Letters

A superconducting artificial atom coupled to a 1D waveguide tests the limits of light–matter interaction in an unexplored coupling regime, which may enable new perspectives for quantum technologies.

In a nematic liquid crystal, electron orbitals align themselves along one axis, as rods. Thermodynamic observations of such rod-like alignments in Cu_xBi₂Se₃ provide evidence for a nematic superconductor.

Drawing microscopic information out of the diffusive dynamics of complex processes often requires an assumption of ergodicity. Precision experiments on a single atom in a periodic potential suggest that this may be too simplistic in many cases.

Our understanding of collective animal behaviour generally assumes that flocks and herds move through homogeneous environments. Colloidal experiments suggest that flocking can be distorted or even suppressed by the introduction of disorder.

Spin currents can be carried by electrons and by magnons. Experiments now show that, in one-dimensional spin chains, spin currents can also be carried by particle-like excitations known as spinons.

Surprising observations in the evolution of electronic states in electron-doped iridates provide fresh insight into the melting of the Mott state and might lead to a fuller understanding of corresponding processes in copper-oxide superconductors.

Valleys in momentum space provide a degree of freedom that could be exploited for applications. A demonstration of valley pseudospin control now completes the generation–manipulation–detection paradigm, paving the way for valleytronic devices.

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.

Observations of topological surface states provide strong evidence that MoTe₂ is a type-II Weyl semimetal, hosting Weyl fermions that have no counterpart in high-energy physics.

Solitonic modes that are redshifted due to a Raman-related effect are reported in optical microcavities, and termed Stokes solitons.

A colloidal particle connected to suspensions of motile bacteria forms a model system for studying microscale engines in contact with active baths. The engine outperforms its passive counterparts due to the presence of non-Gaussian fluctuations.

The acoustic analogue of a topological insulator is shown: a metamaterial exhibiting one-way sound transport along its edge. The system — a graphene-like array of stainless-steel rods — is a promising new platform for exploring topological phenomena.

Condensed-matter physics meets quantum optics in a study of light–matter interaction in the strong-coupling regime using a two-dimensional electron gas in a high-quality-factor terahertz cavity.

Images of the second-generation Dirac cones that form when graphene is placed on hexagonal boron nitride show the potential of using superlattices to engineer the electronic band structure of van der Waals heterostructures.

Using a technique inspired by Ramsey spectroscopy it is now possible to coherently control free electrons in an electron microscope.

The prediction of an antiferromagnetic semimetal that breaks both time-reversal and inversion symmetry but respects their combination could provide a platform for studying the interplay between Dirac fermions and magnetism.

The response of amorphous solids to external stress is not very well understood. A study now shows that certain glasses, upon decreasing temperature, undergo a phase transition characterized by diverging nonlinear elastic moduli.

A scanning tunnelling spectroscopy study focuses on the lightly doped region of the phase diagram of a cuprate superconductor to reveal the microscopic evolution of a high-temperature superconductor from a charge-ordered insulator.

The control of long-range interactions is an essential ingredient for the study of exotic phases of matter using atoms in optical lattices. Such control is demonstrated using Rydberg dressing: the coupling of ground state atoms to Rydberg states.

The common policy of replacing infected individuals with healthy substitutes can have the effect of accelerating disease transmission. A dynamic network model suggests that standard modelling approaches underplay the effect of network structure.