Articles in 2020

Groups of fish tend to move in an organized fashion. Here the authors investigate the behaviour of schools of freshwater fish and find that schooling is induced by noise; the smaller the group size, the greater the noise and hence the greater the alignment.

The mathematical modelling of how information spreads in social networks has latterly gained fresh urgency. A study of realistic structured populations now identifies the threshold at which the propagation of rumours becomes contagious, thereby inducing a phase transition.

Active, non-conservative interactions can give rise to elastic moduli that are forbidden in equilibrium and enter the antisymmetric part of the stiffness tensor. The resulting solids function as distributed elastic engines that can perform work on their surroundings through quasistatic strain cycles.

The relationship between the dynamics and spatial order of active matter gives rise to a rich phenomenology that is not fully understood. A study of bacteria swimming in a patterned liquid crystalline environment is a case in point, and provides a way to streamline the chaotic movements of swimming bacteria into polar jets.

The hybridized modes of an asymmetric plasmonic dimer show avoided crossing of both the real and imaginary parts. This can lead to plasmonic exceptional points, which are used for biosensing with very high sensitivity.

Herbertsmithite is an experimental realization of the so-called quantum kagome antiferromagnet, a system that is predicted to host a spin liquid state down to zero temperature. Detailed NMR measurements now confirm that this is the case, and that its ground state is indeed gapless.

Percolation transitions underpin a generic class of phenomena associated with the degree of connectedness in networks. A detailed numerical study now uncovers a universal scaling in the size of the largest cluster identified in such percolation models.

Mode-locking of lasers can be understood as self-organization, and the three-dimensional case of spatiotemporal mode-locking can described using attractor dissection theory, which helps develop an intuition for this complex case.

The phenomenon of many-body localization gives rise to entirely new phases of quantum matter when it is driven away from equilibrium. A numerical study now shows that one of these phases—the discrete time crystal—can also occur in a classical spin chain.

The internal structure of the neutron has now been probed by highly energetic photons scattering off it. Combined with previous results for protons, these measurements reveal the contributions of quark flavours to the nucleon structure.

A detailed theoretical and experimental investigation of homogeneous cell tissues finds that they can undergo spontaneous spatial symmetry breaking through a purely electrophysiological mechanism.

An experiment with three alternating-current generators demonstrates converse symmetry breaking—a phenomenon whereby the system achieves frequency synchronization when its component systems are tuned asymmetrically.

Following an impulsive laser excitation of a single molecule, a dispersed vibrational wave-packet is partially rephased by a second pulse, and a wave-packet echo is observed. This wave-packet echo probes ultrafast intramolecular processes in the isolated molecule.

The variational quantum unsampling protocol provides a way to realize verification and inference of near-term quantum circuit outputs. This protocol is then experimentally verified on a quantum photonic processor.

The optical analogue of electromagnetically induced transparency and absorption can be modulated by chiral optical states at an exceptional point, which is shown in a system of indirectly coupled microresonators.

The electrons that contribute to the Mott insulator state in single-layer 1T-TaSe2 are shown to also have a rich variation in their orbital occupation. As more layers are added, both the insulating state and orbital texture weaken.