Fluid Dynamics
Self-similar breakup of a liquid ligament with a solid particle
Sanjay Shukla and Federico Toschi
The breakup of thinning (stretching)
liquid ligaments is strongly influenced by localized perturbations arising from
impurities or suspended particles. Using numerical simulations and analytical modelling, we investigate the role of a solid particle on the breakup dynamics of a stretching
liquid ligament. We show that particle-induced perturbations trigger a universal pinch-off dynamics in the viscous regime. Once the ligament surface approaches the particle, the subsequent breakup becomes self-similar and independent of the particle size. We derive an analytical expression for the pinch-off time based on the interplay between ligament stretching and Rayleigh-Plateau instability, which agrees quantitatively with simulations. Our results reveal a universal mechanism by which localized perturbations control the breakup of ligaments containing solid particles.
Read the full abstract ▾
Chemical Physics · Cross-listed from quant-ph
Quantum master equation approach for the multiphonon up-pumping model
Jiong Cheng, Yanqiang Yang, Wenlin Li et al. (+1 more)
A fully
quantum multiphonon up-pumping model is proposed to characterize coherent energy transfer in energetic materials (EMs) subjected to external shock. After eliminating the degrees of freedom of the
phonon bath within a mean-field approximation, we derive a
quantum master equation governing the energy transfer among vibrational modes. Our analysis reveals that doorway modes of different frequencies undergo distinct levels of effective coherent driving and dissipation, induced by the shocked
phonon environment. This not only clarifies the microscopic origin of coherent
phonon generation, but also reveals the possibility of modulating such coherent driving and dissipation. Based on numerical simulations of a simplified model using the master equation, we demonstrate how doorway modes extract energy from the
phonon environment and subsequently excite higher-frequency molecular vibrational modes. This work offers a renewed perspective for understanding the mechanisms of energy transfer in energetic materials.
Read the full abstract ▾
All authors Jiong Cheng, Yanqiang Yang, Wenlin Li, Xun Li
Applied Physics
Integrated Circuit Architecture for Real-Time Sensing with Embedded Microbial Whole-Cell Sensors
Amritha Janardanan, Soner Sonmezoglu, Stefano Sonedda et al. (+6 more)
Bacteria sense a diverse range of environmental analytes with high sensitivity and temporal resolution. Engineering and synthetic biology approaches enabled harnessing this capability through development of whole-
cell biosensors that respond to specific molecules of interest. However, converting these responses into electrical signals in real time, across different environmental conditions, in miniaturized, field-deployable microelectronic devices, remains challenging. Here we present a bioelectronic platform that directly couples engineered bacteria to an integrated
circuit (IC) chip through custom on-chip microelectrodes, enabling real-time, electronic readout of analyte sensing through bacterial flagellar motor dynamics. Using non-Faradaic electrochemical impedance measurements the device resolves both the direction and speed of motor rotation with a signal-to-noise ratio (SNR) of 15 dB. The IC is further integrated with a microfluidic system that enables controlled delivery and removal of analytes, nutrients and bacteria. When combined with whole-
cell biosensors engineered to detect specific analytes, this work provides a miniature, portable platform for continuous monitoring in a range of
liquid environments.
Read the full abstract ▾
All authors Amritha Janardanan, Soner Sonmezoglu, Stefano Sonedda, Tom J. Zajdel, James L. Flewellen, Meera Lester, Behzad Rad, Michel M. Maharbiz, Teuta Pilizota
Atomic Physics · Cross-listed from quant-ph
High-fidelity molecular quantum logic gates resilient to interaction fluctuation
Yan Lu and Xiao-Feng Shi
Optically trapped polar molecules are promising for
quantum information processing, yet the accuracy of an entangling molecular gate is limited by the uncertainty of dipole-dipole interactions~(DDI) from the molecular motion in traps. We show that two $\pi$ pulses of global microwave excitation can yield a high-fidelity controlled-phase gate when assisted by two single-
qubit gates. The gate is resilient to the uncertainty of DDI because it does not rely on populating DDI-coupled states. Further, the controlled phase is fully tunable by varying the relative phase of the two global microwave pulses, and, hence, the gate can find applications in a wide range of
quantum algorithms involving
quantum Fourier transform. Moreover, we introduce a motional-mode separation technique to
quantum mechanically study the influence of the molecular motion, which shows that the gate fidelity can be over 0.9999 with typical experimental conditions.
