Reviews & Analysis

Disordered systems that are far from equilibrium relax slowly towards their equilibrium. Now, we learn that the irreversible plastic deformations that form the wrinkles of a crumpled sheet result in a complex energy landscape that ages logarithmically.

When a system is driven across a second-order phase transition, defects can form because it cannot respond quickly enough to the new conditions. The Kibble–Zurek mechanism explains this physics, and has now been invoked for Ising-type domains.

Local thermodynamic measurements of a twisted transition metal dichalcogenide heterostructure reveal competition between unconventional charge order and Hofstadter states. This results from the presence of both flat and dispersive electronic bands, whose energetic ordering can be experimentally tuned.

A trilayer copper oxide superconductor, which exhibits the highest superconducting critical temperature as a function of the number of copper–oxygen planes, is shown to have unusual doped hole distribution and interaction between the planes.

Hubbard excitons are elusive quasiparticles that are predicted to form in strongly correlated insulators. Detecting their internal structure and dynamics clarifies the involvement of spin fluctuations in their binding and recombination processes.

The liquid-crystal-like order of cells in epithelial tissues aids rearrangements, but there is disagreement over the dominant liquid crystal phase. Now, a unified approach reveals that two distinct symmetries dominate at different scales.

Describing interdependencies and coupling between complex systems requires tools beyond what the framework of single networks offers. This Review covers recent developments in the study and modelling of multilayer networks.

The guiding of magnetic fields by soft ferromagnetic solids is well known and exploited in magnetic shielding applications. Now, ferroelectric nematic liquids are shown to analogously guide electric fields.

An experimental approach enables the observation of the microscopic details of the relaxation of a highly equilibrated glass back to the liquid phase in real time. This points to a scenario where devitrification proceeds via localized seeds separated by macroscopic length scales.

Chains of coupled superconducting islands known as Josephson junction arrays were predicted to be insulating at high impedance, but superconducting behaviour has been observed. A study of the arrays’ transport suggests thermal effects are responsible.

Time-varying photonics offers ways to manipulate light–matter interactions as never thought before. An experiment with photonic time interfaces reveals how they can enable broadband coherent control of waves.

A milestone for the coherence time of a macroscopic mechanical oscillator may be a crucial advance for enabling the development of quantum technologies based on optomechanical architectures and for fundamental tests of quantum mechanics.

Drops sitting on an array of parallel fibres spontaneously move along the fibres when subject to an airflow perpendicular to the array. The drops show long-range aerodynamic interactions with their downstream and upstream neighbours, and these can catalyse drop coalescence and removal of drops from the fibres — relevant for applications such as fog harvesting and filtration.

A new binding mechanism between trapped laser-cooled ions and atoms has been observed. This advancement offers a novel control knob over chemical reactions and inelastic processes on the single particle limit.

The near-zero thermal expansion of Invar alloy Fe₆₅Ni₃₅ is technologically important but still unexplained. Measurements show that this phenomenon can be explained by the cancellation of magnetic and phonon contributions to the alloy’s entropy.