What happens when a photon is absorbed by a superconductor? Although vortex-antivortex pairs have long been suspected to play a central role in superconducting photon detection, their dynamics following photon absorption have eluded direct observation. By monitoring quantized voltage signals generated by photon-induced vortices, the authors reveal their generation statistics and demonstrate photon-number resolution. This work provides a rare microscopic view of photon detection in superconductors, and opens a route toward fast superconducting photon-number-resolving detectors.

[Phys. Rev. Applied 26, 034005] Published Wed Sep 02, 2026

Atomic interferometers offer extraordinary inertial sensitivity, yet their intrinsically periodic response has long prevented continuous operation over a wide dynamic range. The authors demonstrate a dual-channel closed-loop atomic beam interferometer, enabling simultaneous quantum feedback for rotation and acceleration. By converting periodic matter-wave interference into continuously tracked control parameters, the scheme overcomes the conventional half-fringe limitation while preserving precision. This advance brings practical quantum inertial navigation a significant step closer.

[Phys. Rev. Applied 26, 034003] Published Tue Sep 01, 2026

Stopping and localizing elastic waves can concentrate energy for high-sensitivity sensing and harvesting, but this often requires intricately tuned lattices or symmetry-restricted piezoelectric transducers. This study finds that flexoelectricity—the universal coupling between strain gradients and electric polarization—could be combined with higher-order elasticity to create stable, tunable zero-group-velocity extrema and stationary-inflection modes. Introducing a defect cavity for tighter localization increases both open-circuit voltage and mass responsivity. The resulting self-sensing, electrically reconfigurable resonators could enable compact devices for diverse applications.

[Phys. Rev. Applied 26, 024063] Published Mon Aug 24, 2026

Starting from a quartz-crystal microbalance, the authors develop a battery-free wireless sensing technology that enables remote measurements of structural strain and gas concentration over distances exceeding 50 m. The system enhances the electromechanical coupling between an AT-cut quartz resonator (packaged in a slightly pre-bent state) and electromagnetic waves, enabling long-range sensing without onboard power sources or electrical connections. The ability to perform battery-free long-range sensing is promising for smart infrastructure monitoring, with applications in bridges, pipelines, nuclear facilities, and industrial plants.

[Phys. Rev. Applied 26, 024067] Published Mon Aug 24, 2026

Powerful and efficient numerical techniques have been central to theoretical research on quantum mechanical systems for decades. In the era of quantum advantage demonstrations, it is paramount to develop strong benchmarks that truly represent the classical frontier. This study presents a high-performance parallel implementation and large-scale demonstration of quantum dynamics simulated with OR-represented quantum algebra at a huge scale, retaining over a trillion Pauli strings while maintaining strong scaling behavior, using the supercomputer Fugaku. This algorithm enriches the body of classical high-performance methods and challenges current quantum advantage efforts.

[Phys. Rev. Applied 26, 024046] Published Tue Aug 18, 2026

Superconducting nanowire single-photon detectors with high count rates are important for quantum information processing, optical communication, and photon-starved imaging. Their timing performance is limited by excess jitter, though, and the underlying physics is not fully understood. This study identifies stochastic baseline fluctuations caused by the finite memory of ac-coupled readout circuits as an important source of timing jitter at high count rates, and establishes a quantitative framework to predict their impact. Also, under pulsed illumination the timing jitter is found to reach a maximum at about half of the laser’s repetition rate.

[Phys. Rev. Applied 26, 024049] Published Tue Aug 18, 2026

Volatile resistive switching in correlated-electron systems is promising for electronics applications, but the underlying physics remains obscured. Most studies have focused on inorganic thin films on substrates with strong thermal coupling to their surroundings, but here the authors investigate in a bulk organic single crystal with an exceptionally sharp metal-insulator transition. Bulk-sensitive microscopic NMR reveals the coexistence of metallic and insulating regions in the resistive-switched state, while weak thermal coupling to the surroundings allows temperature locking near the transition temperature and an “inverse Ohm’s law”, with voltage inversely proportional to current.

[Phys. Rev. Applied 26, 024041] Published Mon Aug 17, 2026

Quantum dot–based spin qubits require ultrafast, high-fidelity charge readout for quantum error correction and real-time feedback. Improving readout sensitivity has often required complex high-impedance resonators or specialized circuits. This work shows that optimizing a gate lever arm directly coupled to an in situ superconducting microwave resonator dramatically enhances readout sensitivity, achieving integration times at the tens of nanoseconds scale without the use of high-impedance devices, and revealing how readout noise evolves across distinct physical regimes. These results show a practical route toward faster, more scalable architectures for fault-tolerant quantum computing.

[Phys. Rev. Applied 26, 024040] Published Fri Aug 14, 2026

Pyrite FeS${}_2$ is an earth-abundant, low-cost semiconductor with application potential, particularly if it can be synthesized at high quality from natural resources. This study demonstrates that common iron ores can be converted directly to semiconductor-quality FeS${}_2$ without additional purification, because unexpected purification occurs during processing and few elements effectively dope the material. The resulting single crystals boast carrier densities down to 10${}^{16}$ cm${}^{-3}$ and mobilities up to 100 cm${}^2$V${}^{-1}$s${}^{-1}$, similar to those grown from high-purity precursors. This could unlock an attractive new revenue stream for an abundant natural resource.

[Phys. Rev. Applied 26, 024033] Published Thu Aug 13, 2026

Spin waves hold promise for compact analog computing, but routing them via focused-ion-beam irradiation in yttrium iron garnet is hindered by a nonmonotonic wavelength response to ion dose. By combining atomic force microscopy and time-resolved magneto-optical Kerr effect microscopy with analytical, ion-damage, and micromagnetic modeling, this study links this response to the progression from elastic and plastic deformation to partial amorphization and the resulting magnetoelastic fields. This physical understanding will enable predictably engineered irradiation-defined spin-wave landscapes and future graded-index magnetoelastic magnonic devices.

[Phys. Rev. Applied 26, 024028] Published Wed Aug 12, 2026

Superconducting qubits are promising for quantum computing, but their performance is hindered by correlated errors from environmental factors like ionizing radiation and cryocooler vibrations. The authors distinguish these error types in the same device by their distinct features, and use accelerometers to directly link specific errors to pulse tube vibrations. This study also reveals that qubits engineered to resist radiation are protected against these vibration-induced errors as well. Identifying the sources of correlated errors will inform future mitigation strategies for building more robust quantum computers.

[Phys. Rev. Applied 26, 024025] Published Tue Aug 11, 2026

Magnonics, in which information is processed with spin waves instead of electronic charge, offers a path to energy-efficient computing beyond CMOS, but scaling has been held back because shrinking conventional waveguides sharply slows spin waves and shortens their reach. Using experiment, simulation, and analytical modeling, the authors show that Ga:YIG waveguides as narrow as 145 nm support exchange-dominated spin waves moving at 600 m/s, much faster than in plain YIG, with a group velocity almost independent of waveguide width. This fast, long-lived, geometry-independent transport makes Ga:YIG a compelling platform for nanoscale magnonic logic and hybrid spin-wave–CMOS architectures.

[Phys. Rev. Applied 26, 014103] Published Thu Jul 30, 2026

The spontaneous Nernst effect in ferromagnetic metals is relevant for thermal-management applications and transverse heat-to-electricity generation, but material optimization is limited by our incomplete understanding of the underlying physics. The authors evaluate the transport coefficients using Boltzmann transport and a rigid two-band model, explicitly treating transverse current density due to Berry curvature as a Fermi-surface property. What they find stands in stark contrast to the ordinary Nernst effect. Their physical insights and proposed recipes for tailoring band structure could lead to improved magnets made from 3d transition metals for thermoelectric applications.

