Showing 1–50 of 325 results for author: Li, P

MorphoGP: A Nonparametric Framework for Predicting Equilibrium Beach Profiles Under Tidal Influence

Authors: Xi Wu, Yanqing Wei, Hang Yin, Pengze Li, Hongshuai Qi, Xi Chen

Abstract: The prediction of equilibrium beach profiles under tidal influence is of fundamental importance for sustainable coastal development, informing shoreline protection strategies and managing coastal ecosystems under changing environmental conditions. However, it remains challenging due to the highly nonlinear interactions among wave, tide, and sedimentary processes. Traditional empirical and numerica… ▽ More The prediction of equilibrium beach profiles under tidal influence is of fundamental importance for sustainable coastal development, informing shoreline protection strategies and managing coastal ecosystems under changing environmental conditions. However, it remains challenging due to the highly nonlinear interactions among wave, tide, and sedimentary processes. Traditional empirical and numerical models often exhibit limited adaptability across diverse coastal environments, with especially pronounced limitations in beach systems where tidal processes are important . To improve data-driven prediction under these conditions, this study proposes MorphoGP, a unified category-specific Gaussian process framework for predicting equilibrium beach profiles (EBPs) under tidal influence. The framework first introduces a ContourCluster model based on contrastive learning to classify tide-influenced beach morphologies automatically. Within each morphological category, a specialized Gaussian process expert learns statistical associations between environmental descriptors including waves, tides, and sediments and the beach profile's shape. A Gating Net then integrates the outputs of all experts through a probabilistic weighting mechanism to produce the final prediction. Evaluated on data from over 180 beach profiles from tide-influenced coasts along the Chinese coast, MorphoGP achieves improved predictive performance compared with conventional and deep learning models, reducing the test RMSE by about 59.3\% compared with the best baseline and achieving a final RMSE of 0.297 m. The proposed framework provides a physically informed, data-driven tool for equilibrium beach-profile prediction under tidal influence and coastal management, while stronger process-level physical coupling remains an important direction for future development. △ Less

Submitted 19 August, 2026; originally announced August 2026.

Comments: Accepted by IEEE TGRS

Adjoint shape optimization of oscillatory rarefied gas flows

Authors: Pengshuo Li, Lei Wu

Abstract: A fast-converging and asymptotic-preserving adjoint shape optimization method is proposed for drag reduction of multiscale gas flows in vibrating micro-electro-mechanical systems. The convergence of the Boltzmann kinetic equation is accelerated by macroscopic synthetic equations, whose constitutive relations integrate continuum-limit terms and high-order kinetic corrections to faithfully character… ▽ More A fast-converging and asymptotic-preserving adjoint shape optimization method is proposed for drag reduction of multiscale gas flows in vibrating micro-electro-mechanical systems. The convergence of the Boltzmann kinetic equation is accelerated by macroscopic synthetic equations, whose constitutive relations integrate continuum-limit terms and high-order kinetic corrections to faithfully characterize spatiotemporal rarefaction effects. As such, this method maintains near-continuum limit consistency while retaining high kinetic accuracy in rarefied flow regimes. Fourier stability analysis performed in an infinite domain demonstrates that the present method yields a spectral radius below 0.5, indicating that the numerical deviation from the converged solution is halved per iteration. Numerical simulations are conducted on an oscillating cylinder and a comb-shaped resonator. The results verify the high accuracy of the derived adjoint sensitivities and the excellent drag reduction performance of the proposed method across various Knudsen and Strouhal numbers. Compared with conventional kinetic iteration methods, the present method produces convergent primal and adjoint solutions within dozens of iterations and features asymptotic preserving behavior, permitting spatial cell sizes far larger than the molecular mean free path. This facilitates efficient design of vibrating micro-electro-mechanical systems. △ Less

Submitted 7 August, 2026; originally announced August 2026.

Learning transferable event representations for charmed baryon physics at BESIII

Authors: Kaixuan Huang, Yangu Li, Junpeng Zhao, Peilian Li, Peirong Li, Xiaorui Lyu, Yunxuan Song, Shengsen Sun, Yangheng Zheng

Abstract: Deep learning has become an essential tool in high-energy physics, where the ability to learn transferable event representations can significantly improve model generalization across related physics processes. In this work, we present a Particle Transformer-based framework for learning such representations for charmed baryon physics in the BESIII experiment. The framework is implemented through la… ▽ More Deep learning has become an essential tool in high-energy physics, where the ability to learn transferable event representations can significantly improve model generalization across related physics processes. In this work, we present a Particle Transformer-based framework for learning such representations for charmed baryon physics in the BESIII experiment. The framework is implemented through large-scale pre-training on Monte Carlo simulation samples and subsequent fine-tuning for downstream analyses. Using the production and decays of the charmed baryon $Λ_c^+$ as a benchmark, we develop pre-trained models for both event classification and momentum-direction regression. The classification model learns discriminative event representations for the dominant physics categories, rejecting 97.0\% of background events at a signal efficiency of 90.0\%. Across 12 benchmark $Λ_c^+$ decay channels, fine-tuning from the pre-trained model achieves performance comparable or better than training from scratch, with particularly clear improvements in low-statistics regimes. For the regression task, the pre-trained model improves the momentum-direction prediction across the same benchmark channels. Further improvement is obtained after fine-tuning in the representative semileptonic decay $Λ_c^+ \to p K^- e^+ ν_e$. This strategy provides a scalable solution for a wide range of physics cases at BESIII and can be extended to other high energy experiments. △ Less

Submitted 31 July, 2026; originally announced July 2026.

Comments: 18 pages, 7 figures, 2 tables

Quantum Magnonics: Quantum States Generation and Applications

Authors: Zi-Xu Lu, Xuan Zuo, Xin-Lei Hei, Gang Liu, Zeng-Xing Liu, Qi Guo, Peng-Bo Li, Jie Li

Abstract: Hybrid systems based on magnons in ferromagnetic materials, such as yttrium iron garnet, have achieved remarkable development in the last decade. These include the coupling of magnons to microwave and optical photons, superconducting qubits, phonons, spins, the center-of-mass motion of a ferromagnet, etc. Here, we review both the experimental and theoretical progress in this field, focusing on the… ▽ More Hybrid systems based on magnons in ferromagnetic materials, such as yttrium iron garnet, have achieved remarkable development in the last decade. These include the coupling of magnons to microwave and optical photons, superconducting qubits, phonons, spins, the center-of-mass motion of a ferromagnet, etc. Here, we review both the experimental and theoretical progress in this field, focusing on the generation of magnonic quantum states and their applications in a broad range of fields. Since the strong coupling is a prerequisite for achieving coherent quantum control of magnons and preparing magnonic quantum states, we start by introducing representative strong-coupling experiments in cavity magnonics, then review a series of protocols for creating various magnonic quantum states, such as Fock, cat, squeezed, and entangled states, and discuss their potential applications in macroscopic quantum studies, quantum information science, quantum sensing, magnonic quantum devices, dark matter detection, and so on. Finally, we summarize the review and give an outlook for the future study of quantum magnonics. △ Less

Submitted 30 July, 2026; originally announced July 2026.

Comments: 42 pages, 26 figures. Invited Topical Review by Quantum Science and Technology

Single-atom sensor for low-frequency electric field

Authors: Quan Yuan, Shuang-Qing Dai, Tai-Hao Cui, Pei-Dong Li, Yuan-Zhang Dong, Zhuo-Zhu Wu, Ji Li, Fei Zhou, Jian-Qi Zhang, Liang Chen, Mang Feng

Abstract: Precision measurement of low-frequency electric field (LFEF) signals with frequency from 30 kHz to 300 kHz is crucial for advancing both fundamental science and practical applications, owing to their unique frequency regime. For conventional electromagnetic antennas, the long wavelength (i.e., several kilometers) of the LFEF leads to a severe size constraint that efficient radiation becomes challe… ▽ More Precision measurement of low-frequency electric field (LFEF) signals with frequency from 30 kHz to 300 kHz is crucial for advancing both fundamental science and practical applications, owing to their unique frequency regime. For conventional electromagnetic antennas, the long wavelength (i.e., several kilometers) of the LFEF leads to a severe size constraint that efficient radiation becomes challenging to achieve when the antenna size is much smaller than the long wavelength of the LFEF signals, which in turn results in a reduction of measurement sensitivity and compromises antenna's performance. By exploiting the high intrinsic sensitivity of cold trapped ions to weak alternating electric signals via Coulomb interaction, we demonstrate a single-ion phonon laser sensor acted by an injection-locked 40Ca+ ion confined in a surface-electrode trap. Combining the beat frequency technique with the injection-locked phonon laser oscillation, we demonstrate a practical and efficient approach for simultaneous extraction of the frequency, phase, and amplitude from a single measurement, without the need for sideband cooling. This approach achieves precision detection for LFEF signals with the sensitivity of 404 uV/(m * Hz1/2) and the detection limit of 61.5 uV/m. Besides, this approach also shows remarkable robustness against noise. Our study helps realizing practical single-atom sensors in the low-frequency regime, opening avenues for applications in subsurface communication, precision metrology, mass spectrometry, and biomedical monitoring. △ Less

Submitted 20 July, 2026; originally announced July 2026.

Comments: 8 pages, 4 figures

High-rate continuous-variable quantum key distribution coexisting with Tb/s coherent classical transmission in hollow-core fiber

Authors: Xitao Ji, Siyu Chen, Peng Li, Mingming Zhang, Yilun Chen, Jun Gao, Rui Lin, Bacco Davide, Siqi Yan, Ming Tang

Abstract: Quantum key distribution (QKD) can provide secret keys with security rooted in quantum mechanics, but operation alongside high-capacity classical traffic remains limited by the excess-noise budget of weak quantum states in conventional solid-core fiber. Here, we combine ultralow-loss anti-resonant hollow-core fiber with residual-carrier-assisted discrete-modulation continuous-variable QKD (DM-CV-Q… ▽ More Quantum key distribution (QKD) can provide secret keys with security rooted in quantum mechanics, but operation alongside high-capacity classical traffic remains limited by the excess-noise budget of weak quantum states in conventional solid-core fiber. Here, we combine ultralow-loss anti-resonant hollow-core fiber with residual-carrier-assisted discrete-modulation continuous-variable QKD (DM-CV-QKD) to address both propagation-induced coexistence noise and low-SNR phase recovery. Over a 24.3-km hollow-core link with 3.3-dB end-to-end loss, a dual-polarization 15-Gbaud DM-CV-QKD channel achieves an average asymptotic secret-key rate (SKR) of 153.22 Mb/s and a finite-size SKR of 149.99 Mb/s, while 39 coherent wavelength-division-multiplexed channels deliver an aggregate data rate of 7.6 Tb/s and a net data rate of 7.2 Tb/s. The system can even sustain a positive SKR under a high classical launch power of up to 15 dBm, without an optical bandpass filter (BPF). Finite-size analysis against collective attacks further yields a projected positive secret-key rate at a 100-km-equivalent condition. These results show that an anti-resonant hollow-core fiber, combined with carrier-assisted phase recovery, can greatly extend the operating regime of shared-fiber quantum-secured coherent links, pointing to a promising approach for integrating high-rate CV-QKD with high-capacity optical networks. △ Less

Submitted 16 July, 2026; originally announced July 2026.

