906v1

Fermi gas energetics in low-dimensional metals of spessial geometry

Changes in the metal properties, caused by periodic indents in the metal surface, have been studied within the limit of quantum theory of free electrons. It was shown that due to destructive interference of de Broglie waves, some quantum states ins...

arxiv.org/abs/0909.0154v1

Quantum state depression in semiconductor quantum well

In this study, the quantum state depression (QSD) in semiconductor quantum well (QW) is investigated. The QSD emerge from the ridged geometry of the QW boundary. Ridges impose additional boundary conditions on the electron wave function and some qu...

arxiv.org/abs/2403.20294v1

Invertibility of Discrete-Time Linear Systems with Sparse Inputs

One of the fundamental problems of interest for discrete-time linear systems is whether its input sequence may be recovered given its output sequence, a.k.a. the left inversion problem. Many conditions on the state space geometry, dynamics, and spect...

arxiv.org/abs/1110.0988v1

Theoretical light curves of dipole oscillations in roAp stars

Context. The dipole modes are the most common geometry of oscillations in roAp stars inferred from photometric measurements and are therefore of special interest for asteroseismic purposes. Aims. We present a theoretical and analytical study of the l...