Showing 1–50 of 442 results for author: Lu, Y

Probing Coherent Many-Body Spin Dynamics in a Molecular Tweezer Array Quantum Simulator

Authors: Yukai Lu, Connor M. Holland, Callum L. Welsh, Xing-Yan Chen, Lawrence W. Cheuk

Abstract: Models of interacting quantum spins are used in many areas of physics ranging from the study of magnetism and strongly correlated materials to quantum sensing. In this work, we study coherent many-body dynamics of interacting spin models realized using polar molecules trapped in rearrangeable optical tweezer arrays. Specifically, we encode quantum spins in long-lived rotational states and use the… ▽ More Models of interacting quantum spins are used in many areas of physics ranging from the study of magnetism and strongly correlated materials to quantum sensing. In this work, we study coherent many-body dynamics of interacting spin models realized using polar molecules trapped in rearrangeable optical tweezer arrays. Specifically, we encode quantum spins in long-lived rotational states and use the electric dipolar interaction between molecules, together with Floquet Hamiltonian engineering, to realize $1/r^3$ XXZ and XYZ models. We microscopically probe several types of coherent dynamics in these models, including quantum walks of single spin excitations, the emergence of magnon bound states, and coherent creation and annihilation of magnon pairs. Our results establish molecular tweezer arrays as a new quantum simulation platform for interacting quantum spin models. △ Less

Submitted 19 March, 2026; originally announced March 2026.

Comments: 29 pages, 12 figures

Local Robustness of Bound States in the Continuum through Scattering-Matrix Eigenvector Continuation

Authors: Ya Yan Lu, Jiaxin Zhou

Abstract: We consider the diffraction of time-harmonic plane waves by a periodic structure, governed by the Helmholtz equation. Bound states in the continuum (BICs) are quasi-periodic fields that remain $L^{2}$-bounded over one period and occur at frequencies embedded in the continuous spectrum. Perturbations that break a BIC can lead to ultra-strong resonances, enabling various applications in photonics. E… ▽ More We consider the diffraction of time-harmonic plane waves by a periodic structure, governed by the Helmholtz equation. Bound states in the continuum (BICs) are quasi-periodic fields that remain $L^{2}$-bounded over one period and occur at frequencies embedded in the continuous spectrum. Perturbations that break a BIC can lead to ultra-strong resonances, enabling various applications in photonics. Employing the implicit function theorem, we demonstrate how a simple BIC continuously deforms into a propagating field as system parameters vary in a neighborhood, with the frequency adjusting accordingly. In this setting, the incident coefficients of the field persist as an eigenvector of the scattering matrix with a fixed eigenvalue. By introducing a mapping $\mathcal{P}$ from the parameters to these coefficients, the zeros of $\mathcal{P}$ correspond precisely to BICs. When such a zero is isolated and the dimensions of the domain and range coincide, the BIC can be related to the mapping degree of $\mathcal{P}$ in a small neighborhood. This perspective clarifies the phase singularity associated with BICs and provides a general topological interpretation of their local robustness with respect to the given parameters. Moreover, it yields a practical numerical criterion for detecting and verifying BICs via computation of the mapping degree of $\mathcal{P}$. △ Less

Submitted 9 March, 2026; originally announced March 2026.

Comments: 38 pages, 5 figures

Commissioning and Full Realization of the PLASEN System at BRIF

Authors: W. C. Mei, H. R. Hu, Y. F. Guo, Z. Yan, X. F. Yang, S. J. Chen, D. Y. Chen, Y. P. Lin, Y. S. Liu, C. Zhang, Y. P. Jing, T. X. Gao, X. Shen, Y. Y. Jia, Y. T. Lin, H. X. Zhang, S. W. Bai, B. Tang, X. Ma, G. F. Song, S. Ye, M. Y. Lu, J. Y. Dong, B. K. Dong, J. H. Lv , et al. (15 additional authors not shown)

Abstract: A PLASEN (Precision LAser Spectroscopy for Exotic Nuclei) system, consisting of a compact radio-frequency quadrupole cooler-buncher (RFQ-cb) and a collinear resonance ionization spectroscopy setup, has now been fully commissioned with radioactive ion beams at the Beijing Radioactive Ion-beam Facility (BRIF). Using both stable and radioactive Rb ion beams from BRIF, we demonstrated that the large b… ▽ More A PLASEN (Precision LAser Spectroscopy for Exotic Nuclei) system, consisting of a compact radio-frequency quadrupole cooler-buncher (RFQ-cb) and a collinear resonance ionization spectroscopy setup, has now been fully commissioned with radioactive ion beams at the Beijing Radioactive Ion-beam Facility (BRIF). Using both stable and radioactive Rb ion beams from BRIF, we demonstrated that the large beam energy spread observed at BRIF has been successfully handled by employing the RFQ-cb, enabling the delivery of high-quality bunched radioactive ion beams for collinear resonance ionization spectroscopy experiments. Under these conditions, we performed laser spectroscopy of exotic nuclei, achieving high resolution (about 100 MHz spectral linewidth) and high sensitivity (up to 1:200 efficiency). This fully operational PLASEN system will serve as a state-of-the-art experimental platform at BRIF for research in multiple fields such as nuclear, atomic and molecular physics. △ Less

Submitted 4 March, 2026; originally announced March 2026.

Air-stable bright entangled photon-pair source from graphene-encapsulated van der Waals ferroelectric NbOI2

Authors: Mayank Joshi, Mengting Jiang, Yu Xing, Yuerui Lu, Jie Zhao, Ping Koy Lam, Syed M Assad, Xuezhi Ma, Young-Wook Cho

Abstract: Van der Waals (vdW) ferroelectrics are emerging nonlinear photonic materials that combine large second-order susceptibility \c{hi}(2) with heterostructure compatibility, offering an attractive route toward miniaturized spontaneous parametric down-conversion (SPDC) sources. However, vdW SPDC sources operating under continuous irradiation in air remain limited in low brightness and poor operational… ▽ More Van der Waals (vdW) ferroelectrics are emerging nonlinear photonic materials that combine large second-order susceptibility \c{hi}(2) with heterostructure compatibility, offering an attractive route toward miniaturized spontaneous parametric down-conversion (SPDC) sources. However, vdW SPDC sources operating under continuous irradiation in air remain limited in low brightness and poor operational stability, as oxygen and moisture exposure, together with pump-induced heating, lead to material degradation and permanent damage. Here we demonstrate an air-stable, bright SPDC source based on ferroelectric NbOI2 enabled by graphene encapsulation. Graphene provides robust environmental protection and can effectively supress pump induced degradation by enhancing heat dissipation. We report a record photon-pair generation absolute rate of 258 Hz and a normalized brightness of 19,900 Hz/(mW.mm). Leveraging this stabilized platform, we further generate polarization entangled photon pairs with 94% fidelity with respect to the maximally entangled Bell states from graphene-encapsulated 90° twisted bilayer NbOI2. Our results establish a practical and air-stable vdW ferroelectric SPDC platform that overcomes key limitations of existing vdW quantum light sources and provides a viable pathway toward scalable, integrated entangled photon sources for on chip quantum photonics. △ Less

Submitted 4 March, 2026; originally announced March 2026.

Modulating biodiversity through higher-order interactions and intraspecific competition in rock-paper-scissors dynamics

Authors: Chunpeng Du, Haoshu Wang, Yikang Lu, Lijuan Qin, Junpyo Park

Abstract: Understanding the mechanisms that govern species coexistence and biodiversity represents a fundamental challenge in ecology. This study extends the classic rock-paper-scissors model by introducing a context-dependent higher-order interaction mechanism where intraspecific competition is dynamically regulated by local resource availability. Crucially, our quantitative analysis reveals that higher-or… ▽ More Understanding the mechanisms that govern species coexistence and biodiversity represents a fundamental challenge in ecology. This study extends the classic rock-paper-scissors model by introducing a context-dependent higher-order interaction mechanism where intraspecific competition is dynamically regulated by local resource availability. Crucially, our quantitative analysis reveals that higher-order interactions significantly modulate the system's structural organization: Enhanced strength of higher-order interactions leads to a decrease in spatial wavelength, resulting in the formation of more compact species domains. However, this structural change makes the system more sensitive to mobility, shifting the extinction threshold to lower values. These findings highlight the dual role of resource-mediated higher-order regulation: it promotes local pattern formation but alters the system's resilience to dispersal, providing new theoretical perspectives for biodiversity conservation. △ Less

Submitted 28 February, 2026; originally announced March 2026.

Comments: 10 pages, 10 figures,47 conferences

Polarization Engineering of Second-Harmonic Generation in 3R-MoS$_2$ Waveguides

Authors: Renkang Song, Junbo Xu, Yanzhen Yin, Yu Yin, Xu Jiang, Zhichen Zhao, Lei Zhou, Jintian Lin, Gaozhong Wang, Vasily Kravstov, Kyoung-Duck Park, Ivan Iorsh, Yuerui Lu, Jun Wang, Guangwei Hu, Zhanshan Wang, Di Huang, Tao Jiang

Abstract: Chip-scale nonlinear optics enables strong light-matter interactions within compact devices, serving as a fundamental platform for multifunctional integrated photonics from classical optical signal processing to quantum information technologies. Transition metal dichalcogenide (TMDC) waveguides have recently emerged as a highly promising platform owing to their giant material nonlinearity and exte… ▽ More Chip-scale nonlinear optics enables strong light-matter interactions within compact devices, serving as a fundamental platform for multifunctional integrated photonics from classical optical signal processing to quantum information technologies. Transition metal dichalcogenide (TMDC) waveguides have recently emerged as a highly promising platform owing to their giant material nonlinearity and extended interaction lengths. To date, however, research has predominantly focused on conversion efficiency, leaving the mechanisms governing the polarization state of nonlinear signal largely unexplored. Here, we establish a comprehensive framework for engineering the polarization of second-harmonic generation (SHG) in 3R-MoS$_2$ waveguides. By synergizing polarization-resolved measurements with theoretical modeling, we reveal that the SHG polarization is determined by guided-mode interactions constrained by waveguide geometry and crystal symmetry, and further reshaped during propagation. We demonstrate that thickness-dependent guided-mode confinement and in-plane crystal symmetry provide robust, static control over SHG polarization, while propagation length offers a dynamic tuning knob for continuously tailoring the nonlinear output. Our findings provide a deterministic approach for on-chip polarization engineering, opening opportunities for reconfigurable nonlinear light sources and quantum photonic circuits. △ Less

Submitted 28 February, 2026; originally announced March 2026.