Kolmogorov turbulence across multi-fractal gas in Polaris Flare

Authors: Xunchuan Liu, Pak-Shing Li, Yihuan Di

Abstract: We reveal a pristine, scale-invariant 3D Kolmogorov velocity cascade ($α_V^{\mathrm{3D}} \sim 2/3$) spanning $0.05$--$20$~pc in the Polaris Flare using \texttt{PPCOS} $^{12}\text{CO}$ data. A transition scale at $\sim 0.5$~pc marks a bifurcation in the structure functions' exponents, below which the degree of intermittency is also saturated. By deriving an analytical mapping relation (… ▽ More We reveal a pristine, scale-invariant 3D Kolmogorov velocity cascade ($α_V^{\mathrm{3D}} \sim 2/3$) spanning $0.05$--$20$~pc in the Polaris Flare using \texttt{PPCOS} $^{12}\text{CO}$ data. A transition scale at $\sim 0.5$~pc marks a bifurcation in the structure functions' exponents, below which the degree of intermittency is also saturated. By deriving an analytical mapping relation ($α_V^{\mathrm{3D}}=α_V-\frac{1}{3}α_I$), we obtain the scale-invariant value of $α_V^{\mathrm{3D}}$, proving that the apparent transition stems from geometric projection and a changing density fractal dimension rather than a turbulent mode shift. Kolmogorov turbulence is smoothly inherited from the large-scale cold neutral medium, remaining uninterrupted by compression or gravity below 0.1 pc. △ Less

Submitted 1 July, 2026; originally announced July 2026.

Comments: submitted

Sub-Terahertz Channel Performance under Snowfall

Authors: Kefeng Huang, Jiabiao Zhao, Yuheng Song, Yapeng Ge, Jie Yang, Wanzhu Chang, Xiaoxiang Li, Wenbo Liu, Peian Li, Hong Liang, Jianjun Ma

Abstract: The terahertz (THz) band promises terabit-per-second links but is highly sensitive to snowfall. Natural snowflakes are non-spherical. Yet existing THz studies treat them as spheres under Mie theory, and no ITU-R model covers THz snow attenuation. This work combines line-of-sight measurements at 120, 140, and 160 GHz with physics-based scattering modeling. The measured loss is compared against the… ▽ More The terahertz (THz) band promises terabit-per-second links but is highly sensitive to snowfall. Natural snowflakes are non-spherical. Yet existing THz studies treat them as spheres under Mie theory, and no ITU-R model covers THz snow attenuation. This work combines line-of-sight measurements at 120, 140, and 160 GHz with physics-based scattering modeling. The measured loss is compared against the ITU-R P.1817-1 optical model, Mie models, and a discrete dipole approximation (DDA) for randomly oriented hexagonal-plate ice crystals, each with the Scott and Gunn-Marshall size distributions. Over the measured band, ITU-R P.1817-1 overestimates and the Mie models underestimate the loss. The shape-aware DDA-Scott model agrees best, with the lowest RMSE at every frequency. From DDA-Scott, we derive a compact modified ITU-R expression in carrier frequency and liquid-water-equivalent (LWE) rate. It reproduces the reference to within 2.5 dB/km over 100-500 GHz and 0-3 mm/h. A Rician K-factor analysis shows the channel stays LoS-dominated, so snowfall degrades the link mainly through attenuation, not multipath fading. A QPSK/16-QAM link-budget analysis then quantifies the cost of the spherical assumption. Mie-based margins overestimate the tolerable snowfall rate by 3.4 across 120-160 GHz, rising toward 5.8 in the upper transparency windows by model extrapolation. The model is further mapped into snow-limited range and adaptive-modulation switching boundaries. These results support future ITU-R recommendations for THz channels under snowfall. △ Less

Submitted 28 June, 2026; originally announced June 2026.

Comments: Submitted to IEEE Transactions on Terahertz Science and Technology

Finite-Time Electrometry with a Quantum-Regime Single-Ion Phonon Laser

Authors: Pei-Dong Li, Yuan-Zhang Dong, Zhuo-Zhu Wu, Jia-Wei Wang, Ji Li, Jian-Qi Zhang, Zhi-Jiao Deng, Liang Chen, Mang Feng

Abstract: The phonon laser realized in a trapped ion, i.e., a self-sustained mechanical oscillator, has demonstrated the unique characteristics in practically detecting externally applied electric signals without the prerequisite of sideband cooling. Entering the quantum regime via sideband cooling is expected to further improve its sensing performance. Here we report the first experimental realization of a… ▽ More The phonon laser realized in a trapped ion, i.e., a self-sustained mechanical oscillator, has demonstrated the unique characteristics in practically detecting externally applied electric signals without the prerequisite of sideband cooling. Entering the quantum regime via sideband cooling is expected to further improve its sensing performance. Here we report the first experimental realization of a quantum-regime single-ion phonon laser ($\bar{n}<10$) using a trapped $^{40}\mathrm{Ca}^+$ ion and demonstrate electrometry based on its phase-space symmetry-breaking response to weak resonant electric fields. By tuning the phonon-laser parameters, we reveal that the sensing performance is fundamentally governed by the finite-time relaxation dynamics of the underlying open quantum system. We find that a slow Liouvillian relaxation, correlated with the finite experimental interaction window, effectively enhances the dynamic susceptibility while maintaining the structural robustness of the limit cycle. This regime, when applied to the detection of electric fields, produces a shot-noise-limited peak sensitivity of $14.15 \pm 0.77~μ\mathrm{V/m}/\sqrt{\mathrm{Hz}}$ and a minimum detectable field variation of $δE_{\mathrm{min}} \approx 1.83~μ\mathrm{V/m}$. Our results establish quantum phonon lasers as a practical platform for advanced sensing and highlight the central role of Liouvillian dynamics in non-equilibrium electrometry. △ Less

Submitted 18 June, 2026; originally announced June 2026.

Comments: 6 pages, 4 figures; plus Supplementary Materials

A unified resource-pool architecture for high-dimensional direct-detection optical communication

Authors: Jingze Liu, Zhijuan Gu, Xinyang Yu, Ziwen Zhou, Zhuyixiao Liu, Mingming Zhang, Yuxuan Xiong, Peng Li, Zhongyao Luo1, Jiajie Yuan, Hao Wu, Zhipei Sun, Siqi Yan, Yu Yu, Ming Tang

Abstract: Increasing optical communication capacity without proportionally increasing receiver complexity remains a key challenge for direct-detection links. Conventional systems typically assign wavelength, polarization and intensity to fixed, separately recovered functions, so that alphabet expansion is accompanied by additional demultiplexing, polarization handling, receiver branches and electronic proce… ▽ More Increasing optical communication capacity without proportionally increasing receiver complexity remains a key challenge for direct-detection links. Conventional systems typically assign wavelength, polarization and intensity to fixed, separately recovered functions, so that alphabet expansion is accompanied by additional demultiplexing, polarization handling, receiver branches and electronic processing. Here we introduce a unified resource-pool architecture for high-dimensional direct-detection optical communication, in which wavelength, polarization and intensity are jointly organized as a composite optical symbol space and recovered through optical-domain joint projection rather than dimension-by-dimension separation. The receiver is implemented with an integrated disordered photonic processor that transforms each composite optical state into a reproducible multi-output electrical fingerprint for single-shot direct recovery. In a dual-wavelength transmission experiment, the system resolves 4096 composite symbols, corresponding to 12 bits per symbol slot, with a bit error rate of 4.25e-4 after 10 km standard-fiber transmission. Additional experiments demonstrate dense polarization alphabets, wavelength-indexed state-space expansion and high-launch-power operation over hollow-core fiber. These results establish disorder-enabled joint projection in an integrated photonic processor as a route to hardware-efficient high-dimensional direct-detection communication beyond conventional dimension-partitioned receiver architecture. △ Less

Submitted 18 June, 2026; originally announced June 2026.

Comments: 24 pages, 5 figures

General framework for incoherent topological structured light and optical information encoding

Authors: Ao Zhou, Dong Xu, Yaning Zhou, Peng Li, Pujuan Ma, Xin Liu, Lin Liu, Jianlin Zhao, Zhigang Chen, Yangjian Cai, Chunhao Liang

Abstract: Topology provides a powerful language for describing global invariants in physical systems, yet optical topology has been explored predominantly with fully coherent light. Recent studies have shown that incoherent light can host topological structures mediated by coherence singularities; however, a general framework for their construction and control has been lacking. Here, we introduce an incoher… ▽ More Topology provides a powerful language for describing global invariants in physical systems, yet optical topology has been explored predominantly with fully coherent light. Recent studies have shown that incoherent light can host topological structures mediated by coherence singularities; however, a general framework for their construction and control has been lacking. Here, we introduce an incoherent Milnor polynomial, which establishes a theoretical framework for real-space incoherent topological structured light, in which topology and statistical coherence emerge as independent and jointly addressable degrees of freedom. This framework overcomes a fundamental limitation of coherent topological structured light, enabling arbitrary intensity engineering without altering the underlying topological configuration. Experimentally, we realize incoherent Hopf-linked and trefoil-knotted coherence singularities with programmable statistical coherence. We further demonstrate a robust optical information-encoding scheme inspired by Rubik's-cube-like rotations, where statistical coherence determines far-field intensity patterns associated with the cube's initial states, and topological structures govern controlled rotations acting as encryption keys. Our results advance incoherent topological structured light from a physical curiosity to a programmable photonic platform, opening new avenues for optical information encoding, statistical photonics, and coherence-engineered functionalities beyond coherent optical topology. △ Less

Submitted 6 June, 2026; originally announced June 2026.

Comments: 26pages, 4 figures

Hyperon-Nucleon Spectrometer

Authors: Xiaozhi Bai, Xu Cao, Zhe Cao, Jinhui Chen, Kai Chen, Qibo Chen, Shi Chen, Xin Chen, Yuquan Chen, Zhenyu Chen, Jianping Dai, Heng-Tong Ding, Dongshuo Du, Shuxian Du, Limin Duan, Zhe Duan, Anhui Feng, Jie Feng, Yicheng Feng, Jinlin Fu, Xiaofeng Fu, Chaosong Gao, Liang Ge, Wenwen Ge, Lisheng Geng , et al. (215 additional authors not shown)

Abstract: Chirality lies at the heart of low-energy QCD, governing the symmetry structure that shapes hadron masses and strong interaction dynamics. Among the most compelling open questions tied to chiral dynamics and spontaneous chiral symmetry breaking is the longstanding $Λ$ polarization puzzle, in which $Λ$ hyperons produced in unpolarized hadronic collisions exhibit a surprisingly large transverse pola… ▽ More Chirality lies at the heart of low-energy QCD, governing the symmetry structure that shapes hadron masses and strong interaction dynamics. Among the most compelling open questions tied to chiral dynamics and spontaneous chiral symmetry breaking is the longstanding $Λ$ polarization puzzle, in which $Λ$ hyperons produced in unpolarized hadronic collisions exhibit a surprisingly large transverse polarization that remains theoretically unexplained. This whitepaper presents the proposal for the Hyperon-Nucleon Spectrometer (H-NS) at the High-Intensity heavy-ion Accelerator Facility (HIAF). Leveraging the high energy and high intensity of HIAF's proton and heavy-ion beams, the H-NS experiment will perform systematic studies of hyperon polarization phenomena and their underlying mechanisms in proton-proton ($pp$), proton-nucleus ($pA$), and nucleus-nucleus ($AA$) collisions in the fixed target mode. A wide-range beam energy scan, including proton beams from 3 GeV up to 9.3 GeV (HIAF) and up to 32 GeV (upgraded HIAF), will be conducted to examine the dependence of polarization on collision energy. The spectrometer is designed with specialized detectors capable of high-precision reconstruction of final-state baryon polarizations. Among its many interesting and important measurements, H-NS will simultaneously measure hyperon and proton spin observables to explore the polarization mechanism in hadronic interactions and the spin structure of baryons. Furthermore, the use of $pA$ and $AA$ collisions will enable detailed investigations of cold and hot nuclear matter effects on spin polarization. Its physics program and detector development will significantly benefit the future Electron-ion Collider in China. △ Less

Submitted 4 June, 2026; originally announced June 2026.

