After modeling the surface gap, the bulk gap, and the electrode-material interface gap, and considering the effect of spin-orbit coupling strength on the effective mass, we reveal that the surface quasipolarons at the edge states are the main charge carrier of nonlinear photocurrent in a double perovskite family of ${\mathrm{Ca}}_{\mathrm{x}}{\mathrm{Cu}}_{4-x}{\mathrm{Ti}}_4{\mathrm{O}}_{12}$ ($x=3$, 2, and 1). The photocurrent is the quadratic function of voltage, which is measured in two ways of the bulk mode and the surface mode, in the visible light with the wavelength of 385, 405, 450 and 660 nm and at the temperature of 150, 180, 210, 240, 270, and 300 K, respectively. When there is the electrode effect, we discuss the electron-phonon coupling, the spin-orbit coupling, the effective mass, the flat band, and the quasipolaron size. Particularly in the surface mode, we estimate the spin-orbit coupling and the electron-phonon coupling. The computational and experimental results suggest that the antiferromagnetically dielectric insulator in the ceramic form is a potential candidate for broad-spectrum and wide-temperature-range photodetectors.

We investigated the competing mechanisms of spin Hall magnetoresistance (SMR) and ordinary magnetoresistance (OMR) in van der Waals A-type antiferromagnet ${\text{CrPS}}_4/\text{Pt}$ heterostructures. By engineering the Pt thickness, we demonstrate a clear crossover from an SMR-dominated regime in thin (5 nm) Pt bilayers to an OMR-dominated regime in thick (30 nm) ones, providing a reliable protocol for isolating the elusive SMR signal from the OMR signal. Strikingly, a robust SMR persists at room temperature, far exceeding the bulk Néel temperature ($T_{\mathrm{N}}\approx 38\mathrm{K}$), which we attribute to a magnetic proximity-induced interfacial state. A field-dependent phase shift in the SMR angular response across $T_{\mathrm{N}}$ reveals that this interfacial magnetism is distinct from the bulk antiferromagnetic order. Complementary anomalous Hall effect measurements independently confirm the existence of this interfacial magnetization. Our work not only establishes ${\text{CrPS}}_4$ as a promising room-temperature spintronic material but also establishes thickness-dependent magnetotransport as a powerful tool for probing interfacial magnetic phenomena in antiferromagnetic heterojunctions.

Spatial photonic Ising machines (SPIMs) exploit free-space Fourier propagation to perform parallel optical computation of spin-spin couplings, providing a promising platform for large-scale combinatorial optimization. However, their fidelity is limited by intrinsic optical aberrations and nonuniform incident-field amplitudes, which distort the mapping between the modulating plane and the corresponding Fourier plane, thereby degrading energy resolution and annealing reliability. In this work, we propose an in situ differentiable complex-field calibration framework. Based on paired random phase patterns and Fourier-plane captured intensity distributions, the implicit system error can be numerically backpropagated to an exact complex-amplitude distribution on a pixel sampling grid. In single-spin-flip tests, the typical relative deviation between the measured energy and the theoretical value is reduced to 1.31%. Under general SPIM annealing settings, the coefficient of determination between the experimental and theoretical Hamiltonian reaches 0.9998. This work provides a plug-and-play in situ calibration route toward ultrahigh Hamiltonian-evaluation fidelity in more complicated SPIMs.

The centroid oscillation of an offset laser pulse propagating in a preformed plasma channel is investigated through theoretical analysis and three-dimensional particle-in-cell simulations. For nonrelativistic laser pulses, the mode leakage of a finite channel and the temporal walk-off between the fundamental and high-order modes of a finite-duration laser induce a decay in the laser centroid oscillation. An analytical model characterizing these decay mechanisms is derived and validated by simulations. For relativistic laser pulses, the slice-based centroid oscillation frequency develops an axial chirp due to relativistic channel modification and photon deceleration. This chirp leads to phase mixing across different axial slices of the pulse, resulting in a rapid damping of the overall centroid oscillation. Understanding this oscillation damping is crucial for mitigating electron beam-pointing jitter and maintaining beam quality in high-energy, channel-guided laser wakefield accelerators.

