Controlling the residual potential of test masses via the photocurrent-equilibrium mechanism is a promising method for space-based gravitational-wave detectors. This paper systematically investigates the photocurrent-equilibrium mechanism under the cooperative interaction between photon distribution and electric field. An analytical model for the residual potential is developed, and all photoelectric combinations that achieve zero residual potential are identified. Furthermore, a photoelectric decoupling method is proposed and experimentally validated using a torsion pendulum system. The results demonstrate a linear relationship ($R^2$ > 0.99) between the residual potential at equilibrium and instantaneous injection voltage for both illumination cases (test mass illumination and electrode housing illumination), enabling control within ±7 mV and meeting the requirements of space-based gravitational-wave detectors. This study elucidates the cooperative mechanism of photoelectricity and provides critical experimental validation for in-orbit applications.

We demonstrate a double-layer all-optical inference platform for classification using cascaded nonlinear diffraction. The system utilizes a dual-pass configuration through a nonlinear optical crystal, shaping a superposition of Laguerre-Gaussian modes across two layers to steer optical intensity into class-specific detector regions. By optimizing via an in situ genetic algorithm with 10 trainable degrees of freedom, we achieve 88.65% accuracy on the ten-class Modified National Institute of Standards and Technology (MNIST) dataset, leveraging crystal temperature as a critical hyperparameter to optimize noncollinear mode mixing. This work establishes a robust pathway for high-accuracy, low-complexity all-optical computing through structured light and cascaded nonlinear optical interactions.

Metamaterials derive their unconventional properties from engineered microstructures, with periodic lattices providing a versatile framework for modeling wave propagation. Dispersion relations, obtained from Bloch-Floquet theory, govern how waves propagate, attenuate, or localize within such systems. Extending interactions beyond nearest neighbors, through nonlocality, substantially enriches the design space of band diagrams, enabling phenomena such as negative or zero group velocities, rotonlike extrema, and band-gap localization. However, existing approaches to dispersion tailoring often rely on analytical formulations or Fourier-based identifications, which become impractical for complex coupling mechanisms and offer limited control over physical constraints such as stiffness positivity. This work introduces a general interpolation-based framework for customizing dispersion relations in uniform nonlocal lattices. Rather than reconstructing full dispersion curves, the method enforces prescribed frequency-wave number points as interpolation constraints, enabling localized and tunable control of wave behavior. The formulation is applied to both spring- and beam-interaction lattices, and demonstrated on an Euler-Bernoulli beam model with adjustable nonlocal couplings. Through systematic parameter tuning, the framework enables the creation of rotons, the adjustment of group-velocity dispersion, and the design of evanescent waves with controlled exponential decay within band gaps, all while ensuring real, positive-only stiffness parameters and passive mechanical behavior. Altogether, this parametric interpolation strategy provides a physically consistent and computationally efficient route for engineering advanced phononic functionalities in periodic nonlocal systems.

We present a technique based on an ensemble of nitrogen-vacancy (N-$V$) centers in diamond capable of imaging magnetic fields with high spatiotemporal resolution and sensitivity. A focused laser beam is raster scanned using an acousto-optic deflector and N-$V$ center fluorescence is read out with a single photodetector, enabling near shot-noise-limited imaging. The method operates in what we term quasi-continuous-wave optically detected magnetic resonance (qCW-ODMR), a regime closely related to pulsed-ODMR schemes used to mitigate power broadening. In this qCW regime, N-$V$ centers experience short optical pump pulses for spin polarization and readout while the microwave field continuously drives the spin transitions. We systematically characterize this regime and show that the spin response is governed by a tunable interplay between coherent evolution and relaxation, determined by the temporal spacing between pump laser pulses. Notably, the technique does not require precise microwave pulse control, thus simplifying experimental implementation. To demonstrate its capabilities, we image time-varying magnetic fields from a microwire with submillisecond temporal resolution. This approach enables flexible spatial sampling and, with our diamond, achieves $\mathrm{nT}/\sqrt{\mathrm{Hz}}$-level per-pixel sensitivity, making it a promising platform for imaging weak, dynamic magnetic fields in biological and other complex systems.