Comments: 69 pages, Hyperon-Nucleon Spectrometer (H-NS) white paper

Scalable All-Optical Fibre-Mode Data Transmission with Profiles-Preserved Decoding

Authors: Rundong Fan, Yamin Zheng, Pei Li, Xixiao Cao, Haoyang Wu, Zheng Cai, Lei Huang

Abstract: Optical fibres are the primary medium for optical signal transmission, and their guided modes provide a high-dimensional basis for modal-domain information encoding. However, conventional demultiplexing approaches typically convert fibre modes into fundamental Gaussian modes and require repeated mode conversions, while existing profiles-preserved methods are generally restricted to fewer than thre… ▽ More Optical fibres are the primary medium for optical signal transmission, and their guided modes provide a high-dimensional basis for modal-domain information encoding. However, conventional demultiplexing approaches typically convert fibre modes into fundamental Gaussian modes and require repeated mode conversions, while existing profiles-preserved methods are generally restricted to fewer than three modes. High-quality fibre-mode data transmission therefore requires a scalable all-optical decoder capable of separating strongly overlapping modal channels while preserving their intrinsic spatial profiles. Here, we establish a scalable profiles-preserved all-optical decoding method for high-dimensional fibre-mode data transmission. By introducing a microlens-array-assisted decoding architecture with channel-dependent spherical phase compensation, the proposed method accommodates mode-dependent effective focal-length variations, enabling scalable modal-channel separation while preserving high-quality modal profiles at the output plane. Experimentally, the optical decoder resolved fields containing eight fibre modes, achieving a mode fidelity exceeding 0.72, a worst-channel crosstalk of $-5.57~\mathrm{dB}$ and a mean non-target crosstalk of $-21.34~\mathrm{dB}$, while reconstructing the relative modal weights with an error below 0.1. Semantic transmission experiments using digits and Chinese characters further demonstrated effective recovery of the encoded information from the decoded modal signals. We expect this work to provide a scalable route towards high-dimensional all-optical fibre-mode data transmission. △ Less

Submitted 27 May, 2026; originally announced May 2026.

A High-Performance, Cross-Platform Open-Source Solver for the Incompressible Navier-Stokes Equations in FEALPy

Authors: Wang Pengxiang, Huang Xianbo, Peng Li, Wei Huayi

Abstract: To address the dual challenges of performance portability across heterogeneous hardware and the high usability barriers of conventional computational fluid dynamics (CFD) software, this paper introduces FEALPy.CFD, a high performance, open-source solver for the incompressible Navier-Stokes equations developed within the FEALPy framework. The solver's core innovation is its backend-agnostic design,… ▽ More To address the dual challenges of performance portability across heterogeneous hardware and the high usability barriers of conventional computational fluid dynamics (CFD) software, this paper introduces FEALPy.CFD, a high performance, open-source solver for the incompressible Navier-Stokes equations developed within the FEALPy framework. The solver's core innovation is its backend-agnostic design, which supports multiple computational backends like NumPy, PyTorch, and JAX to enable seamless switching between CPU and GPU computations with minimal code modification, thereby maximizing hardware utilization and code portability. Its highly modular architecture provides a library of composable components for various spatial discretization schemes, greatly simplifying the development and integration of new algorithms.Validation on benchmark cases confirms that the implemented numerical schemes achieve their theoretical orders of convergence. Furthermore, the capability to select a suitable backend architecture for different computational tasks fully leverages the hardware's potential, delivering substantial efficiency gains. By lowering the technical barrier to high-performance, cross-platform fluid dynamics simulation, FEALPy.CFD offers a powerful and accessible tool for academic research, engineering applications, and reproducible computational science. △ Less

Submitted 24 May, 2026; originally announced May 2026.

ACM Class: G.1.8

Artificial Intelligence Reshapes Microwave Photonics

Authors: Peng Li, Xihua Zou, Jia Ye, Wei Pan, Lianshan Yan

Abstract: As a rapidly emerging interdisciplinary field that intrinsically integrates microwave and photonics, microwave photonics (MWP) provides disruptive solutions to overcome the fundamental bandwidth of conventional electronic systems. By exploiting the inherently ultra-wide bandwidth and low-loss characteristics of photonic technologies, MWP enables the generation, transmission, processing, and detect… ▽ More As a rapidly emerging interdisciplinary field that intrinsically integrates microwave and photonics, microwave photonics (MWP) provides disruptive solutions to overcome the fundamental bandwidth of conventional electronic systems. By exploiting the inherently ultra-wide bandwidth and low-loss characteristics of photonic technologies, MWP enables the generation, transmission, processing, and detection of microwave, millimeter-wave, and terahertz signals. Representative breakthroughs include fully photonic microwave radar systems, photonic analog-to-digital converters with bandwidth up to 320 GHz, and photonic wireless communication systems achieving data rate as high as 616 Gbit/s. Meanwhile, the rapid growth of artificial intelligence (AI) is reshaping scientific research, engineering, and daily life in unprecedented ways, such as AI for science/engineering and AI co-scientist/assistant. Correspondingly, AI is profoundly reshaping MWP in all aspects, ranging from signal generation, transmission to signal processing and detection. AI has revolutionized the design, simulation, fabrication, testing, deployment, and maintenance of MWP systems, delivering autonomous operation and exceptional efficiency beyond traditional systems. Motivated by these developments, this Review Paper provides the first comprehensive overview of AI-enabled MWP, systematically summarizing the state-of-the-art advances and presenting insights for both the academic community and the broader public. △ Less

Submitted 20 May, 2026; originally announced May 2026.

Comments: 13 pages, 12 figures

MSC Class: 78-02

Low-field carrier mobilities in silicon irradiated to extreme fluences

Authors: I. Bloch, B. Bruers, C. -T. Klein, H. Lacker, P. Li, M. Ullan, Y. Unno, I. Mandić, C. Scharf

Abstract: The low-field carrier mobilities in <100> silicon were quantified as a function of the 1$\,$MeV neutron-equivalent fluence up to $10^{18}\,$cm$^{-2}$ and for temperatures between 230$\,$K and 260$\,$K. Current measurements were fitted using a mobility model for scattering at ionized impurities. Technology-aided design (TCAD) simulations were compared to measurements and used to estimate the carrie… ▽ More The low-field carrier mobilities in <100> silicon were quantified as a function of the 1$\,$MeV neutron-equivalent fluence up to $10^{18}\,$cm$^{-2}$ and for temperatures between 230$\,$K and 260$\,$K. Current measurements were fitted using a mobility model for scattering at ionized impurities. Technology-aided design (TCAD) simulations were compared to measurements and used to estimate the carrier concentrations, which are parameters in the fit. The fit model describes the data very well, both as a function of fluence and the temperature. At a fluence of $6 \cdot 10^{17}\,$cm$^{-2}$, which is expected for the innermost detector layers at the proposed Future Circular Hadron Collider (FCC-hh), the sum of the mobilities of electrons and holes was found to decrease by $\sim60$%. △ Less

Submitted 10 July, 2026; v1 submitted 18 May, 2026; originally announced May 2026.

Comments: 21st "Trento" Workshop on Advanced Silicon Radiation Detectors

Report number: ATL-ITK-PROC-2026-016

Enhanced detection of electric field signals via squeezing-induced stochastic resonance

Authors: Ya-Qi Wei, Tai-Hao Cui, Quan Yuan, Pei-Dong Li, Yuan-Zhang Dong, Zhuo-Zhu Wu, Ji Li, Jia-Wei Wang, Fei Zhou, Ming-Xiao Li, Liang Chen, Zhu-Jun Zheng, Mang Feng

Abstract: Stochastic resonance (SR) could amplify weak electric-field signals in nonlinear systems by means of the externally injected noises. Here we propose and experimentally demonstrate a modified SR method, termed squeezing-induced SR, implemented in the system involving a trapped ion behaving as a Duffing oscillator. We find that squeezing the phase noise of the oscillator results in amplified fluctua… ▽ More Stochastic resonance (SR) could amplify weak electric-field signals in nonlinear systems by means of the externally injected noises. Here we propose and experimentally demonstrate a modified SR method, termed squeezing-induced SR, implemented in the system involving a trapped ion behaving as a Duffing oscillator. We find that squeezing the phase noise of the oscillator results in amplified fluctuation of the corresponding amplitude, which helps achieve the SR. Since no auxiliary noise source is needed, the squeezing-induced SR may enhance the signal-to-noise ratio by 4.28 $\pm$ 0.39 dB compared to the conventional noise-induced SR under identical conditions of the electric-field detection. This technique offers a promising approach for developing atomic ion sensors for detecting weak electric-field signals. △ Less

Submitted 18 May, 2026; originally announced May 2026.

Parametrically driven pure-quartic solitons

Authors: Pengfei Li, Lijing Xing, Dongdong Wang, Dumitru Mihalache, David Laroze, Boris A. Malomed

Abstract: Parametrically driven solitons are self-trapped modes in various physical settings, including optics, magnetics, etc. So far, the analysis was focused on the existence, stability, and dynamics of such solitons in systems including the second-order group-velocity dispersion (GVD), linear loss, parametric gain, and cubic nonlinearity. Here, we report the existence of quiescent parametrically driven… ▽ More Parametrically driven solitons are self-trapped modes in various physical settings, including optics, magnetics, etc. So far, the analysis was focused on the existence, stability, and dynamics of such solitons in systems including the second-order group-velocity dispersion (GVD), linear loss, parametric gain, and cubic nonlinearity. Here, we report the existence of quiescent parametrically driven pure-quartic solitons (PDPQSs) in the full system, and moving PDPQSs in the absence of losses. A systematic analysis reveals stability domains for the solitons in the system's parameter space. Evolution of unstable states is explored too, and it is demonstrated that collisions between traveling stable PDPQSs are elastic. △ Less

Submitted 15 May, 2026; originally announced May 2026.

