A combination of measurements from the Solar Dynamics Observatory and radiospectroscopy data from the Nançay Radioheliograph now details the mechanism that connects coronal mass ejections from the Sun and the acceleration of particles to relativistic speeds. A spatial and temporal correlation between a coronal 'bright front' and radio emissions associated with electron acceleration demonstrates the fundamental relationship between the two. Article p811; News & Views p758IMAGE: ATMOSPHERIC IMAGING ASSEMBLY ON NASA'S SOLAR DYNAMICS OBSERVATORYCOVER DESIGN: ALLEN BEATTIE

A quantum gas trapped in an optical lattice of triangular symmetry can now be driven from a paramagnetic to an antiferromagnetic state by a tunable artificial magnetic field. Article p738 IMAGE: ROBERT HPPNER COVER DESIGN: ALLEN BEATTIE

The Kibble–Zurek mechanism describes the spontaneous formation of defects in systems that are undergoing a secondorder phase transition at a finite rate. Familiar to cosmologists and condensed-matter physicists, this mechanism is now found to be responsible for the spontaneous creation of solitons in a Bose–Einstein condensate. Article p656; News & Views p605 IMAGE: GABRIELE FERRARI COVER DESIGN: ALLEN BEATTIE

A study of an actomyosin active gel now demonstrates the importance of the crosslinking density of actin polymers in enabling myosin motors to internally drive contraction and rupture the network into clusters. This indicates the central role played by the cytoskeleton in cell division and tissue morphogenesis. Article p591 IMAGE: JOSE ALVARADO, DIRK-JAN SPAANDERMAN, HENK-JAN BOLUIJT AND KOTA MIURA COVER DESIGN: ALLEN BEATTIE

By means of low-temperature scanning tunnelling spectroscopy, a heavy fermion material in its superconducting and mixed states can be imaged. Besides probing the superconducting gap symmetry, the measurements also reveal a pseudogap. Letters p468 and p474; News & Views p458 IMAGE: BRIAN ZHOU AND A. YAZDANI COVER DESIGN: ALLEN BEATTIE

An experiment now demonstrates the deterministic continuous variable teleportation between two atomic ensembles at room temperature. This protocol makes it possible to teleport time-evolving quantum states from one ensemble to the other. Letter p400; News & Views p389 IMAGE: HANNA KRAUTER AND DANIEL SALART COVER DESIGN: ALLEN BEATTIE

Linking two smoke rings or tying a single ring into a knot is no easy feat. Now, however, such topological vortices are created in water using 3D-printed hydrofoils. High-speed imaging shows how the linked rings spontaneously separate, and the knots are able to free themselves. Similar fluid dynamics may also be relevant in plasmas, quantum fluids and optics. Article p253; News & Views p207 IMAGE: DUSTIN KLECKNER AND WILLIAM IRVINE COVER DESIGN: ALLEN BEATTIE

An all-optical method to measure the space–time characteristics of an isolated attosecond pulse, without temporal and spatial averaging, is now demonstrated. The approach will provide further insight into the generation of ultrafast light, and may possibly be used to finely control the pulse characteristics. Letter p159 IMAGE: KYUNG TAEC KIM COVER DESIGN: ALLEN BEATTIE

Linear-stability measures for assessing the state of a dynamical system are inherently local, and thus insufficient to quantify stability against substantial perturbations. The volume of a state's basin of attraction offers a powerful alternative — and points toward a plausible explanation for regularity in real-world networks. Letter p89; News & Views p69 IMAGE: PETER J. MENCK COVER DESIGN: ALLEN BEATTIE

Photonic crystals efficiently control wave propagation on a wavelength scale, but can become very large when long wavelengths are involved. Metamaterials made of resonant unit cells can, however, confine and guide waves even at scales far below their wavelength. Article p55 IMAGE: FABRICE LEMOULT COVER DESIGN: ALLEN BEATTIE