Articles in 2021

Methods for studying Bose–Einstein condensation in ultracold gases have been under development for over 40 years. A highly sophisticated suite of techniques has emerged from rapid technological advances that show no sign of slowing down.

The idea of radiocarbon existing at equilibrium within Earth’s atmosphere has established radiocarbon dating. Adam Fleisher takes a look at its beginnings, achievements and limitations.

Explaining research to scientists beyond our immediate community is a useful skill, but it requires a few adjustments to the way we communicate.

Propagating spin waves known as magnons are expected to carry a dipole moment in the quantum Hall regime. Now, this moment has been detected, demonstrating that the degrees of freedom of spin and charge are entangled in quantum Hall magnons.

Optical box traps create a potential landscape for quantum gases that is close to the homogeneous theoretical ideal. This Review of box trapping methods highlights the breakthroughs in experimental many-body physics that have followed their development.

Spectroscopic techniques can probe atomic and molecular gases with exquisite precision. This Review discusses the wide array of methods that have been developed and applied to study many-body physics in ultracold gases.

A search for transient dark matter in the form of domain walls of axion-like particles finds no statistically significant signal. This places constraints on our theoretical understanding of such scenarios.

Interaction with light can be used to precisely control motional states. This Review surveys recent progress in the preparation of non-classical mechanical states and in the application of optomechanical platforms to specific tasks in quantum technology.

Stacking and twisting two-dimensional materials has led to the observation of a variety of electronic phenomena. Now, magnetic behaviour that is distinct from anything seen in individual layers is induced by a moiré pattern in double bilayer chromium triiodide.

Superconductivity and ordered states formed by interactions—both of which could be unconventional—have recently been observed in a family of kagome materials.

Solitary waves — solitons — occur in a wide range of physical systems with a broad array of attributes and applications. Carefully engineered light–matter interactions have now produced an optomechanical dissipative soliton with promising properties.

Charge density waves are the periodic spatial modulation of electrons in a solid. A new experiment reveals that they can originate from two different electronic bands in a prototypical transition metal dichalcogenide, NbSe₂.

To test the validity of theoretical models, the predictions they make must be compared with experimental data. Instead of choosing one model out of many to describe mass measurements of zirconium, Bayesian statistics allows the averaging of a variety of models.

Information theory sets an upper limit on the ability of bacteria to navigate up chemical gradients. Experiments reveal that cells do so at speeds within a factor of two of the limit, suggesting they are selected to efficiently use information.

High-precision mass measurements of exotic zirconium nuclei are reported, and reveal a double-shell closure for the deformed nucleus ⁸⁰Zr, which is more strongly bound than previously thought.