[Phys. Rev. Applied 26, 014085] Published Mon Jul 27, 2026

Full-field imaging of nanometer-scale surface waves on liquid helium offers possibilities for high-precision experiments, but the cryogenic environment required to maintain superfluidity makes traditional optics impractical. This study overcomes the challenge with a custom holography setup, demonstrated in both a helium-bath cryostat and a cryogen-free refrigerator. The approach is validated by reconstructing the relation between the wave number and frequency of superfluid surface waves, which also highlights its potential for advancing next-generation research in fluid dynamics and quantum simulation.

[Phys. Rev. Applied 26, 014080] Published Fri Jul 24, 2026

Residual ZZ crosstalk can be a significant source of coherent error in superconducting quantum processors. In conventional all-transmon systems, canceling this crosstalk typically requires closely spaced qubit frequencies, which can worsen susceptibility to microwave crosstalk and frequency crowding. This study uses a fluxonium coupler between two transmon qubits to cancel static ZZ crosstalk while operating outside that restrictive frequency regime. The authors identify zero-ZZ operating points with qubit-qubit detuning exceeding 400 MHz, and demonstrate CZ gates with fidelities exceeding 99.6%. This fluxonium-mediated architecture could be a path to low-crosstalk processors.

[Phys. Rev. Applied 26, 014076] Published Thu Jul 23, 2026

Short-range correlations in electrolyte solutions underlie atomic-scale phenomena at electrochemical interfaces, including spatial oscillations in electrostatic potential, solvent polarization, and ion density. Incorporating and parametrizing these effects at interfaces with electronically responsive electrodes remain challenging for continuum modeling. This study develops a practical procedure for parametrizing short-range correlation effects within density-potential-polarization functional theory (DPPFT), which provides a unified description of electrode electronic response and structured electrolytes under constant-potential conditions.

[Phys. Rev. Applied 26, 014066] Published Wed Jul 22, 2026

(In,Ga)N quantum wells, the light-emitting layers at the heart of highly efficient GaN LEDs, have enabled the solid-state lighting revolution. Even so, the physics of disorder-induced carrier localization in these layers remains controversial. The authors show that accurate modeling of their disorder effects lead to accurate predictions of their basic optical properties, from emission lineshape to Stokes shift. Contrary to expectations, carrier localization is only partial, and the same physics explains the peculiar properties of red (In,Ga)N LEDs. This study provides a framework for understanding localization effects in III-nitride materials, and for designing tomorrow’s emitters.

[Phys. Rev. Applied 26, 014034] Published Fri Jul 10, 2026

Josephson transmission lines are key elements of superconducting devices for microwave amplification and signal processing. Their response to strong microwave drives, though, remains puzzling. The authors study a strongly nonlinear regime in which the phase-length variation of a probe wave grows, develops pronounced oscillations, and finally saturates as pump power increases. This effect is due to the nonlinear oscillatory renormalization of the Josephson inductance, with propagation losses hiding the oscillations. The results are an important step toward understanding the response of these systems, which are promising for the design of strongly nonlinear superconducting devices.

[Phys. Rev. Applied 26, 014028] Published Thu Jul 09, 2026

Magnetic imaging based on solid-state quantum sensors has proved useful for characterizing the properties and functions of magnetic materials. However, these sensors are often restricted to measuring fields along specific directions that may not necessarily align with material anisotropy axes. This study demonstrates a different approach based on spin-½-like sensors in hexagonal boron nitride, which have an isotropic response to magnetic fields. These sensors are used to measure spin-reorientation transitions in the ferrimagnet TbMn${}_6$Sn${}_6$, highlighting their potential for magnetic imaging under arbitrary fields.

[Phys. Rev. Applied 26, 014022] Published Wed Jul 08, 2026

When is quantum better? Quantum annealers are promising for tackling hard optimization tasks, but claims of quantum advantage depend critically on comparison to strong classical methods. Revisiting a recent benchmark for approximate optimization, this work shows that a GPU-based simulated bifurcation machine, driven by classical chaotic dynamics, closes the reported quantum-classical scaling gap. The results demonstrate that the instances studied previously were too small to establish a robust advantage, under careful runtime accounting. A class of sparse spin-glass instances is identified as a more realistic case in which future quantum annealers could show genuine scaling advantage.

[Phys. Rev. Applied 26, 014024] Published Wed Jul 08, 2026

Quantum turbulence is a hallmark of nonequilibrium quantum dynamics, arising in systems ranging from superfluid helium to Bose-Einstein condensates. Its simulation is hindered by the high computational cost due to the vast range of length scales involved. The authors employ matrix-product states to efficiently capture the interscale correlation structure of quantum turbulent flows, reducing memory requirements by several orders of magnitude compared to conventional algorithms. These advances extend the capabilities in simulating phenomena involving multiscale physics, and have the potential to facilitate the discovery of properties of very large systems that are far from equilibrium.

[Phys. Rev. Applied 25, 064069] Published Mon Jun 29, 2026

The distribution of quantum entanglement and teleportation in real-world environments underlies current efforts in quantum communication and networking, and requires designing devices such that extraneous noise photons do not obscure photon detection. This study analyzes the physics of filtering entangled-photon sources for both high noise rejection and purity, for multiphoton applications in high-noise scenarios. Using these methods, entanglement is successfully distributed through 50 km of optical fiber while coexisting high-power classical Internet signals generate substantial background noise.

[Phys. Rev. Applied 25, 064064] Published Mon Jun 22, 2026

Measurements of mechanical sensors can now resolve the fundamental thermal noise floor over a broad frequency band, promising faster acquisition and access to transient signals. However, stronger measurements impart stronger back-action forces. Studying the thermal noise of a “trampoline” resonator inside an optical cavity reveals that back-action yields surprisingly strong noise correlations among the many modes, even those well-separated in frequency, which alters the spectrum everywhere—even at the resonance peaks themselves. These correlations can generate a low-noise band away from the resonance frequency, allowing single-mode sensitivity without artifacts due to frequency noise.

[Phys. Rev. Applied 25, 064062] Published Thu Jun 18, 2026

Synthetic frequency dimensions offer a powerful means to simulate lattice physics, yet realizing single-photon quantum dynamics in such systems remains challenging. The authors use a superconducting qubit paired with a long, low-loss coaxial cable and a SQUID modulator to construct a programmable synthetic frequency lattice for microwave photons. Their observations of quantum random walks, Bloch oscillations, and unidirectional frequency conversion at the single-photon level establish superconducting circuits as a flexible platform for quantum simulation in synthetic dimensions.

[Phys. Rev. Applied 25, 064058] Published Wed Jun 17, 2026

Although a solid-state frequency reference based on nitrogen-vacancy (N-$V$) centers in diamond is attractive for compact, multifunctional timekeeping and sensing, their strong lattice coupling produces temperature sensitivity that has precluded a stable clock. This study uses the electron’s zero-field splitting and the nitrogen’s nuclear quadrupole splitting in a composite frequency reference that cancels first-order temperature dependence, reducing thermal drift by more than an order of magnitude. The results establish a practical route toward robust, chip-scale diamond clocks that simultaneously support magnetic, electric, thermal, and inertial sensing in a single integrated platform.