Comments: 15 pages, 4 figures

Neutral species facilitate coexistence among cyclically competing species under birth and death processes

Authors: Yikang Lu, Wenhao She, Xiaofang Duan, Junpyo Park

Abstract: Natural birth and death are fundamental mechanisms of population dynamics in ecosystems and have played pivotal roles in shaping population dynamics. Nevertheless, in studies of cyclic competition systems governed by the rock-paper-scissors (RPS) game, these mechanisms have often been ignored in analyses of biodiversity. On the other hand, given the prevalence and profound impact on biodiversity,… ▽ More Natural birth and death are fundamental mechanisms of population dynamics in ecosystems and have played pivotal roles in shaping population dynamics. Nevertheless, in studies of cyclic competition systems governed by the rock-paper-scissors (RPS) game, these mechanisms have often been ignored in analyses of biodiversity. On the other hand, given the prevalence and profound impact on biodiversity, understanding how higher-order interactions (HOIs) can affect biodiversity is one of the most challenging issues, and thus HOIs have been continuously studied for their effects on biodiversity in systems of cyclic competing populations, with a focus on neutral species. However, in real ecosystems, species can evolve and die naturally or be preyed upon by predators, whereas previous studies have considered only classic reaction rules among three species with a neutral, nonparticipant species. To identify how neutral species can affect the biodiversity of the RPS system when species' natural birth and death are assumed, we consider a model of neutral species in higher-order interactions within the spatial RPS system, assuming birth-and-death processes. Extensive simulations show that when neutral species interfere positively, they dominate the available space, thereby reducing the proportion of other species. Conversely, when the interference is harmful, the density of competing species increases. In addition, unlike traditional RPS dynamics, biodiversity can be effectively maintained even in high-mobility regimes. Our study reaffirms the critical role of neutral species in preserving biodiversity. △ Less

Submitted 18 February, 2026; originally announced February 2026.

Comments: 10 pages, 12 figures

BSoNet: Deep Learning Solution for Optimizing Image Quality of Portable Backscatter Imaging Systems

Authors: Linxuan Li, Wenjia Wei, Yunfei Lu, Wenwen Zhang, Yanlong Zhang, Wei Zhao

Abstract: Portable backscatter imaging systems (PBI) integrate an X-ray source and detector in a single unit, utilizing Compton scattering photons to rapidly acquire superficial or shallow structural information of an inspected object through single-sided imaging. The application of this technology overcomes the limitations of traditional transmission X-ray detection, offering greater flexibility and portab… ▽ More Portable backscatter imaging systems (PBI) integrate an X-ray source and detector in a single unit, utilizing Compton scattering photons to rapidly acquire superficial or shallow structural information of an inspected object through single-sided imaging. The application of this technology overcomes the limitations of traditional transmission X-ray detection, offering greater flexibility and portability, making it the preferred tool for the rapid and accurate identification of potential threats in scenarios such as borders, ports, and industrial nondestructive security inspections. However, the image quality is significantly compromised due to the limited number of Compton backscattered photons. The insufficient photon counts result primarily from photon absorption in materials, the pencil-beam scanning design, and short signal sampling times. It therefore yields severe image noise and an extremely low signal-to-noise ratio, greatly reducing the accuracy and reliability of PBI systems. To address these challenges, this paper introduces BSoNet, a novel deep learning-based approach specifically designed to optimize the image quality of PBI systems. The approach significantly enhances image clarity, recognition, and contrast while meeting practical application requirements. It transforms PBI systems into more effective and reliable inspection tools, contributing significantly to strengthening security protection. △ Less

Submitted 12 February, 2026; originally announced February 2026.

Comments: 13 pages, 8 figures, accepted by IEEE Transactions on Computational Imaging

High-Throughput In-Situ Fabrication of Fibrous Membranes Enables Scalable Passive Radiative Cooling

Authors: Hanzhuo Shao, Xiaoli Huang, Xuemei Huang, Jin Zhao, Nailin Xing, Hua Xu, Weijie Song, Yuehui Lu

Abstract: Deploying fibrous membranes for passive daytime radiative cooling (PDRC) on large and irregular surfaces is highly desirable but remains challenging, owing to the slow deposition rates and the need for electrically conductive substrates in conventional electrospinning. Here, we demonstrate a high-throughput in-situ strategy for fabricating nanocomposite PDRC fibrous membranes via solution blow spi… ▽ More Deploying fibrous membranes for passive daytime radiative cooling (PDRC) on large and irregular surfaces is highly desirable but remains challenging, owing to the slow deposition rates and the need for electrically conductive substrates in conventional electrospinning. Here, we demonstrate a high-throughput in-situ strategy for fabricating nanocomposite PDRC fibrous membranes via solution blow spinning. This method achieves deposition rates 8-12 times faster than electrospinning and can be applied directly onto nonplanar, nonconductive objects. The resulting membranes, composed of styrene-ethylene-butylene-styrene (SEBS) fibers embedded with Y2O3 nanoparticles, achieve sub-ambient cooling of up to 7.0 °C outdoors, effectively delaying ice melting. Moreover, they are fully recyclable through simple cleaning, dissolution, and reprocessing. This scalable and sustainable fabrication route provides a versatile and practical platform for integrating PDRC fibrous membranes across diverse surfaces, paving the way toward real-world thermal management applications. △ Less

Submitted 6 February, 2026; originally announced February 2026.

Comments: 50 pages, 17 figures

Extended Rydberg Lifetimes in a Cryogenic Atom Array

Authors: Junlan Jin, Yue Shi, Youssef Aziz Alaoui, Jingxin Deng, Yukai Lu, Jeff D. Thompson, Waseem S. Bakr

Abstract: We report on the realization of a $^{133}$Cs optical tweezer array in a cryogenic blackbody radiation (BBR) environment. By enclosing the array within a 4K radiation shield, we measure long Rydberg lifetimes, up to $406 (36)\,μ$s for the $55 P_{3/2}$ Rydberg state, a factor of 3.3(3) longer than the room-temperature value. We employ single-photon coupling for coherent manipulation of the ground-Ry… ▽ More We report on the realization of a $^{133}$Cs optical tweezer array in a cryogenic blackbody radiation (BBR) environment. By enclosing the array within a 4K radiation shield, we measure long Rydberg lifetimes, up to $406 (36)\,μ$s for the $55 P_{3/2}$ Rydberg state, a factor of 3.3(3) longer than the room-temperature value. We employ single-photon coupling for coherent manipulation of the ground-Rydberg qubit. We measure a small differential dynamic polarizability of the transition, beneficial for reducing dephasing due to light intensity fluctuations. Our results pave the path for advancing neutral-atom two-qubit gate fidelities as their error budgets become increasingly dominated by $T_1$ relaxation of the ground-Rydberg qubit. △ Less

Submitted 5 February, 2026; originally announced February 2026.

Comments: 6 pages, 4 figures

Shaping the learning signal in a combined Q-learning rule to improve structured cooperation

Authors: Chunpeng Du, Zongyang Li, Yali Zhang, Yikang Lu, Attila Szolnoki

Abstract: Q-learning provides a standard reinforcement learning framework for studying cooperation by specifying how agents update action values from repeated local interactions outcomes. Although previous work has shown that reputation can promote cooperation in such systems, most models introduce reputation by modifying payoffs, encoding it directly in the state or changing partner selection, which makes… ▽ More Q-learning provides a standard reinforcement learning framework for studying cooperation by specifying how agents update action values from repeated local interactions outcomes. Although previous work has shown that reputation can promote cooperation in such systems, most models introduce reputation by modifying payoffs, encoding it directly in the state or changing partner selection, which makes it difficult to isolate the role of the learning signal itself. Here, we construct the reinforcement signal as a weighted combination of reputation and game payoffs, leaving the game and network structure unchanged. We find that increasing the weight on reputation generally promotes cooperation by consolidating clusters, but this effect is conditional on the learning dynamics. Specifically, this promoting effect vanishes in two regimes: when the learning rate is extremely small, which prevents effective information propagation and when the discount factor approaches one, as distant future expectations obscure the immediate reputational advantage. Outside these limiting cases, the efficacy of reputation in promoting cooperation is attenuated by higher learning rates but amplified by larger discount factors. These results advance the understanding of cooperative dynamics by demonstrating that cooperation can be stabilized through the reputational shaping of learning signals alone, providing critical insights into the interplay between social information and individual learning parameters. △ Less

Submitted 29 January, 2026; originally announced January 2026.

Comments: 11 pages, 7 figures

ACM Class: J.4

Journal ref: Chaos, Solitons and Fractals 206 (2026) 117986

CM-GAI: Continuum Mechanistic Generative Artificial Intelligence Theory for Data Dynamics

Authors: Shan Tang, Ziwei Cao, Zhenling Yang, Jiachen Guo, Yicheng Lu, Wing Kam Liu, Xu Guo

Abstract: Generative artificial intelligence (GAI) plays a fundamental role in high-impact AI-based systems such as SORA and AlphaFold. Currently, GAI shows limited capability in the specialized domains due to data scarcity. In this paper, we develop a continuum mechanics-based theoretical framework to generalize the optimal transport theory from pure mathematics, which can be used to describe the dynamics… ▽ More Generative artificial intelligence (GAI) plays a fundamental role in high-impact AI-based systems such as SORA and AlphaFold. Currently, GAI shows limited capability in the specialized domains due to data scarcity. In this paper, we develop a continuum mechanics-based theoretical framework to generalize the optimal transport theory from pure mathematics, which can be used to describe the dynamics of data, realizing the generative tasks with a small amount of data. The developed theory is used to solve three typical problem involved in many mechanical designs and engineering applications: at material level, how to generate the stress-strain response outside the range of experimental conditions based on experimentally measured stress-strain data; at structure level, how to generate the temperature-dependent stress fields under the thermal loading; at system level, how to generate the plastic strain fields under transient dynamic loading. Our results show the proposed theory can complete the generation successfully, showing its potential to solve many difficult problems involved in engineering applications, not limited to mechanics problems, such as image generation. The present work shows that mechanics can provide new tools for computer science. The limitation of the proposed theory is also discussed. △ Less

Submitted 28 January, 2026; originally announced January 2026.