Near-field radiative heat transfer (NFRHT), primarily caused by evanescent wave tunneling in the near-field region, between a doped silicon metasurface (${\mathrm{M}}_{\mathrm{Si}}$) and a ${\mathrm{Si}\mathrm{O}}_2$ slab was investigated, employing rigorous coupled-wave analysis (RCWA) with the scattering matrix formalism. It was found that NFRHT is significantly enhanced in the frequency bands, owing to the hybrid modes coexcited by the surface plasmon polaritons of the ${\mathrm{M}}_{\mathrm{Si}}$ and the surface phonon polaritons of ${\mathrm{Si}\mathrm{O}}_2$. A transient all-optical method was proposed for NFRHT, based on focused ion beam (FIB) deposition, to measure the heat flux between patterned surfaces. It was experimentally demonstrated that, in a small near-field region, such as 100 nm, compared with RCWA, the effective medium theory (EMT) exhibits large deviations and cannot explain the physical mechanism of NFRHT well in artificial structures of a micrometer-scale period. In addition, the NFRHT mechanism was clarified by comparing the patterned ${\mathrm{M}}_{\mathrm{Si}}$ and unpatterned ${\mathrm{Si}\mathrm{O}}_2$, paving the way for the physical research and applications of NFRHT.

Thermal and photothermal effects play an increasing role at the nanoscale due to the general decrease in thermal conductances and the increasing role of interfaces. Here, we present a noncontact optomechanical analysis of the thermal and photothermal properties of suspended nanowires based on pump-probe response measurements: a probe laser measures the nanowire deformations and property changes caused by an intensity-modulated pump laser launching thermal waves propagating along the one-dimensional conductor. The spatiotemporal structure of the thermal waves propagating within the nanowire is imaged by exploiting the temperature-induced optical reflectivity changes of the nanowire. The analysis of the dominant photothermal contributions to the nanowire response in the spectral and spatial domains allows us to reach a quantitative understanding of their photothermal responses and, in particular, to quantify the interfacial contact resistance, detect internal optical Mie resonances, and image absorption inhomogeneities. Finally, we investigate how those thermal waves, through the temperature dependence of the local material stiffness, are responsible for a dynamical modulation of the nanowire vibration frequency in the resolved-sideband regime, providing novel analytical tools to further inspect the structural properties of nano-optomechanical systems with a large signal-to-noise ratio. The precise discrimination between the dominant photothermal mechanisms is enabled here by the measurement and analysis of their temporal transfer functions, in combination with the position and wavelength dependence of their photothermal response. The combination of those local and nonlocal measurements and analytical methods is generic and critical to correctly understand and mitigate the photothermal dynamical backaction processes. They allow us to refine our understanding of this often unwanted source of measurement backaction and help improve the intrinsic sensitivity of those ultrasensitive force probes.

Flying-focus techniques produce laser pulses whose focal points travel at arbitrary, controllable velocities. While this flexibility can enhance a broad range of laser-based applications, existing techniques constrain the motion of the focal point to the propagation direction of the pulse. Here, we introduce a flying-focus configuration that decouples the motion of the focus from the propagation direction. A chirped laser pulse focused and diffracted by a diffractive lens and grating creates a focal point that can move both along and transverse to the propagation direction. The focal length of the lens, grating period, and chirp can be tuned to control the direction and velocity of the focus. Simulations demonstrate this control for a holographic configuration suited to high-power pulses, in which two off-axis pump beams with different focal lengths encode the equivalent phase of a chromatic lens and grating in a gas or plasma. For low-power pulses, conventional solid-state or adaptive optics can be used instead. Multidimensional control over the focal trajectory enables new configurations for applications, including laser wakefield acceleration of ions, nonlinear Thomson scattering, and surface-plasmon emission of terahertz radiation.