[Phys. Rev. Applied 25, 064046] Published Thu Jun 11, 2026

To control sequential snap-through in multistable mechanical systems, we need to understanding the bifurcation structures that organize the energy landscape, yet we lack a general framework linking bifurcations to elastic instabilities. This study uses analysis, simulations, and experiments to reveal two fundamental mechanisms driving sequential snap-through: one governed by the stiffness of individual bistable units, the other by the competition of limit forces (switching fields) between units. Tuning stiffness and limit-force perturbations allows custom saddle-node-bifurcation pairs and stable traversal paths, offering a universal strategy to program such energy landscapes.

[Phys. Rev. Applied 25, 064029] Published Mon Jun 08, 2026

Research and development of fusion energy has recently gained a strong impetus from private investment. While less of a proliferation risk than conventional fission systems, modified fusion systems could produce material usable in nuclear weapons. This paper examines an innovative use of antineutrino detectors to find misuse of fusion systems. Since antineutrinos are so penetrating, this technique carries near-zero interference with fusion energy system operation.

[Phys. Rev. Applied 25, 064004] Published Tue Jun 02, 2026

Detecting vanishingly small electromagnetic signals underpins major advances in cosmology, sensing, and quantum information science. Graphene bolometers promise breakthrough performance, yet are typically limited to specialized, nonscalable devices. The authors present a wafer-scale sensor architecture based on epitaxial graphene on silicon carbide. By harnessing the exceptional bolometric response of graphene in the strong localization regime, it achieves microwave sensitivity rivaling top state-of-the-art devices. The exceptionally low heat capacity close to the Dirac point opens a new frontier in calorimetric detection of individual microwave photons in the 10 GHz band.

[Phys. Rev. Applied 25, 064007] Published Tue Jun 02, 2026

Building a large-scale superconducting quantum computer requires operating multiple chips together, which calls for a signal channel to pass quantum information between them. Because fabricated chips are not exactly alike, a signal released by one may not be cleanly received by another, and the usual fixes add control wiring that hampers scaling. The authors implement broadband resonators as the signal interface, whose wide frequency acceptance mitigates chip-to-chip mismatch and removes the need to retune chips into agreement. This approach strips away hardware overhead and offers a flexible route toward the modular networks that large quantum computers will rely on.

[Phys. Rev. Applied 25, 064008] Published Tue Jun 02, 2026

Quantum-limited amplifiers enable fast, high-fidelity readout of superconducting quantum processors. Traditionally, they are powered by strong microwave pump tones, which introduce significant technical overhead and hinder scaling of readout systems. This work combines inelastic Cooper-pair tunneling and impedance engineering in a practical broadband quantum-limited amplifier powered by a dc source. This approach dramatically simplifies the readout architecture, which will help scale quantum computers to useful sizes.

[Phys. Rev. Applied 25, 064009] Published Tue Jun 02, 2026

Gravity-gradient sensing based on cold atoms boasts high precision and shows great potential in geophysical research and resource exploration. This study develops and optimizes a vertical free-fall cold-atom gravity gradiometer. Measurement performance is immune to vibration, tilting, and phase noises; it is limited only by the detection noise. The authors also perform tests to simulate the presence of high-density ore bodies, to further validate the instrument’s measurement performance and exploration capacity. This work supplies practical technical solutions and optimization strategies for efficient, high-precision field exploration with such gradiometers.

[Phys. Rev. Applied 25, 054074] Published Thu May 28, 2026

Magnonics has arisen as a promising platform for integrated radio-frequency devices, offering inherent nonreciprocity and reconfigurability. The efficiency of spin-wave excitation in microdevices, however, remains a major practical limitation. Here micrometer-sized rf antennas on yttrium iron garnet films are studied using propagating spin-wave spectroscopy, to identify dominant loss mechanisms and improve transducer performance. Insertion losses below 10 dB and strong nonreciprocal transmission are achieved by reducing Ohmic losses, enabling significant isolation at micrometer length scales. These results are an important step toward practical integrated magnonic rf devices.

[Phys. Rev. Applied 25, 054064] Published Tue May 26, 2026

Magnetic resonance force microscopy (MRFM) is promising for three-dimensional imaging of nuclear-spin densities in nanoscale objects, with applications spanning biology, chemistry, and physics. However, high-resolution volumetric MRFM remains limited by long acquisition times and the difficulty of reconstructing faithful images. This study uses simulations to assess strained Si${}_3$N${}_4$ resonators as MRFM force sensors, and introduces a multislice scanning protocol combined with compressed sensing and optimized reconstruction algorithms. The results show that this advanced approach can improve reconstruction quality and reduce acquisition times by up to two orders of magnitude.

[Phys. Rev. Applied 25, 054048] Published Tue May 19, 2026

Solid-state quantum emitters such as N-$V$ centers in diamond are central to quantum information and sensing technologies, but their study has largely been via serial, single-emitter measurements. Here the authors use cryogenic photoluminescence-excitation imaging to enable parallel, subdiffraction-resolved interrogation of hundreds of N-$V$ centers across wide fields of view. They find an unexpected overabundance of closely spaced N-$V$ clusters, indicating spatially correlated—not random—defect formation. This work both advances our understanding of diamond growth and highlights naturally occurring N-$V$ clusters as a scalable resource for entanglement-enhanced quantum technologies.

[Phys. Rev. Applied 25, 054049] Published Tue May 19, 2026

Nitrogen-vacancy-center (N-$V$) diamond is a powerful platform for vector quantum magnetometry, vital for biological imaging and precision navigation. However, progress has been held back since cavity-enhanced microwave readout is limited to single-axis sensing. The authors expand this technique by using a sinusoidal bias field to sequentially address the N-$V$ orientations, unlocking full vector magnetometry and opening a new space for sensor optimization. They also identify a subtle but important interplay between microwave noise and the time‑varying bias field. By modeling its impact on sensitivity, this study provides new insight to guide the design of next‑generation sensing systems.

[Phys. Rev. Applied 25, 054039] Published Fri May 15, 2026

Laser and clock noise dominate the raw data streams of space-based gravitational-wave detectors, necessitating extensive on-ground postprocessing to recover scientific signals. Optical frequency combs offer a unified solution by coherently linking these two noise sources. Through detailed modeling of optical and electrical signals, the authors show that key noise characteristics—including offsets, drifts, and jitter—can be retrieved from the existing intersatellite laser carrier exchange used for gravitational-wave sensing. Experiments demonstrate clock synchronization with an accuracy of 0.47 ns or better, along with a noise performance of 15 pm/$\sqrt{Hz}$.

[Phys. Rev. Applied 25, 054042] Published Fri May 15, 2026

Arbitrary control of electromagnetic waves is pivotal to the development of high-performance communications, sensing, and analog computing systems, but complex field transformations imply narrowband performance due to the resonant/frequency-dispersive nature of their realization. This work shows that metamaterials can be engineered to provide unprecedented field control over broad bandwidths of operation while remaining reflectionless. The main advantages of the proposed approach over earlier techniques, such as transformation optics, are discussed. These metamaterials provide a route toward broadband devices that perform complex functionalities, such as spatial signal preprocessing.

[Phys. Rev. Applied 25, 054036] Published Thu May 14, 2026

Microscale ultrasound acoustofluidics has become an important tool for handling cells and microparticles in lab-on-a-chip technology, but it fails in separation and focusing of submicrometer particles, due to dissipation processes in the viscous boundary layer. Here a theoretical proof-of-concept analysis shows that by embedding the microfluidic channel in a properly designed fused-silica metamaterial, the vibrational motion of the fluid and the metamaterial can be matched, which prevents formation of the viscous boundary layer. This increases the $Q$ factor of the ultrasound resonance modes by several orders of magnitude, reduces acoustic streaming, and enables nanoparticle focusing.

