Optical image differentiation is a key operation for edge extraction in imaging and machine vision, yet most existing implementations rely on momentum-domain filtering elements and are typically developed within a scalar-wave framework. Here we demonstrate a nonlinear vectorial mechanism for optical image differentiation based on parametric wave mixing. By solving the full vector wave equation with a nonlinear polarization source term, we show analytically that frequency conversion intrinsically generates cross-polarized field components that correspond to spatial derivatives of the incident field. Exploiting the polarization-selective phase-matching conditions of second-order nonlinear crystals, particularly uniaxial crystals, we propose filter-free imaging schemes that simultaneously perform spatial differentiation and wavelength conversion. This nonlinear vector differentiation platform enables compact, wavelength-agile, and edge-enhanced imaging, offering alternative opportunities for midinfrared imaging and all-optical signal processing.

We theoretically investigate a high-efficiency and broadband microwave storage and retrieval scheme employing a superconducting artificial chiral molecule embedded in a one-dimensional transmission line. By optimizing the parametric coupling, the chiral $\mathrm{\Lambda }$-type molecule enables near 100% storage efficiency and fidelity across a bandwidth of 100 MHz. Our results provide a feasible pathway toward implementing microwave quantum memories compatible with broadband quantum networks.

Measurement-induced quantum computation with continuous-variable cluster states utilizes teleportation to transmit and alter quantum states via measurement-and-feedforward control. One of the key challenges of this approach is the deterioration of quantum states caused by the noise added due to imperfect entanglement of the cluster. We analyze the propagation of a quantum non-Gaussian state with nonlinear squeezing through a small cluster state. We show that a nonlinear feedforward in the deterministic teleportation protocol reduces the added noise and improves the nonlinear squeezing transferred. In a probabilistic regime, the improvement can be manifested even with current experimental resources. Better processing of non-Gaussian states can bring us closer to the necessary interplay between cluster states and non-Gaussianity required by quantum computing.

Identity authentication between communicating parties is a fundamental prerequisite for secure communication. Classical authentication systems face serious threats from the advent of quantum computing. In contrast, quantum identity authentication (QIA) can provide security based on the fundamental principle of quantum mechanics and has consequently attracted significant research interest. However, currently most QIA schemes either belong to one-way identity authentication or suffer from information leakage during the identity authentication process. Here, we for the first time propose a bidirectional QIA scheme with zero-knowledge proof. This scheme will not disclose any information other than the authenticity of the statement itself, and it possesses the merits of simple structure and easy execution. Theoretical analysis has been conducted on the completeness, robustness, and zero-knowledge nature of the proposed scheme. Furthermore, corresponding experimental demonstrations have been carried out by utilizing entanglement sources. This work has effectively improved the practical security and practicability of QIA, paving the way for the construction of a large-scale quantum internet in the future.

Arrays of Josephson junctions can be tuned through anomalous metallic, quantum-critical, and insulating regimes. We introduce an alternative experimental probe, capturing microwave radiation across all three regimes, using a two-dimensional array of superconductor-semiconductor hybrid Josephson junctions as a model system. Our approach allows in situ calibration of the sample’s circuit parameters and provides isolation from measurement back-action effects. We measure the radiation temperature of the anomalous metal and find that it is hotter than both the quantum-critical and insulating regimes. We further show that the anomalous metallic regime is more susceptible to additional heating than other regimes, explaining its emergence in otherwise thermalized systems. Turning to the quantum-critical regime, we discover nonlinear scaling of radiative noise with applied bias, consistent with theoretical predictions of universal nonequilibrium behavior at quantum-critical points.

The search for material systems exhibiting a large spin Hall effect is central to the development of ultrafast, energy-efficient spintronic technologies. We systematically investigate the spin Hall angle (SHA) in Ru-Pt binary alloys using three complementary techniques: spin-torque magneto-optic Kerr effect, spin-torque ferromagnetic resonance, and time-domain terahertz emission spectroscopy. Within the measured composition range, a maximum SHA of 0.158 is observed in ${\mathrm{Ru}}_{38}{\mathrm{Pt}}_{62}$, representing a 56% enhancement over Pt while maintaining a resistivity below $70\mathrm{\mu \Omega }\mathrm{cm}$. Notably, these high SHA values are achieved in as-grown sputtered films across the full composition range without the need for complex fabrication procedures or high-temperature annealing. These results establish Ru-Pt as a scalable model alloy system in which composition-driven disorder, together with gradual structural evolution, governs spin-charge conversion, providing a practical pathway for optimizing materials for spin-orbit torque devices.