The nonlinearity of magnetization precession and spin waves is a cornerstone of contemporary magnonics. We investigate nonlinear magnetization dynamics in a thin epitaxial iron film driven by femtosecond laser pulses in regimes of homogeneous precession and propagating magnetostatic spin-wave packets. The magnetization precession anharmonicity, the generation of higher-order harmonics, and the dynamical rectification are experimentally demonstrated. The numerical solution of the nonlinearized Landau-Lifshitz-Gilbert equation reveals that these effects stem from the asymmetry in the energy potential and are essentially thresholdless. This asymmetry is readily achievable when an external magnetic field with a strength comparable to the magnetic anisotropy field is applied close to the hard axis. This work establishes a connection between the geometry of the energy profile and nonlinear responses, paving the way for designing magnonic devices with controlled harmonic generation and nonlinear spin-wave interaction.

Quantum computers based on cold-atom arrays offer long-lived qubits with programmable connectivity, yet the relatively low fidelity of site-selective, single-qubit control limits their programmability. We introduce an artificial-intelligence (AI) framework that overcomes this limitation. Trained on atom-laser dynamics in the presence of atomic motion in optical tweezers, a deep neural network autonomously designs robust composite pulses that increase local control fidelities tenfold while remaining compatible with existing control hardware. We further demonstrate the robustness of these pulses regarding optical aberrations and beam misalignment. This approach establishes AI-trained pulse compilation for high-fidelity qubit control, and can be readily extended to other atomlike platforms, such as trapped ions and solid-state color centers.

Skipper charge-coupled devices (CCDs) are ultralow-threshold detectors capable of detecting energy deposits in silicon at the electronvolt scale. Skipper CCDs are increasingly used in rare-event searches, including experiments such as SENSEI, DAMIC-M, Oscura, and CONNIE, where one of the major challenges is mitigating low-energy backgrounds. In this work, we present results on trap characterization in a silicon skipper-CCD produced in the same fabrication run as the SENSEI experiment at SNOLAB. Lattice defects contribute to backgrounds in rare-event searches through single-electron charge trapping. To investigate this, we use the charge-pumping technique at different temperatures to identify dipoles produced by traps in the CCD channel. We fully characterize a fraction of these traps and use this information to extrapolate their contribution to the single-electron background in SENSEI. We find that this subpopulation of traps does not contribute significantly, but more work is needed to assess the impact of the traps that cannot be characterized.

Escalating data volumes and security demands challenge traditional encryption, necessitating high-capacity, robust optical solutions. While optical knots offer topological protection, current constructions are restricted to simple torus knots. We overcome this limitation by introducing a framework for lemniscate knots, a generalized family that unlocks a rich variety of topologies through novel geometric control. Distinct from conventional realizations in the transverse component, we experimentally realize these knots within the longitudinal component—a largely unexplored polarization subspace—using inverse design. Crucially, we exploit the inherent faintness under paraxial conditions to establish an intrinsically covert topological carrier. Furthermore, we demonstrate a hybrid encryption scheme integrating these knots with the Advanced Encryption Standard. This scheme achieves hexadecimal encoding that provides multilayered protection, simultaneously expanding information capacity and bolstering cryptographic security. This work expands the topological toolkit and unlocks the longitudinal dimension for robust, high-capacity, and secure optical information processing.