Near-field effects on cathodoluminescence outcoupling in perovskite thin films

Authors: Robin Schot, Imme Schuringa, Álvaro Rodríguez Echarri, Lars Sonneveld, Tom Veeken, Yang Lu, Samuel D. Stranks, Albert Polman, Bruno Ehrler, Saskia Fiedler

Abstract: Halide perovskite semiconductors are a promising material for high-efficiency solar cells. Their optical properties can vary within and between crystallographic grains. We present spatially-resolved cathodoluminescence (CL) spectroscopy at 2 keV and 5 keV on polycrystalline CsPbBr3 perovskite films to study these variations at the nanoscale. The CL maps show a strongly reduced intensity near the p… ▽ More Halide perovskite semiconductors are a promising material for high-efficiency solar cells. Their optical properties can vary within and between crystallographic grains. We present spatially-resolved cathodoluminescence (CL) spectroscopy at 2 keV and 5 keV on polycrystalline CsPbBr3 perovskite films to study these variations at the nanoscale. The CL maps show a strongly reduced intensity near the polycrystalline grain boundaries. We perform numerical simulations of the far-field emission of the electron beam-generated optical near fields using the surface profiles from AFM as input. We find that near grain boundaries the light outcoupling is strongly reduced due to enhanced internal reflection and light trapping at the curved surfaces. Lateral variations in CL intensity inside grains are due to Fabry-Perot-like resonances in the film, with the substrate acting as a back reflector. Our results show that near-field coupling and interference effects can dominate nanoscale luminescence maps of halide perovskite films. The results are broadly relevant for the analysis of cathodoluminescence and photoluminescence of corrugated thin films. △ Less

Submitted 27 January, 2026; originally announced January 2026.

Generative metamaterials based on large language models

Authors: Zhenyang Gao, Gengchen Zheng, Pengyuan Ren, Hongsong Wang, Kun Zhou, Minh-Son Pham, Yi Wu, Yu Zou, Chu Lun Alex Leung, Yuanyuan Tian, Yang Lu, Haowei Wang, Hongze Wang

Abstract: Mechanical metamaterials utilize intricate architectural designs to achieve advanced properties beyond those of their bulk counterparts. Existing metamaterial designs often rely on design inspirations and extensive experimental and numerical studies operated by design professionals, which can be time- and resource-consuming and limited in exploring the vast design space. Here, we transform metamat… ▽ More Mechanical metamaterials utilize intricate architectural designs to achieve advanced properties beyond those of their bulk counterparts. Existing metamaterial designs often rely on design inspirations and extensive experimental and numerical studies operated by design professionals, which can be time- and resource-consuming and limited in exploring the vast design space. Here, we transform metamaterial design by developing ChatMetamaterials based on large language models, a prompt-based generative metamaterial design engine capable of inventing architecture codes, and conducting reasoning-based diagnostics and evolution for complex metamaterial systems based on simple text prompts or hand-drawn sketches. This approach changes the way metamaterials are designed, and provides new opportunities for high-throughput metamaterial discovery. △ Less

Submitted 25 January, 2026; originally announced January 2026.

Exceptional-point-like Sensing near Hermitian Critical Points

Authors: Jiang-Shan Tang, Long-Qi Xiao, Hao-Dong Wu, Yuwei Jing, Han Zhang, Ya-Ping Ruan, Wuming Liu, Yan-Qing Lu, Keyu Xia

Abstract: A non-Hermitian system at an exceptional point (EP), a specific critical point (CP) associated with the parity-time symmetric phase transition, exhibits a sublinear response to perturbation and promise unprecedented sensitivity beyond the linear-response Hermitian sensors, so far operating at the diabolic points (DP). Despite great advancements, its sensitivity enhancement is fundamentally limited… ▽ More A non-Hermitian system at an exceptional point (EP), a specific critical point (CP) associated with the parity-time symmetric phase transition, exhibits a sublinear response to perturbation and promise unprecedented sensitivity beyond the linear-response Hermitian sensors, so far operating at the diabolic points (DP). Despite great advancements, its sensitivity enhancement is fundamentally limited by the divergent Petermann factor, intrinsically rooted in the non-Hermitian eigenvector degeneracy, and practically by the system complexity. Here, we report the CP-resulting square-root response to the refractive index change and enhanced sensitivity in a simple chiral Hermitian cavity without phase transitions. Because of the inherent eigenvector orthogonality, this CP-based Hermitian sensor exhibits an EP-like response and enhanced sensitivity, breaking the Petermann-factor limit of sensitivity in non-Hermitian counterparts. This work paves the way towards exploring the Hermitian CPs for ultrasensitive sensing outperforming both the EP- and DP-based sensors. △ Less

Submitted 23 January, 2026; originally announced January 2026.

Comments: 23 pages, 10 figures

Programmable branched flow of light

Authors: Shan-shan Chang, Daxing Xiong, Ze-huan Zheng, Li-Wei Wang, Yan-qing Lu, Lu-Jian Chen, Jian-Hua Jiang, Jin-hui Chen

Abstract: We demonstrate deterministic control of branched flow of light using anisotropic nematic liquid crystals. By sculpting the director field via photoalignment, we create spatially programmable optical potentials that govern light scattering and propagation. This platform enables configurable, anisotropic branched flow of light and reveals a universal scaling law for its characteristic features, dire… ▽ More We demonstrate deterministic control of branched flow of light using anisotropic nematic liquid crystals. By sculpting the director field via photoalignment, we create spatially programmable optical potentials that govern light scattering and propagation. This platform enables configurable, anisotropic branched flow of light and reveals a universal scaling law for its characteristic features, directly connecting disordered photonics with mesoscopic wave transport. Under extreme anisotropy, we observe a pronounced directional channeling effect, driven by anomalous symmetry-breaking velocity diffusion, which concentrates light propagation along preferential directions while suppressing transverse spreading. These findings establish a tunable material platform for harnessing branched flow of light, opening pathways toward on-chip photonic circuits that exploit disorder-guided transport, scattering-resilient endoscopic imaging, and adaptive optical interfaces in complex media. △ Less

Submitted 20 January, 2026; originally announced January 2026.

Comments: Comments are welcome

An efficient numerical method for simulating two-dimensional non-periodic metasurfaces

Authors: Fuhao Liu, Ya Yan Lu

Abstract: Metasurfaces are extremely useful for controlling and manipulating electromagnetic waves. Full-wave numerical simulation is highly desired for their design and optimization, but it is notoriously difficult, even for two-dimensional metasurfaces, when they comprise a huge number of subwavelength elements. This paper focuses on two-dimensional non-periodic metasurfaces that contain only a relatively… ▽ More Metasurfaces are extremely useful for controlling and manipulating electromagnetic waves. Full-wave numerical simulation is highly desired for their design and optimization, but it is notoriously difficult, even for two-dimensional metasurfaces, when they comprise a huge number of subwavelength elements. This paper focuses on two-dimensional non-periodic metasurfaces that contain only a relatively small number of distinct subwavelength elements. We develop an efficient numerical method based on Neumann-to-Dirichlet operators, the finite element method and local function expansions. Our method drastically reduces the total number of unknowns and is capable of simulating two-dimensional metasurfaces with $10^{5}$ subwavelength elements on a personal computer. Numerical examples demonstrate that the method maintains high accuracy while offering significant advantages in both computational time and memory usage compared to the classical full-domain finite element method, making it particularly suited for the analysis of large metasurfaces. △ Less

Submitted 18 January, 2026; originally announced January 2026.

Evolutionary vaccination dynamics under higher-order reinforcement pressure

Authors: Yikang Lu, Ying Wang, Alfonso de Miguel-Arribas, Lei Shi, Yamir Moreno

Abstract: Vaccination games in higher-order settings remain underexplored, despite their importance in shaping opinions and collective decisions. Here, we introduce a parsimonious behavioral-epidemiological model to evaluate how peer reinforcement pressure influences vaccination uptake. The framework consists of a two-layer multiplex: an epidemic layer governed by the SIR process on a square lattice, and a… ▽ More Vaccination games in higher-order settings remain underexplored, despite their importance in shaping opinions and collective decisions. Here, we introduce a parsimonious behavioral-epidemiological model to evaluate how peer reinforcement pressure influences vaccination uptake. The framework consists of a two-layer multiplex: an epidemic layer governed by the SIR process on a square lattice, and a behavioral layer represented by a hypergraph of triadic interactions. Individuals update their vaccination strategy via imitation, modulated by a reinforcement parameter $α$ when peer support is present. We find that higher-order structure alone induces clusters of vaccinated individuals that act as protective barriers. Low but nonzero reinforcement ($α\approx 0.5$) maximizes coverage and suppresses outbreaks, while both negligible ($α\approx 0$) and moderate ($α> 0.1$) reinforcement reduce uptake, as excessive confirmation lowers adaptability and enables non-vaccinators to re-emerge. Our work bridges complex contagion theory with evolutionary game dynamics, offering insights into how contact structure and peer reinforcement jointly shape vaccination behavior. △ Less

Submitted 17 January, 2026; originally announced January 2026.

Comments: 15 pages, 6 figures in main text, 1 appendix with 2 figures

From Agent-Based Markov Dynamics to Hierarchical Closures on Networks: Emergent Complexity and Epidemic Applications

Authors: A. Y. Klimenko, A. Rozycki, Y. Lu

Abstract: We explore a rigorous formulation of agent-based SIR epidemic dynamics as a discrete-state Markov process, capturing the stochastic propagation of infection or an invading agent on networks. Using indicator functions and corresponding marginal probabilities, we derive a hierarchy of evolution equations that resembles the classical BBGKY hierarchy in statistical mechanics. The structure of these eq… ▽ More We explore a rigorous formulation of agent-based SIR epidemic dynamics as a discrete-state Markov process, capturing the stochastic propagation of infection or an invading agent on networks. Using indicator functions and corresponding marginal probabilities, we derive a hierarchy of evolution equations that resembles the classical BBGKY hierarchy in statistical mechanics. The structure of these equations clarifies the challenges of closure and highlights the principal problem of systemic complexity arising from stochastic but generally not fully chaotic interactions. Monte Carlo simulations are used to validate simplified closures and approximations, offering a unified perspective on the interplay between network topology, stochasticity, and infection dynamics. We also explore the impact of lockdown measures within a networked agent framework, illustrating how SIR dynamics and structural complexity of the network shape epidemic with propagation of the COVID-19 pandemic in Northern Italy taken as an example. △ Less

Submitted 5 January, 2026; originally announced January 2026.