Terahertz radiation pulses can be generated efficiently through femtosecond laser excitation of a ferromagnetic/nonmagnetic heterostructure, wherein an ultrafast laser-induced spin current results in an electromagnetic THz pulse due to spin-charge conversion. It is, however, still poorly understood how the THz emission amplitude and its bandwidth in the frequency regime can be optimized. Here, we perform a systematic analysis of the THz emission from various magnetic heterostructures. The dynamics of the spin current is described by the semiclassical, superdiffusive spin-transport model, and the energy dependence of the spin Hall effect of hot electrons is taken into account, leading to emission profiles for $\text{Co}(2\mathrm{nm})/\text{Pt}(4\mathrm{nm})$ bilayer in good agreement with experiment. To identify the optimal conditions for THz emission, we study the properties of the emitted THz wave profile by systematically varying the layer thicknesses of metallic bilayers, their interfacial spin-current transmission properties, their materials’ dependence, and the influence of the pump laser-pulse width, allowing us to give optimization guidelines. We find that thin nonmagnetic layer thicknesses of 5–6 nm provide the largest bandwidth in the case of $\text{Co}/\text{Pt}$ and that the peak frequency of the THz emission depends only on the geometry of the emitter and not on the laser pulse width. The THz bandwidth is conversely found to depend on several factors such as exciting laser pulse width, layers’ thicknesses, and interface transmission-reflection properties, with the limitation that an increase in the bandwidth by tuning the interface properties comes with a trade-off in the energy efficiency of the emitter. Finally, we propose a double pulse excitation protocol of a trilayer system that could provide broadband THz emission with a large bandwidth. Our results contribute to establishing guidelines for optimizing spintronic THz generation.

Resonator-photon-induced dephasing presents a critical challenge for superconducting qubit coherence. This study examines the influence of the frequency and number of coherent photons on quantum coherence degradation. Our measurements show that the dephasing profile across photon frequencies closely follows the resonator’s spectral characteristics, establishing a direct link between dephasing dynamics and resonator-qubit interaction parameters. Of note, dynamical decoupling demonstrated robust performance in mitigating coherence decay under a wide range of photon conditions. This underscores its potential for addressing various forms of coherent photon noise, including ac Stark shifts and additional photon-mediated dephasing.

Voltage-controlled spin manipulation at the atomic scale is a central challenge for realizing all-electrical spintronic devices. Here, we present real-time simulations demonstrating a voltage-driven spin memory effect in a nanographene junction. Using the mean-field Hubbard approximation in combination with time-dependent nonequilibrium Green’s function method, we show that antisymmetric electrode coupling enables deterministic switching between spin-polarized states solely by direct current voltage. Positive and negative voltage pulses drive transitions between two bistable spin configurations, while spin-resolved tunneling currents provide distinct and robust electrical readout signals. The system exhibits a pronounced hysteresis in polarization under cyclic bias, forming a controllable memory loop. These results establish a microscopic mechanism for voltage-induced spin manipulation and pave the way for the design of all-electrical spintronic memory architecture.

We demonstrate the free rotation of an acoustic metasurface driven entirely by a nondissipative acoustic radiation torque, resulting from the transfer of orbital angular momentum from sound to matter. This direct observation of mechanical angular recoil establishes a quantitative link between the incident vortex field and the induced torque, with measured angular velocities, which are supported by analytical modeling. Recent advances in the design of arbitrary acoustic metasurfaces allow this rotational acoustomechanics to be extended to translational degrees of freedom, providing a simple and versatile route for noncontact acoustic actuation along multiple mechanical degrees of freedom. As such, this work contributes to the field of acoustic micromanipulation, fluid-structure interactions, and sound-driven mechanical systems.

Harmonic amplitudes in microcantilever oscillators carry critical information for nanoscale force and material characterization, yet their decay behavior across different environments remains insufficiently quantified. Here, we characterize multiharmonic cantilever spectra in air and liquid under tapping and free-vibration conditions, revealing a consistent two-regime power-law decay separated by a knee at mode index $n^{\star }$ that shifts systematically with environment. Employing robust segmented regression, bootstrap confidence intervals, and modal lifetime overlap analysis, we identify the knee as a stable spectral feature linked to transitions in viscous confinement and near-surface interphase memory. This framework enables compact parametrization of harmonic spectra and may provide a practical route to distinguish medium-dominated dissipation from interfacial viscoelastic effects. Our findings advance the understanding of cantilever-fluid-interphase dynamics and suggest new avenues for quantitative multiharmonic nanomechanical metrology.