Comments: 5 pages, 3 figures, to be published in Optics Letters

Analysis of Electromagnetic Scattering from Semiconductor Nanostructures by Solving Coupled Volume Integral and Two-fluid Hydrodynamic Equations

Authors: Doolos Aibek Uulu, Meruyert Khamitova, Rui Chen, Liang Chen, Ping Li, Hakan Bagci

Abstract: Semiconductor-based plasmonic nanostructures support localized surface plasmon modes in the infrared region. Unlike metallic nanostructures, they support both free electrons and holes, requiring a two-fluid hydrodynamic Drude equation (HDE) to accurately capture spatial dispersion effects and low-frequency acoustic plasmon modes that cannot be described by single-fluid models. In this work, a volu… ▽ More Semiconductor-based plasmonic nanostructures support localized surface plasmon modes in the infrared region. Unlike metallic nanostructures, they support both free electrons and holes, requiring a two-fluid hydrodynamic Drude equation (HDE) to accurately capture spatial dispersion effects and low-frequency acoustic plasmon modes that cannot be described by single-fluid models. In this work, a volume integral equation (VIE)-based solver is proposed for the analysis of electromagnetic scattering from semiconductor nanostructures. The proposed approach couples the VIE, formulated in terms of the electric flux density and the free-electron and hole polarization currents, with the two-fluid HDE. The coupled system is discretized using a tetrahedral mesh and solved efficiently using a two-level iterative solver. In contrast to finite-element-based methods, the proposed VIE-based approach does not require domain-wide meshing and inherently satisfies the radiation condition, thereby eliminating artificial absorbing boundaries. Numerical results for InSb-type semiconductor nanostructures demonstrate the accuracy and efficiency of the proposed VIE-based solver and its ability to capture unique optical phenomena, such as acoustic plasmon resonances and the blueshift of localized surface plasmon resonances, that cannot be described by the single-fluid HDE or classical Drude-based models. △ Less

Submitted 30 April, 2026; originally announced April 2026.

SeisDiff-intp: a unified prompt-guided flow matching framework for multi-tasks seismic interpretation

Authors: Donglin Zhu, Peiyao Li, Ge Jin

Abstract: The increasing demand for deep learning in seismic interpretation has highlighted significant challenges, particularly the reliance on massive, labeled datasets and the inefficiency of training isolated models for individual tasks. To address these limitations, we introduce a unified, prompt-guided flow-matching framework (SeisDiff-intp) capable of executing multiple seismic interpretation tasks w… ▽ More The increasing demand for deep learning in seismic interpretation has highlighted significant challenges, particularly the reliance on massive, labeled datasets and the inefficiency of training isolated models for individual tasks. To address these limitations, we introduce a unified, prompt-guided flow-matching framework (SeisDiff-intp) capable of executing multiple seismic interpretation tasks within a single model. By conditioning on varying prompts, the model dynamically switches between interpretation objectives without requiring structural modifications. Furthermore, to overcome the scarcity of labeled data for complex subsurface features, we propose an integrated generative augmentation strategy. By employing the flow matching setting, the framework can synthesize diverse and geologically realistic training pairs, specifically targeting structurally complex. Experimental results demonstrate that the proposed approach, coupled with generative augmentation, delivers high-quality, task-specific interpretations with stable and reproducible inference behavior. Ultimately, this approach provides a scalable, flexible, and robust alternative to single-task deep learning based seismic interpretation models. △ Less

Submitted 13 April, 2026; originally announced April 2026.

Strong-field ionization of atoms with bright squeezed vacuum light

Authors: Haodong Liu, Xiaoxiao Long, Peizeng Li, Zijian Lyu, Yunquan Liu

Abstract: Strong-field ionization is the cornerstone of attosecond physics, which has been extensively studied under coherent-state driving. Recently, the interface between attosecond physics and quantum optics has emerged as a new frontier. Yet, owing to experimental limitations, the role of the quantum nature of light in atomic strong-field ionization has remained unexplored. Here, we demonstrate strong-f… ▽ More Strong-field ionization is the cornerstone of attosecond physics, which has been extensively studied under coherent-state driving. Recently, the interface between attosecond physics and quantum optics has emerged as a new frontier. Yet, owing to experimental limitations, the role of the quantum nature of light in atomic strong-field ionization has remained unexplored. Here, we demonstrate strong-field ionization of xenon atoms driven by bright squeezed vacuum (BSV) with average pulse energy up to 10 \textmu J. We show that, as a nonclassical state with zero mean field and strong intensity fluctuations, BSV selectively enhances the spider-like holographic structures in the photoelectron momentum distributions. Using a quantum-light-corrected quantum-trajectory Monte Carlo (q-QTMC) model, we attribute this effect to the intrinsic coherence of trajectory pairs emitted within the same subcycle field fluctuation. These dynamically correlated paths exhibit enhanced phase stability and remain robust against dephasing, whereas asynchronous paths are filtered out by field noise. Our results reveal a quantum-fluctuation-induced mechanism for coherence protection in strong-field processes, positioning BSV as an effective coherence filter and establishing a new regime of quantum-enabled noise-resilient ultrafast dynamics. △ Less

Submitted 8 April, 2026; originally announced April 2026.

Sparsely repeated 21.7 Tb/s Net-Rate Transoceanic Transmission with 266 km Ultra-Long Spans Enabled by Low IMI and Low loss Hollow Core Fiber

Authors: Rajiv Boddeda, Carina Castineiras Carrero, Haïk Mardoyan, Amirhossein Ghazisaeidi, Peng Li, Shuhai Li, Lei Zhang, Jie Luo, Jérémie Renaudier

Abstract: We demonstrate 21.7-Tb/s net-rate transmission across 6660-km with 266-km ultra-long spans of HCF. By exploiting a newly designed GTA-ST-HCF, high-power booster, and adaptive channel rates, we realize WDM transoceanic transmission with fewer than 30 repeaters. We demonstrate 21.7-Tb/s net-rate transmission across 6660-km with 266-km ultra-long spans of HCF. By exploiting a newly designed GTA-ST-HCF, high-power booster, and adaptive channel rates, we realize WDM transoceanic transmission with fewer than 30 repeaters. △ Less

Submitted 6 April, 2026; originally announced April 2026.

Journal ref: Optical Fiber Communication Conference (OFC) 2026, Technical Digest Series (Optica Publishing Group, 2026), paper TH4B.7

High-Resolution Coherent DFS Over 20km Ultra-Low-Loss Anti-Resonant Hollow-Core Fiber with Live Traffic

Authors: Rajiv Boddeda, Arnaud Dupas, Haïk Mardoyan, Christian Dorize, Fabien Boitier, Peng Li, Zhang Lei, Jie Luo, Pierre Brochard, Carina Castineiras, Jelena Pesic, Florian Pulka, Jérémie Renaudier

Abstract: We demonstrate sub-meter resolution Coherent DFS and detect acoustic oscillations using a stabilized laser on 20 km of anti-resonant HCF with <0.10 dB/km loss without impacting live traffic of 1.2 Tbps on the adjacent channel. We demonstrate sub-meter resolution Coherent DFS and detect acoustic oscillations using a stabilized laser on 20 km of anti-resonant HCF with <0.10 dB/km loss without impacting live traffic of 1.2 Tbps on the adjacent channel. △ Less

Submitted 6 April, 2026; originally announced April 2026.

Journal ref: Optical Fiber Communication Conference (OFC) Postdeadline Papers 2025, Postdeadline Paper Digest (Optica Publishing Group, 2025), paper Th4C.6

Self-scaling tensor basis neural network for Reynolds stress modeling of wall-bounded turbulence

Authors: Zelong Yuan, Yuzhu Pearl Li

Abstract: Recent advances in data-driven turbulence modeling have established tensor basis neural networks (TBNN) as a physically grounded framework for Reynolds-stress closure in Reynolds-averaged Navier-Stokes (RANS) simulations. However, their robustness in wall-bounded turbulent flows remains limited across Reynolds numbers and geometries due to the lack of an intrinsic scaling mechanism. In this work,… ▽ More Recent advances in data-driven turbulence modeling have established tensor basis neural networks (TBNN) as a physically grounded framework for Reynolds-stress closure in Reynolds-averaged Navier-Stokes (RANS) simulations. However, their robustness in wall-bounded turbulent flows remains limited across Reynolds numbers and geometries due to the lack of an intrinsic scaling mechanism. In this work, we propose a self-scaling tensor basis neural network (STBNN) for Reynolds-stress modeling of wall-bounded turbulence. The model incorporates an invariant velocity-gradient normalization derived from the first two invariants of the velocity-gradient tensor, providing an intrinsic and geometry-independent scale that balances strain and rotation effects without relying on empirical coefficients or wall-distance inputs. Owing to its frame-indifferent formulation, the approach preserves Galilean and rotational invariance while maintaining a physically interpretable representation of Reynolds-stress anisotropy. STBNN is evaluated through a priori and a posteriori studies using direct numerical simulation (DNS) data of canonical wall-bounded flows, including plane channel and periodic hill flows. In a priori tests, the model accurately reproduces Reynolds-stress anisotropy, with correlation coefficients exceeding 99% and relative errors below 10%, while capturing near-wall scaling and logarithmic-layer behavior. In a posteriori RANS simulations, STBNN predicts mean velocity profiles in close agreement with DNS and improves prediction of separation and reattachment compared with linear and quadratic eddy-viscosity models and the baseline TBNN. Notably, a model trained at low Reynolds numbers generalizes to higher Reynolds numbers and unseen geometries. These results demonstrate the effectiveness of the proposed framework for data-driven Reynolds-stress modeling in wall-bounded turbulent flows. △ Less

Submitted 10 April, 2026; v1 submitted 31 March, 2026; originally announced March 2026.

Comments: 35 pages, 15 figures, 6 tables

Near-Field Coupling of Polypropylene Dielectric Waveguide Routed Near PCB Board at Terahertz Frequencies

Authors: Wenbo Liu, Jiabiao Zhao, Kefeng Huang, Peian Li, Boquan Xu, Yang Cao, Weidong Hu, Jianjun Ma

Abstract: The growing demand for high-capacity, low-loss short-reach links in highly integrated electronic systems makes it necessary to understand how terahertz (THz) dielectric waveguides behave in realistic PCB-level packaging environments. In this article, we investigate the channel transmission of a 3D-printed polypropylene dielectric waveguide placed near representative PCB substrates. Continuous-wave… ▽ More The growing demand for high-capacity, low-loss short-reach links in highly integrated electronic systems makes it necessary to understand how terahertz (THz) dielectric waveguides behave in realistic PCB-level packaging environments. In this article, we investigate the channel transmission of a 3D-printed polypropylene dielectric waveguide placed near representative PCB substrates. Continuous-wave THz measurements are carried out for bare, fully copper-clad, and periodic copper-trTerahertz (THz) dielectric waveguides are promising physical channels for short-reach interconnects, but their air-clad guided fields may interact with nearby printed-circuit-board (PCB) structures in compact packages. In this work, we experimentally and numerically investigate PCB-proximity-induced excess transmission loss in 3D-printed polypropylene rectangular dielectric waveguides over 220-325 GHz. Continuous-wave transmission measurements are performed for bare FR4, continuous waveguide-facing copper, and periodic copper-trace PCB configurations under controlled clearance and alignment conditions. The results show that direct contact with bare FR4 can induce a frequency-selective high-loss band, which is attributed to phase-matched leakage from the guided waveguide mode into a substrate-supported leaky branch. This finding highlights PCB proximity as a critical layout factor and provides practical guidance for clearance control and metallization design in compact THz dielectric-waveguide packages.ace PCBs with different waveguide-PCB separations, while terahertz time-domain spectroscopy is used to characterize the dielectric properties of the substrate materials. △ Less

Submitted 5 June, 2026; v1 submitted 25 March, 2026; originally announced March 2026.

