Volume 2 Issue 1, 15 January 2020

As the Japan Proton Accelerator Research Complex (J-PARC) celebrates its 10th anniversary, scientists look back on a challenging yet successful decade of research made possible by national and international collaboration.

Scientists benchmark quantum simulations of a textbook condensed matter system on the IBM 20-qubit quantum computer.

The three-body problem is relevant for astrophysical phenomena such as black hole mergers. It famously lacks a general analytical solution, but a new statistical solution relates the distributions of final and initial states, while requiring fewer assumptions than previous approaches.

Writing in Physical Review Letters the XENON collaboration reports how it is pushing the limits of the XENON1T experiment, further constraining the regions where light dark matter could be lurking.

In 2019, new optical phenomena have been revealed in stacks of atomically thin semiconducting transition metal dichalcogenides. These effects can be understood in terms of well-known, but also new, exotic, types of exciton.

The Hubble constant can be estimated from measurements of both the early and late Universe, but the two estimates disagree. In 2019 a number of independent measurements using different methods made this discrepancy harder to ignore.

Artificial spin ices are metamaterials displaying fascinating phenomena arising from the collective behaviour of nanoscale magnets. We review recent developments in terms of emergent magnetic monopoles, phase transitions, dynamics and geometries, and discuss future directions for research and potential applications.

Pseudo-electromagnetic fields emerge in inhomogeneous materials. This Review discusses the properties of such fields in the context of 3D topological semimetals, the origin and consequences of pseudo-fields in real materials and their field theory description.

Cosmological computer simulations of galaxy formation emerged as the primary tool to study structure formation in the Universe. This Technical Review describes the main techniques and ingredients of such simulations and their application to develop and constrain galaxy formation theories.