Practical quantum advantage hinges on executing deep quantum circuits within the coherence limits of noisy intermediate-scale quantum processors. The absence of native, high-fidelity multiqubit gates remains a major bottleneck, as their decomposition into single- and two-qubit gates leads to prohibitive depth and error overhead. Here, we propose a hardware-efficient protocol that directly implements a native controlled-controlled-Z gate in a tunable-coupler superconducting circuit. Our theoretical protocol activates a resonant three-qubit interaction via a time-frequency-correlated virtual process, explicitly relying on the dynamic resonant exchange within the $|101⟩\leftrightarrow |020⟩$ transition manifold. This approach is compatible with standard tunable-coupler architectures without requiring additional control resources. Through a systematic calibration workflow combining pulse shaping and active cancellation of residual phases, we demonstrate a gate fidelity exceeding 99% within 165 ns—significantly outperforming decomposed sequences. Comprehensive error budgeting confirms that the gate performance remains robust against realistic experimental imperfections. Furthermore, we show that this scheme can be naturally extended to a continuous $\mathrm{CCPhase}(\theta )$ gate set. This work provides a direct, high-fidelity route to three-qubit entanglement, offering promising prospects for efficient execution of quantum algorithms on near-term superconducting hardware.

Very-low-field magnetic resonance imaging offers significant advantages in portability and cost but faces challenges in maintaining a high signal-to-noise ratio (SNR). In vertical-field configurations, conventional quadrature coils often suffer from inherent structural asymmetry, leading to complex decoupling requirements and significant orthogonal losses. To address this challenge, we propose a symmetrical quadrature coil composed of two sets of series-connected spiral coils based on the working principle of circularly polarized magnetic fields. By employing structurally identical units for both orthogonal channels, the design inherently ensures channel consistency and achieves high interport isolation without additional decoupling circuits. A multiobjective particle swarm optimization algorithm was employed to optimize the geometric parameters, balancing the trade-off between SNR and field homogeneity. Furthermore, an “orthogonal loss” metric was introduced to quantify the deviation from ideal circular polarization. Importantly, comparative analysis reveals that the proposed symmetrical coil exhibits superior $B_1^{-}$ field strength and significantly lower orthogonal loss compared to conventional Helmholtz-Saddle configurations, achieving an average $B_1^{-}$ field strength enhancement of 1.8 times in a large region of interest (ROI). A prototype symmetrical quadrature coil was fabricated and experimentally validated. Simulation and experimental results demonstrate excellent agreement, with an orthogonal loss of only 1.9% observed at the coil isocenter. Measured data confirm that the orthogonal loss remains well controlled within the central ROI, demonstrating that the structural symmetry effectively preserves quadrature purity. This work offers new perspectives on the design of circularly polarized volume coils and receiving coils for vertical-field MRI systems.

Graph neural networks (GNNs) are designed to extract latent patterns from graph-structured data, making them particularly well suited for crystal representation learning. Here, we propose a GNN model tailored for estimating electronic transport coefficients in inorganic thermoelectric crystals. The model encodes crystal structures and physicochemical properties in a multiscale manner, encompassing global, atomic, bond, and angular levels. It achieves state-of-the-art performance on benchmark datasets with remarkable extrapolative capability. By combining the proposed GNN with ab initio calculations, we successfully identify compounds exhibiting outstanding electronic transport properties and further perform interpretability analyses from both global and atomic perspectives, tracing the origins of their distinct transport behaviors. Interestingly, the decision process of the model naturally reveals underlying physical patterns, offering new insights into computer-assisted materials design.

High-quality quantum communications that enable important capabilities, such as distributed quantum computing and sensing, will require quantum repeaters for providing high-quality entanglement. To realize high-rate heralded entanglement for quantum repeaters, Chen et al. [Phys. Rev. Appl. 19, 054029 (2023)] proposed a scheme for heralded-multiplexed generation of quasideterministic entangled photon pairs, called zero-added-loss multiplexing (ZALM). Here, we propose a design of the ZALM source using time-bin entanglement and spectral shearing. Additionally, we provide an analysis of experimentally relevant spectral-shearing parameters to optimize the spectral multiplexing. Moreover, we experimentally verify the compatibility of time-bin pulses and spectral shearing, as supported by observation of no appreciable phase shift when the same shearing is applied to both time bins. These results expand the benefits of applying a ZALM source to time-bin entanglement use cases. Moreover, more fully demonstrating time-bin and spectral shearing compatibility clears a path toward a broader use of spectral shearing that provides a deterministic frequency shift of high utility.