Comments: 22 pages, 10 figures

Journal ref: Entropy 2026, 28(1), 63

High-flux cold lithium-6 and rubidium-87 atoms from compact two-dimensional magneto-optical traps

Authors: Yun-Xuan Lu, An-Wei Zhu, Christine E. Frank, Xin-Yi Huang, Xin-Yu Luo

Abstract: We report a compact setup with in-series two-dimensional magneto-optical traps (2D MOTs) that provides high-flux cold lithium and rubidium atoms. Thanks to the efficient short-distance Zeeman slowing, the maximum 3D MOT loading rate of lithium atoms reaches a record value of $6.6\times 10^{9}$ atoms/s at a moderate lithium-oven temperature of 372 degrees Celsius, which is 44 times higher than that… ▽ More We report a compact setup with in-series two-dimensional magneto-optical traps (2D MOTs) that provides high-flux cold lithium and rubidium atoms. Thanks to the efficient short-distance Zeeman slowing, the maximum 3D MOT loading rate of lithium atoms reaches a record value of $6.6\times 10^{9}$ atoms/s at a moderate lithium-oven temperature of 372 degrees Celsius, which is 44 times higher than that without the Zeeman slowing light. The flux of rubidium is also as high as $2.3\times10^9$ atoms/s with the rubidium oven held at room temperature. Meanwhile, the entire vacuum-chamber system, including an ultra-high-vacuum science cell, is within a small volume of $55\times65\times70~\mathrm{cm}^3$. Our work represents a substantial improvement over traditional bulky and complex dual-species cold-atom setups. It provides a good starting point for the fast production of a double-degenerate lithium-rubidium atomic mixture and large samples of ultracold lithium-rubidium ground-state molecules. △ Less

Submitted 1 January, 2026; v1 submitted 30 December, 2025; originally announced December 2025.

Comments: Added references for section 1; adjusted the linewidth of figure 8, results unchanged

Polymer-inspired mechanical metamaterials

Authors: Zhenyang Gao, Pengyuan Ren, Yifeng Dong, Gengchen Zheng, Min-Son Pham, Xiao Shang, Shaojia Wang, Shuo Yang, Zijue Tang, Yongbing Li, Hua Sun, Yi Wua, Hongjian Jiang, Lan Zhang, Tobin Filleter, Lingyu Kong, Kun Zhou, Haowei Wanga, Yang Lu, Yu Zou, Hongze Wang

Abstract: Metamaterials benefit from unique architected patterns to achieve lightweight with exceptional mechanical properties inaccessible to conventional materials. Typical mechanical metamaterials mimic crystal structures with close-packed lattices, exhibit high structural stiffness but suffer from reduced flexibility and abrupt fracture similar to atomic debonding. Here, we demonstrate a new class of po… ▽ More Metamaterials benefit from unique architected patterns to achieve lightweight with exceptional mechanical properties inaccessible to conventional materials. Typical mechanical metamaterials mimic crystal structures with close-packed lattices, exhibit high structural stiffness but suffer from reduced flexibility and abrupt fracture similar to atomic debonding. Here, we demonstrate a new class of polymer-inspired metamaterials by translating, understanding, and programming the deformation and strengthening mechanics of polymers. By combining the metamaterial programmability with polymer-like mechanics, we also program crosslinking, proto-crystalline order, and entanglements of free chains to enable polymeric functional programmability of the metamaterials on the macroscale. This macroscale polymeric programmability not only allows synthetic, nature-inspired strengthening combinations that are unattainable in microscale polymer networks, but also turns polymer-inspired metamaterials into a programmable experimental platform for exploring new deformation strengthening strategies, opening pathways to functional applications such as soft, humanoid-like tissues for robotic joints and compliant connectors. △ Less

Submitted 18 December, 2025; originally announced December 2025.

Light matter interaction in van der Waals heterostructures with Mie voids

Authors: Zhuoyuan Lu, Kirill Koshelev, Pavel Tonkaev, Ziyu Chen, Dawei Liu, Wenkai Yang, Yuri Kivshar, Yuerui Lu

Abstract: Recently introduced concept of Mie voids allows to enhance the field localization inside air cavities embedded in high-index materials. Mie voids provide an alternative approach to conventional dielectric resonators that confine optical fields within bulk high-index materials. Building on this concept, here we present a hybrid photonic platform that integrates monolayer WS2 with Mie void resonator… ▽ More Recently introduced concept of Mie voids allows to enhance the field localization inside air cavities embedded in high-index materials. Mie voids provide an alternative approach to conventional dielectric resonators that confine optical fields within bulk high-index materials. Building on this concept, here we present a hybrid photonic platform that integrates monolayer WS2 with Mie void resonators patterned in a high-index Bi2Te3 substrate. By carefully aligning the dipolar void resonance with the excitonic transition of WS2, we achieve substantially enhanced photoluminescence and second-harmonic generation. Far-field imaging of the harmonic fields reveals spatially resolved hotspots that directly map localized resonant modes, with their positions tunable by cavity geometry and pump wavelength. This approach enables real-space control of nonlinear emission at the single-resonator level, offering a robust and reconfigurable platform for next-generation nonlinear photonics and surface-enhanced optical sensing. △ Less

Submitted 18 December, 2025; originally announced December 2025.

Spatial-spectral mapping for long-duration broadband terahertz pulse generation in on-chip waveguide arrays

Authors: Yibo Huang, Yao Lu, Haoyu Duan, Chao Wang, Xitan Xu, Jiwei Qi, Qiang Wu, Jingjun Xu

Abstract: Conventional approaches to terahertz (THz) pulse generation are restricted by the Fourier-transform limit, which hinders the creation of sources that combine long duration with broad bandwidth--a capability crucial for many spectroscopic and sensing applications. In this work, we overcome this challenge in the terahertz domain using an on-chip gradient waveguide array. The key is to spectrally dis… ▽ More Conventional approaches to terahertz (THz) pulse generation are restricted by the Fourier-transform limit, which hinders the creation of sources that combine long duration with broad bandwidth--a capability crucial for many spectroscopic and sensing applications. In this work, we overcome this challenge in the terahertz domain using an on-chip gradient waveguide array. The key is to spectrally disperse the pulse into spatially separated channels within a lithium niobate chip, effectively decoupling the design of temporal and spectral properties. We validate the source by distinguishing amino acid mixtures, demonstrating its tailored biosensing potential. This work establishes a novel mechanism for integrated THz generation, offering considerable promise for broadband spectroscopy and on-chip photonics. △ Less

Submitted 11 December, 2025; originally announced December 2025.

Comments: 12 pages, 4 figures; references bibtex

Beam-test evaluation of pre-production Low Gain Avalanche Detectors for the ATLAS High Granularity Timing Detector

Authors: A. Aboulhorma, M. Ait Tamlihat, H. M. Alfanda, O. Atanova, N. Atanov, I. Azzouzi, J. Barreiro Guimarães da Costa, T. Beau, D. Benchekroun, F. Bendebba, G. Bergamin, Y. Bimgdi, A. Blot, A. Boikov, J. Bonis, D. Boumediene, C. Brito, A. S. Brogna, A. M. Burger, L. Cadamuro, Y. Cai, N. Cartalade, R. Casanova Mohr, R. Cherkaoui El Moursli, Y. Che , et al. (207 additional authors not shown)

Abstract: The High Granularity Timing Detector (HGTD) will be installed in the ATLAS experiment as part of the Phase-II upgrade for the High Luminosity-Large Hadron Collider (HL-LHC). It will mitigate pile-up effects in the forward region, and measure per bunch luminosity. The design of HGTD is based on Low Gain Avalanche Detector (LGAD) sensors. This paper presents the results of beam-test campaigns conduc… ▽ More The High Granularity Timing Detector (HGTD) will be installed in the ATLAS experiment as part of the Phase-II upgrade for the High Luminosity-Large Hadron Collider (HL-LHC). It will mitigate pile-up effects in the forward region, and measure per bunch luminosity. The design of HGTD is based on Low Gain Avalanche Detector (LGAD) sensors. This paper presents the results of beam-test campaigns conducted at CERN and DESY in 2023 and 2024 on single LGADs from HGTD pre-production test structures, before and after neutron irradiation up to fluences of $2.5 \times 10^{15}~\mathrm{n_{eq}/cm^2}$. The tested LGADs can meet HGTD requirements in terms of charge collection, time resolution, and hit efficiency, even under HL-LHC end-of-life conditions, supporting their deployment in the final detector. △ Less

Submitted 30 January, 2026; v1 submitted 1 December, 2025; originally announced December 2025.

A 160 ° x 160 ° Dynamic Holographic Meta-Projector

Authors: Feng-Jun Li, Ruixing Xia, Qianmei Deng, Yuze Lu, Xiangping Li, Fangwen Sun, Dong Zhao, Zi-Lan Deng, Kun Huang

Abstract: Holography can reconstruct immersive light fields for virtual and augmented reality by modulating optical wavefront. Due to huge pixel sizes, current spatial light modulators (SLMs) have small field-of-view (FOV) for holographic displays. Despite various methods for etendue expansion, the largest full-screen FOV for dynamic holography is only 70 ° X 70 °, which remains insufficient for large-scale… ▽ More Holography can reconstruct immersive light fields for virtual and augmented reality by modulating optical wavefront. Due to huge pixel sizes, current spatial light modulators (SLMs) have small field-of-view (FOV) for holographic displays. Despite various methods for etendue expansion, the largest full-screen FOV for dynamic holography is only 70 ° X 70 °, which remains insufficient for large-scale, high-resolution, three-dimensional displays. Here, we report a pixel-interpolation-assisted holographic meta-projector that substantially expands the FOV by integrating multiple subwavelength metasurface pixels within each microscale pixel of a traditional SLM. Leveraging large-angle diffraction of the metasurface and implementing k-space distortion correction for ultra-wide angles, we experimentally demonstrate dynamic holographic image reconstruction with a FOV of 160 ° X 160 ° -equivalent to a system numerical aperture of 0.985-at a high framerate of 60 Hz, surpassing the temporal resolution threshold of human vision. This system represents the state-of-the-art near-full-screen holographic dynamic display, thereby opening the door to high-dynamic-range and large-FOV holographic displays. △ Less

Submitted 27 November, 2025; originally announced November 2025.

