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obtained. These networks can be driven out of equilibrium through light irradiation and undergo a series of dynamics events, ending in different defect structures. The the dynamics spatiotemporal evolutions of the topological defects through continuum simula-tions. By dispersing nematic with amphiphilic molecules, they also demonstrate a simultaneous transformation of disclination-guided, molecular self-assembly patterns.

A case of antiferrochirality in a liquid crystal phase of counter-rotating staircases Y. X. Li, et al., Nature Communications, 13, 384, 2022. Chirality, or absence of mirror symmetry, as a one of the most common but fascinating phenomena in our daily life have attracted scientists in various fields, from physics to mathematics, biology to chemistry, for centuries. However, producing and controlling the sense of handedness in systems composed of mirror-symmetric elements is still a grand challenge. In this work, the authors show that liquid-crystalline columns with longrange helical order can form by spontaneous selfassembly of straight-or bent-rod molecules without inclusion of any chiral moiety. The formed liquid crystal phase consists of counter-rotating twisted columns with elliptical or star-like cross-sections. There is long-range order between helical columns but not between molecules. Two of the compounds involved contain a chromophore; the helical configuration enables their efficient π-π stacking, making them interesting for optoelectronic applications. The authors also provide a simple theory based on interacting quadrupoles which confirms that the observed structure is energetically the optimal packing of helices of linear polycatenar dumbbells. W. D. Wang, et al., Science Advances, 8, eabk0685, 2022. The idea of Shannon entropy has been broadly used to investigate the relationship between information and structures in molecular and material systems. However, it is difficult to directly observing and manipulating atoms and molecules in molecular and material systems, which hampers them to serve as model systems for further studying the relationship between information and structures. In this work, the authors use hundreds of spinning micro-disks trapped at the air-water interface as a model system to demonstrate the relation between the information and the self-organised patterns. They show that a wide range of global patterns with varying degrees of order can be produced by carefully tuning local pairwise interactions and local symmetries. They use the formulation of the Shannon entropy to the graphs corresponding to the patterns and show how neighbour distances arise naturally as the informationbearing variable for calculating the Shannon entropy. The authors use the distribution of neighbour distances to reproduce in silico patterns characterised by the same orientational orders, thereby highlighting a direct link between information and order. They also show that the entropy by neighbour distances is a more powerful observable for detecting both spatial and temporal changes of the patterns than the orientational order parameters.

Order and information in the patterns of spinning magnetic micro-disks at the air-water interface
Blue phase III: Topological fluid of skyrmions J. Pisljar, et al., Physical Review X, 12, 011003, 2022. Skyrmions are continuous but topologically nontrivial vortex-like field configurations that behave like particles. They have been observed in many physical systems from spin textures to chiral ferromagnets and chiral complex fluids. In this work, the authors show experimentally and numerically that the blue phase (BP) III of a chiral liquid crystal is a 3D fluid of chiral skyrmion filaments of the nematic orientational field, entangled with a 3D network of topological defect lines. The dynamic behaviour of 3D skyrmion fluid from BPIII is presented, giving evidence of slow and fast fluctuations in bulk BPIII. By fabricating a very thin BPIII layer, individual skyrmions are isolated and observed. By measuring their dynamics, evidence of longlived half-skyrmions with lifetimes of the order of 10s is given. The director structure of the skyrmions is produced through Landau-de Gennes modelling, together with optical simulation of their appearance under an optical microscope which is in full agreement with experiments. The authors also demonstrate the possible applications of BP skyrmions, and the competing advantages of soft matter skyrmionics over the magnetic skyrmions in the solid state. M. Y. B. Zion, et al., Nature Communications, 13, 184, 2022. Active systems composed of self-propelled particles exhibit various complex emergent collective dynamic behaviours and have received great attention. In this work, the authors introduce a new class of synthetic micro-swimmers that are driven solely by light. By coupling a light absorbing particle to a fluid droplet, they produce a colloidal chimera that transforms optical power into propulsive thermo-capillary action. The swimmers' internal drive allows them to operate for a long duration (days) and remain active when crowded, forming a high density fluid phase. Above a critical concentration, swimmers form a long-lived crowded state that displays internal dynamics. When passive particles are introduced, the dense swimmer phase can rearrange to spontaneously corral the passive particles. The authors derive a geometrical, depletion-like condition for corralling by identifying the role the passive particles play in controlling the effective concentration of the micro-swimmers.

Cooperation in a fluid swarm of fuel-free microswimmers
Guiding self-assembly of active colloids by temporal modulation of activity B. Zhang, et al., Physical Review Letters, 128, 018004, 2022. Spontaneous emergence of correlated states such as flocks and vortices is a prime example of collective dynamics and self-organisation observed in active matter. The challenge is to develop a set of principles that facilitate the control and manipulation of emergent active structures. In this work, the authors show that dielectric rolling colloids energised by a pulsating electric field self-organise into alternating square lattices with a lattice constant controlled by the parameters of the field. The spatiotemporal properties of the emergent collective patterns and the underlying mechanics of the self-organisation are investigated through experiments and simulations. The authors reveal the resistance of the dynamic lattices to compression and expansion stresses leading to a hysteretic behaviour of the lattice constant.

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No potential conflict of interest was reported by the author(s).

Yuan Shen
Department of Physics and Astronomy, University of Manchester, Manchester, UK yuan.shen@postgrad.manchester.ac.uk