Read the full abstract ▾
Optics · Cross-listed from cond-mat.str-el
Filling-Sensitive Spectral Complexity from Hilbert-Space Holonomy in Fragmented Non-Hermitian Systems
Jiong-Hao Wang, Maria Zelenayova, Christopher Ekman et al. (+1 more)
We show that
Hilbert-space holonomy provides a
geometric organizing principle for spectral reality in fragmented non-Hermitian many-body systems, complementary to conventional
symmetry protection. In two minimal fragmented models, complex spectra can arise only within the most symmetric sectors: half filling in the
fermion model and zero magnetization in the
spin chain. Adding or removing a single particle, or flipping a single
spin, renders the spectra entirely real despite unchanged periodic boundary conditions, reminiscent of boundary-condition sensitivity in systems with a non-Hermitian skin effect. We explain this by viewing nonreciprocal hopping amplitudes as a discrete gauge field on the Krylov graph: trivial holonomy permits a diagonal similarity transformation to the Hermitian limit, whereas nontrivial holonomy obstructs it and allows complex spectra. In certain regimes, trivial holonomy admits an emergent-boundary interpretation, and longer-range models exhibit finite real and complex regions governed by the same criterion.
Read the full abstract ▾
All authors Jiong-Hao Wang, Maria Zelenayova, Christopher Ekman, Emil J. Bergholtz
Fluid Dynamics
Large-eddy simulation of moderately dense evaporating sprays with particle-informed super-resolution
Ruyue Cheng, Ali Shamooni, Andreas Kronenburg et al. (+2 more)
In large-eddy simulation (LES) of dense sprays or sprays with pronounced clustering, evaporation rates can be inaccurate when the mesh is too coarse to provide realistic boundary conditions for the widely employed single droplet evaporation model. This is especially relevant to
liquid spray combustion in practical applications. Deep learning-based super-resolution (SR) has recently emerged as a promising method for LES subgrid-scale modeling, capable of enhancing flow field resolution. This technique appears well-suited to reconstruct the local gas fields within the inter-droplet space that can be used to correct the evaporation rates. However, it has not yet been applied for this purpose. This paper presents an innovative SR approach $-$ particle-informed super-resolution (PISR) $-$ that approximates high-resolution flow fields for improved evaporation computation. It is validated with a priori, a posteriori and generalization tests on moderately dense sprays. The results show that PISR-LES can closely replicate the evaporation rates computed in a carrier-phase direct numerical simulation (CP-DNS), significantly reducing the discrepancy in the fuel mass fraction field between LES and CP-DNS. Furthermore, the PISR model exhibits robust generalization to cases unseen in training when varying air temperature, droplet diameter, turbulent Reynolds number and spray pattern.