Comments: 5 figures

Edge-based reputation promotes cooperation in simplicial complexes

Authors: Chunpeng Du, Fei Fang, Alfonso de Miguel-Arribas, Yikang Lu, Yanan Wang, Xin Pan, Yamir Moreno

Abstract: Understanding how cooperation emerges and persists is a central challenge in the evolutionary dynamics of social and biological systems. Most prior studies have examined cooperation through pairwise interactions, yet real-world interactions often involve groups and higher-order structures. Reputation is a key mechanism for guiding strategic behavior in such contexts, but its role in higher-order n… ▽ More Understanding how cooperation emerges and persists is a central challenge in the evolutionary dynamics of social and biological systems. Most prior studies have examined cooperation through pairwise interactions, yet real-world interactions often involve groups and higher-order structures. Reputation is a key mechanism for guiding strategic behavior in such contexts, but its role in higher-order networks remains underexplored. In this study, we introduce an edge-based reputation mechanism, incorporating both direct and indirect reputation, to investigate the evolution of cooperation in simplicial complexes. Our results show that coupling reputation mechanisms with higher-order network structures strongly promotes cooperation, with direct reputation exerting a stronger influence than indirect reputation. Moreover, we reveal a nonlinear interplay between network topology and reputation mechanisms, highlighting how multi-level structures shape collective outcomes. These findings provide a novel theoretical framework for understanding cooperation in complex social systems. △ Less

Submitted 27 November, 2025; originally announced November 2025.

Comments: 14 pages, 6 figures

Autonomous labeling of surgical resection margins using a foundation model

Authors: Xilin Yang, Musa Aydin, Yuhong Lu, Sahan Yoruc Selcuk, Bijie Bai, Yijie Zhang, Andrew Birkeland, Katjana Ehrlich, Julien Bec, Laura Marcu, Nir Pillar, Aydogan Ozcan

Abstract: Assessing resection margins is central to pathological specimen evaluation and has profound implications for patient outcomes. Current practice employs physical inking, which is applied variably, and cautery artifacts can obscure the true margin on histological sections. We present a virtual inking network (VIN) that autonomously localizes the surgical cut surface on whole-slide images, reducing r… ▽ More Assessing resection margins is central to pathological specimen evaluation and has profound implications for patient outcomes. Current practice employs physical inking, which is applied variably, and cautery artifacts can obscure the true margin on histological sections. We present a virtual inking network (VIN) that autonomously localizes the surgical cut surface on whole-slide images, reducing reliance on inks and standardizing margin-focused review. VIN uses a frozen foundation model as the feature extractor and a compact two-layer multilayer perceptron trained for patch-level classification of cautery-consistent features. The dataset comprised 120 hematoxylin and eosin (H&E) stained slides from 12 human tonsil tissue blocks, resulting in ~2 TB of uncompressed raw image data, where a board-certified pathologist provided boundary annotations. In blind testing with 20 slides from previously unseen blocks, VIN produced coherent margin overlays that qualitatively aligned with expert annotations across serial sections. Quantitatively, region-level accuracy was ~73.3% across the test set, with errors largely confined to limited areas that did not disrupt continuity of the whole-slide margin map. These results indicate that VIN captures cautery-related histomorphology and can provide a reproducible, ink-free margin delineation suitable for integration into routine digital pathology workflows and for downstream measurement of margin distances. △ Less

Submitted 27 November, 2025; originally announced November 2025.

Comments: 20 Pages, 5 Figures

End-to-end deep learning for superoscillatory subtraction imaging

Authors: Zhongwei Jin, Keyi Chen, Qiuyu Ren, Zhigang Dai, Ruoping Yao, Zhi Hong, Bin Fang, Fangzhou Shu, Shengtao Mei, Yiping Lu

Abstract: Breaking the diffraction limit in optical imaging is crucial for resolving subwavelength details in a wide range of applications, where superoscillatory imaging and subtraction imaging are two common strategies for surpassing conventional resolution limits. We propose an end-to-end deep learning framework that integrates superoscillatory focusing and subtraction imaging into a single jointly-optim… ▽ More Breaking the diffraction limit in optical imaging is crucial for resolving subwavelength details in a wide range of applications, where superoscillatory imaging and subtraction imaging are two common strategies for surpassing conventional resolution limits. We propose an end-to-end deep learning framework that integrates superoscillatory focusing and subtraction imaging into a single jointly-optimized vectorial Debye integral neural network pipeline, eliminating the traditional two-step acquisition and manual weighting process. With this end-to-end neural network, we further improve the focusing capability of the system to the sub-100-nm regime, enabling deep-subwavelength imaging resolution. △ Less

Submitted 8 December, 2025; v1 submitted 20 November, 2025; originally announced November 2025.

Stochastic Kinetics of Protein Molecules in a Gene Expression Model under Burst Approximation

Authors: Yuntao Lu, Yunxin Zhang

Abstract: The burst approximation is a widely-used technique to simplify stochastic gene expression models. However, both analytical results and efficient algorithms are currently unavailable for general models under the burst approximation. In this article, we systematically analyze surrogate models with multiple gene states. Analytical solution to the chemical master equation is provided, which is further… ▽ More The burst approximation is a widely-used technique to simplify stochastic gene expression models. However, both analytical results and efficient algorithms are currently unavailable for general models under the burst approximation. In this article, we systematically analyze surrogate models with multiple gene states. Analytical solution to the chemical master equation is provided, which is further exploited from two perspectives. Theoretically, several inequalities are established using functional analysis. We conclude that the steady-state distribution of protein copy number is bounded from above by a constant multiple of some negative binomial distribution if the burst size is geometrically distributed. Computationally, efficient algorithms are developed under three circumstances based on the standard binomial moment method. △ Less

Submitted 18 November, 2025; originally announced November 2025.

Comments: 20 pages

MSC Class: 60J28

Asymptotically circularly polarized bound states in the continuum

Authors: Nan Zhang, Ya Yan Lu

Abstract: We study a class of bound states in the continuum (BICs) in all-dielectric periodic structures, near which resonant states approach ideal circularly polarized states (CPSs). We term these BICs {\em asymptotically circularly polarized BICs} ({\em acp}-BICs) and identify two types: single-angle and all-angle. Single-angle {\em acp}-BICs permit convergence to left- or right-handed CPSs only along a s… ▽ More We study a class of bound states in the continuum (BICs) in all-dielectric periodic structures, near which resonant states approach ideal circularly polarized states (CPSs). We term these BICs {\em asymptotically circularly polarized BICs} ({\em acp}-BICs) and identify two types: single-angle and all-angle. Single-angle {\em acp}-BICs permit convergence to left- or right-handed CPSs only along a single momentum-space direction, whereas all-angle {\em acp}-BICs exhibit convergence to CPSs of a single handedness throughout the entire momentum space, rendering them exceptionally promising for chiral optical applications. We reveal that the existence of {\em acp}-BICs is underpinned by total reflection of circularly polarized waves. Moreover, all-angle {\em acp}-BICs qualify as super-BICs, with uniform nearby polarization being an intrinsic property. In addition, a bifurcation theory is developed to analyze the emergence of genuine CPSs from {\em acp}-BICs under $C_{2}$-symmetric structural perturbations. Our results suggest {\em acp}-BICs as a platform for singular and chiral optical responses in all-dielectric systems. △ Less

Submitted 16 November, 2025; originally announced November 2025.

Lattice design of a storage-ring-based light source for generating high-power fully coherent EUV radiation

Authors: Yujie Lu, Ao Liu, Changliang Li, Kun Wang, Qinglei Zhang, Weishi Wan, Weijie Fan, Junhao Liu, Ruichun Li, Yanxu Wang, Konglong Wu, Ji Li, Chao Feng

Abstract: We present the physical design and systematic optimization of a high-performance storage ring tailored for the generation of high-power coherent radiation, with particular emphasis on the extreme ultraviolet (EUV) regime. The proposed ring adopts a Double Bend Achromat (DBA) lattice configuration and integrates 12 superconducting wigglers to significantly enhance radiation damping and minimize the… ▽ More We present the physical design and systematic optimization of a high-performance storage ring tailored for the generation of high-power coherent radiation, with particular emphasis on the extreme ultraviolet (EUV) regime. The proposed ring adopts a Double Bend Achromat (DBA) lattice configuration and integrates 12 superconducting wigglers to significantly enhance radiation damping and minimize the natural emittance. And a bypass line is adopted to generate high power coherent radiation. Comprehensive linear and nonlinear beam dynamics analyses have been conducted to ensure beam stability and robustness across the operational parameter space. The optimized design achieves a natural emittance of approximately 0.8 nm and a longitudinal damping time of around 1.4 ms, enabling the efficient buildup of coherent radiation. Three-dimensional numerical simulations, incorporating the previously proposed angular dispersion-induced microbunching (ADM) mechanism, further confirm the system's capability to generate high-power EUV coherent radiation, with output powers reaching the order of several hundred watts. These results underscore the strong potential of the proposed design for applications in coherent photon science and EUV lithography. △ Less

Submitted 6 November, 2025; originally announced November 2025.

Encoding computationally hard problems in triangular Rydberg atom arrays

Authors: Xi-Wei Pan, Huan-Hai Zhou, Yi-Ming Lu, Jin-Guo Liu

Abstract: Rydberg atom arrays are a promising platform for quantum optimization, encoding computationally hard problems by reducing them to independent set problems with unit-disk graph topology. In Nguyen et al., PRX Quantum 4, 010316 (2023), a systematic and efficient strategy was introduced to encode multiple problems into a special unit-disk graph: the King's subgraph. However, King's subgraphs are not… ▽ More Rydberg atom arrays are a promising platform for quantum optimization, encoding computationally hard problems by reducing them to independent set problems with unit-disk graph topology. In Nguyen et al., PRX Quantum 4, 010316 (2023), a systematic and efficient strategy was introduced to encode multiple problems into a special unit-disk graph: the King's subgraph. However, King's subgraphs are not the optimal choice in two dimensions. Due to the power-law decay of Rydberg interaction strengths, the approximation to unit-disk graphs in real devices is poor, necessitating post-processing that lacks physical interpretability. In this work, we develop an encoding scheme that can universally encode computationally hard problems on triangular lattices, based on our innovative automated gadget search strategy. Numerical simulations demonstrate that quantum optimization on triangular lattices reduces independence-constraint violations by approximately two orders of magnitude compared to King's subgraphs, substantially alleviating the need for post-processing in experiments. △ Less

Submitted 29 October, 2025; originally announced October 2025.

