Volume 17 Issue 12, December 2021

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.

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.

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.

Most systems exhibiting topological superconductivity are artificial structures that require precise engineering. Now, a layered material shows tantalizing signs of the phenomenon.

Integrating quantum technology with existing telecom infrastructure is hampered by a mismatch in operating frequencies. An optomechanical resonator now offers a strain-mediated spin–photon interface for long-distance quantum networks.

Interacting quantum systems are difficult to formulate theoretically, but Nikolai Bogoliubov offered a workaround more than 70 years ago that has stood the test of time. Now, correlations that are a crucial feature of his theory have been observed.

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.

Laser cooling underpins the field of ultracold quantum gases. This Review surveys recent methodological advances that are pushing quantum gases into new regimes.

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.

Ultracold gases provide a platform for idealized realizations of many-body systems. Thanks to recent advances in quantum gas microscopy, collective quantum phenomena can be probed with single-site resolution.

Large arrays of atoms and molecules can be arranged and controlled with high precision using optical tweezers. This Review surveys the latest methodological advances and their applications to quantum technologies.

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.

The freedom to manipulate quantum gases with external fields makes them an ideal platform for studying many-body physics. Floquet engineering using time-periodic modulations has greatly expanded the range of accessible models and phenomena.

The detailed structure of each atomic species determines what physics can be achieved with ultracold gases. This review discusses the exciting applications that follow from lanthanides’ complex electronic structure.

The evolution of many-body magnetic spin systems is influenced by many factors, including inhomogeneity and the presence of interfaces. These effects have now been measured in a far-from-equilibrium binary mixture of ultracold gases.

Interactions between atoms in a Bose–Einstein condensate cause quantum fluctuations and the creation of additional correlations between pairs of atoms. These effects have now been directly observed, confirming long-standing theoretical predictions.

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.

Twisted bilayer graphene hosts flat electronic bands, but their relationship to the observed correlated phases is still debated. Here, it is shown that electron–electron interactions can help to flatten the bands and generate the correlated phases.

Experiments on cell monolayers on corrugated hydrogels reveal the effects of local curvature on the shape of cells and nuclei. A vertex model lends support to the idea that the modulation of tissue thickness may enable curvature sensing.

As tissues grow, a small fraction of cells can give rise to a large fraction of the tissue. A model borrowed from forest fires suggests that this can occur spontaneously in development as a collective property of the cell interaction network.

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.

A search for axion-like dark matter with a quantum sensor that enhances potential signals is reported. This work constrains the parameter space of different interactions between nucleons and axion-like particles and between nucleons and dark photons.

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.

Scanning tunnelling microscopy provides evidence for topological superconductivity in a naturally occurring transition metal dichalcogenide material.

Quantum networks require a connection between quantum memories and optical links, which often operate in different frequency ranges. An optomechanical device exploiting the strain dependence of a colour-centre spin provides such a spin–optics interface at room temperature.

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.

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.