[Phys. Rev. Applied 25, 054026] Published Mon May 11, 2026

Precise mapping of the geomagnetic field is essential for geophysics, space weather, and navigation, but current magnetometers are limited by sensitivity, dynamic range, and compactness. The authors present the OSCAR-QUBE quantum magnetometer based on nitrogen-vacancy centers in diamond, achieving vector magnetic-field measurements aboard the International Space Station in a compact device with sensitivity below 300 nT/√Hz. They further validate its performance through direct comparison to geomagnetic field models, showing good agreement with the expected field in low Earth orbit. This establishes diamond-based quantum magnetometry as viable for compact, high-performance space missions.

[Phys. Rev. Applied 25, 054017] Published Thu May 07, 2026

Spin correlations and their coupling to the lattice underpin magnetostrictive functionality, yet conventional probes capture only its collective response. By selectively exciting crystal-field-split d–d transitions, the authors isolate site-specific spin contributions through the generation of acoustic strain pulses. Their distinct temperature dependences expose multiple spin-correlation channels, and uncover negative thermal expansion in Fe${}_2$Mo${}_3$O${}_8$ driven by spontaneous magnetostriction. This approach opens an ultrafast-acoustics route to resolving magnetic contributions to mechanical response.

[Phys. Rev. Applied 25, 054014] Published Wed May 06, 2026

Traveling-wave parametric amplifiers (TWPAs), essential components of superconducting quantum processors, are built from artificial transmission lines for which dispersion relations must be tailored to favor specific parametric processes, while suppressing spurious ones. A unified framework to guide the design of such dispersion relations has been lacking. This study develops such a framework, borrowing concepts from periodic structures and filter synthesis. Innovative architectures are revealed, including an “ambidextrous” right-left-handed TWPA.

[Phys. Rev. Applied 25, 054016] Published Wed May 06, 2026

Single-photon detection is central to optical quantum communication and computation. Its speed and integrability into photonic chips are currently limited by the physical processes by which the photon is absorbed. This work shows that a nanophotonic optical parametric amplifier (OPA) can be used as an ultrafast single-photon detector, bypassing these absorption mechanisms in favor of optical amplification. In addition, a path for OPA-based single-photon detectors to reach state-of-the-art performance is discussed. This approach opens the door to integrated ultrafast single-photon detection, to enable ultrafast optical quantum information processing.

[Phys. Rev. Applied 25, 044078] Published Mon Apr 27, 2026

Detecting single microwave photons is important in, for example, primary thermometry in dilution cryostats, dark-matter detection, and detection of a single spin in a crystal lattice. Such detectors are not commercially available and are challenging to design, due to the very low energies of gigahertz photons. The improved device presented in this study uses a qubit coupled to harmonic oscillators and a drive line to encode the detection event using a four-wave mixing process. This single-photon detector could impact engineering solutions to improve cryostat-wiring thermalization, detection of chemical species at ultralow concentrations, and axion detection.

[Phys. Rev. Applied 25, 044064] Published Thu Apr 23, 2026

Precise control of noble-gas thin films is essential for emerging quantum platforms such as electron-on-neon qubits, but progress has been limited by the lack of real-time diagnostics and reproducible growth control. Here researchers demonstrate in situ monitoring of neon-film growth by tracking the frequency shift of a high-$T_c$ superconducting microwave resonator during neon deposition. This study reveals stochastic film thinning in the vicinity of neon’s triple point, and identifies routes toward controlled film growth, with broad implications for quantum device fabrication and cryogenic materials engineering.

[Phys. Rev. Applied 25, 044065] Published Thu Apr 23, 2026

Forecasting chaotic signals is important for applications ranging from sensing to communication to climate modeling. Compact hardware for real-time prediction remains challenging, as it must combine high energy efficiency with the nonlinear dynamics and memory needed for computation in a single physical system. Here a magnetic vortex-state microdisk acts as a magnon-scattering reservoir, converting one-dimensional microwave input into high-dimensional spectral output that predicts the chaotic Mackey-Glass benchmark with high accuracy over hundreds of future time steps. Spectral resolution must be carefully tuned, and combining multiple device geometries systematically boosts performance.

[Phys. Rev. Applied 25, 044047] Published Fri Apr 17, 2026

High-precision laser interferometry between spacecraft is critical for future gravity missions, yet achieving nanometer-level accuracy remains hindered by challenges in beam alignment and stability, particularly due to spacecraft attitude jitter. To overcome these disturbances, this study presents an interferometric architecture featuring a monoaxial laser ranging interferometer with active beam-steering loops and differential wavefront sensing. Experiments validate pointing stability below 10 µrad/√Hz, while also revealing polarization effects and tilt-to-length coupling noise.

[Phys. Rev. Applied 25, 044039] Published Wed Apr 15, 2026

Electrochemical conversion of NO to NH${}_3$ is vital for sustainable ammonia synthesis and environmental remediation, but suffers from sluggish reaction kinetics. The authors identify the topological nodal-line semimetal CaAgAs as a highly efficient and selective catalyst, with a free-energy change ΔG of just 0.22 eV and drumheadlike topological surface states near the Fermi level that provide enhanced surface density of states to facilitate charge transfer. Strain engineering can reduce ΔG to 0.08 eV. Notably, symmetry-breaking transitions that eliminate the topological phase degrade catalytic performance, showing that here topology offers a robust and tunable design principle.

[Phys. Rev. Applied 25, 044023] Published Thu Apr 09, 2026

Resonant dispersive wave emission in hollow-core optical fibers offers a promising route to the vacuum-ultraviolet (VUV) sources essential for ${}^{229}$Th nuclear clocks. Unfortunately, standard capillaries force a strict trade-off between the large core diameters needed for efficient input coupling and the high intensities required for efficient nonlinear conversion. The authors use a gas-filled tapered capillary fiber to avoid the trade-off, combining a large input aperture with adiabatic field concentration. This yields a widely tunable source with doubled efficiency specifically at the 148.38-nm isomer energy, in a scalable architecture for much-needed high-flux tabletop VUV tools.

[Phys. Rev. Applied 25, L041001] Published Wed Apr 01, 2026

Although nonlocal connectivity is essential for universal logical gates and low-overhead quantum error correction, it is largely absent from today’s superconducting platforms, which are restricted to nearest-neighbor coupling. This work demonstrates an on-chip coupler with centimeter-scale interaction length, to provide high-fidelity, low-crosstalk nonlocal qubit coupling and serve as a building block for binary-tree connectivity graphs, reducing the average entangling distance from $O$($N$) to $O$(ln $N$). This capability supports the implementation of innovative quantum algorithms on superconducting processors, and strengthens their competitiveness with other hardware platforms.

[Phys. Rev. Applied 25, 034096] Published Tue Mar 31, 2026

Thermoelectric technology is promising for energy conversion and solid-state refrigeration. As is well known, though, the strong coupling among the Seebeck coefficient, electrical conductivity, and lattice thermal conductivity substantially limits thermoelectric efficiency. Guided by orbital-mixing theory and first-principles calculations, the authors propose a biaxial-strain strategy to increase the Seebeck coefficient without sacrificing electrical conductivity (enhancing the power factor) and to weaken chemical bonding (suppressing lattice thermal conductivity), in two candidate materials. Consequently, tensile strains of 1–3% yield can double or triple the figure of merit at 300 K.

