Volume 13 Issue 4, April 2017

That we now live in the grip of post-factualism would seem naturally repellent to most physicists. But in championing theory without demanding empirical evidence, we're guilty of ignoring the facts ourselves.

A study of Λ_b baryon decays has provided the first direct experimental evidence that spinning matter and antimatter differ. This result may help us understand the puzzling matter–antimatter imbalance in the Universe.

Early forms of life could have started by molecular compounds coming together under conditions dense enough to promote reactions. But how might these droplets have undergone what we now know as cell division? The answer may be simpler than we think.

Ensembles of magnetic colloids can undergo an instability triggering the formation of clusters that move faster than the particles themselves. The many-body process relies on hydrodynamics alone and may prove useful for load delivery in fluidics.

Striking visualization of the flows generated by starfish larvae in their fluid environment offers unique insight into how these organisms live. The beautiful vortices they create betray a dynamic mechanism for trading swimming off against feeding.

Light beams with controllable orbital angular momentum can be generated in the extreme-ultraviolet or soft-X-ray regime, pushing the application of twisted light to the nanoscale.

Adiabatic processes are useful in quantum control, but they are slow. A way around this is to exploit shortcuts to adiabaticity, which can speed things up — for instance, by boosting stimulated Raman adiabatic passage.

Photoemission is usually driven by the energy of the illuminating laser pulses, but in the strong-field regime, the photoemission from an array of plasmonic nanoparticles is shown to be controlled by the light’s electric field.

Resonances in the tunnelling spectra of a two-dimensional electron system provide strong evidence that the electrons arrange themselves into a Wigner crystal lattice with long-range ordering.

High-harmonic generation in a solid turns out to be sensitive to the interatomic bonding — a very useful feature that could enable the all-optical imaging of the interatomic potential.

An optical second-harmonic generation study of a series of transition metal monopnictide Weyl semimetals reveals a giant, anisotropic nonlinear optical response in these systems.

Engineering moiré superlattices by stacking two-dimensional crystals could enable lateral superstructures to be formed where the local topological phase is periodically modulated, creating topological mosaics that are electrically switchable.

Unlike the usual picture of Anderson localization, in three-dimensional quasicrystals light waves can localize without disorder, thanks to their short mean free path.

Valleytronics — exploiting a system’s pseudospin degree of freedom — is being increasingly explored in sonic crystals. Now, valley transport of sound is reported for a macroscopic triangular-lattice array of rod-like scatterers in a 2D air waveguide.

Collections of rolling colloids are shown to pinch off into motile clusters resembling droplets sliding down a windshield. These stable dynamic structures are formed through a fingering instability that relies on hydrodynamic interactions alone.

Larval starfish use an outer layer of cilia to generate vortices in the fluid around their bodies. Spectacular imaging and mathematical modelling are combined to reveal that these dynamics are alternately optimized for swimming and feeding.

A laboratory study of turbulent flows reproduces the properties of jets in the atmospheres of gas giants, providing a better understanding of how these jets could extend deep into the planetary atmosphere.

CP violation has deep implications for particle physics and cosmology. Previously observed only in meson decays, signs of CP violation have now been spotted in baryon decays by analysing the proton–proton collision data from the LHCb detector.

Classical light is as good as quantum light to characterize a quantum channel. This unexpected result has practical consequences that make an experimentalist’s life easier in some situations.

Single atoms on a surface can be useful in spintronics applications, but their spin lifetime is limited by relaxation. By cleverly employing an STM tip, one can probe the spin dynamics and disentangle different effects leading to relaxation.

Droplets are an appealing picture for protocells in origin-of-life studies, but it’s unclear how they would have propagated by growth and division. Theory suggests that chemically active droplets spontaneously split into equal daughter droplets.

Optical-lattice clocks have pushed the limits of frequency measurement — to such an extent that a tiny difference in altitude affects the clock's tick rate, as Hidetoshi Katori elucidates.