Fundamental impossibility of a superradiant neutrino laser

Authors: Yu-Kun Lu, Hanzhen Lin, Wolfgang Ketterle

Abstract: Here we address the fundamental question whether an idealized system of $N$ atoms will show collective behavior and superradiance when it emits fermions instead of photons. We show that the maximum emission is $\propto N$ and not $\propto N^2$ which proves the absence of superradiance and shows that the recent proposal to realize a superradiant neutrino laser is impossible. This can be understood… ▽ More Here we address the fundamental question whether an idealized system of $N$ atoms will show collective behavior and superradiance when it emits fermions instead of photons. We show that the maximum emission is $\propto N$ and not $\propto N^2$ which proves the absence of superradiance and shows that the recent proposal to realize a superradiant neutrino laser is impossible. This can be understood as either destructive interference of fermionic transition amplitudes, or Pauli blockade by collective excitations with fermionic nature. On the other hand, states with low excitation can show collective behavior. We derive the exact solution of the fermionic Dicke problem and analyze the decay dynamics in various regimes. △ Less

Submitted 24 October, 2025; originally announced October 2025.

Can Bose-Einstein condensates enhance radioactive decay?

Authors: Hanzhen Lin, Yukun Lu, Wolfgang Ketterle

Abstract: This paper lays out the principles of how Bose-Einstein condensates can modify radioactive decay. We highlight the challenges of many modes and short coherence times due to the $\approx$ MeV energies of the emitted radiation. Recent proposals for gamma ray and neutrino lasers claim that using a Bose-Einstein condensate as a source would solve these issues. We show that this is not the case, and th… ▽ More This paper lays out the principles of how Bose-Einstein condensates can modify radioactive decay. We highlight the challenges of many modes and short coherence times due to the $\approx$ MeV energies of the emitted radiation. Recent proposals for gamma ray and neutrino lasers claim that using a Bose-Einstein condensate as a source would solve these issues. We show that this is not the case, and the proposed experiments would have a gain of only $10^{-20}$ or smaller. We also analyze proposals for gamma ray lasers based on stimulated annihilation of positronium Bose-Einstein condensates. △ Less

Submitted 31 October, 2025; v1 submitted 24 October, 2025; originally announced October 2025.

Comments: Updated reference

Acoustic Emission Cascade Predicting Progression to Failure of Rock and Bone

Authors: Andrew P. Bunger, Yunxing Lu, Ayyaz Mustafa, Michael M. McDowell

Abstract: Quasi brittle materials such as rock and bone are understood to fail via microcrack coalescence. The accompanying Acoustic Emission (AE) event rate is known to increase as failure progresses. Here we examine the progression of the AE event rate for both rock and bone under conditions where failure progresses under fixed loading. The experiments for rock entail subjecting granite beams to a fixed l… ▽ More Quasi brittle materials such as rock and bone are understood to fail via microcrack coalescence. The accompanying Acoustic Emission (AE) event rate is known to increase as failure progresses. Here we examine the progression of the AE event rate for both rock and bone under conditions where failure progresses under fixed loading. The experiments for rock entail subjecting granite beams to a fixed loading under three point bending and monitoring the time-dependent failure. For bone, human cadaver skulls are loaded under pinning loads similar to those used for immobilization of the head for neurosurgical procedures. AE rates are shown to be consistent with a rate dependent material failure law including a quasi-linear cascade of the inverse AE energy rate in the lead up to failure that is shown here to arise because of a coupling wherein a response rate is a power law of a driver and the driver is, in turn, a power law of the accumulated response. For both materials and experimental configurations this cascade provides warning of impending failure. For granite beams there is accurate prediction of failure time over the final 30 percent of the specimens lifetimes, which ranged from 35 seconds to two days. For skull fracture, the commencement of the failure cascade provides 30-70 seconds for warning of failure, which would be sufficient for basic remedial action to avoid patient injury in a surgical application. △ Less

Submitted 23 October, 2025; originally announced October 2025.

Comments: 29 pages, 13 figures

Grain volume distribution alters the critical phenomena in complex granular systems

Authors: Teng Man, Yimin Lu, Zhongrong Wang, Herbert Huppert, Alessio Zaccone, Honglei Sun

Abstract: The grain size distribution (GSD) plays an important role in the mechanical properties of amorphous disordered systems and complex granular materials. Varying GSD causes segregation issues and alters critical behaviors. This work used the discrete element method (DEM) to investigate the rheological and critical behaviors of sheared granular flows with various GSDs. The results show that, while a u… ▽ More The grain size distribution (GSD) plays an important role in the mechanical properties of amorphous disordered systems and complex granular materials. Varying GSD causes segregation issues and alters critical behaviors. This work used the discrete element method (DEM) to investigate the rheological and critical behaviors of sheared granular flows with various GSDs. The results show that, while a unified rheological relation can be obtained, a characteristic length scale, which is associated with the contact probability and can be obtained from any GSD, is embedded within such a polydisperse disordered system. We further acquire a correlation function between critical solid fractions and dimensionless grain volume distributions. This work elucidates the effect of particle volumes on the rheology and micromechanics of dry granular systems and provides further insights in better incorporating the influence of other particle properties into a unified framework, which is helpful and critical for the corresponding engineering and geophysical problems. △ Less

Submitted 16 October, 2025; originally announced October 2025.

Optical Computation-in-Communication enables low-latency, high-fidelity perception in telesurgery

Authors: Rui Yang, Jiaming Hu, Jian-Qing Zheng, Yue-Zhen Lu, Jian-Wei Cui, Qun Ren, Yi-Jie Yu, John Edward Wu, Zhao-Yu Wang, Xiao-Li Lin, Dandan Zhang, Mingchu Tang, Christos Masouros, Huiyun Liu, Chin-Pang Liu

Abstract: Artificial intelligence (AI) holds significant promise for enhancing intraoperative perception and decision-making in telesurgery, where physical separation impairs sensory feedback and control. Despite advances in medical AI and surgical robotics, conventional electronic AI architectures remain fundamentally constrained by the compounded latency from serial processing of inference and communicati… ▽ More Artificial intelligence (AI) holds significant promise for enhancing intraoperative perception and decision-making in telesurgery, where physical separation impairs sensory feedback and control. Despite advances in medical AI and surgical robotics, conventional electronic AI architectures remain fundamentally constrained by the compounded latency from serial processing of inference and communication. This limitation is especially critical in latency-sensitive procedures such as endovascular interventions, where delays over 200 ms can compromise real-time AI reliability and patient safety. Here, we introduce an Optical Computation-in-Communication (OCiC) framework that reduces end-to-end latency significantly by performing AI inference concurrently with optical communication. OCiC integrates Optical Remote Computing Units (ORCUs) directly into the optical communication pathway, with each ORCU experimentally achieving up to 69 tera-operations per second per channel through spectrally efficient two-dimensional photonic convolution. The system maintains ultrahigh inference fidelity within 0.1% of CPU/GPU baselines on classification and coronary angiography segmentation, while intrinsically mitigating cumulative error propagation, a longstanding barrier to deep optical network scalability. We validated the robustness of OCiC through outdoor dark fibre deployments, confirming consistent and stable performance across varying environmental conditions. When scaled globally, OCiC transforms long-haul fibre infrastructure into a distributed photonic AI fabric with exascale potential, enabling reliable, low-latency telesurgery across distances up to 10,000 km and opening a new optical frontier for distributed medical intelligence. △ Less

Submitted 15 October, 2025; originally announced October 2025.

Autler-Townes spectroscopy of a Rydberg ladder

Authors: Tai Xiang, Yue-Hui Lu, Jacquelyn Ho, Tsai-Chen Lee, Zhenjie Yan, Dan M. Stamper-Kurn

Abstract: Ladder-type two-photon excitation of an atom from a ground state $|g\rangle$, to an intermediate excited state $|e\rangle$, and, finally, to a Rydberg state $|r\rangle$, has a variety of uses from quantum information to sensing. A common scheme for detecting this transition optically is through electromagnetically induced transparency (EIT). However, in inverted wavelength schemes, where the groun… ▽ More Ladder-type two-photon excitation of an atom from a ground state $|g\rangle$, to an intermediate excited state $|e\rangle$, and, finally, to a Rydberg state $|r\rangle$, has a variety of uses from quantum information to sensing. A common scheme for detecting this transition optically is through electromagnetically induced transparency (EIT). However, in inverted wavelength schemes, where the ground-to-excited transition wavelength is shorter than the excited-to-Rydberg transition wavelength, the strength of the EIT feature on the lower-leg beam is strongly reduced in a Doppler-broadened medium. Here, we report on an alternative two-photon spectroscopic feature, which we term the two-photon Autler-Townes resonance, observed on the upper-leg beam. Compared to the EIT signal, this feature's superior signal-to-noise ratio allows one to resolve Rydberg resonances with principal quantum number as high as $n=80$. We also show that such a feature can be utilized to generate an error signal for stabilizing the frequency of the upper-leg beam. △ Less

Submitted 24 February, 2026; v1 submitted 15 October, 2025; originally announced October 2025.

Comments: 7 pages, 5 figures

Journal ref: Phys. Rev. A 113, (2026) 013126

Long-Range Chiral Pairing enables Topological Superconductivity in Triangular Lattices without Spin-Orbit Coupling and Magnetic Field

Authors: Yizhi Li, Yanyan Lu, Jianxin Zhong, Lijun Meng

Abstract: This paper demonstrates a pathway to topological superconductivity in monolayer triangular lattices through long-range pairing without requiring spin-orbit coupling and magnetic field, contrasting conventional frameworks reliant on superconductivity and spin-orbit coupling and time-reversal symmetry (TRS) breaking. Berry curvature analysis reveals spontaneous TRS-breaking-induced peaks or valleys… ▽ More This paper demonstrates a pathway to topological superconductivity in monolayer triangular lattices through long-range pairing without requiring spin-orbit coupling and magnetic field, contrasting conventional frameworks reliant on superconductivity and spin-orbit coupling and time-reversal symmetry (TRS) breaking. Berry curvature analysis reveals spontaneous TRS-breaking-induced peaks or valleys under long-range pairing, signaling nontrivial topology superconducting state. Notably, the increase in the long-range pairing strength only changes the size of the energy band-gap, without triggering a topological phase transition. This characteristic is verified by calculating Berry curvature and topological edge states. In zigzag and armchair-edge ribbons of finite width, the topological edge states are regulated by the ribbon boundary symmetry and the interact range of long-range pairing. Under nearest-neighbor pairing, the topological edge states maintain particle-hole symmetry and matches the corresponding Chern number. However, next-nearest-neighbor and third-nearest-neighbor pairings break the particle-hole symmetry of the topological edge states in armchair-edge ribbon. This work proposes a mechanism for realizing topological superconductivity without relying on spin-orbit coupling and magnetic field, offering a theoretical foundation for simplifying the design of topological quantum devices. △ Less

Submitted 14 October, 2025; originally announced October 2025.