[Phys. Rev. Applied 25, 034086] Published Fri Mar 27, 2026

Cryogenic electronics requires amplifiers that can operate at millikelvin temperatures with low noise, while dissipating almost no power—two serious challenges. The authors propose and numerically analyze a fully voltage-controlled three-terminal superconducting transconductance amplifier based on thermally modulating a SINIS structure via quasiparticle injection through an additional NIS tunnel junction. Simulations predict millisiemens-level transconductance and high current gain with nanowatt power dissipation, suggesting a possible route to scalable low-power cryogenic amplification for quantum technologies and low-temperature detectors.

[Phys. Rev. Applied 25, 034087] Published Fri Mar 27, 2026

High-coherence superconducting quantum technologies demand as little microwave loss as possible, and niobium-based devices are often limited by dissipation associated with surface oxides. Inspired by processing developed for accelerator cavities, the authors employ a strategy to reduce oxide-related loss in a three-dimensional niobium cavity, achieving ultralow dissipation in the single-photon regime at millikelvin temperatures. This improved performance is largely preserved across multiple cooldown cycles, and after hours of air exposure. These results highlight oxide engineering as a practical route to longer-lived niobium-based qubits and resonators.

[Phys. Rev. Applied 25, 034076] Published Tue Mar 24, 2026

Probabilistic processors promise significant efficiency gains over GPUs, but scaling is bottlenecked by a reliance on hard-to-manufacture hardware for random number generation. In this study, researchers overcome this hurdle by demonstrating circuits built entirely from standard transistors that harness intrinsic thermal noise to efficiently sample from programmable probability distributions. Because these probabilistic circuits can be seamlessly integrated alongside standard CMOS cells, this approach paves the way for scalable, near-term probabilistic computing.

[Phys. Rev. Applied 25, 034061] Published Wed Mar 18, 2026

Birefringence in optical fiber causes polarization mode dispersion (PMD), which can broaden telecommunication signals, degrade fiber-sensor measurements, and scramble polarization-encoded quantum states. Though widely studied, PMD is typically modeled using statistical descriptions that obscure its underlying physical origins. The authors present BIFROST, a first-principles model that links PMD to specific physical parameters such as core geometry, temperature, and bend radius. Using this model, they simulate the impact of environmental variations on PMD compensation and demonstrate how knowledge of fiber properties (e.g. fiber spinning) can be applied to emerging quantum networks.

[Phys. Rev. Applied 25, 034054] Published Tue Mar 17, 2026

Hybrid sound-magnet interactions attract growing interest for advanced signal processing and computing, but generating complex, controllable nonlinear magnetic responses in such systems remains challenging for chip-scale platforms. The authors use a device that concentrates high-frequency sound waves to strongly couple a magnetic film to acoustic motion, revealing nonlinear magnetoelastic waves that generate phase-locked harmonic and subharmonic magnetic signals. Notably, the subharmonic process closely resembles optical parametric down-conversion. These nonlinear magnon-phonon hybrid excitations may represent an important step toward quantum magnonics with propagating excitations.

[Phys. Rev. Applied 25, 034056] Published Tue Mar 17, 2026

Noise-aware compilation on near-term quantum processors requires accurate noise models, but standard ones often miss algorithm- and hardware-specific error mechanisms, and full characterization can be costly. In this study a data-efficient framework combines a physically motivated parametrized noise model with Bayesian optimization, to infer algorithm- and hardware-specific error parameters from routine circuit-execution data. Remarkably, models trained only on small-circuit data generalize well to larger validation circuits, yielding 65% better model fidelity. This provides a scalable, low-overhead route to more predictive, application-aware noise models for quantum compilation workflows.

[Phys. Rev. Applied 25, 034051] Published Mon Mar 16, 2026

Optical coherence tomography (OCT) using undetected photons is a promising technique for studying layered materials at wavelengths including the midinfrared, where traditional methods face challenges. However, OCT relies on large optical setups that require high laser power and are difficult to miniaturize. This work explores performance benchmarks for integrated sensors, which offer a path toward smaller, more practical devices, and finds that a less-common system configuration exploiting induced coherence works particularly well in integrated setups. This result not only improves performance but also provides useful guidance for designing future compact quantum sensing systems.

[Phys. Rev. Applied 25, 034031] Published Tue Mar 10, 2026

Spin shuttling is a promising strategy for scaling silicon-based quantum processors by overcoming the connectivity constraints inherent in quantum dots. This study employs Pauli spin blockade to characterize spin-shuttling coherence at different external magnetic fields, facilitating a systematic investigation of the impact of various operational parameters, which can drive up to a twentyfold variation in error rates. Through targeted optimization, the authors achieve an average shuttling fidelity of 99.8%. Their findings provide critical insights for optimizing high-performance spin shuttling in future large-scale quantum processors.

[Phys. Rev. Applied 25, 034016] Published Thu Mar 05, 2026

Pulsed squeezed light is a key resource for continuous-variable quantum information processing and photonic quantum technologies, and can be generated efficiently using Si${}_3$N${}_4$ microresonators. Under strong pulsed pumping, however, nonlinear effects complicate control of such light’s temporal and spectral properties, limiting performance and practical utility. This study in the high-gain regime investigates the impact of pump detuning and pulse duration on key metrics, including output photon flux and various correlations. Its results deepen our understanding of pulsed squeezed light in chip-scale resonators, and provide guidance for optimizing integrated quantum light sources.

[Phys. Rev. Applied 25, 034008] Published Tue Mar 03, 2026

Defect-free mixed-species atom arrays are promising for quantum computing, simulation, and metrology, but their scalability has been hindered. This study overcomes the barriers by expanding the tweezer-array size, improving atom-transfer efficiency, and introducing a powerful rearrangement algorithm. The authors successfully assemble defect-free arrays containing 120 mixed-species atoms with a filling fraction of 98.3% and a 14% defect-free probability—a real leap beyond prior demonstrations. This enhanced approach can be extended to other atomic species and is expected to accelerate progress in quantum error correction, many-body quantum simulations, and precision metrology.

[Phys. Rev. Applied 25, 034009] Published Tue Mar 03, 2026

While spin-correlated radical pairs have shown promise for molecular-scale quantum technologies, core questions remain about how they function as a chemical compass for magnetosensing. Conventional thinking suggests that unavoidable interradical interactions and uncontrolled dissipation should degrade magnetic field sensitivity. However, this theory work shows that interradical motion in biophysical settings can push magnetometry close to the Cramér-Rao bound and increase precision to subdegree levels. Even more remarkably, environmental complexity and spin-spin interactions can increase the fraction of usable information encoded in the spin dynamics, rather than degrading coherence.

[Phys. Rev. Applied 25, 024074] Published Tue Feb 24, 2026

The stellarator concept for future fusion reactors has a key advantage over the tokamak, being practically immune to large-scale disruptions. The authors show, however, that a rapid shutdown of stellarator coil currents (with fast dissipation of poloidal magnetic flux) can nonetheless drive an avalanche of runaway electrons, even without any interruption of the net toroidal plasma current. The problem is far less serious than in a tokamak, but some runaways are inevitably present in an activated fusion device, so an accidental rapid coil ramp-down could produce a dangerous runaway current. Some form of dedicated intervention is likely necessary.

[Phys. Rev. Applied 25, 024065] Published Fri Feb 20, 2026

Fast transport of Na${}^{+}$ limits the rate capability of next-generation sodium-ion batteries, and remains a longstanding challenge for high-energy cathode materials. Using an ab initio evolutionary search combined with first-principles calculations, this study identifies two metastable NaMnO${}_2$ polymorphs that host unusually open Na coordination environments, stabilized by high-pressure synthesis. These phases exhibit extremely low Na${}^{+}$ migration barriers, while maintaining competitive operating voltages and robust structures during (de)sodiation. The results highlight metastability as a powerful design principle for fast-ion-conducting cathodes beyond conventional layered frameworks.

