Magnetic fields play roles in a variety of scientific and medical applications. Using solid-state spins in diamond, researchers experimentally demonstrate the measurement of magnetic fields as small as 100 fT in a tiny sensor volume.

A crystal cavity for light and sound has been chilled close to its motional ground state.

Studies of the fractional quantum Hall effect rely on understanding the Hamiltonians whose eigenstates are described by its wave functions. A geometric approach is used to calculate the Hamiltonian pseudopotentials for electron gases with arbitrary geometries.

There are only a handful of materials in nature that exhibit sequential temperature-dependent transitions from a paramagnetic metal to a ferromagnetic metal phase and then onto a ferromagnetic insulator phase. Now, scientists have used spectroscopy and theoretical calculations to reveal details about such transitions in polycrystalline K${}_2$Cr${}_8$O${}_{1}6$.

The evolution of an isolated quantum system has applications in many fields of atomic physics, condensed matter physics, and cosmology. A theoretical study shows how an ensemble of interacting quantum spins exhibits different relaxation dynamics depending on the energy of the prepared initial states.

Quantum states play key roles in advanced cryptographic methods. Now, experiments show that quantum state tomography can be optimized by employing certain mathematical constructions.

A theoretical analysis quantifies the technical resources required to build a quantum computer based on photons.

Quantum key distribution, a process employed in encrypted transactions, relies on Einstein-Podolsky-Rosen steering when one party has untrusted devices. For the first time, a formal framework of steering as a physical resource is presented.

Secure cryptography has been a long-standing goal of quantum applications. Now, researchers experimentally show how a quantum setup can transmit a pattern of 1s and 0s over a 25-km optical fiber by interfering two independent lasers.

Quantum technology that enables two distant parties to securely communicate is of great interest in cryptography. New research shows how implementations of quantum key distribution can be significantly simplified by not co-transmitting a local oscillator reference between the two communicating parties.

Quantum effects such as coherence and entanglement increase a system’s ability to store energy.

High-temperature superconductivity—the property of zero electrical resistance at relatively high temperature—is manifested in very limited classes of materials. An examination of the unique relationship between electronic structures and lattice structural units of the two known classes of high-temperature superconductors helps to identify possible new classes of these materials.

Exotic excitations known as anyons are found in fractional quantum Hall states. Now, a systematic method establishes that certain symmetric theories of anyons cannot be realized in two dimensions.

High-resolution tracking of the population abundances in a simple, closed microbial ecosystem shows that the intrinsic dynamics of the system are strongly deterministic.

Particle interference is a critical component of optical quantum computing and communication. Now, researchers examine multiphoton quantum interference both theoretically and experimentally by manipulating the distinguishability of photons.

Previous studies have shown that single nuclear spins and nuclear spin pairs can be detected. Scientists analyze time-periodic sensing protocols using Floquet theory, a powerful new method for relating experimental features to the characteristics of the detected spin or small cluster of spins.

Because photons interact weakly with themselves and experience low decoherence, they are a promising avenue for quantum information science. Theorists show how the temporal modes of single-photon states can form an alphabet for communication across a quantum information network.

Superconducting cuprates are of great interest in condensed-matter physics, and now a new study shows that another transition-metal oxide, Sr${}_2$IrO${}_4$, may be analogous to cuprates in its high-temperature superconductivity.

Many of tomorrow’s photonic devices, including optical biosensors, may rely on light signals with highly particular polarization properties. A new experiment shows that an ultrathin layer of gold particles can selectively absorb or reflect a light beam depending on its polarization handedness.

Superconducting qubit experiments cannot be conducted without nonreciprocal devices such as circulators and directional amplifiers. Researchers show that both of these kinds of devices can be realized using a single Josephson circuit.

The Meissner effect, which explains the levitation of magnetic objects, involves the expulsion of external magnetic flux from a superconductor. Now, researchers show that the inverse effect can also occur in which external magnetic flux is amplified.

Interactions between molecules and light modes can alter the chemical structures of molecules. By examining strong coupling from a microscopic perspective it is possible to predict the modifications that molecules will undergo.

Spintronics devices often use the accumulation of spins, probed by magnetoresistance, to convey information, and now researchers identify the origin of junction magnetoresistance in artificially engineered oxide heterostructures.

Coupling the frequency of an electromagnetic cavity to the square of mechanical displacement of the cavity structure has been proposed for realizing quantum nondemolition measurements. Such measurement systems are now one step closer with the realization of a tunable microscale photonic crystal cavity with coupling that is some 5 orders of magnitude larger than in conventional Fabry-Pérot resonators.

Black hole horizons have been shown to have characteristic entropies and temperatures. A new investigation shows similarities between the entropy of a black hole and a metallic state of high-temperature superconductors.

