Volume 17 Issue 9, September 2021

The European Researchers’ Night provides a platform for scientists to engage with the public.

Nonlinearity and topology are both linked to symmetries, but what happens when the two are combined is not a trivial question. In a nonlinear photonic higher-order topological insulator, solitons localize on the corners together with the topological modes.

Single-molecule experiments can now quantify the surface forces that compete to package tethered DNA into a protein-rich condensate — providing much-needed mechanistic insight into the phase behaviour of the entangled genome in the nucleus.

Frictional sliding starts with a crack front propagating across an interface — a process that is well described by fracture mechanics. Experiments now show that the onset of crack formation is governed by physics that is yet to be fully understood.

Spin waves can carry information that could be used for data processing, but producing and controlling them can be challenging. Now it is possible to generate short-wavelength coherent spin waves that can travel at high speed over a long distance.

The flagella of microorganisms have provided inspiration for many synthetic devices, but they’re typically not easy to produce. A new class of swimmer makes it look simple by spontaneously growing a tail that it can whip to self-propel.

Antiferromagnetic systems are a source of several interesting many-body phases. Now a Heisenberg antiferromagnet has been made from ultracold bosons, providing a highly tunable starting point for experimental investigations that simulate such models.

The nonlinear properties of photonic topological insulators remain largely unexplored, as band topology is linked to linear systems. But nonlinear topological corner states and solitons can form in a second-order topological insulator, as shown by experiments.

Ultrashort light pulses generate nanometre-scale wavepackets of magnons that propagate coherently and at high speed in an antiferromagnet. This pushes antiferromagnetic magnonics forward as a future platform for information processing.

In vitro experiments and theory reveal that a protein associated with DNA transcription mediates condensation of a protein–DNA phase via a first-order transition. The forces uncovered in the study may contribute to chromatin remodelling in the cell.

Many quantum machine learning algorithms have been proposed, but it is typically unknown whether they would outperform classical methods on practical devices. A specially constructed algorithm shows that a formal quantum advantage is possible.

Measurement-based quantum computing performs quantum gates on entangled states without difficult multi-qubit coherent dynamics. A set of gates sufficient for universal quantum computing has now been implemented on a programmable optical platform.

Excitons have been predicted to form spontaneously—without external excitation—in some materials. Low-temperature ARPES measurements on Ta₂NiSe₅ now provide evidence for such an excitonic insulator and for so-called preformed excitons.

Macroscale patterns seen in biological systems such as animal coats or skin can be described by Turing’s reaction–diffusion theory. Now Turing patterns are shown to also exist in bismuth monolayers, an exemplary nanoscale atomic system.

Frictional motion between two surfaces in contact starts with the formation of nucleating rupture fronts. It is now shown that these emerge from nucleation fronts, which develop from a certain stress level onwards and with a characteristic velocity.

A study of the dynamics of polymer translocation through synthetic nanopores provides a direct observation of tension propagation—a non-equilibrium description of the process of unfolding that a polymer undergoes during translocation.

A class of synthetic microswimmers self-assembled from alkane oil drops in a surfactant solution offers a rechargeable platform for studying how microorganisms exploit flagellar elasticity to move around.

Insights into the structure of the Vlasov equation that governs the evolution of collisionless plasmas from observations have been limited. Now the spatial gradient term for electrons is analysed with recent data from the MMS mission.

The uptake of graphene-based materials calls for standardization. Silvia Milana explains what this entails.