[Phys. Rev. Applied 25, 024060] Published Thu Feb 19, 2026

Probing the interface of topological insulators and ferromagnets has proven persistently challenging, despite its relevance for spintronic applications such as spin-charge interconversion. This work provides a powerful methodology to separate bulk and interfacial spin processes based on their different dynamics. The authors optically inject femtosecond spin currents from a ferromagnetic metal into an adjacent thin film of the topological insulator Bi${}_2$Te${}_3$. The twofold dynamics of the resulting femtosecond charge current contain signatures of spin-charge interconversion by the bulk inverse spin Hall effect and the interfacial inverse Edelstein effect.

[Phys. Rev. Applied 25, 024054] Published Wed Feb 18, 2026

Efficient, precise control of trapped-ion qubits is essential to scaling up quantum computing technology using that platform, and one approach utilizes integrated photonic waveguides to individually address the qubits. However, crosstalk is typically mitigated by spacing the waveguides far beyond the scale of the qubits, which hinders mode matching and efficiency. The authors identify relatively simple and easily implemented design choices that yield low crosstalk with such systems while keeping the waveguide pitch close to the qubit pitch, to facilitate light delivery and collection.

[Phys. Rev. Applied 25, 024055] Published Wed Feb 18, 2026

Global quantum networking will be needed for quantum secured communication, and for linking distant quantum computers. Its terrestrial realization is held back by exponential photon loss in optical fibers, though, so we turn to space. The authors propose a quantum repeater architecture based on low-earth-orbit satellites that transmit entangled photons to single-atom quantum memories. They quantify the system’s expected performance, in terms of entanglement distribution rates and fidelities, and suggest a multiplexing approach to enable entanglement creation across distances of 10,000–20,000 km, bringing a global quantum Internet within reach.

[Phys. Rev. Applied 25, 024050] Published Tue Feb 17, 2026

Laser spectroscopy of the Th-229 nuclear isomer promises a fresh class of optical clocks, and precision tests of fundamental physics, but progress has been limited by the lack of an intense, narrow-linewidth continuous-wave laser near 148 nm. This work proposes a resonance-enhanced four-wave-mixing scheme to generate coherent continuous-wave light at 148 nm in cadmium vapor, using readily available pump lasers. The approach predicts tens of microwatts of output power with high coherence, potentially enabling coherent driving of the extremely weak nuclear transition, and thus overcoming a key technical bottleneck for nuclear-clock development and vacuum-ultraviolet precision spectroscopy.

[Phys. Rev. Applied 25, 024034] Published Wed Feb 11, 2026

The scalability of high-fidelity superconducting two-qubit gates is being held back by the struggle to balance high gate speed with low crosstalk and minimal calibration complexity. This study uses a transmon coupler, driven by analytically derived microwave pulses, between two fluxonium qubits to implement a fast conditional phase gate. Careful pulse shaping can suppress unwanted excitations sufficiently to allow gate times below 60 ns. This insight into optimized control pulses for frequency-selective two-qubit gates offers a robust pathway to tomorrow’s lower-error, easier-to-calibrate superconducting quantum processors.

[Phys. Rev. Applied 25, 024020] Published Thu Feb 05, 2026

Air bridges rise above the plane of a circuit and are essential elements for dense, low-crosstalk signal routing in superconducting quantum circuits, but the microwave loss that they typically introduce has limited their scalability and functionality. This work presents a subtractive hard-mask fabrication process for niobium air bridges with no measurable extra loss. Beyond routing, the authors use these structures to form low-loss vacuum-gap capacitors, and incorporate those into transmon qubits with lifetimes above 50 µs. These results establish niobium air bridges as scalable, low-loss building blocks for superconducting quantum hardware.

[Phys. Rev. Applied 25, 024007] Published Tue Feb 03, 2026

Devising efficient light coupling between optical fibers and silicon nitride photonic integrated circuits is critical in a wide range of applications, but common Gaussian-beam approximations fail to capture the complex physics of lensed fibers. This study employs a comprehensive co-optimization strategy that integrates high-resolution scanning electron microscopy with rigorous three-dimensional simulations to model and experimentally validate the coupling process. The actual emission profile of lensed fibers deviates significantly from the widely assumed paraxial Gaussian beam, a crucial insight that allows the authors to predict and achieve coupling efficiencies exceeding 80% per facet.

[Phys. Rev. Applied 25, 014078] Published Fri Jan 30, 2026

The predictability of quantum measurement outcomes is relevant for developing applications in quantum information, and potential sources of useful quantum correlations now extend even to top-antitop quark pairs produced in high-energy colliders. This study presents a comprehensive framework for assessing predictability, using error measures inherited from statistical learning theory. Building on an existing foundation, the authors propose a modified entanglement-based protocol for quantum key distribution, demonstrating enhanced resilience to noise compared to the standard BB84 protocol, and leveraging the strength and capabilities of quark-pair states as resources for quantum cryptography.

[Phys. Rev. Applied 25, 014063] Published Tue Jan 27, 2026

Time-resolved photoconductivity (PCD) sits at the heart of semiconductor characterization, yet many implementations probe only a narrow slice of the system’s properties—typically using a single microwave frequency paired with a single excitation wavelength. This work presents a versatile, contactless microwave PCD instrument that combines a broadband coplanar-waveguide sensor with flexible readout electronics, enabling an extensive detection range, temperature-dependent studies, and multiphoton excitation. This platform is equally relevant for industrial silicon wafers and emerging quantum materials, from perovskites to wide-band-gap power semiconductors and topological systems.

[Phys. Rev. Applied 25, 014055] Published Fri Jan 23, 2026

Controlled conversion between distinct classes of multipartite entangled states is crucial for quantum technologies, but direct interconversion is impossible, due to the states’ inequivalence under local operations. More sophisticated dynamical protocols are required; unfortunately, conventional adiabatic methods face a trade-off between fidelity and speed. This study employs inverse engineering to design accelerated adiabatic passages in a spin-chain system, enabling rapid W-to-GHZ conversion, as experimentally verified on an NMR quantum processor. The work highlights the potential of inverse engineering for efficient quantum state manipulation in many-body systems.

[Phys. Rev. Applied 25, 014056] Published Fri Jan 23, 2026

Strain engineering and electric field control are key to optimizing the properties of electron-spin qubits hosted in electrostatically defined Si/Si-Ge quantum dots, and compared to thick Si-Ge heterostructures, thin Si/Si-Ge membranes offer more control. This article reports the fabrication of micrometer-thick Si/Si-Ge heterostructures suspended by a silicon substrate over an area of a few hundred micrometers. The authors characterize the elastic properties of these membranes and identify two mechanical modes useful for strain-field engineering, which helps to increase the valley splitting and thus the coherence time and shuttling fidelity of electron spins.

[Phys. Rev. Applied 25, 014054] Published Thu Jan 22, 2026

Controlling high-vacuum gas dynamics is critical to many technologies, especially for portable quantum sensors. This article shows how purpose-designed surface textures can influence high-vacuum particle propagation in controlled ways to improve device performance. Using 3D printing to experimentally realize such textures in ultrahigh-vacuum-compatible materials, the authors show an example application in which textured surfaces are able to triple the pumping rate of a nonevaporable getter pump. This approach offers significant technical advantage in numerous high-vacuum settings, and will be of particular benefit to portable quantum technologies.

