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Time crystals, which break time translation symmetry, have garnered significant interest in both quantum and classical systems due to their potential applications and fundamental implications. This study demonstrates the emergence of classical discrete space-time crystals in chiral liquid crystals, revealing the behavior of Majorana-like quasiparticles within facilitating period-doubling phenomena across various conditions.

Topologically protected vortex knots are shown to undergo fusion and fission, with electric pulses acting as a switch between the two processes. This might enable applications in electro-optics and photonics.

A continuous mesoscale space-time crystal phase is reported from a nematic liquid crystal driven by light.

Femtosecond laser pulses can generate self-organized nonlinear gratings in nanophotonic waveguides, providing both quasi-phase-matching and group-velocity matching for second-harmonic generation, and enabling simultaneous χ² and χ³ nonlinear processes for laser-frequency-comb stabilization.

The study of nematic hosts with anisotropic colloidal particles is reported, but not on the chiral counterparts. Here, the authors report on biaxial properties in a system of colloidal rods with designed surface anchoring doped into a chiral nematic host.

Optical micro-printing provides a way to directly self-assemble photonic microchips with chiral liquid-crystalline photonic elements.

Some biological macromolecules can control their own assembly into elegant hierarchical structures. Synthetic supramolecules are catching up fast, promising new advances for optical and biomedical materials. See Letter p.364

The formation of soliton macromolecules or metamaterial analogues of polymers with inter-soliton binding resembling strong covalent-like chemical bonds has not been considered so far. Zhao et al. experimentally create and theoretically, model soliton macromolecules, called “polyskyrmionomers”, introducing polymer-mimicking designs of topological chiral meta matter that promise technological utility in data storage and electro-optics.

Topological defect structures that swim have been realized in liquid crystals. Now, a range of structures with topology reminiscent of a Möbius strip swim and transform into one another.

Liquid crystal (LC) applications typically rely on defining the non-topological spatial patterns of the optical axis. Here, the authors demonstrate the topological steering of light by LC nematic vortices, futher establishing an analogy between topological light steering by LC vortices and cosmic strings.

The recently discovered elastic hexadecapole has been thought to result from a conic anchoring condition. In order to understand it at a fundamental level, the authors introduce a model for this anchoring in the context of a Landau-de Gennes free energy functional.

Hopf solitons are three-dimensional particle-like field distortions with nontrivial topology. Tai et al. show stable Hopf solitons in a liquid crystal material in the absence of an electric field or geometric confinement, their transformation and hopping-like dynamics in response to electric pulses.

Existing lithographic methods for the micropatterning of reduced graphene oxide (rGO) are limited by mask production. Here, the authors fabricate fully 3D rGO microstructures in an aqueous nematic liquid crystal of two-dimensional GO flakes via a scalable, mask-free pulsed near-infrared laser approach.

While flocking and schooling are more often associated with birds and fish, these types of behaviour can also be observed in inanimate systems. Here the authors demonstrate schooling of topological solitons in a liquid crystal system powered by oscillating electric fields.

Elasticity-mediated particle interaction in a hosting medium holds promise for material engineering of unusual structures. Yuan et al. show that the gold microparticles can induce elastic multipoles of different symmetries when dispersed in a nematic liquid crystal as building blocks for various crystals.

Topological defects can be spontaneously generated to thermodynamically stabilize a variety of peculiar condensed matter phases for technological applications. Here, Ackerman et al. show electrically controllable self-assembly of knotted defects into periodic arrays in chiral liquid crystals.

Windows are one of the least energy efficient parts of the building envelope because of poor thermal insulation. Abraham et al. develop a cellulose-based aerogel as a thermal barrier for windows that retains their optical properties.

Researchers demonstrate systems in which optical solitons coexist and interact with topological solitonic structures localized in the molecular alignment field of a soft birefringent medium. The findings could lead to solitonic tractor beams and new light–matter self-patterning phenomena.

Biological motors which convert energy into mechanical work inspire the fabrication of synthetic motors. Here the authors demonstrate self-assembled colloidal motors which are driven to a range of responses controlled by the feedback between light polarization and deformation of a liquid crystal.

Colloidal systems can form bulk phases such as liquid and crystals, but they also exhibit interesting behaviours that have no atomic analogues. Here, by dispersing solid polymer microspheres in a nematic liquid crystal, Senyuk et al. demonstrate spontaneous formation of hexadecapolar nematic colloids.

Dispersion of colloidal disks in a nematic liquid crystal reveals several low-symmetry phases, including monoclinic colloidal nematic order, with interchange between them achieved through variations in temperature, concentration and surface charge.

When colloidal particles are placed into a liquid crystal host the anisotropic surface interactions produce spatial elastic distortions described as elastic multipoles. Here the authors provide a recipe to construct higher order multipoles, in particular the 16-, 32-, and 64-poles.

A skyrmion is a topological object originally introduced to model elementary particles and a baby skyrmion is its two-dimensional counterpart which can be realized as a defect in liquid crystals. Here the authors show that an electric field can drive uniform motion of baby skyrmions in liquid crystals.

Three-dimensional topological solitons are realized in a fluid chiral ferromagnet formed by colloidal dispersions of magnetic nanoplates.

Chiral nematic liquid-crystal phases consist of rod-shaped molecules that have a preference to twist. However, applied fields force them to exist without the twist. Introducing particle-like twists, so called torons, using laser light relieves this frustration by facilitating the reappearance of the twist. The presence of torons could extend the use of liquid crystals in electro-optic and photonic devices.

Shape complementarity is the primary way to control the symmetry of nanoparticle assemblies. Here, the authors introduce a governing force that dominates symmetry control of nanorod superlattices, using it to obtain an unexpected and highly thermostable tetragonal lattice.

Colloidal chiral springs and helices are formed by light inside a nematic liquid crystal suspension, predefining the mesoscopic superstructures self-assembled in such systems.

Unstructured light controls the elastic monopole moments of nematic liquid-crystal colloidal particles and switches them to quadrupoles, with like-charged monopoles attracting and oppositely charged ones repelling, enabling reconfigurable dynamic self-assembly.

Colloidal particles dispersed in liquid crystals induce nematic fields and topological defects that are dictated by the topology of the colloidal particles. However, little is known about such interplay of topologies. It is now shown that knot-shaped microparticles in liquid crystals induce defect lines that get entangled with the colloidal knots, and that such mutually tangled configurations satisfy topological constraints and follow predictions from knot theory.

Structures containing multiple skyrmions inside a larger skyrmion—called skyrmion bags—are experimentally created in liquid crystals and theoretically predicted in magnetic materials. These may have applications in information storage technology.

Topologically distinct colloidal particles introduced into a nematic liquid crystal align and generate topology-constrained three-dimensional director fields and defects in the liquid crystal fluid that can be manipulated with a variety of methods, opening up a new area of exploration in the field of soft matter.

Cyanobacteria convert light and energy into physical movement. Here, the effect of light intensity gradients on the motion of dense bacterial filaments is investigated, revealing self-assembly of 2D and 3D active nematic states, and changes in orientational and velocity order parameters.