Comments: Submitted to Nano Communication Networks

Microtearing Thresholds and Second-Stable Ballooning in the DIII-D Pedestal: Reduced Modeling and Core-Edge Implications

Authors: David R. Hatch, Leonhard A. Leppin, Mike T. Kotschenreuther, Saeid Houshmandyar, Swadesh M. Mahajan, Joseph Schmidt, Ping-Yu Li

Abstract: Global and local linear gyrokinetic simulations of 42 pedestal equilibria from three DIII-D discharges are used to investigate pedestal stability and its impact on pedestal structure and confinement. Microtearing modes (MTMs) and kinetic ballooning modes (KBMs) represent the main ion scale instabilities. For all three discharges, MTMs lie near a stability boundary in the mid-pedestal and exhibit t… ▽ More Global and local linear gyrokinetic simulations of 42 pedestal equilibria from three DIII-D discharges are used to investigate pedestal stability and its impact on pedestal structure and confinement. Microtearing modes (MTMs) and kinetic ballooning modes (KBMs) represent the main ion scale instabilities. For all three discharges, MTMs lie near a stability boundary in the mid-pedestal and exhibit threshold behavior, with growth rates increasing at and beyond pre-ELM pressure gradients. Pedestal MTMs retain conventional signatures but also show enhanced particle transport and partial density-gradient drive, indicating they can constrain pedestal {\it pressure} rather than electron temperature alone. KBMs are typically second-stable in this region due to low magnetic shear and large pressure gradients, though they can become active near the pedestal foot where magnetic shear is higher. These findings suggest MTMs play the role of inter-ELM pressure limit in the mid-pedestal when KBM is second stable. A preliminary quasilinear mixing-length transport model, with properly tuned free parameters, reproduces experimental temperature and density profiles when coupled to ASTRA. When applied to a case with doubled separatrix density, the model predicts reduced pedestal pressure consistent with ITPA H-mode confinement trends, attributable to increased MTM and ETG transport. These results clarify pedestal-limiting mechanisms and establish a physics-based link between separatrix conditions, pedestal structure, and global confinement. This work lays the foundation for new predictive modeling capabilities for core-edge integration in burning plasma regimes. △ Less

Submitted 24 March, 2026; originally announced March 2026.

Modeling Temperature Profiles in the Pedestal of NSTX with Reduced Models

Authors: P. -Y. Li, D. R. Hatch, L. A. Leppin, J. Schmidt, J. F. Parisi, M. Lampert, M. Kotschenreuther, S. M. Mahajan

Abstract: This paper describes new modeling capabilities for predicting H-mode pedestal profiles in spherical tokamaks. Temperature profiles for NSTX discharges 132543 and 132588 are modeled by coupling the \textsc{astra} transport solver with neoclassical transport and gyrokinetic-based reduced models for electron temperature gradient (ETG) and kinetic ballooning mode (KBM) instabilities. A quasi-linear su… ▽ More This paper describes new modeling capabilities for predicting H-mode pedestal profiles in spherical tokamaks. Temperature profiles for NSTX discharges 132543 and 132588 are modeled by coupling the \textsc{astra} transport solver with neoclassical transport and gyrokinetic-based reduced models for electron temperature gradient (ETG) and kinetic ballooning mode (KBM) instabilities. A quasi-linear surrogate model for ion-scale transport is developed using linear \textsc{gene} simulations, requiring only a single free parameter calibrated to one discharge. Time-evolving the temperatures with fixed density yields good agreement with experiments for both discharges. Systematic analysis of the transport mechanisms reveals that neoclassical transport is huge across the entire pedestal region for the ion channel. ETG turbulence is large in the plasma edge and low density gradient region, contributing substantially to the electron channel. However, KBM/MHD-like modes also drive significant transport in both the ion and electron thermal channels, making them essential for accurate pedestal modeling. Further refinements, including explicit $E \times B$ shear suppression and scaled ETG transport, produce quantitative but not qualitative improvements. This work lays the foundation for predictive modeling of future devices. △ Less

Submitted 20 March, 2026; originally announced March 2026.

Design and First Results of COFFEE3: A 55nm HVCMOS Pixel Sensor Prototype for High-Energy Physics Applications

Authors: Xiaomin Wei, Zijun Xu, Weiguo Lu, Yang Zhou, Zhan Shi, Leyi Li, Xiaoxu Zhang, Pengxu Li, Jianpeng Deng, Yang Chen, Yujie Wang, Zhiyu Xiang, Mei Zhao, Cheng Zeng, Mengke Cai, Boxin Wang, Yuman Cai, Bingchen Yan, Anqi Wang, Yu Zhao, Zexuan Zhao, Zheng Wei, Huimin Wu, Ruiguang Zhao, Hongbo Zhu , et al. (3 additional authors not shown)

Abstract: Motivated by the stringent requirements of the Upstream Pixel (UP) tracker in the LHCb Upgrade II and the Inner Tracking detector (ITK) of the Circular Electron Positron Collider, the COFFEE series of pixel sensor chips have been developed using a 55nm High-Voltage CMOS (HVCMOS) process. The primary objective is to achieve a time resolution of a few nanoseconds under a hit density of up to 100 MHz… ▽ More Motivated by the stringent requirements of the Upstream Pixel (UP) tracker in the LHCb Upgrade II and the Inner Tracking detector (ITK) of the Circular Electron Positron Collider, the COFFEE series of pixel sensor chips have been developed using a 55nm High-Voltage CMOS (HVCMOS) process. The primary objective is to achieve a time resolution of a few nanoseconds under a hit density of up to 100 MHz/cm$^2$, while maintaining fine spatial resolution ($\sim$10 $μ$m) and reasonable power consumption ($<$200 mW/cm$^2$). Building on the process validation of the COFFEE2 prototype, this work presents the design and preliminary test results of COFFEE3-a prototype integrating two distinct readout architectures. Architecture 1, tailored for the current triple-well process, adopts NMOS-only in-pixel circuitry and innovative column-level readout to handle high hit densities. The time walk of pixel-level signal is controlled within 10 ns, and the Time of Arrival (TOA) and Time over Threshold (TOT) are measured with a system clock with the period of 25 ns in peripheral circuits. Architecture 2, developed for future possible processes with p-type buried layer isolation, features pixel-level time measurement and storage. A chip-level Time-to-Digital Converter (TDC) is used and the part of Voltage-Controlled Delay Line (VCDL) is copied in each pixel to get a high time resolution. The TOA resolution is estimated to be 4.2 ns and the TOT resolution 8.4 ns. COFFEE3, with a layout size of 3$\times$4 mm$^2$, was manufactured and has undergone preliminary tests. Charge injection tests for analog circuits, and laser tests for full readout chains, confirm that both architectures operate as expected. Next step work will focus on characterizing key performance such as the timing resolution, radiation hardness, and tracking performance of minimum ionising particles. △ Less

Submitted 18 March, 2026; originally announced March 2026.

Time-resolving the birth of photoelectrons in strong-filed ionization with an isolated attosecond pulse

Authors: Kunlong Liu, Yidian Tian, Pengcheng Li

Abstract: To time-resolve attosecond electronic dynamics in general photoionization processes, the technique that retrieves the phase of emitted electronic wave packets without intercepting the interactions is essential. Here, we theoretically demonstrate a scheme that uses isolated attosecond pulses (IAPs) to achieve this goal. Our approach utilizes the coherent interference between the electronic wave pac… ▽ More To time-resolve attosecond electronic dynamics in general photoionization processes, the technique that retrieves the phase of emitted electronic wave packets without intercepting the interactions is essential. Here, we theoretically demonstrate a scheme that uses isolated attosecond pulses (IAPs) to achieve this goal. Our approach utilizes the coherent interference between the electronic wave packets of interest and the one produced by a subsequent IAP. It is shown that the photoelectron spectral phase that has eluded direct detection so far can be fully recovered from observable photoelectron spectra without perturbing the electron-release process under investigation. By further performing a time-frequency-like analysis on the photoelectron energy spectra with the spectral phase, we reveal the birth processes of photoelectrons in time and the association between electronic energy and birth time in strong-field ionization driven by circularly polarized laser pulses. The present work explores a promising application of IAPs for ultrafast measurement and opens a viable venue for investigating electronic dynamics with quantum phase information. △ Less

Submitted 24 April, 2026; v1 submitted 17 March, 2026; originally announced March 2026.

Comments: 9 pages, 6 figures

Quantitative 3D imaging of highly distorted micro-crystals using Bragg ptychography

Authors: Peng Li, David Yang, Christoph Rau, Marc Allain, Felix Hofmann, Virginie Chamard

Abstract: Bragg coherent diffraction imaging (BCDI) fails to reliably retrieve phases in micro-crystals exhibiting strong strain inhomogeneities, which restricts its applicability. Here we show that three-dimensional Bragg ptychography (3DBP) overcomes this limitation by enabling stable inversion for large lattice distortions. Using a combination of experimental measurements and numerical tests, we compare… ▽ More Bragg coherent diffraction imaging (BCDI) fails to reliably retrieve phases in micro-crystals exhibiting strong strain inhomogeneities, which restricts its applicability. Here we show that three-dimensional Bragg ptychography (3DBP) overcomes this limitation by enabling stable inversion for large lattice distortions. Using a combination of experimental measurements and numerical tests, we compare the performance limits of the two approaches and demonstrate that 3DBP tolerates lattice distortions more than six times larger than BCDI. We also establish the sensitivity of both methods on a weakly distorted crystal, for which 3DBP yields smoother amplitude and phase fields with reduced short-length-scale artifacts. 3DBP thus provides a reliable route for imaging micro-crystals with large lattice distortions, expanding the scope of coherent X-ray Bragg microscopy to strongly deformed systems. △ Less

Submitted 12 March, 2026; originally announced March 2026.

Comments: 4 figures

Experimental characterisation of a combined LVDT position sensor and voice-coil actuator for gravitational wave detectors

Authors: K. A. Kukkadapu, P. Li, H. Van Haevermaet, A. N. Koushik, W. Beaumont, N. van Remortel

Abstract: A detailed characterisation of a combined Linear Variable Differential Transformer (LVDT) position sensor and voice-coil (VC) actuator designed for seismic isolation systems in gravitational wave detectors is presented. A dedicated experimental setup and a finite-element simulation framework were developed to measure and model a representative Einstein Telescope pathfinder Type-A LVDT+VC assembly.… ▽ More A detailed characterisation of a combined Linear Variable Differential Transformer (LVDT) position sensor and voice-coil (VC) actuator designed for seismic isolation systems in gravitational wave detectors is presented. A dedicated experimental setup and a finite-element simulation framework were developed to measure and model a representative Einstein Telescope pathfinder Type-A LVDT+VC assembly. The setup employs a precision translation stage and balance to quantify LVDT displacement response and VC force output under controlled conditions. We found a good agreement between experiment and simulation: the measured LVDT response was determined with an uncertainty of 0.5% and differed by only 1.3% from the model prediction, demonstrating high linearity over a $\pm$5~mm range. In addition, the VC force measurements agreed within the total uncertainty: the maximum normalised force was determined with a precision of 2.3% and matched the simulated value with only 0.6% discrepancy. These results validate the combined sensor-actuator design and our measurement methodology. The demonstrated linear response and stable actuation confirm that this LVDT+VC device can be used for low-frequency suspension control. Our framework therefore provides a validated tool to optimise existing sensor and actuator designs, and to study novel prototypes for next-generation gravitational wave detectors. △ Less

Submitted 13 June, 2026; v1 submitted 6 March, 2026; originally announced March 2026.