[Phys. Rev. Applied 25, 014047] Published Wed Jan 21, 2026

Superconducting resonators are a popular way to study dissipation in superconducting quantum circuits induced by two-level systems (TLS) due to their ease of fabrication, but measuring unsaturated TLS loss in quarter-wave resonators remains difficult due to the intrinsic frequency fluctuations of the TLS and low signal-to-noise ratio of the measurement. This study demonstrates that spatially extending the quarter-wave resonator to be many wavelengths long mitigates these difficulties and significantly reduces measurement uncertainty. This new resonator design provides a tool for researchers to examine the effects of material and fabrication processes on superconducting circuit performance.

[Phys. Rev. Applied 25, 014045] Published Tue Jan 20, 2026

Superconducting circuits for quantum computation are controlled via microwave signals, which are typically assumed to be too weak to disturb the superconducting material itself. When these microwave drives become sufficiently strong, though, multiple photons can combine to break Cooper pairs of electrons in the device, leading to qubit errors. The authors develop a theoretical framework to predict when this effect occurs, and demonstrate its relevance for emerging qubit designs and readout schemes that rely on strong driving. These results reveal a previously overlooked error mechanism for superconducting qubits, and provide guidance on how to mitigate the effects.

[Phys. Rev. Applied 25, 014042] Published Fri Jan 16, 2026

Stochastic magnetic tunnel junctions (MTJs) are promising building blocks for neuromorphic and probabilistic computing, but conventional approaches rely on thermally unstable superparamagnetic devices with limited reliability and tunability. In this work, thermally stable perpendicular MTJs are electrically driven to produce random telegraph noise using nanosecond spin-torque pulses, the response being well described by a simple Poisson process. This approach enables broad, continuous tuning of both fluctuation rate and probability bias in a single device, pointing to a practical route for combining memory elements with programmable stochastic functionality on a single hardware platform.

[Phys. Rev. Applied 25, 014035] Published Wed Jan 14, 2026

Qubits based on hole spins in germanium have seen remarkable progress over the last few years, and are currently one of the most promising spin-qubit platforms for quantum computing. Nevertheless, disorder scatters the charge and spin properties of the qubits within a quantum chip, which poses a challenge for scaling up. The accurate assessment of variability is crucial for establishing reliable roadmaps toward large-scale spin-qubit quantum computers. This study uses numerical simulations to quantify the expected variability of hole-spin qubits in realistic Ge devices, focusing on charge traps at interfaces. It turns out that charge properties don’t vary so much, but spin properties do.

[Phys. Rev. Applied 25, 014018] Published Thu Jan 08, 2026

This work demonstrates a photonic dense associative memory, which is important for high-capacity associative memory, combinatorial optimization, and computer vision. Here scalable, higher-order interactions beyond pairwise couplings would be key to progress. The authors use a spatial light modulator and second-harmonic generated light to implement both two- and four-body interactions. Four-body interactions are shown to increase storage capacity by a factor of 10 for uncorrelated patterns and a factor of up to 50 for correlated patterns, and to yield further benefits as well. These results point to a scalable route for energy-efficient, high-capacity optical neural networks.

[Phys. Rev. Applied 25, 014011] Published Tue Jan 06, 2026

Quantum dots emitting in the telecommunication bands are an excellent candidate for deterministic single-photon sources for fiber-based quantum technologies. However, challenges remain in optimizing their optical properties. This Letter presents a detailed study of the optical properties of InAs quantum dots with optimized growth via molecular beam epitaxy. The authors realize high-quality single-photon emitters operating in the telecom O and C bands, and their growth technique is promising for further photonic technologies as well.

[Phys. Rev. Applied 25, L011002] Published Tue Jan 06, 2026

Magnon polarons are essential for coherent control in acoustic and spintronic devices, but conventional structures based on magnetic thin films on thick piezoelectric substrates suffer from weak magnon-phonon coupling, due to poor spatial mode overlap. The authors overcome this limitation by employing a mode-matched planar magnomechanical system, with a thin piezoelectric film and a micrometer-thick magnetic layer. This configuration enables deeply distributed magnon modes and enhances magnetoelastic interactions with microwave phonons. As a result, the team observes clear formation of magnon polarons, manifested as pronounced avoided crossings in the spectra.

[Phys. Rev. Applied 24, 064053] Published Fri Dec 19, 2025

Optical coherence tomography is widely used in biomedical imaging and materials science, but dispersion in the sample can strongly reduce both resolution and penetration depth. Quantum optical coherence tomography (QOCT) can cancel this dispersion and double the axial resolution, yet existing implementations rely on dim sources and interference signals that are difficult to filter and stabilize. This work demonstrates a robust cross-correlation QOCT scheme based on a Michelson interferometer fed by a bright collinear entangled-photon source, which suppresses parasitic terms, improves the signal-to-noise ratio by a factor of four over standard QOCT, and preserves dispersion cancellation.

[Phys. Rev. Applied 24, 064048] Published Thu Dec 18, 2025

Cutting-edge methods for spatiotemporal control of laser beams deliver impact in many disciplines, from quantum technology and advanced manufacturing to photonics and biology. Innovation requires light fields exhibiting scalable two-dimensional (2D) parallelization, full inividual control, and fast reaction to changing external parameters with low latency. The authors present a model-based control system fulfilling those requirements: reactive, real-time 2D multibeam laser patterning and scanning with strict intensity matching. A timely case study generates large-scale 2D architectures of random-access quantum memories of atomic qubits.

[Phys. Rev. Applied 24, 064046] Published Wed Dec 17, 2025

Optical detection of atoms or molecules in microtrap arrays is one of the enabling techniques for quantum simulation and computation. In many settings the individual traps are not optically resolved, and detection accuracy depends crucially on an image-processing algorithm. This study introduces an optimal method, rooted in estimation theory, that can drastically improve detection accuracy compared to familiar algorithms. It also provides a rigorous definition for the signal-to-noise ratio of the problem, which can be used to define the practical conditions under which accurate detection is possible, and to rationalize the design of future experiments in affected fields.

[Phys. Rev. Applied 24, 064039] Published Thu Dec 11, 2025

Understanding magnetic structures is essential for advancing materials science, spintronics, and geology, but reconstructing magnetization from an experimentally measured magnetic field map has been a challenging inverse problem. The authors introduce a GPU-accelerated method that recovers spatially varying magnetization with minimal prior assumptions and is robust to realistic experimental conditions. This approach reveals magnetic textures such as ferromagnetic domains, topological skyrmions, and a magnetic moiré superlattice. This capability provides a versatile tool for decoding complex magnetization profiles and expands the reach of next-generation quantum magnetic sensing.

[Phys. Rev. Applied 24, 064020] Published Fri Dec 05, 2025

Smith-Purcell radiation (SPR) is a powerful light-generation mechanism, but the devices are limited by static grating geometries. The authors introduce a reconfigurable SPR modulation on a two-dimensional chirped metallic metagrating without changing the nanostructure. By shifting the electron beam, the system delivers tunable emission angles, switchable focal spots, dual-focus functionality, and dual-wavelength output. Angle-resolved cathodoluminescence experiments reveal precise control of SPR dispersion. This work demonstrates a versatile free-electron photonic platform, paving the way for actively tunable, multifunctional light sources for integrated photonic applications.

[Phys. Rev. Applied 24, 064004] Published Mon Dec 01, 2025

Nuclear magnetic resonance is a valuable technique for studying a wide variety of quantum materials, but the small magnetic moments involved make it particularly challenging to apply to thin films or two-dimensional materials. This work implements a superconducting meander-line surface coil that achieves a high filling factor, even for very thin samples, and enables one to obtain an NMR signal and perform spin-echo measurements on a sample of boron just 150 nm thick. The article also provides a roadmap for improving this approach to achieve measurements in the single-layer limit, which is quite promising for the study of magnetism and correlated electrons in two-dimensional systems.

