scholarly journals The Orbit-Polynomial: A Novel Measure of Symmetry in Networks

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 36100-36112 ◽  
Author(s):  
Matthias Dehmer ◽  
Zengqiang Chen ◽  
Frank Emmert-Streib ◽  
Abbe Mowshowitz ◽  
Kurt Varmuza ◽  
...  
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Author(s):  
Peter J. Knowles

AbstractWe present a new approach for the assignment of a point group to a molecule when the structure conforms only approximately to the symmetry. It proceeds by choosing a coordinate frame that minimises a measure of symmetry breaking that is computed efficiently as a simple function of the molecular coordinates and point group specification.


Nanophotonics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 1337-1347 ◽  
Author(s):  
Simon R. Pocock ◽  
Paloma A. Huidobro ◽  
Vincenzo Giannini

AbstractThe existence of topologically protected edge modes is often cited as a highly desirable trait of topological insulators. However, these edge states are not always present. A realistic physical treatment of long-range hopping in a one-dimensional dipolar system can break the symmetry that protects the edge modes without affecting the bulk topological number, leading to a breakdown in bulk-edge correspondence (BEC). Hence, it is important to gain a better understanding of where and how this occurs, as well as how to measure it. Here we examine the behaviour of the bulk and edge modes in a dimerised chain of metallic nanoparticles and in a simpler non-Hermitian next-nearest-neighbour model to provide some insights into the phenomena of bulk-edge breakdown. We construct BEC phase diagrams for the simpler case and use these ideas to devise a measure of symmetry-breaking for the plasmonic system based on its bulk properties. This provides a parameter regime in which BEC is preserved in the topological plasmonic chain, as well as a framework for assessing this phenomenon in other systems.


2005 ◽  
Vol 26 (2) ◽  
pp. 313-323 ◽  
Author(s):  
Meifeng Dai ◽  
Lixin Tian

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1659
Author(s):  
Edward Bormashenko ◽  
Irina Legchenkova ◽  
Mark Frenkel ◽  
Nir Shvalb ◽  
Shraga Shoval

A continuous measure of symmetry and the Voronoi entropy of 2D patterns representing Voronoi diagrams emerging from the Penrose tiling were calculated. A given Penrose tiling gives rise to a diversity of the Voronoi diagrams when the centers, vertices, and the centers of the edges of the Penrose rhombs are taken as the seed points (or nuclei). Voronoi diagrams keep the initial symmetry group of the Penrose tiling. We demonstrate that the continuous symmetry measure and the Voronoi entropy of the studied sets of points, generated by the Penrose tiling, do not necessarily correlate. Voronoi diagrams emerging from the centers of the edges of the Penrose rhombs, considered nuclei, deny the hypothesis that the continuous measure of symmetry and the Voronoi entropy are always correlated. The Voronoi entropy of this kind of tiling built of asymmetric convex quadrangles equals zero, whereas the continuous measure of symmetry of this pattern is high. Voronoi diagrams generate new types of Penrose tiling, which are different from the classical Penrose tessellation.


2007 ◽  
Vol 40 (8) ◽  
pp. 2237-2250 ◽  
Author(s):  
David Milner ◽  
Shmuel Raz ◽  
Hagit Hel-Or ◽  
Daniel Keren ◽  
Eviatar Nevo
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