Read the full abstract ▾
All authors Ruyue Cheng, Ali Shamooni, Andreas Kronenburg, Jan Wilhelm Gärtner, Thorsten Zirwes
Atmospheric and Oceanic Physics
Matrix structure and convergence behaviour of the matched eigenfunction method for computing heave wave forces on generalized concentric bodies
Yinghui Bimali, Rebecca McCabe, Collin Treacy et al. (+3 more)
Structural survival of offshore structures is crucial for the growing marine economy. Calculating the added mass, radiation damping, and excitation coefficients to quantify wave loads with the traditional boundary element method (BEM) presents a computational bottleneck. The matched eigenfunction expansion method (MEEM), a long-known but rarely-used alternative, offers computational benefits due to its semi-analytical nature. However, previous work fails to directly compare its accuracy and computational performance with BEM, leaving the extent of its utility unknown. Furthermore, the geometry-dependent convergence for cylindrical and slanted geometries has not yet been documented, making the method's practicality for general geometries unclear. This paper presents a unifying MEEM framework for modeling an arbitrary number of fixed or heaving surface-piercing annular cylinders with continuous and radially-monotonic body profiles, and explores the method's block
matrix structure, convergence behavior, ability to accurately approximate slanted geometries, and computational advantages over the BEM solver Capytaine. The numerical experiments show that MEEM can compute hydrodynamic coefficients of slanted geometries within 5% of Capytaine, even for angles as steep as 15 degrees from vertical. Finally, MEEM can achieve 2% convergence of its hydrodynamic coefficients an order of magnitude faster than Capytaine with a
matrix size two orders of magnitude smaller, making it a computationally effective alternative to traditional BEM solvers. These contributions enable hydrodynamic analysis of a broad range of shapes with increased speed and confidence, paving the way for future optimization studies to yield improved designs.
Read the full abstract ▾
All authors Yinghui Bimali, Rebecca McCabe, Collin Treacy, Kapil Khanal, En Lo, Maha Haji
Accelerator Physics
A novel accelerating structure based on a tapered parallel-plate waveguide with an integrated dielectric terahertz-driven accelerator
Andres Leiva Genre, Zoltán Tibai, Luis Nasi et al. (+4 more)
We present a novel dielectric terahertz-driven accelerator (DTA) that integrates a dual-pillar grating structure within a tapered parallel-plate waveguide (TPPWG). This compact setup enables efficient particle acceleration using multi-cycle, narrowband terahertz (THz) pulses. The TPPWG serves a dual role: it enhances the THz field via
geometric tapering and delivers it to the dielectric structure by efficient coupling. Experimental validation of the THz field inside the waveguide is conducted using electro-optic sampling. Optimization of waveguide parameters through time-domain simulations reveals a sixfold peak electric field amplification at the end of the waveguide. The dielectric accelerator is tailored for maximum acceleration by adjusting the DTA pillar radius and
vacuum channel gap for relativistic electron beams. Particle-in-
cell (PIC) simulations demonstrate that the structure supports net acceleration with gradients up to 120 MeV per m for 0.1 GV per m field strengths, and can accommodate bunch charges up to 10 pC with minimal degradation. Energy spread
evolution and beam dynamics are discussed in detail, including the role of phase slippage and bunch length. This work establishes the DTA-integrated TPPWG as a compact and scalable platform for high-gradient THz-driven acceleration, combining simple fabrication and design, strong field enhancement, and compatibility with existing electron sources. It opens new pathways toward practical, tabletop accelerators for scientific and industrial applications.
Read the full abstract ▾
All authors Andres Leiva Genre, Zoltán Tibai, Luis Nasi, Mátyás Kiss, Gábor Almási, János Hebling, Szabolcs Turnár
Optics
Resonant Electric-Magnetic Toroidal Duality in Height-Modulated Hexagonal Metasurfaces
Oleksiy Breslavets, Yuri Savin and Zoya Eremenko
Toroidal modes enable high-Q resonances, but electric toroidal excitations remain unexplored compared to
magnetic ones. This work establishes electric-
magnetic toroidal duality in a hexagonal metasurface. Using finite element simulations, we analyze electric and
magnetic toroidal modes in a hexagonal silicon nanorod supercell under mirror-
symmetry breaking via height modulation. Eigenfrequencies, Q-factors, power flow, and polarization responses are computed. We identify electric TO and ATO modes with complementary near-field
topologies to
magnetic analogues. Direct frequency intersections (
magnetic and electric TO/ATO) yield high-Q quasi-BICs. Polarization selectivity reverses between families: 0{\deg} excites
magnetic TO/electric ATO; 90{\deg} excites
magnetic ATO/electric TO. A loss hierarchy (
magnetic TO >
magnetic ATO > electric ATO > electric TO) and protective layers compatibility are demonstrated. Electric and
magnetic toroidal responses are dual manifestations of the same
symmetry, providing a unified design framework for high Q metasurfaces in sensing, nonlinear optics, and loss-tolerant devices.