Comments: 13 pages, 6 figures

Astigmatism-free 3D Optical Tweezer Control for Rapid Atom Rearrangement

Authors: Yue-Hui Lu, Nathan Song, Tai Xiang, Jacquelyn Ho, Tsai-Chen Lee, Zhenjie Yan, Dan M. Stamper-Kurn

Abstract: Reconfigurable arrays of neutral atoms are a leading platform for quantum computing, quantum simulation, and quantum metrology. The most common method for atom reconfiguration using optical tweezers relies on frequency chirping of acousto-optic deflectors (AODs). However, chirp-induced acoustic lensing limits the speed of atom transport by deformation of the tweezer profile and warping of the twee… ▽ More Reconfigurable arrays of neutral atoms are a leading platform for quantum computing, quantum simulation, and quantum metrology. The most common method for atom reconfiguration using optical tweezers relies on frequency chirping of acousto-optic deflectors (AODs). However, chirp-induced acoustic lensing limits the speed of atom transport by deformation of the tweezer profile and warping of the tweezer trajectory. We use a three-dimensional acousto-optic deflector lens (3D-AODL) to mitigate both effects, a design predicted to halve current state-of-the-art long-range transport times. Additionally, we introduce fading-Shepard waveforms that bypass the finite AOD bandwidth and thus enable sustained axial displacement. We demonstrate unrestricted 3D motion within a cuboid volume of at least 200 $μ$m $\times$ 200 $μ$m $\times$ 136 $μ$m, with tweezer velocities exceeding 4.2 m/s. The ability to move optical tweezers along arbitrary trajectories in 3D should enable rapid in-plane and out-of-plane rearrangement of atoms in 2D or 3D tweezer arrays and optical lattices, as well as omnidirectional trajectories and dynamical engineering of optical potentials. This technology has the potential to advance quantum control and atom manipulation in current atom-array quantum computers, boosting clock rates and enabling rapid sorting in geometries scalable to millions of qubits. △ Less

Submitted 9 January, 2026; v1 submitted 13 October, 2025; originally announced October 2025.

Comments: 8 pages, 5 figures in the main body; 15 pages, 7 figures in the supplement and reference section

Higher symmetry breaking and non-reciprocity in a driven-dissipative Dicke model

Authors: Jacquelyn Ho, Yue-Hui Lu, Tai Xiang, Tsai-Chen Lee, Zhenjie Yan, Dan M. Stamper-Kurn

Abstract: Higher symmetries in interacting many-body systems often give rise to new phases and unexpected dynamical behavior. Here, we theoretically investigate a variant of the Dicke model with higher-order discrete symmetry, resulting from complex-valued coupling coefficients between quantum emitters and a bosonic mode. We propose a driven-dissipative realization of this model focusing on optomechanical r… ▽ More Higher symmetries in interacting many-body systems often give rise to new phases and unexpected dynamical behavior. Here, we theoretically investigate a variant of the Dicke model with higher-order discrete symmetry, resulting from complex-valued coupling coefficients between quantum emitters and a bosonic mode. We propose a driven-dissipative realization of this model focusing on optomechanical response of a driven atom tweezer array comprised of $n$ sub-ensembles and placed within an optical cavity, with the phase of the driving field advancing stepwise between sub-ensembles. Examining stationary points and their dynamical stability, we identify a phase diagram for $n\geq 3$ with three distinctive features: a $\mathbb{Z}_n$ ($\mathbb{Z}_{2n}$) symmetry-breaking superradiant phase for even (odd) $n$, a normal unbroken-symmetry phase that is dynamically unstable due to non-reciprocal forces between emitters, and a first-order phase transition separating these phases. This $n$-phase Dicke model may be equivalently realized in a variety of optomechanical or opto-magnonic settings, where it can serve as a testbed for studying high-order symmetry breaking and non-reciprocal interactions in open systems. △ Less

Submitted 24 March, 2026; v1 submitted 5 October, 2025; originally announced October 2025.

Comments: 13 pages, 9 figures

Journal ref: Physical Review Research 8, no. 1 (2026): 013311

Parametric dependence of unidirectional guided resonances in periodic structures

Authors: Lijun Yuan, Ya Yan Lu

Abstract: Unidirectional guided resonances (UGRs) in periodic structures are special resonant modes that exhibit strict one-sided radiation, even though radiation in both sides is allowed, offering significant advantages for various applications. Under a structural perturbation, a UGR typically turns to a regular resonant mode that radiates to both sides. Existing numerical results indicate that to find UGR… ▽ More Unidirectional guided resonances (UGRs) in periodic structures are special resonant modes that exhibit strict one-sided radiation, even though radiation in both sides is allowed, offering significant advantages for various applications. Under a structural perturbation, a UGR typically turns to a regular resonant mode that radiates to both sides. Existing numerical results indicate that to find UGRs in any periodic structure, it is necessary to tune at least one parameter. In this work, we develop a rigorous theory on the parametric dependence of UGRs. We show that in the presence of a single radiation channel, a UGR can exist continuously with respect to a structural parameter, provided that another parameter (associated with a generic perturbation) is properly tuned. Moreover, from a periodic structure with a generic bound state in the continuum (BIC), it is always possible to obtain a continuous family of UGRs by tuning one parameter. This implies that UGRs with arbitrarily large quality factor can be easily obtained. Our work provides a theoretical basis for designing useful photonic devices based on UGRs. △ Less

Submitted 2 October, 2025; originally announced October 2025.

DPSformer: A long-tail-aware model for improving heavy rainfall prediction

Authors: Zenghui Huang, Ting Shu, Zhonglei Wang, Yang Lu, Yan Yan, Wei Zhong, Hanzi Wang

Abstract: Accurate and timely forecasting of heavy rainfall remains a critical challenge for modern society. Precipitation exhibits a highly imbalanced distribution: most observations record no or light rain, while heavy rainfall events are rare. Such an imbalanced distribution obstructs deep learning models from effectively predicting heavy rainfall events. To address this challenge, we treat rainfall fore… ▽ More Accurate and timely forecasting of heavy rainfall remains a critical challenge for modern society. Precipitation exhibits a highly imbalanced distribution: most observations record no or light rain, while heavy rainfall events are rare. Such an imbalanced distribution obstructs deep learning models from effectively predicting heavy rainfall events. To address this challenge, we treat rainfall forecasting explicitly as a long-tailed learning problem, identifying the insufficient representation of heavy rainfall events as the primary barrier to forecasting accuracy. Therefore, we introduce DPSformer, a long-tail-aware model that enriches representation of heavy rainfall events through a high-resolution branch. For heavy rainfall events $ \geq $ 50 mm/6 h, DPSformer lifts the Critical Success Index (CSI) of a baseline Numerical Weather Prediction (NWP) model from 0.012 to 0.067. For the top 1% coverage of heavy rainfall events, its Fraction Skill Score (FSS) exceeds 0.45, surpassing existing methods. Our work establishes an effective long-tailed paradigm for heavy rainfall prediction, offering a practical tool to enhance early warning systems and mitigate the societal impacts of extreme weather events. △ Less

Submitted 20 September, 2025; originally announced September 2025.

Thermal Cycling Reliability of Hybrid Pixel Sensor Modules for The ATLAS High Granularity Timing Detector

Authors: Y. Li, A. Aboulhorma, M. Ait Tamlihat, H. M. Alfanda, N. Atanov, O. Atanova, I. Azzouzi, J. Barreiro Guimarães Da Costa, T. Beau, D. Benchekroun, F. Bendebba, Y. Bimgdi, A. Blot, A. Boikov, J. Bonis, D. Boumediene, C. Brito, A. S. Brogna, A. M. Burger, L. Cadamuro, Y. Cai, N. Cartalade, R. Casanova Mohr, Y. Che, X. Chen , et al. (203 additional authors not shown)

Abstract: The reliability of bump connection structures has become a critical aspect of future silicon detectors for particle physics. The High Granularity Timing Detector (HGTD) for the ATLAS experiment at the High-Luminosity Large Hadron Collider will require 8032 hybrid pixel sensor modules, composed of two Low Gain Avalanche Diode sensors bump-bonded to two readout ASICs and glued to a passive PCB. The… ▽ More The reliability of bump connection structures has become a critical aspect of future silicon detectors for particle physics. The High Granularity Timing Detector (HGTD) for the ATLAS experiment at the High-Luminosity Large Hadron Collider will require 8032 hybrid pixel sensor modules, composed of two Low Gain Avalanche Diode sensors bump-bonded to two readout ASICs and glued to a passive PCB. The detector will operate at low temperature (-30 degrees Celsius) to mitigate the impact of irradiation. The thermomechanical reliability of flip-chip bump connections in HGTD modules is a critical concern, particularly due to their characteristically lower bump density (pixel pitch dimensions of 1.3 mm by 1.3 mm). This paper elaborates on the challenges arising from this design characteristic. Finite element analysis and experimental testing were employed to investigate failure modes in the flip-chip bump structures under thermal cycling from -45 degrees Celsius to 40 degrees Celsius and to guide the module redesign. The optimized design demonstrates significantly enhanced robustness and is projected to fulfill the full lifetime requirements of the HGTD. △ Less

Submitted 17 September, 2025; originally announced September 2025.

