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We give the global homotopy classification of nematic textures for a general domain with weak anchoring boundary conditions and arbitrary defect set in terms of twisted cohomology, and give an explicit computation for the case of knotted…

Soft Condensed Matter · Physics 2016-07-07 Thomas Machon , Gareth P. Alexander

Liquid crystalline systems exhibiting both macroscopic chirality and smectic order experience frustration resulting in mesophases possessing complex three-dimensional order. In the twist-grain-boundary phase, defect lattices mediate the…

Soft Condensed Matter · Physics 2009-12-18 Elisabetta A. Matsumoto , Gareth P. Alexander , Randall D. Kamien

Using molecular simulations and classical density functional theory, we study the liquid-crystalline phase behaviour of a series of bent rod-like mesogens with a controlled degree of chirality introduced through a twist at the centre of the…

Soft Condensed Matter · Physics 2025-11-18 Anna Ashkinazi , Hemani Chhabra , Anouar El Moumane , Maxime M. C. Tortora , Jonathan P. K. Doye

Recent experiments on monolayers of spindle-like cells plated on adhesive stripe-shaped domains have provided a convincing demonstration that certain types of collective phenomena in epithelia are well described by active nematic…

Soft Condensed Matter · Physics 2020-01-22 Ludwig A. Hoffmann , Koen Schakenraad , Roeland M. H. Merks , Luca Giomi

We present a theory of a single point, line or plane defect coupling to the square of the order parameter in a metallic system near a quantum critical point at or above its upper critical dimension. At criticality, a spin droplet is…

Strongly Correlated Electrons · Physics 2009-11-07 A. J. Millis , D. K. Morr , J. Schmalian

We propose a general formalism to characterize orientational frustration of smectic liquid crystals in confinement by interpreting the emerging networks of grain boundaries as objects with a topological charge. In a formal idealization,…

Topological defects are one of the most conspicuous features of liquid crystals. In two dimensional nematics, they have been shown to behave effectively as particles with both, charge and orientation, which dictate their interactions. Here,…

Soft Condensed Matter · Physics 2021-07-14 Daniel J. G. Pearce , Karsten Kruse

The geometric shape, symmetry, and topology of colloidal particles often allow for controlling colloidal phase behavior and physical properties of these soft matter systems. In liquid crystalline dispersions, colloidal particles with low…

Soft Condensed Matter · Physics 2024-10-14 Ye Yuan , Ivan I. Smalyukh

We study the phase behaviour of cholesteric liquid crystal shells with different geometries. We compare the cases of tangential and no anchoring at the surface, focussing on the former case, which leads to a competition between the…

Soft Condensed Matter · Physics 2023-03-01 Giuseppe Negro , Livio Nicola Carenza , Giuseppe Gonnella , Davide Marenduzzo , Enzo Orlandini

We use molecular dynamics to study the ordering of a nematic liquid crystal around a spherical particle or droplet. Homeotropic boundary conditions and strong anchoring create a hedgehog director configuration on the particle surface and in…

Soft Condensed Matter · Physics 2013-03-19 D. Andrienko , G. Germano , M. P. Allen

This review introduces the elasticity theory of two-dimensional crystals and nematic liquid crystals on curved surfaces, the energetics of topological defects (disclinations, dislocations and pleats) in these ordered phases, and the…

Soft Condensed Matter · Physics 2014-01-21 Vinzenz Koning , Vincenzo Vitelli

We investigate theoretically the wetting properties of cholesteric liquid crystals at a planar substrate. If the properties of substrate and of the interface are such that the cholesteric layers are not distorted the wetting properties are…

Focal conic domains, are defects characteristic of layered liquid crystal phases. Their association can built flowers where petals are the ellipses of the Dupin cyclides involved in these defect. We report here the observation of focal…

Soft Condensed Matter · Physics 2023-11-08 Randall D. Kamien , Yuriy Nastishin , Brigitte Pansu

The Peach-Koehler force between disclination lines was originally formulated in the study of crystalline solids, and has since been adopted to provide a notion of interactions between disclination lines in nematic liquid crystals. Here, we…

Soft Condensed Matter · Physics 2024-12-13 Joseph Pollard , Richard G. Morris

Within the framework of continuum theory, we draw a parallel between ferromagnetic materials and nematic liquid crystals confined on curved surfaces, which are both characterized by local interaction and anchoring potentials. We show that…

Soft Condensed Matter · Physics 2022-02-22 Gaetano Napoli , Oleksandr V. Pylypovskyi , Denis D. Sheka , Luigi Vergori

Recently, it was observed that water droplets suspended in a nematic liquid crystal form linear chains (Poulin et al., Science 275, 1770 (1997)). The chaining occurs, e.g., in a large nematic drop with homeotropic boundary conditions at all…

Soft Condensed Matter · Physics 2009-10-31 Holger Stark , Joachim Stelzer , Ralf Bernhard

Using tools and concepts from contact topology we show that non-vanishing twist implies conservation of the layer structure in cholesteric liquid crystals. This leads to a number of additional topological invariants for cholesteric…

Soft Condensed Matter · Physics 2018-06-04 Thomas Machon

Even though chiral nematic phases were the first liquid crystals experimentally observed more than a century ago, the origin of the thermodynamic stability of cholesteric states is still unclear. In this Letter we address the problem by…

Soft Condensed Matter · Physics 2014-09-05 S. Belli , S. Dussi , M. Dijkstra , R. van Roij

There is considerable interest in understanding and controlling topological defects in nematic liquid crystals (LCs). Confinement, in the form of droplets, has been particularly effective in that regard. Here, we employ the Landau-de Gennes…

Chiral twisting of the molecular orientation within the layer of a smectic-A liquid crystal has been investigated using circular dichroism spectroscopy. The results indicate that a rotation of the layers away from the alignment direction is…

Soft Condensed Matter · Physics 2009-10-31 M. S. Spector , S. K. Prasad , B. T. Weslowski , R. D. Kamien , J. V. Selinger , B. R. Ratna , R. Shashidar