Read the full abstract ▾
Medical Physics
Cross-View Attention Fusion Net: A Prior-Guided Dual-View Representation Learning for Cardiac Output Estimation from Short-Term PPG Signals
Yaowen Zhang, Bo Cui, Libera Fresiello et al. (+3 more)
Accurate cardiac output (CO) estimation from photoplethysmography (PPG) is promising for unobtrusive hemodynamic monitoring, but remains difficult since CO is jointly determined by cardiac function and vascular tone. Conventional feature-based models use physiologically meaningful PPG descriptors, yet depend on accurate pulse detection and may miss latent temporal relationships. In contrast, fully end-to-end deep learning models learn directly from raw PPG but often underuse established PPG-derived prior information. Here, we introduce the Cross-View
Attention Fusion Network (CVAF-Net), a prior-guided dual-view deep learning model for CO estimation from short, fixed-length PPG segments. CVAF-Net processes raw PPG as a temporal view and a feature sequence map (FSM) as a structured prior-guided view, and fuses the two representations through cross-view
attention. The model was independently evaluated using 5-, 15-, and 30-s segments from three
datasets: simulated pulse waves (3323 subjects), vasoconstriction provocation (79 subjects), and resting/cycling activities (10 subjects), and was compared with multiple machine learning and deep learning
benchmarks. CVAF-Net outperformed most
benchmark methods and achieved performance comparable to a state-of-the-art
Transformer-based model, with a mean absolute error (MAE) of 0.19 L/min (MAPE: 3.95%) on simulated data and high accuracy in real-world settings (minimum MAE: 1.20 L/min). Importantly, CVAF-Net reduced FLOPs by twelvefold compared with the leading
Transformer-based model. Plausibility analysis showed physiologically consistent CO estimates, with expected correlations with age ($\rho = -0.274$), heart rate ($\rho = 0.894$), and systemic vascular resistance ($\rho = -0.740$). These findings indicate that CVAF-Net provides an accurate, computationally efficient, and generalizable approach for continuous wearable-based CO monitoring.
Read the full abstract ▾
All authors Yaowen Zhang, Bo Cui, Libera Fresiello, Peter H. Veltink, Dirk W. Donker, Ying Wang
Optics
Engineering Tunable Synthetic Su-Schrieffer-Heeger Chains in Liquid Crystal Microcavities
Joanna Mędrzycka, Luciano S. Ricco, Piotr Kapuściński et al. (+8 more)
Optical microcavities have emerged as a powerful platform for emulating topological phases challenging to realize in conventional materials, offering precise control over dispersion, light confinement, and interactions. Among them,
liquid crystal microcavities (LCMCs) offer exceptional tunability at room temperature, enabling voltage-controlled polarisation splitting, photonic
spin-orbit coupling, and photonic potentials generated by self-assembled textures, such as cholesteric torons and uniform lying helix (ULH). Here, we design a LCMC hosting a dimerized ULH texture and show that the corresponding photonic potential describes two coupled Su-Schrieffer-Heeger chains with orthogonal linear polarisations, acting as an effective pseudospin degree of freedom. The applied voltage tunes the interchain coupling, enabling polarisation-dependent interactions. These results establish LCMCs as a versatile platform for tunable synthetic topological
Hamiltonians.
Read the full abstract ▾
All authors Joanna Mędrzycka, Luciano S. Ricco, Piotr Kapuściński, Marcin Muszyński, Przemysław Morawiak, Rafał Mazur, Rafał Węgłowski, Eva Oton, Przemysław Kula, Wiktor Piecek, Jacek Szczytko
Accelerator Physics
Design and Development of the P-cubed Target Insertion Device (P$^3$-TID)
Ramiro Mena-Andrade, Jean-Louis Grenard, Kevin Guergar et al. (+12 more)
The P-cubed Target Insertion Device (P$^3$-TID) is a research instrument dedicated to test novel positron source target configurations inside of the proof-of-principle PSI Positron Production (P-cubed or P$^3$) experiment at the Paul Scherrer Institute. The device allows an easy installation, positioning and replacement of different fixed targets. The present article describes its mechanical design at a detailed level.