The fractional Josephson effect (a $4\pi$-periodic current-phase relation, CPR) serves as a definitive signature of topological superconductivity mediated by chiral Majorana modes (CMMs). Here, we propose a cascaded topological heterostructure comprising two stacked proximity-induced topological superconductor (TSC)/quantum anomalous Hall insulator/TSC Josephson junctions under a transverse electric field. A rigid $4\pi$-periodic supercurrent emerges due to CMM interference, exhibiting two distinct transport signatures: (1) an intrinsic 0-$\pi$ state transition governed by the central superconductor’s phase; (ii) an extrinsic anomalous Josephson effect modulated by the transverse electric field. We demonstrate that the $4\pi$-periodic CPR synchronizes with zero-energy crossing displacements of nonlocal Andreev bound states, arising from nonlocal Andreev reflections mediated by CMMs. The study provides experimental designs to verify CMMs via both the fractional Josephson effect and quantized crossed Andreev reflection conductance, with applications in phase-controllable Josephson devices and topological transistors.

The automated design of parameterized quantum circuits for variational algorithms in the noisy intermediate-scale quantum (NISQ) era faces a fundamental limitation, as conventional differentiable architecture searches rely on classical models that fail to represent quantum gate interactions adequately under hardware noise. We introduce Quantum-Based Self-Attention for Differentiable Quantum Architecture Search (QBSA-DQAS), a metalearning framework featuring quantum-based self-attention and hardware-aware multiobjective searching for automated architecture discovery. The framework employs a two-stage quantum-based self-attention module. First, it computes contextual dependencies by mapping architectural parameters through parameterized quantum circuits, extracting high-dimensional feature representations that replace classical similarity metrics with quantum-derived attention scores. Second, it applies positionwise quantum transformations for feature enrichment. Architecture searching is guided by a task-agnostic multiobjective function, jointly optimizing noisy expressibility and the probability of successful trials. A postsearch optimization stage applies gate commutation, fusion, and elimination to reduce circuit complexity. Experimental validation demonstrates superior performance in variational quantum eigensolver (VQE) tasks and large-scale wireless sensor networks (WSNs). For VQE tasks on ${\mathrm{H}}_2$, QBSA-DQAS achieves 0.9 accuracy, compared with 0.89 for a standard differentiable quantum architecture search, outperforming classical applied attention baselines. Postsearch optimization via deterministic simplification rules reduces the complexity of the discovered circuits by up to 44% in gate count and 47% in depth without accuracy degradation. The framework maintains robust performance across three molecules and five IBM Quantum hardware noise models. For WSN routing, discovered circuits achieve 8.6% energy reduction versus the quantum approximate optimization algorithm and 40.7% versus the classical greedy method. These results establish the effectiveness of quantum-native architecture searching for NISQ applications.

Kinetic inductance traveling-wave parametric amplifiers (KI-TWPAs) offer broadband near-quantum-limited amplification with high saturation power. Because of the high critical magnetic fields of high-kinetic inductance, KI-TWPAs should be resilient to magnetic fields. In this work, we study how magnetic field and temperature affect the performance of a KI-TWPA based on a thin-$\mathrm{Nb}\mathrm{Ti}\mathrm{N}$ inverse microstrip with a $\mathrm{Nb}$ ground plane. This KI-TWPA can provide substantial signal-to-noise-ratio improvement ($\mathrm{\Delta }\mathrm{SNR}$) up to in-plane magnetic fields of 0.35 T and out-of-plane fields of 50 mT, considerably higher than what has been demonstrated with TWPAs based on Josephson junctions. The field compatibility can be further improved by incorporating vortex traps and by using materials with higher critical fields. We also find that the gain does not degrade when the temperature is raised to 3 K (limited by the $\mathrm{Nb}$ ground plane), while $\mathrm{\Delta }\mathrm{SNR}$ decreases with temperature, consistent with expectations. This demonstrates that KI-TWPAs can be used in experiments that need to be performed at relatively high temperatures. The operability of KI-TWPAs in high magnetic fields opens the door to a wide range of applications in spin qubits, spin ensembles, topological qubits, low-power NMR, and the search for axion dark matter.

