Volume 1 Issue 3, March 2019

Gail Marcus discusses the current social, political and economic factors shaping the development of nuclear power worldwide.

Paul Howarth discusses the current challenges and opportunities in nuclear research and development.

Many small research reactors used as neutron sources are being shut down. To replace them, new facilities are being developed. In particular, compact accelerator-based neutron sources can take up many of the activities previously supported by reactor-based facilities.

New experiments on swarms of Caenorhabditis elegans reveal that the worm can form a dynamical network that can be understood using active matter physics, and controlled using genetic manipulation.

How the mass of super-Earths affects mantle convection is a key question for understanding rocky exoplanet structure and thermal dynamics. New material models based on ab initio mineral calculations characterize convection, with implications for magnetism, planetary cooling, atmospheric composition and habitability.

Calculations show that contrary to the commonly accepted idea, sound waves carry a tiny negative mass and create a gravitational field that is associated with it.

Three Nature papers report the complete topological classification of all known non-magnetic crystalline compounds, revealing thousands of new candidate topological materials waiting to be explored in the lab.

Multidimensional self-trapped states exist in many models of physical systems. However, they are highly unstable in media with the universal cubic nonlinearity. We review different mechanisms that may stabilize them, including non-Kerr nonlinearities, spin–orbit coupling and quantum fluctuations, among others.

Metamaterials are rationally designed composites made of tailored building blocks, leading to effective medium properties beyond their ingredients. This Review surveys 3D metamaterials with unprecedented physical properties in electromagnetism and optics, acoustics and mechanics and transport, made possible by advances in design and manufacturing.

In this Review, the principles developed for fabricating reliable molecular junctions and tuning their intrinsic properties are examined from the point of view of the electrode, the interface and molecular engineering. The various functionalities demonstrated in molecular junctions through molecular design are discussed, along with the open challenges in the field.