The transconductance $g_m=d{I}_D/d{V}_G$ of a field-effect transistor (FET) is conventionally read as a proxy for carrier density. We show that it is instead a spectroscopic probe of the carrier distribution: because $g_m$ weights the spectral current $j(E)$ by the gate-voltage derivative $\partial f(E)/\partial V_G$ and integrates over energy, it is sensitive to the shape of $f(E)$, not merely its integrated weight $n$. We develop an energy-resolved transport framework for two-dimensional (2D) FETs and, within a gate-independent spectral-kernel approximation, derive the decomposition $g_m=g_m^{(n)}+g_m^{(\alpha )}$ into the conventional density-modulation term $g_m^{(n)}$ and a distribution-shape-driven term $g_m^{(\alpha )}$. The latter, obtained as the residual after subtracting the smooth density-modulation background from the measured $g_m$, exhibits a characteristic anomalous peak at a gate voltage $V_G^{\text{pk}}$. This peak has no counterpart in equilibrium transport and cannot be explained by carrier density modulation alone. With the spectral kernel calibrated, the peak position and height—extracted from standard dc/lock-in $g_m$ sweeps—constrain the hot-carrier energy $E_0$, spectral width $\sigma$, and generation threshold $n_c$, realizing a steady-state, all-electrical spectroscopy of the carrier distribution. An optional time-resolved extension further recovers the carrier relaxation time $\tau$ from the transient response following a pump excitation, establishing the 2D FET as a distribution-function spectrometer that requires no optical readout.

Time-continuous quantum error correction, necessary to protect quantum information under time-dependent Hamiltonians, relies on weak continuous syndrome measurements. Implementing these measurements requires a continuous coupling among at least two qubits and a meter, a demanding requirement. We show that, under continuous operation, common parity-measurement protocols in the circuit quantum electrodynamics platform corrupt the logical information. The failure arises from approximating the three-body interaction by a sum of two-body couplings to the meter, which prevents simultaneous suppression of measurement backaction on the logical and error subspaces. We argue that the same mechanism applies more generally beyond the circuit quantum electrodynamics setting. Taken together, our results impose a practical limitation on continuous stabilizer quantum error correction and point to the viable alternatives—architectures that realize native three-body interactions or erasure-based encodings in which the error subspace need not be protected.

We propose a method of spatial resolution enhancement in metrology (thermometry, magnetometry, pH estimation, and similar methods) using blinking fluorescent nanosensors by combining sensing with superresolution optical fluctuation imaging. By utilizing the idea of quantum superresolution imaging by photon statistics, the applicability of the proposed methodology is extended to the low-brightness regime. The efficiency of the approach is demonstrated by numerical simulations performed for several model configurations, representing steplike and continuous variation of the sensed parameter, high- and low-brightness regimes, and one- and two-dimensional structures. The second- and fourth-order cumulant images provide improvement of the contrast and enable successful reconstruction of smaller features of the modeled parameter distribution relatively to the intensity-based approach. We believe that blinking fluorescent sensing agents, when complemented with the developed image analysis technique, could be routinely utilized in the life science sector to recognize the local changes in the spectral response of blinking fluorophores, such as those delivered targetly to a specific cell or even organelle. It is extremely useful for the local measurements of changes in living cells’ physical parameters due to applying any external “forces,” including disease effects, aging, healing, or response to treatment.

Floquet engineering of cavity magnon-polaritons by periodically modulating the magnon frequency has recently attracted much interest as a way to manipulate the energy spectrum of magnon-photon hybrid systems. However, modulating the frequency of magnons by a time-varying bias magnetic field can be challenging. We demonstrate cavity magnon-polariton Floquet engineering by modulating the microwave cavity frequency, allowing large modulation depth and bandwidth. We apply commensurate two-frequency Floquet modulations with the higher frequency at twice and three times the lower frequency and demonstrate that the resulting spectrum depends on the relative amplitude and phase of the two drive tones. In comparison with single-frequency Floquet modulations, the spectrum has qualitatively different features; in particular, new anticrossings appear between previously uncoupled sidebands. Our platform offers an alternative way to manipulate Floquet quasienergy levels in hybrid systems.

