Ring-exchange interactions are basic elements needed for realizing topological quantum computation. These interactions and anyonic statistics have been engineered using ultracold atoms in an optical lattice. Article p1195 IMAGE: HAN-NING DAI, UNIVERSITY OF HEIDELBERG COVER DESIGN: BETHANY VUKOMANOVIC

Water droplets skid across hot surfaces, hovering imperceptibly as they undergo rapid vaporization. Elastic solids are now shown to exhibit a variant of this behaviour, engaging in sustained bouncing by coupling vapour release to elastic deformation. Letter p1095 IMAGE: SCOTT WAITUKAITIS, LEIDEN UNIVERSITY COVER DESIGN: BETHANY VUKOMANOVIC

Triggering and sustaining fusion reactions — with the goal of overall energy production — in a tokamak plasma requires efficient heating. Radio-frequency heating of a three-ion plasma is now experimentally shown to be a potentially viable technique. IMAGE: YEVGEN KAZAKOV (LPP-ERM/KMS); COMPUTED WITH THE TORIC CODE (M. BRAMBILLA AND R. BILATO, IPP-GARCHING) COVER DESIGN: BETHANY VUKOMANOVIC

Swarms and statistical physics seem like natural bedfellows, but concepts like scaling are yet to prove directly applicable to insect group dynamics. A study of midges suggests they are, and that they may give rise to a new universality class.Article p914 IMAGE: COBBS LAB – COLLECTIVE BEHAVIOR IN BIOLOGICAL SYSTEM, SAPIENZA UNIVERSITY OF ROME COVER DESIGN: BETHANY VUKOMANOVIC

The normal state of the ruthenate Sr2RuO4 is not that of a conventional metal but one with enhanced correlation effects, which may help to elucidate the origin of the unconventional superconductivity observed in this material.Article p799 IMAGE: PHILIP DERRY, OXFORD UNIVERSITY COVER DESIGN: BETHANY VUKOMANOVIC

An inelastic neutron scattering study of the two-dimensional antiferromagnet Ca2RuO4 reveals evidence for a condensed-matter analogue of the Higgs mode, and its subsequent decay into transverse Goldstone modes.Letter p633; Letter p638IMAGE: ADELA MIKLIKOVA, CEITEC MUCOVER DESIGN: BETHANY VUKOMANOVIC

An enhanced production of particles containing strange quarks has been discovered in proton–proton collisions at the LHC by the ALICE Collaboration. The enhancement depends on the strangeness content of the hadrons and grows with the number of charged particles produced, behaviour that may be connected to the formation of a primordial state of matter. Letter p535; News & Views p531 IMAGE: DAVID DOBRIGKEIT CHINELLATO, UNIVERSIDADE ESTADUAL DE CAMPINAS (UNICAMP), BRAZIL COVER DESIGN: BETHANY VUKOMANOVIC

The success of machine-learning techniques in handling big data sets has now been exploited in the classification of condensed-matter phases and phase transitions. Letter p431; Letter p435; News & Views p420 IMAGE: JUAN CARRASQUILLA COVER DESIGN: BETHANY VUKOMANOVIC

Unlike the usual picture of Anderson localization, in three-dimensional quasicrystals light waves can localize without disorder thanks to their short mean free path. Letter p363 IMAGE: KAHYUN HUR, KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY COVER DESIGN: BETHANY VUKOMANOVIC

Cavity spectroscopy measurements elucidate the Fermi polaron nature of the optical excitations in monolayer transition metal dichalcogenides. Letter p255 IMAGE: ATAC IMAMOGLU, ETH ZURICH COVER DESIGN: BETHANY VUKOMANOVIC

Superconducting circuits, coupled to form a ring in which a photonic excitation can circulate between sites, are established as a versatile platform for studying the interplay of strong particle interactions and external fields. Article p146; News & Views p110 IMAGE: M. FANG/MARTINIS LAB, UCSB COVER DESIGN: BETHANY VUKOMANOVIC

Spindle-shaped cells readily form nematic structures marked by topological defects. When confined, the defect distribution is independent of the domain size, activity and type of cell, lending a stability not found in non-cellular active nematics. Letter p58 IMAGE: GUILLAUME DUCLOS, INSTITUT CURIE COVER DESIGN: BETHANY VUKOMANOVIC