[Phys. Rev. Applied 24, 054076] Published Tue Nov 25, 2025

In clinical magnetic resonance spectroscopy (MRS), the signal-to-noise ratio per unit time (SNR${}_t$) dictates how efficiently one can acquire diagnostic-quality spectra. The common assumption is that stronger magnets always improve SNR${}_t$, without fully accounting for constraints on the specific absorption rate (SAR). This study analyzes how SNR${}_t$ scales with magnetic field strength under realistic SAR limits. Surprisingly, for a given pulse sequence there exists an optimal field that maximizes SNR${}_t$. This insight should improve clinical MRS by prioritizing the “just right” field strength and SAR-aware pulse timing to achieve truly time-efficient spectroscopy.

[Phys. Rev. Applied 24, 054066] Published Fri Nov 21, 2025

Nanoscale superconducting quantum interference devices (SQUIDs) integrated on scanning probes are important for high-resolution magnetic imaging at low temperatures. Progress has been limited by a lack of robust sensors that can both be fabricated on the wafer scale and provide the highest spatial resolution. The authors combine optical lithography and focused-ion-beam milling to produce niobium nano-SQUIDs on silicon cantilevers, achieving high spatial resolution and sensitivity in magnetic fields of up to 0.5 T at 4.2 K. These sensors can image individual magnetic skyrmions and nanoscale magnetization patterns, significantly expanding the applicability of scanning SQUID microscopy.

[Phys. Rev. Applied 24, 054041] Published Fri Nov 14, 2025

Generation of low-frequency signals in the ionosphere has direct applications for over-the-horizon radar and related processes. The mechanism proposed in this study uses a ground-based modulated rf signal to resonantly excite plasma oscillations in the ionosphere’s F layer, creating low-frequency signals that propagate back to the earth’s surface. The authors find that a 94-GHz signal, modulated at 9 MHz and operated at 1 MW, can generate a 9-MHz signal on the ground, 500 km from the interaction regime in the ionosphere, at intensities sufficient for detection. This points to practical mobile radar units and atmospheric monitoring.

[Phys. Rev. Applied 24, 054040] Published Thu Nov 13, 2025

Cryogenically compatible phase shifters are essential for the development of on-chip quantum photonic processors based on solid-state quantum emitters. Conventional thermo-optic phase shifters, however, fail to operate effectively at the low temperatures required for coherent single-photon generation. To overcome this limitation, researchers develop nano-optoelectromechanical systems (NOEMS) based on slot-mode waveguides and integrate them with quantum dots, resulting in a small, low-loss on-chip photon router. This technique offers a pathway to scale quantum photonic circuits with integrated deterministic emitters, and can be directly applied to a wide range of photonic platforms.

[Phys. Rev. Applied 24, 054016] Published Thu Nov 06, 2025

Hybrid platforms that join light, sound, and spin promise chip‑scale quantum transducers and precision sensors. Yttrium iron garnet (YIG) has the right mix of transparency and low magnetic damping, but making suspended nanostructures that confine all three excitations on one chip remains a tough challenge. The authors use focused‑ion‑beam milling to carve an air‑suspended YIG photonic crystal nanobeam that supports a confined optical mode plus colocalized gigahertz mechanical and magnonic modes. This approach opens a route to tunable magneto‑optomechanics and, with higher optical quality factors, could underpin efficient microwave-to-optical conversion for integrated quantum networks.

[Phys. Rev. Applied 24, 054017] Published Thu Nov 06, 2025

Spin currents in systems without net magnetization are critical for developing next-generation spin-orbit-torque and spintronic memory technologies. While altermagnets should provide such spin currents, they can also originate from pure interfacial effects. The authors take angle-dependent magnetotransport measurements of epitaxial ruthenium dioxide–permalloy heterostructures, revealing that strong interfacial effects dominate over potential altermagnetic contributions. This insight into interfacial spin-transport mechanisms is essential for advancing altermagnet-based spintronic applications.

[Phys. Rev. Applied 24, 054018] Published Thu Nov 06, 2025

The emerging FLASH radiotherapy (FLASH-RT) technology, featuring ultrahigh dose rate (UHDR) instantaneous radiation to increase the response differences of normal tissues and tumors to ionizing radiation, is recognized as having significant clinical application value. A major challenge for its clinical translation, though, is achieving multiangle UHDR radiation at the millisecond time scale, in a compact system, to combine the FLASH effect with precise radiotherapy techniques. Building upon breakthroughs in several technologies, this study presents a compact multiangle x-ray FLASH-RT (MAX-FLASH) system that can be installed in most hospital radiotherapy treatment rooms.

[Phys. Rev. Applied 24, 054015] Published Wed Nov 05, 2025

A tunable voltage source with ultralow noise would move the frontier in experimental quantum electronics. The authors have developed a cryogenic superconducting voltage source that provides the same metrological precision as a Josephson voltage standard, while being widely and continuously tunable. They demonstrate how the source can be coupled to quantum circuits, and that it has extremely low noise over a huge voltage range. This tunable Josephson voltage source opens possibilities for observing fresh physical phenomena, and has applications in quantum information and mesoscopic physics.

[Phys. Rev. Applied 24, 054003] Published Mon Nov 03, 2025

This study develops a method to overcome the effect of loss in optical fibers, which is one of the main obstacles to long-distance quantum communication. The work discusses an architecture for quantum repeaters, in which information is encoded in error-correcting codes capable of handling both photon loss and logical errors. Advantages of this approach are that it can work with very limited resources at each repeater station, and is more robust to errors than previous techniques. The results can promote long-distance quantum communication at very high rates.

[Phys. Rev. Applied 24, 044090] Published Wed Oct 29, 2025

Quantum overlapping tomography (QOT), which focuses on reconstructing subsystems of quantum systems, has emerged as a promising approach for quantum state learning, especially when full-state tomography is infeasible. QOT has attracted considerable interest and seen substantial development, but has not yet reached its ultimate limit. The authors introduce a unified framework for optimal QOT by mapping the problem to the “clique cover” model from graph theory. This framework provides superlative efficiency and experimental feasibility in measurement strategies. This validation of QOT’s utility paves the way for advanced quantum system characterization and state-property learning.

[Phys. Rev. Applied 24, 044091] Published Wed Oct 29, 2025

Generating of out-of-plane-polarized spin currents is essential for advancing spintronic applications, yet remains challenging due to the inherent limitations of conventional heavy metals, as well as difficulties in fabricating suitable materials. The authors overcome this challenge through structural design of heavy-metal layers with asymmetry, inducing the desired spin currents and enabling deterministic switching of perpendicular magnetization without applying a magnetic field. The team also identifies the essential structural conditions required for out-of-plane spin polarization within these configurations. This approach offers a feasible pathway toward practical spintronic devices.

[Phys. Rev. Applied 24, 044086] Published Tue Oct 28, 2025

The spatial photonic Ising machine (SPIM) is a promising architecture that leverages the scalability and parallelism of photons to solve Ising problems in combinatorial optimization. SPIMs have been held back fundamentally by limited computational accuracy. This study overcomes that limitation through a hybrid approach, integrating aberration correction with a dynamic algorithm to update simultaneously a number of flipped spins, rather than just one. The method demonstrably improves computational accuracy and presents a way for SPIMs to scale to significantly larger systems (order 10${}^5$ spins), a milestone on the path to practical application.

[Phys. Rev. Applied 24, 044087] Published Tue Oct 28, 2025