Measurement and Modeling of Structure-Induced Surface Scattering on Terahertz Channel

Authors: Peian Li, Yapeng Ge, Jiacheng Liu, Wenbo Liu, Jiayuan Cui, Jiabiao Zhao, Qiang Niu, Yuping Yang, Xiangzhu Meng, Yiming Zhao, Jianjun Ma

Abstract: As terahertz (THz) frequencies emerge as promising candidates for next-generation wireless networks, accurate characterization of propagation mechanisms in indoor/outdoor environments becomes essential for system design and performance optimization. This article presents an experimental and theoretical investigation of structure-induced indoor surface scattering on THz channels, examining how mate… ▽ More As terahertz (THz) frequencies emerge as promising candidates for next-generation wireless networks, accurate characterization of propagation mechanisms in indoor/outdoor environments becomes essential for system design and performance optimization. This article presents an experimental and theoretical investigation of structure-induced indoor surface scattering on THz channels, examining how material properties and structural configurations jointly govern channel power and angular distribution. Six representative indoor surfaces are characterized, revealing that intrinsic structural inhomogeneity -- particularly the quasi-periodic earlywood-latewood arrangement in pine wood -- induces measurable angular scattering whose dominant lobes and angular shifts are reproduced by a beam-propagation modeling (BPM) framework. Material-covered surface configurations are further investigated, demonstrating that thin dielectric covering layers can substantially modify reflection characteristics through thickness- and frequency- dependent thin-film interference effects. Wide-angle bistatic measurements conducted in a conference-room environment reveal that structured indoor elements, such as folded curtains, can enhance angular scattering and extend spatial coverage. These findings establish that structure-induced surface scattering mechanisms offer potential for constructing non-line-of-sight THz links in indoor environments. △ Less

Submitted 27 February, 2026; originally announced February 2026.

Comments: Submitted to IEEE Transactions on Antenna and Propagation

Flat-top solitons and anomalous interactions in media with even-order dispersions and competing nonlinearities

Authors: Xueqing He, Shijie Hao, Lijing Xing, Dumitru Mihalache, Boris A. Malomed, Pengfei Li

Abstract: Flat-top (FT) solitons are optical pulses that arise from the balance of dispersion and self-phase modulation in media with the competing cubic-quintic nonlinearity. Previously, FT solitons were studied only in the case of the second-order dispersion ($m=2$). Following the recent observation of pure-quartic solitons (corresponding to $m=4$), we here construct families of FT solitons in the setting… ▽ More Flat-top (FT) solitons are optical pulses that arise from the balance of dispersion and self-phase modulation in media with the competing cubic-quintic nonlinearity. Previously, FT solitons were studied only in the case of the second-order dispersion ($m=2$). Following the recent observation of pure-quartic solitons (corresponding to $m=4$), we here construct families of FT solitons in the setting with pure-high-even-order dispersion (PHEOD), including $m=4,6,8$, and $10$, and address interactions between them. The PHEOD solitons are completely stable, and, unlike the conventional solitons, they feature oscillatory tails. Interactions between the PHEOD solitons are anomalous, featuring repulsion and attraction between in- and out-of-phase solitons, respectively. These results expand the variety of optical solitons maintained by diverse dispersive nonlinear media. △ Less

Submitted 17 February, 2026; originally announced February 2026.

Comments: 5 pages, 4 figures, to be published in Optics Letters

Nonlinear quadrupole topological insulators

Authors: Rujiang Li, Wencai Wang, Yongtao Jia, Ying Liu, Pengfei Li, Boris A. Malomed

Abstract: Higher-order topological insulators (HOTIs) represent a family of topological phases that go beyond the conventional bulkboundary correspondence. d-dimensional n-th order HOTIs maintain (d - n)-dimensional gapless boundary states (in particular, zero-dimensional corner states in the case of d = n = 2). HOTIs of the Wannier type cam be extended into the nonlinear regime. Another prominent class of… ▽ More Higher-order topological insulators (HOTIs) represent a family of topological phases that go beyond the conventional bulkboundary correspondence. d-dimensional n-th order HOTIs maintain (d - n)-dimensional gapless boundary states (in particular, zero-dimensional corner states in the case of d = n = 2). HOTIs of the Wannier type cam be extended into the nonlinear regime. Another prominent class of HOTIs, in the form of multipole insulators, was investigated only in the linear regime, due to the challenge of simultaneously achieving both negative hopping and strong nonlinearity. Here we propose the concept of nonlinear quadrupole topological insulators (NLQTIs) and report their experimental realization in an electric circuit lattice. Quench-initiated dynamics gives rise to nonlinear topological corner states and topologically trivial corner solitons, in weakly and strongly nonlinear regimes, respectively. Furthermore, we reveal the formation of two distinct types of bulk solitons, one existing in the middle finite gap under the action of weak nonlinearity, and another one found in the semi-infinite gap under strong nonlinearity. This work realizes another member of the nonlinear HOTI family, suggesting directions for exploring novel solitons across a broad range of topological insulators. △ Less

Submitted 6 February, 2026; originally announced February 2026.

Comments: to be published in Chaos, Solitons & Fractals

Scalable Spatio-Temporal SE(3) Diffusion for Long-Horizon Protein Dynamics

Authors: Nima Shoghi, Yuxuan Liu, Yuning Shen, Rob Brekelmans, Pan Li, Quanquan Gu

Abstract: Molecular dynamics (MD) simulations remain the gold standard for studying protein dynamics, but their computational cost limits access to biologically relevant timescales. Recent generative models have shown promise in accelerating simulations, yet they struggle with long-horizon generation due to architectural constraints, error accumulation, and inadequate modeling of spatio-temporal dynamics. W… ▽ More Molecular dynamics (MD) simulations remain the gold standard for studying protein dynamics, but their computational cost limits access to biologically relevant timescales. Recent generative models have shown promise in accelerating simulations, yet they struggle with long-horizon generation due to architectural constraints, error accumulation, and inadequate modeling of spatio-temporal dynamics. We present STAR-MD (Spatio-Temporal Autoregressive Rollout for Molecular Dynamics), a scalable SE(3)-equivariant diffusion model that generates physically plausible protein trajectories over microsecond timescales. Our key innovation is a causal diffusion transformer with joint spatio-temporal attention that efficiently captures complex space-time dependencies while avoiding the memory bottlenecks of existing methods. On the standard ATLAS benchmark, STAR-MD achieves state-of-the-art performance across all metrics--substantially improving conformational coverage, structural validity, and dynamic fidelity compared to previous methods. STAR-MD successfully extrapolates to generate stable microsecond-scale trajectories where baseline methods fail catastrophically, maintaining high structural quality throughout the extended rollout. Our comprehensive evaluation reveals severe limitations in current models for long-horizon generation, while demonstrating that STAR-MD's joint spatio-temporal modeling enables robust dynamics simulation at biologically relevant timescales, paving the way for accelerated exploration of protein function. △ Less

Submitted 11 February, 2026; v1 submitted 2 February, 2026; originally announced February 2026.

Comments: 49 pages, 28 figures. Accepted by ICLR 2026. Project page: https://bytedance-seed.github.io/ConfRover/starmd

Inter-detector differential fuzz testing for tamper detection in gamma spectrometers

Authors: Pei Yao Li, Jayson R. Vavrek, Sean Peisert

Abstract: We extend physical differential fuzz testing as an anti-tamper method for radiation detectors [Vavrek et al., Science and Global Security 2025] to comparisons across multiple detector units. The method was previously introduced as a tamper detection method for authenticating a single radiation detector in nuclear safeguards and treaty verification scenarios, and works by randomly sampling detector… ▽ More We extend physical differential fuzz testing as an anti-tamper method for radiation detectors [Vavrek et al., Science and Global Security 2025] to comparisons across multiple detector units. The method was previously introduced as a tamper detection method for authenticating a single radiation detector in nuclear safeguards and treaty verification scenarios, and works by randomly sampling detector configuration parameters to produce a sequence of spectra that form a baseline signature of an untampered system. At a later date, after potential tampering, the same random sequence of parameters is used to generate another series of spectra that can be compared against the baseline. Anomalies in the series of comparisons indicate changes in detector behavior, which may be due to tampering. One limitation of this original method is that once the detector has `gone downrange' and may have been tampered with, the original baseline is fixed, and a new trusted baseline can never be established if tests at new parameters are required. In this work, we extend our anti-tamper fuzz testing concept to multiple detector units, such that the downrange detector can be compared against a trusted or `golden copy' detector, even despite normal inter-detector manufacturing variations. We show using three NaI detectors that this inter-detector differential fuzz testing can detect a representative attack, even when the tested and golden copy detectors are from different manufacturers and have different performances. Here, detecting tampering requires visualizing the comparison metric vs. the parameter values and not just the sample number; moreover this baseline is non-linear and may require anomaly detection methods more complex than a simple threshold. Overall, this extension to multiple detectors improves prospects for operationalizing the technique in real-world treaty verification and safeguards contexts. △ Less

Submitted 30 January, 2026; originally announced February 2026.

Comments: 7 pages, 6 figures, 2 tables

Frequency-domain general synthetic iterative scheme for efficient simulation of oscillatory rarefied gas flows

Authors: Pengshuo Li, Lei Wu

Abstract: Oscillatory rarefied gas flows are frequently encountered in MEMS, and their efficient numerical simulation remains a major challenge due to the time dependent nature of the problem and the high dimensionality of the Boltzmann kinetic equation. Here, we address this challenge by focusing on the periodic steady state and solving the resulting problem using the frequency domain general synthetic ite… ▽ More Oscillatory rarefied gas flows are frequently encountered in MEMS, and their efficient numerical simulation remains a major challenge due to the time dependent nature of the problem and the high dimensionality of the Boltzmann kinetic equation. Here, we address this challenge by focusing on the periodic steady state and solving the resulting problem using the frequency domain general synthetic iterative scheme (GSIS). The key idea of GSIS is to simultaneously solve the mesoscopic kinetic equation and the macroscopic synthetic equation. The kinetic equation provides high-order constitutive relations, beyond those given by the Newton law of viscosity and the Fourier law of heat conduction, to the synthetic equation. In turn, the synthetic equation, which converges to the periodic steady state much faster than the kinetic equation, boosts the evolution of the kinetic equation toward the periodic steady state. As a result, super convergence is achieved, together with an asymptotic preserving property that allows the use of coarse spatial grids. The analytical Fourier stability analysis and the Chapman-Enskog expansion, together with challenging numerical simulations, are employed to demonstrate the fast convergence and asymptotic-preserving properties of GSIS, revealing that it can be three orders of magnitude faster than conventional kinetic schemes in near continuum flow regimes. △ Less

Submitted 24 January, 2026; originally announced January 2026.

