An imaging study of vortex proliferation near a continuous phase transition in a ferroelectric reveals frozen-in vortices that follow the predictions of the Kibble–Zurek model for cosmological strings formed in the early Universe.Article p970; News & Views p907 IMAGE:XUEYUN WANG AND SANG-WOOK CHEONG COVER DESIGN: ALLEN BEATTIE

Quantum technologies are extremely sensitive to environmental disturbance. Control techniques inspired by classical systems engineering allow selective filtering of the noise spectrum, suppressing time-varying noise over defined frequency bands.Letter p825; News & Views p794 IMAGE: HARRISON BALL AND MICHAEL J. BIERCUK COVER DESIGN: ALLEN BEATTIE

Nonlinear inertial flows usually influence the motion of swimming organisms, but most studies focus on the tractable case of swimmers too small to feel such effects. A mechanistic principle now unifies the varied dynamics of macroscopic swimmers.Letter p758; News & Views p711 IMAGE: MATTIA GAZZOLA COVER DESIGN: ALLEN BEATTIE

How do flocks of birds remain cohesive while dodging predators? A study tracking up to 400 starlings reveals that information propagates in a linear fashion and with no attenuation, meaning that the language of phase transitions in correlated materials can be used to describe flocking behaviour.Article p691 IMAGE: EDWARD SHEN AND COBBS LAB, ISC-CNR, ROME COVER DESIGN: ALLEN BEATTIE

Intense lasers can both ionize atoms and subsequently drive the recollision of the released electrons with their ionized parents. Holography experiments now show that the orientation of the parent can change the recollision process, requiring a refinement of the commonly used strong-field approximation.Letter p594; News & Views p550 IMAGE: MICHAEL SPANNER COVER DESIGN: ALLEN BEATTIE

A cosmological model treating dark matter as a coherent quantum wave agrees well with conventional dark-matter theory on an astronomical scale. But on smaller scales, the quantum nature of wave-like dark matter can explain dark-matter cores that are observed in dwarf galaxies, which standard theory cannot.Letter p496; News & Views p477 IMAGE: HSI-YU SCHIVE COVER DESIGN: ALLEN BEATTIE

Random lasers generate the optical feedback required for stimulated emission by scattering light from disordered particles. Their inherent randomness, however, makes controlling the emission wavelength difficult. It is now shown that this problem can be remedied by carefully matching the pump laser to the specific random medium. The concept is applied to a one-dimensional optofluidic device, but could also be applicable to other random lasers.Letter p426; News & Views p412 IMAGE: PATRICK SEBBAH AND XAVIER NOBLIN, CNRS COVER DESIGN: ALLEN BEATTIE

When superconducting discs are deposited on graphene they induce local superconducting islands. The phase coupling between the islands can be controlled by a gate. Quantum phase fluctuations kill the superconductivity and lead to a metallic state; however, at higher magnetic fields superconductivity can return. Article p380IMAGE: ZHENG HAN AND VINCENT BOUCHIATCOVER DESIGN: ALLEN BEATTIE

Bismuth selenide is a prototypical 3D topological insulator; its electronic spectrum features a Dirac cone populated by surface states. Now, it is experimentally and numerically shown that surface states are destroyed by a bandgap that forms beyond a certain critical compressive strain. Letter p294; News & Views p247IMAGE: YING LIU, YAOYI LI AND LIAN LICOVER DESIGN: ALLEN BEATTIE

Superconductivity in iron pnictides seems to be related to the formation of electronic nematic phases that break the rotational symmetry of the crystal lattice. But the nematic phase in NaFeAs is now shown to persist at high temperatures owing to the presence of antiferroic fluctuations. Article p225; News & Views p184IMAGE: E.P. ROSENTHAL AND CHRISTOPHER GUTIéRREZCOVER DESIGN: ALLEN BEATTIE

Chemical substitution often mimics the effects of applied pressure on a compound, and 'doping' is a standard way to reach a quantum critical point from a given phase. However, CeCoIn5 is a natural quantum critical superconductor, and Cd-doping tunes the system away from criticality. Applied pressure reverses the effect of doping, but although superconductivity is restored, quantum criticality is not. Letter p120; News & Views p94IMAGE: NICHOLAS CURROCOVER DESIGN: ALLEN BEATTIE

The mathematical connection between isostatic lattices — which are relevant for granular matter, glasses and other 'soft' systems — and topological quantum matter is as deep as it is unexpected. Article p39IMAGE: CHARLIE KANECOVER DESIGN: ALLEN BEATTIE