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An evolution of a spherical region, subjected to uniform buoyancy force, is investigated. Incompressibility and axial symmetry are assumed, together with a buoyancy discontinuity at the boundary. The boundary turns into a vortex sheet and…

Fluid Dynamics · Physics 2023-05-12 Paweł Jędrejko , Jun-Ichi Yano , Marta Wacławczyk

The unusual electronic properties of the quantum spin Hall or Chern insulator become manifest in the form of robust edge states when samples with boundaries are studied. In this work, we ask if and how the topologically non-trivial…

Mesoscale and Nanoscale Physics · Physics 2013-10-23 Andreas Rüegg , Sinisa Coh , Joel E. Moore

Based on the concept of complementary media, we propose a novel design which can enhance the electromagnetic wave scattering cross section of an object so that it looks like a scatterer bigger than the scale of the device. Such a…

Optics · Physics 2009-11-13 Tao Yang , Huanyang Chen , Xudong Luo , Hongru Ma

We show that every quadrangulation of the sphere can be transformed into a $4$-cycle by deletions of degree-$2$ vertices and by $t$-contractions at degree-$3$ vertices. A $t$-contraction simultaneously contracts all incident edges at a…

Combinatorics · Mathematics 2017-03-14 Elke Fuchs , Laura Gellert

Eight models for the coherence of the quasi-monochromatic light from spherical incoherent sources are constructed by placing incoherent monopole and dipole sources on the surface of a sphere, inside a ball and on a plane circular disk. All…

Optics · Physics 2019-11-22 Mikhail Charnotskii

We show that dielectric spheres can be cloaked by a shell of amorphously arranged metallic nanoparticles. The shell represents an artificial medium with tunable effective properties that can be adjusted such that the scattered signals of…

Other Condensed Matter · Physics 2012-06-15 Stefan Muhlig , Mohamed Farhat , Carsten Rockstuhl , Falk Lederer

Transport experiments provide conflicting evidence on the possible existence of fractional order within integer quantum Hall systems. In fact integer edge states sometimes behave as monolithic objects with no inner structure, while other…

Mesoscale and Nanoscale Physics · Physics 2012-10-24 Nicola Paradiso , Stefan Heun , Stefano Roddaro , Lucia Sorba , Fabio Beltram , Giorgio Biasiol , L. N. Pfeiffer , K. W. West

Convolution is an efficient technique to obtain abstract feature representations using hierarchical layers in deep networks. Although performing convolution in Euclidean geometries is fairly straightforward, its extension to other…

Machine Learning · Computer Science 2019-01-04 Sameera Ramasinghe , Salman Khan , Nick Barnes

We compare shadows cast by Schwarzschild black holes with those produced by two classes of naked singularities that result from gravitational collapse of spherically symmetric matter. The latter models consist of an interior naked…

High Energy Astrophysical Phenomena · Physics 2018-10-31 Rajibul Shaikh , Prashant Kocherlakota , Ramesh Narayan , Pankaj S. Joshi

We study the optical appearance of a thin accretion disk around the strongly naked static Janis-Newman-Winicour singularity. The solution does not possess a photon sphere, which results in the formation of a complex structure of bright…

General Relativity and Quantum Cosmology · Physics 2020-12-02 Galin Gyulchev , Jutta Kunz , Petya Nedkova , Tsvetan Vetsov , Stoytcho Yazadjiev

We characterize normal $3$-pseudomanifolds with $g_2\leq4$. We know that if a $3$-pseudomanifold with $g_2\leq4$ does not have any singular vertices then it is a $3$-sphere. We first prove that a normal $3$-pseudomanifold with $g_2\leq4$…

Combinatorics · Mathematics 2022-03-25 Biplab Basak , Raju Kumar Gupta

We computer model a free-standing vitreous silica bilayer which has recently been synthesized and characterized experimentally in landmark work. Here we model the bilayer using a computer assembly procedure that starts from a single layer…

Disordered Systems and Neural Networks · Physics 2013-11-01 Mark Wilson , Avishek Kumar , David Sherrington , M. F. Thorpe

A low-energy neutral quasiparticle in a fractional quantum Hall system appears in the latter's energy spectrum on a sphere as a series of many-body excited states labeled by the angular momentum $L$ and whose energy is a smooth function of…

Strongly Correlated Electrons · Physics 2025-11-19 Dung Xuan Nguyen , Dam Thanh Son

Scattering transforms are a new type of summary statistics recently developed for the study of highly non-Gaussian processes, which have been shown to be very promising for astrophysical studies. In particular, they allow one to build…

Instrumentation and Methods for Astrophysics · Physics 2024-11-22 Louise Mousset , Erwan Allys , Matthew A. Price , Jonathan Aumont , Jean-Marc Delouis , Ludovic Montier , Jason D. McEwen

We define and study virtual representation spaces having both positive and negative dimensions at the vertices of a quiver without oriented cycles. We consider the natural semi-invariants on these spaces which we call virtual…

Representation Theory · Mathematics 2014-01-14 Kiyoshi Igusa , Kent Orr , Gordana Todorov , Jerzy Weyman

Releasing shell-shaped Bose-Einstein condensates from their confinement produces a spherically symmetric density distribution characterized by concentric ripples surrounding a central peak. Here we investigate how a vortex-antivortex dipole…

Quantum Gases · Physics 2026-04-23 A. Tononi

We calculate the virtually-cyclic dimension of the mapping class group of a sphere with at most six punctures. As an immediate consequence, we obtain the virtually-cyclic dimension of the mapping class group of the twice-holed torus and of…

Algebraic Topology · Mathematics 2018-05-02 J. Aramayona , D. Juan-Pineda , A. Trujillo-Negrete

Composed of square particles, the tetratic phase is characterised by a four-fold symmetry with quasi-long-range orientational order but no translational order. We construct the elastic free energy for tetratics and find a closed form…

Soft Condensed Matter · Physics 2015-03-20 O. V. Manyuhina , M. J. Bowick

Particle shape is a critical parameter that plays an important role in self-assembly, for example, in designing targeted complex structures with desired properties. In the last decades an unprecedented range of monodisperse nanoparticle…

Soft Condensed Matter · Physics 2015-01-13 Hanumantha Rao Vutukuri , Arnout Imhof , Alfons van Blaaderen

We examine the gravitational collapse and black hole formation of multiple non--spherical configurations constructed from Szekeres dust models with positive spatial curvature that smoothly match to a Schwarzschild exterior. These…

General Relativity and Quantum Cosmology · Physics 2018-05-22 Ismael Delgado Gaspar , Juan Carlos Hidalgo , Roberto A. Sussman , Israel Quiros