We present a continuous-time, neural-network-based approach to optimal control in quantum systems, with a focus on pulse engineering for quantum gates. Leveraging the framework of neural ordinary differential equations (neural ODEs), we construct control fields as outputs of trainable neural networks, thereby eliminating the need for discrete parametrization or predefined bases. This allows for the generation of smooth, control-hardware-agnostic pulses that can be optimized directly using differentiable integrators. As a case study, we design and experimentally implement a short and detuning-robust $\pi /2$ pulse for photon number parity measurements in superconducting transmon circuits. This is achieved through simultaneous optimization for robustness and suppressing the leakage outside of the computational basis. These pulses have very high fidelity ($\approx 99.95\%$) and realize the parity measurement with an efficiency greater than 99.9% over a detuning range of $\approx \pm 20\mathrm{MHz}$, thereby outperforming traditional techniques while retaining comparable gate durations. This showcases the potential of neural ODEs for high-performance quantum control in experimentally relevant settings.

Lightsails are promising spacecraft that can traverse interstellar distances within decades via radiation-pressure propulsion from high-power lasers. The envisioned missions crucially rely on the sail being confined within the propelling laser beam, requiring restoring and damping mechanisms for both translational and rotational degrees of freedom. Here, we use a two-dimensional rigid model to show that full asymptotic stability of planar nanophotonic sails can be achieved through purely optical, relativistic forces and torques, which damp all unstable degrees of freedom. By judiciously optimizing the angular and frequency dispersion of diffraction gratings, we find that damping can be substantially enhanced compared with plane-mirror sails. Over the full operating band for $0.2c$ missions, it is several times larger, while over narrow wavelength bands, the enhancement is by 3 orders of magnitude. Therefore, relativistic effects can, in principle, provide comprehensive and realistic control over lightsail motion.

We report the results of two-photon-excited fluorescence (TPEF) measurements of the $5S_{1/2}\to 5D_{5/2}$ transition of ${}^{85}\mathrm{Rb}$ and ${}^{87}\mathrm{Rb}$ cooled in a magneto-optical trap. We observe TPEF at excitation powers as low as $1\mathrm{\mu }\mathrm{W}$ or fluxes as low as ${2.98}_{-0.94}^{+1.37}\times {10}^{18}\text{photons}{\text{cm}}^{-2}{\mathrm{s}}^{-1}$ (${}^{85}\mathrm{Rb}$) and ${3.31}_{-1.33}^{+2.21}\times {10}^{18}\text{photons}{\text{cm}}^{-2}{\mathrm{s}}^{-1}$ (${}^{87}\mathrm{Rb}$). Our results demonstrate that optically cooled Rb is a promising platform for observing sensitive two-photon spectral signatures at low photon fluxes.

Electron-matter interactions produce elastic and inelastic scattering, forming the basis for imaging and spectroscopy in electron microscopy. However, integrating electron energy-loss spectroscopy (EELS) with 4D-STEM and ptychography remains challenging due to detector geometry conflicts. Hollow ptychography introduced by Song et al., which uses a central aperture to allow low-angle electrons into the EELS spectrometer, suffers from multiple scattering in thicker samples. We propose multislice hollow ptychography (MHP), which incorporates a multislice model to address dynamical scattering and enables robust high-resolution imaging from hollow diffraction patterns while supporting simultaneous EELS acquisition. MHP achieves sub-ångström lateral resolution at intermediate doses (${10}^4–{10}^8{\mathrm{e}}^{-}/{Å}^2$) and enables full three-dimensional (3D) atomic-layer reconstruction at ultrahigh doses ($\ge {10}^8{\mathrm{e}}^{-}/{Å}^2$), limited only by lattice vibrations. Of note, up to 70% of electrons remain available for spectroscopy. This flexible and dose-efficient framework supports correlative 3D imaging and chemical mapping, opening new possibilities for analyzing complex energy and quantum materials.

