Quasiparticles dubbed topological polaritons make their debut in the theoretical world.

Polariton condensates can store bits of information and are characterized by long lifetimes. Researchers experimentally show how a polariton condensate acts as an optical spin memory that can be rapidly flipped.

In active liquid crystals, turbulence can occur in the absence of external forces due to internal active stresses. Researchers show that the geometrical structure of such a turbulent flow is strongly correlated with the presence of topological defects in the liquid crystal.

Optical imaging resolution is ultimately limited by light’s quantum noise, which is manifested by small quantum fluctuations in its electric field. A new technique allows these correlations to be controlled simultaneously at all points in space and has the potential to yield smoother images.

An array of helical elements absorbs radiation of a certain frequency while casting no shadow in light over a range of other frequencies.

With the assistance of lattice vibrations, quantum dots perform as single-photon emitters.

Quantum phase transitions, which are driven by a parameter in the Hamiltonian, can be thought as certain classical phase transitions in the modern formulation of quantum Monte Carlo methods. A new generic tool captures quantum phase transitions in a simple and efficient manner.

Researchers show that electronic systems with a common type of magnetic order form a new glassy state of matter due to imperfections. In this phase, the spins of the electrons are randomly aligned or anti-aligned with a spontaneously chosen axis.

Quantum networks built out of distinct quantum bits (qubits) connected via photons may enable quantum computation and long-distance communication. The high yield integration of high-quality solid-state qubits into an on-chip photonic circuit could provide a stable and scalable architecture to build such a network.

Quantum effects are very sensitive to noise, which is a fundamental limit in all experiments. Researchers show that they nevertheless enable precise measurements of magnetic fields in a noisy environment.

In everyday life, if sound propagates from one location to another, it can propagate backwards just as easily. However, theorists show that it is possible to harness the radiation pressure interaction between light and matter to produce unidirectional sound propagation.

Accelerating electrons to relativistic energies has applications in time-resolved electron diffraction. Experiments and simulations show that inhomogeneities in a laser’s electric field affect the quality of the accelerated electron beam.

Weyl fermions possess exotic properties and can act like magnetic monopoles. Researchers show that TaAs is a Weyl semimetal, demonstrating for the first time that Weyl semimetals can be identified experimentally.

Chemical fluctuations within cells affect biological functioning. An accurate mathematical theory now permits a quantitative understanding of intracellular chemical fluctuations and their impact on the probabilistic behaviors of cells.

Light-matter coupling is an ongoing investigation in modern physics and is expected to play a role in quantum information applications. Using single-atom-controlled samples of ultracold rubidium-87 coupled to Rydberg states, scientists show that many-body systems of various sizes can be coherently manipulated as a single “superatom.”

Understanding the electronic structure of molecules has been a long-standing goal in molecular physics. A new proposal uses artificial benzene molecules to image three-dimensional molecular orbitals.

Systems characterized by interconnected nodes are common in both nature and society. A theoretical method yields exact equations to describe the pruning of networks based on each node’s number of neighbors.

Measurement uncertainty is fundamental to all fields of science. The lower limit on measurement uncertainty for an optical signal composed of multiple entangled modes is analytically determined.

Heat engines translate thermal energy into useful mechanical work. New results show how the power and efficiency of miniaturized heat engines are related, which paves the way for studies of even smaller systems that experience quantum effects.

An oscillatory motion dramatically reduces the number of contaminant molecules at the interface between two surfaces.

X-ray radiation impinging on molecules has many medical applications. X-ray-induced electron dynamics in carbon disulfide is studied in order to probe nuclear and electronic degrees of freedom.

Advanced imaging and spectroscopy techniques make it possible to investigate electronic states in superconductors. Scanning tunneling microscopy shows that time-reversal symmetry is broken at the crystallographic boundaries of superconducting FeSe.

Weyl points can be thought of as magnetic monopoles in momentum space that always appear in pairs. Magnetoresistance measurements indicate the existence of the long-anticipated chiral anomaly in Weyl semimetal TaAs single crystals.