Quantifying spin-orbital-to-charge conversion efficiency is crucial for spin-orbitronics. Two widely used methods for determining these efficiencies are based on ferromagnetic resonance (FMR): spin-pumping FMR for the inverse effect, and spin-torque FMR for the direct effect. A key parameter to achieve accurate quantification, especially for spin-pumping FMR, is the rf field strength, $h_{\mathrm{rf}}$. We present a comprehensive theoretical model and experimental protocol that allow a correct quantification of $h_{\mathrm{rf}}$. It was validated by extensive experimental results and it was rigorously tested across various antenna geometries and ferromagnetic systems. We demonstrate that odd symmetric Lorentzian voltages—which perfectly mimic spin-pumping or spin-torque FMR signals—can arise purely from rectification effects (due to anisotropic magnetoresistance) when $h_{\mathrm{rf}}$ orientation is parallel to the ferromagnetic surface. Through a systematic study of various 10-nm-thick ferromagnetic layers, such as $\mathrm{Ni}$, $\mathrm{Ni}\mathrm{Fe}$, $\mathrm{Fe}$, and $\mathrm{Co}\mathrm{Fe}\mathrm{B}$, we find that, while $\mathrm{Fe}$ and $\mathrm{Co}\mathrm{Fe}\mathrm{B}$ exhibit minimal rectification, $\mathrm{Ni}$ and $\mathrm{Ni}\mathrm{Fe}$ generate strong rectified signals that must be corrected. We further demonstrate that these rectification effects become negligible for ferromagnetic thicknesses $\le 6$ nm, as validated in $\mathrm{Ni}\mathrm{Fe}$/$\mathrm{Pt}$ bilayers, providing an important guideline for the design of future heterostructures.

We study thin films of the high-entropy alloy system $\mathrm{Al}$${}_x$($\mathrm{Cr}$-$\mathrm{Mo}$-$\mathrm{W}$)${}_{1-x}$, grown on $\mathrm{Ta}$ seed layers by magnetron cosputtering. Between $x=0.2$ and $x=0.6$, a resistivity larger than $100\text{μ}\mathrm{\Omega }\mathrm{cm}$ is achieved, with a peak of $180\text{μ}\mathrm{\Omega }\mathrm{cm}$ at $x=0.5$. Around the stoichiometric composition $\mathrm{Al}$-$\mathrm{Cr}$-$\mathrm{Mo}$-$\mathrm{W}$, the alloy forms a bcc solid solution. The harmonic Hall method was used to characterize the spin Hall angle of the alloy series, where a maximum spin Hall angle of $\theta =-0.12\pm 0.01$ is observed for $x=0.25$. The implied spin Hall conductivity is ${\sigma }_{\mathrm{SH}}\approx -72000\hslash /(2e)$ S/m. The experimental results show excellent agreement with density-functional-theory calculations, which show similar trends and values. The results demonstrate that high-entropy alloys with a main-group-element component can form a simple crystal structure and show high resistivity. This suggests that a whole new class of materials for spin Hall device engineering is available with simple methods.

Optical scattering severely degrades wave-front control and energy delivery in complex media, particularly in biological tissue where polarization mixing further complicates light transport. Although wave-front shaping can compensate for scattering-induced distortions, most existing approaches rely on scalar control and access only partial transmission matrices, which fundamentally limit performance. Here, we present a fast vectorial wave-front shaping framework based on direct measurement of the full vector transmission matrix (VTM). The approach combines compact, reference-free, and single-path optical architecture with an efficient reconstruction algorithm based on the alternating direction method of multipliers, enabling simultaneous retrieval of polarization-coupled scattering responses from intensity-only measurements. Full vectorial wave-front control is realized using a single digital micromirror device with superpixel encoding and Fourier-plane polarization discrimination. We demonstrate millisecond-scale operation through strongly scattering and dynamically decorrelating biological tissue. For N = 64 modes per polarization, full VTM acquisition and focusing are completed within a total time of 46.4 ms (including 24.6 ms for measurement and 21.8 ms for algorithmic reconstruction), corresponding to an average time of approximately 362 µs per mode, enabling stable operation under dynamic scattering conditions.