Volume 19 Issue 6, June 2023

The strong interaction is modified in the presence of nuclear matter. An experiment has now quantified with high precision and accuracy the reduction of the order parameter of the system’s chiral symmetry, which is partially restored.

Local magnetometry measurements on a magnetic Chern insulator suggest that the Berry curvature of the topological band — responsible for the intrinsic magnetism — also enables ultra-low current switching of the magnetization.

The production of particle–antiparticle pairs in a vacuum — the Schwinger effect — requires extreme conditions that are out of reach of tabletop experiments. A mesoscopic simulation of this phenomenon has now been carried out in graphene devices.

Two superconductors connected by a weak link form a Josephson junction, a nonlinear circuit element at the heart of many quantum devices. Quantized electrical current steps that were predicted decades ago have now been observed experimentally.

A new variation on cathodoluminescence provides a view of a sample’s optical response with time resolution shorter than an optical cycle.

Boson sampling is a benchmark problem for photonic quantum computers and a potential avenue towards quantum advantage. A scheme to realize a boson sampler based on the vibrational modes in a chain of trapped ions instead has now been demonstrated.

Oil-coated bubbles bursting across interfaces enhance aerosol formation and transmission by producing jets that are smaller and faster than those formed by pristine bubbles.

Atom trap trace analysis has emerged as a powerful technique for detecting trace radioisotopes of noble gases. The successful application of the method to a calcium isotope now opens the possibility of extension to other metal isotopes.

Controlling the spatial distribution of optically active spin defects in solids is a long-standing goal in the quantum sensing and simulation communities. Measurements of the many-body noise generated by the spins were used to verify that a highly coherent and strongly interacting quantum spin system was confined to two dimensions within a diamond substrate.

Photon bound states are quantum states of light that emerge in systems with ultrahigh optical non-linearities. A single artificial atom was used to study the dynamics of these states, revealing that the number of photons within the pulse determines the time delay after the pulse scatters off the atom.

In quantum chromodynamics, the condensation of quark–antiquark pairs breaks the chiral symmetry of vacuum. Experiments with pionic tin atoms demonstrate that the symmetry is partially restored at high densities.

The realization of ultracold molecules in higher bands of an optical lattice sets the stage for the study of the interplay between orbital physics and the Bose–Einstein condensation and Bardeen–Cooper–Schrieffer superfluidity crossover.

Large-system molecular dynamics simulations of films of glass-forming polymers reveal spatially long-range tails of interface-driven gradients of the glass transition temperature, suggestive of a combined local caging and long-range collective elasticity origin of relaxation and vitrification in glass-forming liquids.

Switching of magnetic behaviour is one of the main ideas that drives spintronics. Now, magnetic switching via spin-orbit torque is shown in a moiré bilayer, introducing a platform for spintronic applications.

The observation of band structure features typical of the kagome lattice in FeGe suggests that an interplay of magnetism and electronic correlations determines the physics of this material.

Materials that simultaneously display ferroelectricity and magnetism, and are metallic, are very rare. Now, the two-dimensional electron gas in an oxide heterostructure brings all of this behaviour together.

Observations of the Schwinger effect—the creation of matter by electric fields—have been hindered by the high required field strength. A mesoscopic variant of the Schwinger effect has now been realized in graphene transistors.

Solid-state systems are established candidates to study models of many-body physics but have limited control and readout capabilities. Ensembles of defects in diamond may provide a solution for studying dipolar systems.

It is very challenging to model hydrogen at high pressures and low temperatures because quantum effects become significant. A state-of-the-art numerical study shows that these effects cause important changes to the predicted phase diagram.

It has been predicted that Josephson junction devices could produce quantized currents in analogy to the Shapiro steps of voltage used to define the voltage standard. These dual Shapiro steps have now been observed in a Josephson junction array.

Measurements on a single artificial atom—a quantum dot—coupled to an optical cavity show scattering dynamics that depend on the number of photons involved in the light–matter interaction, which is a signature of stimulated emission.

Reflection cannot only occur at interfaces in space but also in time. Transmission-line metamaterials support time interfaces at which interference has been observed, forming a temporal version of a Fabry–Pérot cavity.

Ultrafast photon–electron spectroscopy commonly requires a driving laser. Now, an inverse approach based on cathodoluminescence spectroscopy has allowed a compact solution to spectral interferometry inside an electron microscope, without a laser.

The scalability of quantum information processing applications is generally hindered by loss and inefficient preparation and detection. A minimal loss network based on phonons has now been realized with trapped ions.

A bursting bubble produces a jet drop previously estimated to be too large to contribute to aerosolization. Oil-coated bubbles produce fast and thin jets, which break up into much smaller drops with potential implications for airborne transmission.

Active fluids exhibit regimes with a complex spatio-temporal structure reminiscent of inertial turbulence. Now, inertial and active turbulence are theoretically shown to be closely related indeed.

Quantum turbulence typically entails reconnecting quantized vortices as seen in quantum fluids. Experiments with superfluid helium now show turbulent dynamics with negligible vortex reconnection, a regime dominated by interacting vortex waves at all length scales.

The calcium isotope ⁴¹Ca is a promising candidate to complement dating methods relying on radiocarbon. Small levels of ⁴¹Ca can be measured with atom-trap trace analysis, which brings the use of ⁴¹Ca a step closer to applications.

Ion acoustic bursts followed by electron acoustic bursts are observed during magnetic reconnection in a laboratory experiment. These bursts have been suggested to mediate energy dissipation.

Not to be confused with Jane Austen’s famous character, the unit darcy goes back to a French engineer, as Stefanie Reichert explains.