Volume 12 Issue 6, June 2016

The announcement confirming the discovery of gravitational waves created sensational media interest. But educational outreach and communication must remain high on the agenda if the general public is to understand such a landmark result.

Three-dimensional rogue waves have been observed in a dusty-plasma system, which provides a wave–particle interaction view on their formation.

An experiment confirms that universal relations describe fermionic systems with p-wave symmetry.

The concept of an evolving jamming density explains a multitude of mechanisms in granular matter. Simulations of systems with friction now consolidate this notion and highlight that the jamming point is a variable that can move in various ways whenever the system is deformed.

The folded surface of the human brain, although striking, continues to evade understanding. Experiments with swelling gels now fuel the notion that brain folding is modulated by physical forces, and not by genetic, biological or chemical events alone.

A renaissance of interest in a numerical technique known as the conformal bootstrap is surveyed, and its implications for the determination of critical exponents in a range of spin models is discussed.

Spin–orbit coupling in two dimensions is essential for observing topological phases in ultracold atoms. Such a coupling was produced in a gas of potassium atoms and a robust Dirac point was observed in the energy dispersions of the dressed atoms.

Single carbon vacancies in graphene can host a positive charge that is tunable. When this charge is large enough such vacancies resemble artificial atoms, with an induced sequence of quasi-bound states that trap nearby electrons.

A magnetotransport study of zirconium pentatelluride now reveals evidence for a chiral magnetic effect, a striking macroscopic manifestation of the quantum and relativistic nature of Weyl semimetals.

Two intriguing manifestations of Hall physics are reported in a topologically insulating heterostructure: a sign-reversal of the anomalous Hall effect and the emergence of a topological Hall effect.

Inelastic Raman scattering is used to probe the critical spin fluctuations in an iron pnictide superconductor, providing insights into the origin of nematic order in this system.

Josephson junctions incorporating ferromagnetic spin valves are shown to be switchable between the 0 and π states, opening up interesting wider implications for possible devices.

A so-called Josephson ϕ₀-junction based on a nanowire quantum dot is reported. By means of electrostatic gating, it is possible to controllably introduce a phase offset taking any value between 0 and π in the ground state of the junction.

Rogue waves have been observed in fluids and other wave contexts. Experiments now show the formation of 3D acoustic rogue waves in dusty plasmas; they result from wave–particle interactions driving the dust particles into high-amplitude dynamics.

Amorphous packings of spheres subject to shear and friction jam above a critical density. Simulations now show that shear results in geometrical patterns that are precursors to jammed structures and that friction effectuates the jamming.

Fibre networks become rigid at a critical connectivity, but biopolymers giving structure to cells aren’t always well connected. Modelling and experiments on collagen networks show that their rigidity constitutes strain-controlled critical behaviour.

A 3D-printed fetal brain undergoes constrained expansion to reproduce the shape of the human cerebral cortex. The soft gels of the model swell in solvent, mimicking cortical growth and revealing the mechanical origin of the brain’s folded geometry.

Doubly magic atomic nuclei — having a magic number of both protons and neutrons — are very stable. Now, experiments revealing unexpectedly large charge radii for a series of Ca isotopes put the doubly magic nature of the ⁵²Ca nucleus into question.

In a Fermi gas with s-wave interactions the contact relations link the thermodynamic and microscopic properties. For the p-wave case two new types of contacts that characterize the interactions have now been measured experimentally.

Controlled motion of a droplet on a hot surface is hampered by the formation of an evaporation layer below the droplet (Leidenfrost effect). But a cleverly patterned surface induces a Leidenfrost–contact-boiling state, directing the droplet’s motion.

Yuqin Zong sheds light on photometry's fundamental unit.