Quantum computing requires stable qubits that can hold information for long periods of time. Researchers assemble a hybrid double quantum dot that is both scalable and possesses a long-lived quantum memory.

Spherical particles are excellent test beds for studies of interparticle collisions. Researchers use tiny spheres to investigate how energy driving can yield the coexistence of a solid and liquid phase.

While manufacturing limitations are imposing constraints on Moore’s law, researchers are searching for novel computing architectures based on quantum-mechanical effects. However, it remains to be shown that quantum annealing techniques consistently outperform classical simulated annealing to minimize optimization problems.

Quantum phenomena include the fractional quantum Hall effect, whose quasiparticle is the composite fermion. Theorists show that composite fermions possess different quantum numbers than the electrons or holes they were derived from.

Theorists show that large photon fluxes can result in the breakdown of photon blockade, an analogy to Coulomb blockade for quantum-well electrons. This breakdown is due to a quantum phase transition in zero dimensions.

Solar cell technology benefits from increased photocurrents. New research uses transformation optics to preferentially concentrate light in hotspots in a metal grating.

Researchers propose an approach to safeguard optical quantum key distribution systems against Trojan-horse attacks.

Surface acoustic waves may work as a “quantum bus” that carries information to different parts of a quantum computer.

The dynamical behavior of quantum systems is relevant to quantum information processing. A new theoretical model describes a phase transition from many-body localized states, in which quantum information is accessible, to thermal states, in which such information is lost in the dynamics.

Developments in ultracold atomic experimental techniques highlight fundamental questions of whether quantum systems obey thermodynamics and statistical mechanics when isolated from their environment. A numerical technique is used to study phase transitions between thermal quantum fluids that obey thermodynamics and frozen quantum glasses that do not.

Novel electronic devices of the future may rely on the magnetoelectric effect, which researchers now show can be controlled in a $3d$ transition metal via Zn doping.

High-temperature superconductivity has numerous applications in industry, yet the origin of this phenomenon remains controversial. A new study reveals how doped LiFe${}_{1-x}$Co${}_x$As exhibits a range of transition temperatures and crossovers between a Fermi-liquid state and a non-Fermi-liquid state.

Many realistic networks, including biological ones, are driven by noise, which can generate sudden changes in system behavior. Using a scalable algorithm for controlling the response to noise in complex biological systems, researchers identify gene targets for new cancer therapies.

Analyzing changes in resistivity is one component of condensed-matter physics research that has applications in the electronics industry. Now, researchers experimentally show that the resistivity of a Cd${}_3$As${}_2$ crystal can be modulated by the geometry of the material’s Fermi surface.

The definition of quantum work differs markedly from the definition found in classical mechanics textbooks. Now, by showing that quantum work distributions can be understood as interference patterns between classical trajectories, researchers bridge the gap between classical and quantum notions of work.

There is interest in modulating emergent phases such as magnetism and superconductivity on short time scales. New theoretical results reveal how the melting of magnetic order proceeds along different pathways depending on whether electrons behave like localized magnetic moments or coherent quasiparticles.

Quantum computing promises to be more efficient and significantly faster than today’s classical computing. Researchers compare the performance of a quantum annealer with that of classical algorithms for the first time on hard spin-glass problems.

Fast-rotating molecules spun up by a laser pulse maintain their alignment despite collisions.

Characterizing the entangled states of quantum objects is both time and resource demanding. Now, researchers experimentally demonstrate an optical setup for partially characterizing entangled states in a much more efficient manner.

The goal of achieving quantum computation requires overcoming the limitation of quantum noise. A new approach shows how noisy local information about noise can be used to reliably correct errors for an ensemble of qubits on a lattice.

Heat machines on the atomic scale are surprisingly similar to their macroscopic classical counterparts. Theorists show that all different engine types become thermodynamically equivalent in the quantum regime.