Exceptional Alkaline Methanol Electrooxidation on Bi-modified Pt3M Intermetallics: Kinetic Origins and an OH Binding Energy Descriptor

Authors: Lecheng Liang, Hengyu Li, Shao Ye, Peng Li, Kaiyang Xu, Jinhui Liang, Binwen Zeng, Bo Shen, Taisuke Ozaki, Zhiming Cui

Abstract: The exploration of advanced CO-free catalysts and clarifying the ambiguous kinetic origins and governing factors would undoubtedly open up opportunities to overcome the sluggish kinetics of methanol electrooxidation and promote the development of direct methanol fuel cells. Herein, we constructed a family of Bi-modified Pt3M intermetallic catalysts (Bi-Pt3M/C, M=Cr, Mn, Co, Zn, In, Ga, and Sn) tha… ▽ More The exploration of advanced CO-free catalysts and clarifying the ambiguous kinetic origins and governing factors would undoubtedly open up opportunities to overcome the sluggish kinetics of methanol electrooxidation and promote the development of direct methanol fuel cells. Herein, we constructed a family of Bi-modified Pt3M intermetallic catalysts (Bi-Pt3M/C, M=Cr, Mn, Co, Zn, In, Ga, and Sn) that follow CO-free dominated pathway and exhibit exceptional catalytic activity. More significantly, leveraging this platform, we have identified the pivotal factor governing the reaction kinetics in CO-free pathway, namely OH binding energy (OHBE). This arises because the rate-determining step (RDS) encompasses both C-H bond activation and water dissociation, whose respective barriers can be reflected by the OHBE. Accordingly, OHBE can act as an activity descriptor. Specifically, Bi-Pt3In/C stands out from other Bi-Pt3M/C and delivers the unprecedented mass activity of 36.7 A mgPt-1 at peak potential, far exceeding state-of-the-art Pt-based catalysts reported to date. Taking Bi-Pt3In/C as a proof of concept, we clearly elucidate the origin of enhanced MOR activity by combining theoretical calculations, kinetic isotope effects, and formaldehyde electrooxidation. Moreover, there exhibits a volcano-type trend between OHBE and the activity of Bi-Pt3M/C. Beyond the discovery of ultrahigh-performance catalysts, these findings provide a detailed mechanistic picture of RDS and offer an innovative design principle for advanced catalysts. △ Less

Submitted 12 December, 2025; originally announced December 2025.

Midinfrared Semiconductor Photonics - A Roadmap

Authors: J. R. Meyer, I. Vurgaftman, S. -Q. Yu, R. Q. Yang, A. M. Andrews, G. Strasser, B. Schwarz, M. Razeghi, L. Shterengas, G. Kipshidze, G. Belenky, L. Sterczewski, W. Zhou, S. Lee, M. Pan, R. Szedlak, N. Schäfer, J. Koeth, R. Weih, A. Rogalski, A. Piotrowski, J. Sobieski, P. Leszcz, J. Piotrowski, M. R. Mirzaei , et al. (34 additional authors not shown)

Abstract: Semiconductor photonic devices operating in the midwave infrared (mid-IR, which we roughly define here as wavelengths spanning 3 to 14 microns) uniquely address a wide range of current practical needs. These include chemical sensing, environmental monitoring, industrial process control, medical diagnostics, thermal imaging, LIDAR, free space optical communication, and security monitoring. However,… ▽ More Semiconductor photonic devices operating in the midwave infrared (mid-IR, which we roughly define here as wavelengths spanning 3 to 14 microns) uniquely address a wide range of current practical needs. These include chemical sensing, environmental monitoring, industrial process control, medical diagnostics, thermal imaging, LIDAR, free space optical communication, and security monitoring. However, mid-IR device technologies are currently still works in progress that are generally much less mature than their near infrared and visible counterparts. Not only are most of the relevant materials more difficult to grow and process, but attainment of the desired optical device performance is often fundamentally more challenging. This Roadmap will review the leading applications for mid-IR optoelectronics, summarize the status and deficiencies of current device technologies, and then suggest possible roadmaps for improving and maturing the performance, manufacturability, and cost of each device type so the critical needs that are uniquely addressed by mid-IR photonics can be satisfied. △ Less

Submitted 5 November, 2025; originally announced November 2025.

Comments: Submitted to Advances in Optics and Photonics

Demonstration of on-chip all-optical switching of magnetization in integrated photonics

Authors: Pingzhi Li, Gijs W. A. Simons, Tianyu Zhang, Philip P. J. Schrinner, Sohrab Kamyar, Ronald Dekker, Diana C. Leitao, Reinoud Lavrijsen, Yuqing Jiao, Bert Koopmans

Abstract: Ultrafast all-optical magnetization switching (AOS) holds great promise for nextgeneration spintronic memory and hybrid spintronic-photonic systems. However, most implementations to date rely on bulky free-space optical setups, limiting scalability and practical integration. As a critical step toward integrated applications, we demonstrate single-pulse AOS within a silicon nitride (Si3N4) photonic… ▽ More Ultrafast all-optical magnetization switching (AOS) holds great promise for nextgeneration spintronic memory and hybrid spintronic-photonic systems. However, most implementations to date rely on bulky free-space optical setups, limiting scalability and practical integration. As a critical step toward integrated applications, we demonstrate single-pulse AOS within a silicon nitride (Si3N4) photonic integrated circuit. Using trains of femtosecond laser pulses guided through on-chip waveguides, we achieve deterministic toggle switching in a sub-micron out-of-plane Co/Gd Hall cross patterned directly atop the photonic waveguide. Electrical readout via the anomalous Hall effect reveals a switching contrast of up to 90% for 500 nm-wide devices. In larger Hall crosses, the contrast decreases and switching becomes stochastic, consistent with spatially non-uniform optical absorption as confirmed by finite-element simulations. This behavior is hypothetically attributed to domain wall relaxation and thermally assisted (de)pinning processes within partially switched regions. Our results highlight the critical role of device scaling in achieving robust on-chip AOS and establish a foundation for ultrafast, energy-efficient, and fully integrated spintronic-photonic platforms. △ Less

Submitted 4 November, 2025; originally announced November 2025.

Comments: 13 pages, 3 figures, 4 supplementary information appendices

MuCol Milestone Report No. 7: Consolidated Parameters

Authors: Rebecca Taylor, Antoine Chancé, Dario Augusto Giove, Natalia Milas, Roberto Losito, Donatella Lucchesi, Chris Rogers, Lucio Rossi, Daniel Schulte, Carlotta Accettura, Simon Adrian, Rohit Agarwal, Claudia Ahdida, Chiara Aime, Avni Aksoy, Gian Luigi Alberghi, Simon Albright, Siobhan Alden, Luca Alfonso, Muhammad Ali, Anna Rita Altamura, Nicola Amapane, Kathleen Amm, David Amorim, Paolo Andreetto , et al. (437 additional authors not shown)

Abstract: This document is comprised of a collection of consolidated parameters for the key parts of the muon collider. These consolidated parameters follow on from the October 2024 Preliminary Parameters Report. Attention has been given to a high-level consistent set of baseline parameters throughout all systems of the complex, following a 10 TeV center-of-mass design. Additional details of the designs con… ▽ More This document is comprised of a collection of consolidated parameters for the key parts of the muon collider. These consolidated parameters follow on from the October 2024 Preliminary Parameters Report. Attention has been given to a high-level consistent set of baseline parameters throughout all systems of the complex, following a 10 TeV center-of-mass design. Additional details of the designs contributing to this baseline design are featured in the appendix. Likewise, explorative variations from this baseline set can be found in the appendix. The data is collected from a collaborative spreadsheet and transferred to overleaf. △ Less

Submitted 31 October, 2025; originally announced October 2025.

Wideband Low-Scattering Dual-Polarized Phased Array with Stepped Ground

Authors: Yu Luo, Shi-Gang Fang, Peng-Fa Li, Yuhao Feng, Shi-Wei Qu, Shiwen Yang

Abstract: This paper proposes a wideband dual-polarized phased array with ultra-wideband scattering cross section (SCS) reduction. The antenna elements are loaded on a bilateral stepped ground. This ground is carefully designed in terms of height difference, step number, and length to achieve phase cancellation near the normal direction. Wideband dipoles with vertical electric coupling are designed. The rad… ▽ More This paper proposes a wideband dual-polarized phased array with ultra-wideband scattering cross section (SCS) reduction. The antenna elements are loaded on a bilateral stepped ground. This ground is carefully designed in terms of height difference, step number, and length to achieve phase cancellation near the normal direction. Wideband dipoles with vertical electric coupling are designed. The radiation frequency band covers the X-band (40%) under VSWR < 2.8. Array patterns are synthesized with the two subarrays, covering the scanning range from -45 to +45 degrees. The monostatic SCSs of the proposed 17 x 8 array prototype have been reduced within 3.6 - 30 GHz, with an averaged reduction of over 19.4/18.9 dB and an averaged in-band reduction of over 15.4/16.6 dB, under the normal x/y polarized incident waves respectively. △ Less

Submitted 17 October, 2025; originally announced October 2025.

Journal ref: IEEE Transactions on Antennas and Propagation (2025) 1-6

Experimental Characterization and Dynamic Modeling of THz Channels Under Fog Conditions

Authors: Jiaobiao Zhao, Kefeng Huang, Xiaoxiang Li, Mingxia Zhang, Peian Li, Jie Yang, Wenbo Liu, Yiming Zhao, Weidong Hu, Jianjun Ma

Abstract: The terahertz (THz) band is a promising candidate for sixth-generation wireless networks, but its deploymen in outdoor environments is challenged by meteorological phenomena, particularly fog, which imposes variable and difficult-to-predict channel degradation. This article introduces dynamic channel model for the THz band explicitly driven by the time-evolving droplet size distribution (DSD) of f… ▽ More The terahertz (THz) band is a promising candidate for sixth-generation wireless networks, but its deploymen in outdoor environments is challenged by meteorological phenomena, particularly fog, which imposes variable and difficult-to-predict channel degradation. This article introduces dynamic channel model for the THz band explicitly driven by the time-evolving droplet size distribution (DSD) of fog, integrating real-time microphysical sensing to capture variations in the fog microstructure. Experimental measurements were conducted at 220 GHz and 320 GHz in a controlled fog chamber to achieve quasi-stationary states, and a larger room-scale setup to characterize dynamic, non-stationary fog evolution. The results confirm that channel power loss is overwhelmingly dominated by absorption rather than scattering, validating the use of the computationally efficient Rayleigh approximation below 1 THz. Statistical analysis revealed exceptionally high Rician K-factors, demonstrating that THz channels maintain strong line-of-sight stability even in dense fog. System-level performance analysis shows that degradation in bit error rate is driven by the slow, gradual evolution of the DSD, rather than fast multipath fading. This finding enables the reliable simplification of the THz fog channel into a near-Gaussian channel model with time-varying signal-to-noise ratio. This microphysics-aware approach established here provides the necessary foundation for developing adaptive system designs centered on SNR tracking for robust future THz networks. △ Less

Submitted 10 October, 2025; originally announced October 2025.