Quantum heuristics have shown promise in solving various optimization problems, including lattice protein folding. Equally relevant is the inverse problem, protein design, where one seeks sequences that fold to a given target structure. The latter problem is often split into two steps: (i) searching for sequences that minimize the energy in the target structure, and (ii) testing whether the generated sequences fold to the desired structure. Here, we investigate the utility of variational quantum algorithms for the first of these two steps on today’s noisy intermediate-scale quantum devices. We focus on the sequence optimization task, which is less resource-demanding than folding computations. We test the quantum approximate optimization algorithm and variants of it, with problem-informed quantum circuits, as well as the hardware-efficient ansatz, with problem-agnostic quantum circuits. While the former approach, with a careful choice of mixer, yields good results in noiseless simulations (success probability $\ge 0.95$ in all instances), its performance drops drastically under noise. With the problem-agnostic circuits, which are more compatible with hardware constraints, improved performance is observed in noisy simulations, compared to their problem-informed counterparts. When running the problem-agnostic circuits on a real quantum device, with parameters taken from simulations, we obtain a significant success probability ($\ge 0.2$) in most instances.

In a typical Rydberg mixer, modulated communication signals are detected using a radio frequency (rf) heterodyne technique. The mixer outputs an intermediate frequency, which must be filtered and mixed down to baseband. In this work, we apply an rf-homodyne technique to simultaneously demonstrate baseband I/Q readout and angle-of-arrival determination of standard communication signals using a dual-ladder Rydberg receiver (DLRR). We also provide a systematic comparison with a conventional Rydberg receiver (CRR) (i.e., with a heterodyne-based receiver). While the signal amplitude of the DLRR does not decay with increasing symbol rate as in a CRR, direct conversion receivers are highly sensitive to low-frequency noise. As a result, the DLRR’s performance is degraded relative to a CRR when subjected to substantial pink noise. We show that both systems behave comparably once pink noise effects have been accounted for.

Integrated plasmonics is advancing rapidly, enabling a wide range of functionalities to be incorporated onto a single chip. Applications span information processing, computation, quantum sensing, and dark matter detection. This progress has driven the development of integrated nonreciprocal devices, which are essential for preventing unwanted feedback that can degrade system performance. While nonreciprocal devices have been realized in edge magnetoplasmon (EMP) materials via classical interference effects, their operation is often limited by the input power range. Here, we demonstrate that topological circulators utilizing asymmetric coupling offer improved input power range, isolation, and insertion loss. In this configuration, we demonstrate that the coupling between a chiral edge magnetoplasmonic resonator and a pair of LC resonators is well described by an effective non-Hermitian two-site Hatano–Nelson model with asymmetric directional couplings, resulting in nonreciprocal behavior. The coherent photon-plasmon interaction enables a circulator with up to $50\mathrm{dB}$ of isolation across a broad range of excitation power. These results suggest that magnetic topological insulators provide a promising platform for realizing asymmetric non-Hermitian couplings at radio frequencies and for exploring regimes of strong directional suppression and possible exceptional-point physics. More broadly, they highlight the potential of topological-material-based microwave devices for future integration with superconducting quantum information platforms.

Two-dimensional (2D) multiferroic materials with polarization-tunable electronic properties provide unprecedented opportunities for designing high-performance ferroelectric tunnel junctions (FTJs). In this work, we focus on ${\text{InCrS}}_3$, a 2D multiferroic derived from ferroelectric ${\text{In}}_2{\mathrm{S}}_3$ via Cr substitution, which exhibits a distinct polarization-modulated electronic phase transition, half-metallic in one polarization state and semiconducting in the other. Using density functional theory combined with the nonequilibrium Green’s function method, we reveal that the transport performance of ${\text{InCrS}}_3$-based FTJs is strongly dependent on the choice of electrode materials, originating from a momentum-selective coupling effect between the electronic states of electrodes and ${\text{InCrS}}_3$. When graphene is used as the electrode, the system exhibits an abnormal transport behavior: the metallic state shows ultralow transmittance due to momentum-space mismatch near the $\mathrm{K}$ point, while the semiconducting state shows much higher transmittance. In contrast, using metallic ${\text{NbS}}_2$ as the electrode restores normal transport behavior, as the electronic states overlap in momentum space around the $\mathrm{\Gamma }$ point. Our findings highlight that electrode selection can fundamentally alter the switching behavior of 2D FTJs and establish momentum matching as a key design principle for achieving high-contrast tunneling electroresistance in ferroelectric memory devices.