Volume 18 Issue 9, September 2022

Statistical correlations between particles play a central role in the study of complex quantum systems. A new study introduces microscopic detection of ultracold molecules and demonstrates the measurement of two-particle correlations.

Trapped ion quantum computers can use two different kinds of ion to avoid crosstalk between adjacent qubits. Encoding two different qubit types in only one ion species can achieve the same goal while reducing experimental complexity.

Cells can sense the mechanical properties of their environment. By adjusting the ruffling of their membranes, cells respond to different viscosities of their surrounding liquid medium.

An experiment with photonic waveguides demonstrates the connection between non-Abelian holonomies and adiabatic particle transport, paving the way to the geometric and topological control of light trajectories.

Tensor networks are mathematical structures that efficiently compress the data required to describe quantum systems. An algorithm for the optimal simulation of quantum dynamics based on tensor networks has now been implemented on a trapped-ion processor.

Random lasers made out of disordered media have a rich but often unpredictable laser light emission, in all directions and over many frequencies. Strategies for taming random lasing are emerging, which have the potential to deliver programmable lasers with unprecedented properties.

Multiple scattering of light in complex and disordered media scrambles optical information. This Perspective showcases how this often detrimental physical mixing can be exploited to extract and process information for optical imaging and computing.

It is not immediately obvious whether photons retain the information they carry when they traverse a disordered or multimodal medium. This Perspective discusses the extent to which the quantum properties of light can be preserved and controlled.

Multiple scattering fundamentally complicates the task of sending light through turbid media, as many applications require. This Review summarizes the theoretical framework and experimental techniques to understand and control these processes.

Seeing—and consequently imaging—through turbid media such as fog is a difficult task, as multiple scattering scrambles the visual information. This Review summarizes techniques that physically or computationally reconstruct the images.

Nonlinearities allow the large number of modes in a multimode fibre to interact and create emergent phenomena. This Review presents the breadth of the high-dimensional nonlinear physics that can be studied in this platform.

The anomalous Hall effect can signify that a material has a spontaneous magnetic order. Now, twisted bilayer graphene shows this effect at half filling, suggesting that the ground state is valley-polarized.

Measurements of four different infinite-layer nickelates show that magnetic behaviour coexists with superconductivity. This is different from what is seen in cuprates, giving a strong distinction between the two classes of oxide superconductors.

Edge modes in chiral topological systems can carry quantum information without backscattering. A topological lattice of superconducting resonators has been coupled to a qubit, providing a platform for chiral quantum electrodynamics and communication.

Qudits are generalizations of qubits that have more than two states, which gives them a performance advantage in some quantum algorithms. The operations needed for a universal qudit processor have now been demonstrated using trapped ions.

Quantum computing with trapped ions requires qubits that can store and manipulate quantum information, and others that can be used for destructive incoherent operations. Different states of ytterbium-171 ions can be used to realize both qubit types

The study of statistical correlations is central to the description of complex quantum objects. Measurements of density correlation functions of ultracold molecules are now possible through the realization of a molecular quantum gas microscope.

Long-lived entanglement is a key resource for quantum metrology with optical clocks. Rydberg-based entangling gates within arrays of neutral atoms enable the generation of clock-transition Bell states with high fidelity and long coherence times.

The simulation of quantum dynamics is a challenging task to solve with classical resources. An experiment with a trapped-ion quantum processor now shows the efficient simulation of the evolution of large-scale many-body quantum systems.

Non-Abelian Thouless pumping, whose outcome depends on the order of pumping operations, has been observed in photonic waveguides with degenerate flat bands.

Control of magnetization is important for applications in spintronics. Now, the piezomagnetic effect allows strain to control the anomalous Hall effect in a metal at room temperature by rotating its antiferromagnetic order.

Avalanches can occur when a porous snow layer lies beneath a dense cohesive snow slab. Field experiments and simulations now reveal different crack-propagation regimes in slab avalanches, similar to rupture propagation following an earthquake.

Wrinkling happens because of mechanical instabilities arising from length mismatches. A theory now describes wrinkling in confined elastic shells and is expected to be relevant for the controlled design of complex wrinkle patterns.

A self-assembled DNA structure is coupled to a nanopore and exhibits continuous rotation in the presence of nanoscale flows driven by electric fields or ionic gradients.

Living cells change their behaviour in response to the viscosity of the medium surrounding them. An in vitro study shows that cells spread wider and move faster in a highly viscous medium, provided they have an actively ruffling lamellipodium.

Epithelial tissues such as those in the gut or skin are strongly polar, generating electric fields that play a role in wound healing and nutrient transport. Changing the field direction in a layer of tissue disrupts its homeostatic stability.

Although the ohm is ‘only’ a derived SI unit, the assumption that it plays an unobtrusive role could not be further from the truth, as Karin Cedergren reveals.