Comments: 15 pages, 12 figures, 7 tables

Morphological and Chemical Changes in Cd-free Colloidal QD-LEDs During Operation

Authors: Ruiqi Zhang, Jamie Geng, Shaun Tan, Shreyas Srinivasan, Taehyung Kim, Mayuran Saravanapavanantham, Kwang-Hee Lim, Mike Dillender, Heejae Chung, Thienan Nguyen, Karen Yang, Yongli Lu, Taegon Kim, Moungi G. Bawendi, Vladimir Bulovic

Abstract: Heavy metal-free quantum-dot light-emitting devices (QD-LEDs) have demonstrated remarkable brightness, saturated color, and high efficiencies across a broad spectral range. However, in contrast to organic LEDs (OLEDs), QD-LED operational lifetimes remain limited, with the underlying degradation mechanisms not fully understood. In the present study, we show that InP/ZnSe/ZnS (red-emitting) and ZnTe… ▽ More Heavy metal-free quantum-dot light-emitting devices (QD-LEDs) have demonstrated remarkable brightness, saturated color, and high efficiencies across a broad spectral range. However, in contrast to organic LEDs (OLEDs), QD-LED operational lifetimes remain limited, with the underlying degradation mechanisms not fully understood. In the present study, we show that InP/ZnSe/ZnS (red-emitting) and ZnTeSe/ZnSe/ZnS (blue-emitting) cadmium-free colloidal QD-LEDs undergo nanoscale morphological changes during operation. Specifically,interparticle coarsening and layer thinning are observed in the electron transport layer (ETL) consisting of ZnMgO nanoparticles (NPs), in the QD emissive layer, and in the organic hole transport layer. This is accompanied by the generation and diffusion of compositional oxygen- and hydrogen-radicals throughout the device, with oxygen accumulating at the electrode/ETL interfance. Moreover, in situ transmission electron microscopy reveals the electron beam exposure, in the presence of hydrogen radicals, accelerates ZnMgO NPs coarsening. To mitigate these degradation pathway, we show that acrylate-based resin-encapsulation treatment stabilize the ETL/QD layers by suppressing the radical formation and halting morphology changes. This approach achieves dramatic stability enhancements, exhibits an 8-fold and 5000-fold lifetime improvement on InP/ZnSe/ZnS and ZnTeSe/ZnSe/ZnS QD-LEDs, respectively. Our findings establish the causal relationships between the morphological degradation, interlayer radical dynamics, and state-of-the-art QD-LEDs instability, providing new insights into a scalable encapsulation treatment that enables efficient and long-lived Cd-free QD-LEDs. △ Less

Submitted 15 September, 2025; originally announced September 2025.

Comments: 34 pages, 5 figures

Moment Estimates and DeepRitz Methods on Learning Diffusion Systems with Non-gradient Drifts

Authors: Fanze Kong, Chen-Chih Lai, Yubin Lu

Abstract: Conservative-dissipative dynamics are ubiquitous across a variety of complex open systems. We propose a data-driven two-phase method, the Moment-DeepRitz Method, for learning drift decompositions in generalized diffusion systems involving conservative-dissipative dynamics. The method is robust to noisy data, adaptable to rough potentials and oscillatory rotations. We demonstrate its effectiveness… ▽ More Conservative-dissipative dynamics are ubiquitous across a variety of complex open systems. We propose a data-driven two-phase method, the Moment-DeepRitz Method, for learning drift decompositions in generalized diffusion systems involving conservative-dissipative dynamics. The method is robust to noisy data, adaptable to rough potentials and oscillatory rotations. We demonstrate its effectiveness through several numerical experiments. △ Less

Submitted 31 August, 2025; originally announced September 2025.

Approximation Error of the Burst Approximation for a Stochastic Gene Expression Model

Authors: Yuntao Lu, Yunxin Zhang

Abstract: Stochastic modeling of gene expression is a classic problem in theoretical biophysics, and the burst approximation is widely used to simplify gene expression models formulated via the chemical master equation. However, the approximation error has been investigated only for the simplest case. This article proposes and analyzes a general stochastic gene expression model with an arbitrary number of g… ▽ More Stochastic modeling of gene expression is a classic problem in theoretical biophysics, and the burst approximation is widely used to simplify gene expression models formulated via the chemical master equation. However, the approximation error has been investigated only for the simplest case. This article proposes and analyzes a general stochastic gene expression model with an arbitrary number of gene states, and quantifies the error introduced by the burst approximation. Using the standard binomial moment method, we derive recurrence relations for binomial moments in steady state. We develop an algorithm to numerically compute binomial moments in a hierarchical manner. In particular, explicit expressions for low-order moments are presented. Compared with surrogate models under the burst approximation, we conclude that the first-order moment of protein counts is preserved, whereas discrepancies generally arise in higher-order moments. By estimating the difference between two second-order moments using functional analysis, we evaluate the validity of the burst approximation. △ Less

Submitted 30 March, 2026; v1 submitted 10 September, 2025; originally announced September 2025.

Comments: 22 pages; References added; Typos corrected

MSC Class: 60J28

Disentangling the Effects of Simultaneous Environmental Variables on Perovskite Synthesis and Device Performance via Interpretable Machine Learning

Authors: Tianran Liu, Nicky Evans, Kangyu Ji, Ronaldo Lee, Aaron Zhu, Vinn Nguyen, James Serdy, Elizabeth Wall, Yongli Lu, Florian A. Formica, Moungi G. Bawendi, Quinn C. Burlingame, Yueh-Lin Loo, Vladimir Bulovic, Tonio Buonassisi

Abstract: Despite the rapid rise in perovskite solar cell efficiency, poor reproducibility remains a major barrier to commercialization. Film crystallization and device performance are highly sensitive to environmental factors during fabrication, yet their complex interactions are not well understood. In this work, we present a systematic framework to investigate the influence of both individual and coupled… ▽ More Despite the rapid rise in perovskite solar cell efficiency, poor reproducibility remains a major barrier to commercialization. Film crystallization and device performance are highly sensitive to environmental factors during fabrication, yet their complex interactions are not well understood. In this work, we present a systematic framework to investigate the influence of both individual and coupled environmental variables on device efficiency and crystallization kinetics. We developed an integrated fabrication platform with precise, independent control over ambient solvent partial pressure, absolute humidity, and temperature during spin-coating and thermal-annealing processes, respectively. Using the platform, we implemented a closed-loop Bayesian optimization framework to efficiently explore the multi-dimensional processing space. We mapped the impact of these environmental variables on device performance and identified coupled effects among them. In-situ grazing-incidence wide-angle X-ray scattering measurements further validated these findings by revealing a nonlinear interaction between absolute humidity and solvent partial pressure during spin-coating, which affects crystallization dynamics. To isolate and quantify these interactions, we developed an interpretable machine learning approach that combines knowledge distillation with Shapley interaction analysis. The model revealed the contribution of each interaction varies across different processing conditions. Our study highlights the importance of integrated ambient sensing and control to achieve repeatable perovskite solar cells, and demonstrates the utility of combining active learning with interpretable machine learning to navigate complex, high-dimensional processing landscapes. △ Less

Submitted 27 August, 2025; originally announced September 2025.

Realizing the Haldane Model in Thermal Atoms

Authors: Jiefei Wang, Jianhao Dai, Ruosong Mao, Yunzhou Lu, Xiao Liu, Huizhu Hu, Shi-Yao Zhu, Xingqi Xu, Han Cai, Da-Wei Wang

Abstract: Topological materials hold great promise for developing next-generation devices with transport properties that remain resilient in the presence of local imperfections. However, their susceptibility to thermal noise has posed a major challenge. In particular, the Haldane model, a cornerstone in topological physics, generally requires cryogenic temperatures for experimental realization, limiting bot… ▽ More Topological materials hold great promise for developing next-generation devices with transport properties that remain resilient in the presence of local imperfections. However, their susceptibility to thermal noise has posed a major challenge. In particular, the Haldane model, a cornerstone in topological physics, generally requires cryogenic temperatures for experimental realization, limiting both the investigation of topologically robust quantum phenomena and their practical applications. In this work, we demonstrate a room-temperature realization of the Haldane model using atomic ensembles in momentum-space superradiance lattices, a platform intrinsically resistant to thermal noise. The topological phase transition is revealed through the superradiant emission contrast between two timed Dicke states in the lattice. Crucially, the thermal resilience of this platform allows us to access a deep modulation regime, where topological transitions to high Chern number phases emerge -- going beyond the traditional Haldane model. Our results not only deepen the understanding of exotic topological phases, but also offer a robust, reconfigurable, and room-temperature-compatible platform that connects quantum simulation to real-world quantum technologies. △ Less

Submitted 10 September, 2025; originally announced September 2025.

Comments: 9 pages, 4 figures

Data-driven solar forecasting enables near-optimal economic decisions

Authors: Zhixiang Dai, Minghao Yin, Xuanhong Chen, Alberto Carpentieri, Jussi Leinonen, Boris Bonev, Chengzhe Zhong, Thorsten Kurth, Jingan Sun, Ram Cherukuri, Yuzhou Zhang, Ruihua Zhang, Farah Hariri, Xiaodong Ding, Chuanxiang Zhu, Dake Zhang, Yaodan Cui, Yuxi Lu, Yue Song, Bin He, Jie Chen, Yixin Zhu, Chenheng Xu, Maofeng Liu, Zeyi Niu , et al. (5 additional authors not shown)

Abstract: Solar energy adoption is critical to achieving net-zero emissions. However, it remains difficult for many industrial and commercial actors to decide on whether they should adopt distributed solar-battery systems, which is largely due to the unavailability of fast, low-cost, and high-resolution irradiance forecasts. Here, we present SunCastNet, a lightweight data-driven forecasting system that prov… ▽ More Solar energy adoption is critical to achieving net-zero emissions. However, it remains difficult for many industrial and commercial actors to decide on whether they should adopt distributed solar-battery systems, which is largely due to the unavailability of fast, low-cost, and high-resolution irradiance forecasts. Here, we present SunCastNet, a lightweight data-driven forecasting system that provides 0.05$^\circ$, 10-minute resolution predictions of surface solar radiation downwards (SSRD) up to 7 days ahead. SunCastNet, coupled with reinforcement learning (RL) for battery scheduling, reduces operational regret by 76--93\% compared to robust decision making (RDM). In 25-year investment backtests, it enables up to five of ten high-emitting industrial sectors per region to cross the commercial viability threshold of 12\% Internal Rate of Return (IRR). These results show that high-resolution, long-horizon solar forecasts can directly translate into measurable economic gains, supporting near-optimal energy operations and accelerating renewable deployment. △ Less

Submitted 8 September, 2025; originally announced September 2025.

Comments: Main text ~12 pages, 4 figures, 0 tables