Nature Physics

Nature Physics, Published online: 08 December 2020; doi:10.1038/s41567-020-01121-y

The uncertainty associated with epidemic forecasts is often simulated with ensembles of epidemic trajectories based on combinations of parameters. We show that the standard approach for summarizing such ensembles systematically suppresses critical epidemiological information.

Nature Physics, Published online: 07 December 2020; doi:10.1038/s41567-020-01082-2

A general approach to derive direction-dependent complex refractive indices close to zero produces infinite families of time-reversible and infinite families of time-irreversible electromagnetic materials, without invoking the concept of topology.

Nature Physics, Published online: 02 December 2020; doi:10.1038/s41567-020-01108-9

Reply to: Economists’ views on the ergodicity problem

Nature Physics, Published online: 02 December 2020; doi:10.1038/s41567-020-01115-w

Alternate reality

Nature Physics, Published online: 02 December 2020; doi:10.1038/s41567-020-01122-x

A scientist’s legacy is defined not only by their research but also by their teaching. Stronger efforts should be made to preserve and celebrate the exposition of physics at all levels.

Nature Physics, Published online: 02 December 2020; doi:10.1038/s41567-020-01106-x

Economists’ views on the ergodicity problem

Nature Physics, Published online: 02 December 2020; doi:10.1038/s41567-020-01095-x

Within the Hartree atomic unit systems, the Schrödinger equation becomes parameter free. But there’s more to it than making a student’s life easier, as Gordon Drake and Eite Tiesinga recount.

Nature Physics, Published online: 30 November 2020; doi:10.1038/s41567-020-01093-z

The interplay of topological properties and non-Hermitian symmetry breaking has been implemented for a range of classical-wave systems. Recent advances, challenges and opportunities are reviewed across the different physical platforms.

Nature Physics, Published online: 30 November 2020; doi:10.1038/s41567-020-01057-3

Three-dimensional structures of vortex loops in a bulk micromagnet GdCo2 have been observed using X-ray magnetic nanotomography. The cross-section of these loops consists of a vortex–antivortex pair stabilized by the dipolar interaction.

Nature Physics, Published online: 24 November 2020; doi:10.1038/s41567-020-01113-y

Author Correction: 15 years of Nature Physics

Nature Physics, Published online: 23 November 2020; doi:10.1038/s41567-020-01084-0

A class of biological matter including elongated cells and filaments can be understood in the framework of active nematic liquid crystals. Within these systems, topological defects emerge and give rise to remarkable collective behaviours.

Nature Physics, Published online: 23 November 2020; doi:10.1038/s41567-020-01056-4

Topological defects in active nematic systems such as epithelial tissues and neural progenitor cells can be associated with biological functions. Here, the authors show that defects can play a role in the layer formation of the soil bacterium Myxococcus xanthus.

Nature Physics, Published online: 23 November 2020; doi:10.1038/s41567-020-01070-6

Bacteria are able to move as vast, dense collectives. Here the authors show that slow movement is key to this collective behaviour because faster bacteria cause topological defects to collide together and trap cells in place.

Nature Physics, Published online: 23 November 2020; doi:10.1038/s41567-020-01083-1

Topological defects in the nematic order of actin fibres in a regenerating organism are shown to be tied to key feature formation. Fibre alignment sets the regenerated body axis and defect sites form organizing centres for the developing body plan.

Nature Physics, Published online: 23 November 2020; doi:10.1038/s41567-020-01052-8

High-harmonic generation up to the seventh harmonic is observed from the intrinsic three-dimensional topological insulator BiSbTeSe2. The parallel components of the even-order harmonics arise directly from the topological surface states.

Nature Physics, Published online: 16 November 2020; doi:10.1038/s41567-020-01080-4

When molecular model systems, such as polycyclic aromatic hydrocarbons, are ionized by ultrashort extreme ultraviolet pulses, their relaxation path proceeds via electron–phonon scattering, linking molecules to typical solid-state matter behaviour.

Nature Physics, Published online: 16 November 2020; doi:10.1038/s41567-020-01073-3

The size-dependent lifetimes observed in the ultrafast molecular relaxation dynamics of an entire class of polycyclic aromatic hydrocarbons can be explained by correlation bands and electron–phonon scattering, reminiscent of solid-state systems.

Nature Physics, Published online: 16 November 2020; doi:10.1038/s41567-020-01061-7

Spin currents are generated from an antiferromagnet/heavy-metal heterostructure using optical excitation on picosecond timescales. This will have applications in antiferromagnetic spintronics.