Comments: Submitting to IEEE Transactions on Terahertz Science and Technology

Twisted bi-layer magnetic photonic crystals

Authors: You-Ming Liu, Shi-Kai Lin, Pei-Shi Li, Yi-Ran Hao, Biao Yang

Abstract: In photonics, twisted bi-layer systems have demonstrated unprecedented control over light-matter interactions, primarily through the modulation of photonic band structures and the formation of Moiré patterns. Meanwhile, magnetic photonic crystals have served as cornerstone platforms for manipulating light propagation, facilitating key applications such as Faraday rotation-based isolators and non-r… ▽ More In photonics, twisted bi-layer systems have demonstrated unprecedented control over light-matter interactions, primarily through the modulation of photonic band structures and the formation of Moiré patterns. Meanwhile, magnetic photonic crystals have served as cornerstone platforms for manipulating light propagation, facilitating key applications such as Faraday rotation-based isolators and non-reciprocal devices. Nevertheless, the synergistic integration of twist engineering and magneto-optical effects in bi-layer architectures remains unexplored. This work introduces twisted magnetic bi-layer photonic crystal slabs as a novel platform to unify these degrees of freedom. By continuously tuning the twist angle between two magneto-active photonic layers, the giant circular dichroism is observed, and the transmitted waves can be perfectly linearly polarized and rotated. These effects arise from the interplay between resonant properties of the Moiré cell and magnetization-dependent coupling of circularly polarized states. This work establishes a foundation for magnetic topological photonics, bridging twistronics and magneto-optics to unlock new mechanisms for dynamic light control in compact and reconfigurable devices. △ Less

Submitted 8 October, 2025; originally announced October 2025.

Wave morphing and flat-top ground states in photonics systems driven by artificial gauge fields

Authors: Peishen Li, Xiaoyu Zhang, Feifan Wang, Ye Chen, Xuefan Yin, Chao Peng

Abstract: In quantum physics, classical optics, and many other wave systems, wave confinement in a potential well is associated with discrete oscillatory states, and the ground state is typically assumed to vanish uniformly. An open question is whether the ground state can counterintuitively support a flat-top, nonzero envelope, offering new opportunities for quantum emitters, optical antennas, and lasers.… ▽ More In quantum physics, classical optics, and many other wave systems, wave confinement in a potential well is associated with discrete oscillatory states, and the ground state is typically assumed to vanish uniformly. An open question is whether the ground state can counterintuitively support a flat-top, nonzero envelope, offering new opportunities for quantum emitters, optical antennas, and lasers. Here, we show that by applying the Byers-Yang theorem with an artificial gauge field, energy levels can be continuously shifted, driving eigenstates to morph into a ground state with a uniform yet nontrivial wave envelope. We implement this concept in a photonic crystal slab where a central bulk region is surrounded by heterogeneous bandgaps that engineer reflective phases acting as an artificial local gauge field. By inducing lasing, we probe directly the evolution of the energy levels, demonstrating wave morphing toward a flat-top ground state via near- and far-field measurements. △ Less

Submitted 22 October, 2025; v1 submitted 25 September, 2025; originally announced September 2025.

Fabrication of thin planar radiopure foils with 82Se for the SuperNEMO Demonstrator

Authors: X. Aguerre, A. Barabash, A. Basharina-Freshville, M. Bongrand, Ch. Bourgeois, D. Breton, R. Breier, J. Busto, C. Cerna, J. Cesar, M. Ceschia, E. Chauveau, S. De Capua, D. Duchesneau, J. J. Evans, D. V. Filosofov, M. Granjon, M. Hoballah, R. Hodák, J. Horkley, A. Jeremie, S. Jullian, J. Kaizer, A. A. Klimenko, O. Kochetov , et al. (50 additional authors not shown)

Abstract: The SuperNEMO Demonstrator, designed to search for double beta decay using enriched 82Se, has been assembled in the Modane Underground Laboratory under the French Alps. Thin foils with radio - purified and enriched 82Se are installed centrally in the detector. A novel foil fabrication method has been developed, improving the radiopurity achieved in the previous generation experiment. It consists o… ▽ More The SuperNEMO Demonstrator, designed to search for double beta decay using enriched 82Se, has been assembled in the Modane Underground Laboratory under the French Alps. Thin foils with radio - purified and enriched 82Se are installed centrally in the detector. A novel foil fabrication method has been developed, improving the radiopurity achieved in the previous generation experiment. It consists of wrapping standalone selenium pads in raw Mylar, combined with selenium purified by a new reverse-chromatography method. This paper describes the features of these foils, their fabrication process, the characterization results, and the integration of the foils into the SuperNEMO Demonstrator. △ Less

Submitted 10 September, 2025; originally announced September 2025.

Comments: 20 pages, 11 figures, 7 tables

Low-Cost and Detunable Wireless Resonator Glasses for Enhanced Eye MRI with Concurrent High-Quality Whole Brain MRI

Authors: Ming Lu, Xiaoyue Yang, Jason Moore, Pingping Li, Adam W. Anderson, John C. Gore, Seth A. Smith, Xinqiang Yan

Abstract: Purpose: To develop and evaluate a wearable wireless resonator glasses design that enhances eye MRI signal-to-noise ratio (SNR) without compromising whole-brain image quality at 7 T. Methods: The device integrates two detunable LC loop resonators into a lightweight, 3D-printed frame positioned near the eyes. The resonators passively couple to a standard 2Tx/32Rx head coil without hardware modifi… ▽ More Purpose: To develop and evaluate a wearable wireless resonator glasses design that enhances eye MRI signal-to-noise ratio (SNR) without compromising whole-brain image quality at 7 T. Methods: The device integrates two detunable LC loop resonators into a lightweight, 3D-printed frame positioned near the eyes. The resonators passively couple to a standard 2Tx/32Rx head coil without hardware modifications. Bench tests assessed tuning, isolation, and detuning performance. B1$^+$ maps were measured in a head/shoulder phantom, and SNR maps were obtained in both phantom and in vivo experiments. Results: Bench measurements confirmed accurate tuning, strong inter-element isolation, and effective passive detuning. Phantom B1$^+$ mapping showed negligible differences between configurations with and without the resonators. Phantom and in vivo imaging demonstrated up to about a 3-fold SNR gain in the eye region, with no measurable SNR loss in the brain. Conclusion: The wireless resonator glasses provide a low-cost, easy-to-use solution that improves ocular SNR while preserving whole-brain image quality, enabling both dedicated eye MRI and simultaneous eye-brain imaging at ultrahigh field. △ Less

Submitted 10 September, 2025; originally announced September 2025.

Journal ref: Magn Reson Med. 2026;96(1):499-507

Double Ionization to CO2 Produces Molecular Oxygen: A Roaming Mechanism

Authors: Qibo Ma, Xintai Hao, Jiaqi Zhou, Xiaorui Xue, Qingrui Zeng, Peng Li, Lei Wang, Xueguang Ren

Abstract: We report a combined experimental and theoretical study on the formation of O2+ by electronimpact double ionization and fragmentation of carbon dioxide (CO2) molecule. Through fragment ions and electron coincidence momentum imaging, we determine unambiguously the ionization mechanism by measuring the projectile energy loss in association with the C+ + O2+ channel. Further potential energy and traj… ▽ More We report a combined experimental and theoretical study on the formation of O2+ by electronimpact double ionization and fragmentation of carbon dioxide (CO2) molecule. Through fragment ions and electron coincidence momentum imaging, we determine unambiguously the ionization mechanism by measuring the projectile energy loss in association with the C+ + O2+ channel. Further potential energy and trajectory calculations enable us to elucidate the dynamical details of this fragmentation process, in which a bond rearrangement pathway is found to proceed via the structural deformation to a triangular intermediate. Moreover, we demonstrate a new roaming pathway for formation of O2+ from CO22+, in which a frustrated C-O bond cleavage leaves the O atom without sufficient energy to escape. The O atom then wanders around varied configuration spaces of the flat potential energy regions and forms a C-O-O2+ intermediate prior to the final products C+ + O2+. Considering the large quantities of free electrons in interstellar space, the processes revealed here are expected to be significant and should be incorporated into atmospheric evolution models. △ Less

Submitted 6 September, 2025; originally announced September 2025.

Noise is All You Need: rethinking the value of noise on seismic denoising via diffusion models

Authors: Donglin Zhu, Peiyao Li, Ge Jin

Abstract: We introduce SeisDiff-denoNIA, a diffusion-based seismic denoising framework that trains directly on noise extracted from field data, eliminating the dependence on synthetic datasets. Unlike conventional denoising methods that require clean signal labels, our approach uses field noise recorded as training targets, enabling the diffusion model to explicitly learn the true noise distribution. We fur… ▽ More We introduce SeisDiff-denoNIA, a diffusion-based seismic denoising framework that trains directly on noise extracted from field data, eliminating the dependence on synthetic datasets. Unlike conventional denoising methods that require clean signal labels, our approach uses field noise recorded as training targets, enabling the diffusion model to explicitly learn the true noise distribution. We further demonstrate the framework on a field DAS-VSP survey, where the model effectively suppresses multiple types of noise, including production, instrument, and environment related noise, while preserving key seismic events. By denoising shot gathers with SeisDiff-denoNIA prior to migration, the resulting images exhibit improved event continuity and enhanced reflection visibility without artificial artifacts. In addition, synthetic experiments show that the method substantially outperforms traditional signal-based diffusion models under low-SNR conditions. These results suggest that explicitly modeling noise is not only viable but advantageous for a broad class of seismic denoising tasks, particularly in challenging field environments. △ Less

Submitted 10 February, 2026; v1 submitted 3 September, 2025; originally announced September 2025.

Comments: This manuscript has been submitted to Geophysics and is currently under review

RoFt-Mol: Benchmarking Robust Fine-Tuning with Molecular Graph Foundation Models

Authors: Shikun Liu, Deyu Zou, Nima Shoghi, Victor Fung, Kai Liu, Pan Li

Abstract: In the era of foundation models, fine-tuning pre-trained models for specific downstream tasks has become crucial. This drives the need for robust fine-tuning methods to address challenges such as model overfitting and sparse labeling. Molecular graph foundation models (MGFMs) face unique difficulties that complicate fine-tuning. These models are limited by smaller pre-training datasets and more se… ▽ More In the era of foundation models, fine-tuning pre-trained models for specific downstream tasks has become crucial. This drives the need for robust fine-tuning methods to address challenges such as model overfitting and sparse labeling. Molecular graph foundation models (MGFMs) face unique difficulties that complicate fine-tuning. These models are limited by smaller pre-training datasets and more severe data scarcity for downstream tasks, both of which require enhanced model generalization. Moreover, MGFMs must accommodate diverse objectives, including both regression and classification tasks. To better understand and improve fine-tuning techniques under these conditions, we classify eight fine-tuning methods into three mechanisms: weight-based, representation-based, and partial fine-tuning. We benchmark these methods on downstream regression and classification tasks across supervised and self-supervised pre-trained models in diverse labeling settings. This extensive evaluation provides valuable insights and informs the design of a refined robust fine-tuning method, ROFT-MOL. This approach combines the strengths of simple post-hoc weight interpolation with more complex weight ensemble fine-tuning methods, delivering improved performance across both task types while maintaining the ease of use inherent in post-hoc weight interpolation. △ Less

Submitted 11 December, 2025; v1 submitted 30 August, 2025; originally announced September 2025.