Water, plasmas, and laser light can all exhibit instabilities. Experiments in two different areas of wave physics are used to investigate the creation and annihilation dynamics of superregular breather waves, which combine to form an instability.

Modulating the phase of electromagnetic waves has many applications in photonic research. A new mechanism allows a thin graphene metasurface to reliably achieve an extremely large phase modulation in THz radiation.

The transition between a superfluid and a normal fluid in two dimensions can be understood in terms of the proliferation of topological defects. Now, scientists theoretically analyze such phase transitions in the far-from-equilibrium context of a quantum fluid of exciton polaritons.

Chaos is a fundamental aspect of many fields of nuclear and atomic physics. Scientists use collisions among magnetic rare-earth atoms to investigate quantum chaos.

Cortical neural circuits have been hypothesized to operate in a regime termed the “edge of chaos.” A new theoretical study puts this regime in a more biologically plausible perspective.

Topological insulators possess properties of both conductors and insulators. A theoretical study demonstrates that the surface state of a Fu-Kane-Mele topological insulator can access all of the other surface states of the material.

Researchers use ideas generated in the study of quantum entanglement to guide the construction of new impurity solvers, enabling analysis of substantially more complex and realistic problems within the cluster dynamical mean-field-theory framework.

Glasses remain a poorly understood material despite their widespread use. A study of the macroscopic elastic properties of a colloidal-glass former during vitrification offers new insights.

Time-reversal symmetry is fundamental to condensed matter physics, and now researchers show how time reversal can be applied locally, using a tensor network representation, and how time-reversal twists can be used to detect topological order.

Theorists studying unexpected quantum states of matter show that the second-neighbor Kitaev can explain materials that are in close proximity to a spin-liquid state.

A proof-of-principle experiment allows single photons to travel in only one direction through an optical fiber.

The act of a quantum measurement reduces the uncertainty in the motion of a vibrating membrane below the fundamental quantum limit.

Fault-tolerant quantum computation has been a long-standing goal in many fields of physics. A new model shows how logical qubits can be encoded using anyon excitations from Majorana fermions arranged on a two-dimensional lattice.

Copying information is fundamental in both nature and human industries. Researchers show how the accuracy of a simple copying process is related to thermodynamics.

Error correction is critical in topological quantum computation, but it restricts the quantum gates that can be easily performed. A proposed model shows how to correct errors and perform complex gates by braiding in realistic qubit systems that support non-Abelian parafermions.

Modeling systems with a large number of interacting electrons is critical to understanding the physical properties of materials and molecules of interest to chemists and physicists. Researchers model a system using a range of numerical techniques and compare results in order to find sources of uncertainty and establish benchmarks.

Majorana particles, which are their own antiparticles and whose recent detection in solid-state systems remains controversial, are expected to play an important role in future quantum computing. Now, scientists predict that graphene may host Majorana particles.

Theorists demonstrate a quantum variant of the Kolmogorov-Arnold-Moser theorem, a theorem in classical mechanics that concerns the crossover between integrability and chaos. Integrability breaking in the Lieb-Liniger model, a model describing one-dimensional Bose gases, leads to a deformation, not destruction, of the model’s conserved quantities.

Correlated quantum many-body systems appear in physics, chemistry, and biology. Researchers simulate and explore such systems using an experimentally controlled superconducting quantum device.

A new metamaterial acts like a cloak over a wide range of microwave frequencies.

Topological effects persist in Weyl semimetals, and now two experiments show how Fermi arcs lead to nonlocal currents in Weyl semimetal samples already at the semiclassical level.

Many-body localization leads to the breakdown of ergodicity in quantum systems and defies description in terms of equilibrium statistical mechanics. Researchers introduce an order parameter that makes it possible to probe how ergodicity and thermalization break down due to many-body localization.

Two-dimensional Mott insulators allow for a remarkable “deconfined” quantum phase transition. A new theoretical and computational study shows that this controversial critical point may be even stranger than previously thought.

Conventional electric circuits use electrons as information carriers, a process that dissipates vast quantities of waste heat. A new design for a spin-wave diode, which produces no Joule heating, is presented.

Novel topological phenomena are believed to arise in systems driven out of equilibrium. Now, researchers make a key step toward realizing such phenomena and establish the requirements for obtaining Floquet insulator steady states.

Optomechanics, which refers to the interplay of light and nanomechanics, has widespread applications in sensing and quantum optics. Researchers demonstrate that an optomechanical system based on single-crystal diamond nanobeams can undergo large self-oscillations.

Researchers explore the limits of quantum theory using pairs of entangled photons and find results consistent with quantum predictions.

Molecular nitrogen plays a role in the assembly of prebiotic molecules, and it protects humans from the Sun’s extreme ultraviolet radiation. Researchers investigate, for the first time, the ultrafast molecular dynamics of nitrogen as it disassociates.