Read the full abstract ▾
All authors Ramiro Mena-Andrade, Jean-Louis Grenard, Kevin Guergar, Régis Seidenbinder, Maria Ilaria Besana, Barbara Humann, Giacomo Lavezzari, Markus Widorski, Anton Lechner, Nicolas Vallis, Mariia Zykova, Dominique Hauenstein, Riccardo Zennaro, Paolo Craievich, Antonio Perillo-Marcone
Atomic Physics
Coherent Molecular Deceleration via Vibrational Bichromatic Force
Meng-Yi Yu, Ya-Nan Lv, Cun-Feng Cheng et al. (+1 more)
We propose a scheme for direct
laser deceleration of molecules based on a vibrational transition-mediated bichromatic force (VBCF). By precisely engineering mid-infrared optical fields, we establish coherent absorption-stimulated emission cycles while exploiting the long lifetime of vibrational excited states to suppress spontaneous decay and decoherence, rendering the deceleration process effectively non-dissipative. Unlike schemes based on electronic transitions, our approach completely circumvents the restrictive Franck-Condon factors. Using the fundamental vibrational transition of $^{13}$CO$_2$ as a test case, we achieve a deceleration of $1.45\times 10^5$~m/s$^2$ with negligible population loss over the full interaction time. This VBCF framework provides a general route to cold molecules applicable to any species with an allowed fundamental vibrational transition, opening broad prospects in cold chemistry and
quantum metrology.
Read the full abstract ▾
All authors Meng-Yi Yu, Ya-Nan Lv, Cun-Feng Cheng, Shui-Ming Hu
Space Physics
Reassessment of Ionospheric Responses to GRB~221009A: Disentangling Instrumental, Illumination and Geophysical Effects
Maosheng He, Quanhan Li, Shun-Rong Zhang et al. (+5 more)
Gamma-ray bursts (GRBs) have long been proposed to perturb Earth's ionosphere, with occasional reports of disruptions in ultra- and extremely-low-frequency
radio signals. The exceptionally bright GRB~221009A was recently claimed to induce multi-altitude ionospheric responses, including perturbations in satellite electric fields, regional total electron content (TEC), and the equatorial electrojet (EEJ). These claims have renewed interest in the potential near-Earth impacts of astrophysical transients. Here we perform an independent reassessment using expanded
datasets spanning multiple altitudes. We find no coherent, burst-like TEC enhancement, show that the reported electric-field anomalies recur under specific illumination conditions each orbit, and demonstrate that the EEJ fluctuations preceded the burst and coincide with
solar-wind variability. Together, these results indicate that the reported GRB-induced ionospheric responses are fully attributable to other natural geophysical processes and instrumental artefacts, thereby resolving a high-profile controversy and clarifying the true limits of GRBs'ionospheric effects.
Read the full abstract ▾
All authors Maosheng He, Quanhan Li, Shun-Rong Zhang, Jeffrey M. Forbes, Jiuhou Lei, Libo Liu, Jiankui Shi, Chi Wang
Computational Physics · Cross-listed from cond-mat.mtrl-sci
Predicting Organic Solar Cell Performance and Stability from Fast, Morphology-aware Current-Voltage Modeling
Yasin Ameslon, Larry Lüer, Jens Harting et al. (+2 more)
Understanding the relationship between morphology and performance in organic
solar cells is essential for developing devices that are both high performing and resilient to aging. This work introduces a unique method capable of calculating the current-voltage (JV) curve of complex heterojunction morphologies containing up to five phases (donor amorphous, donor crystalline, acceptor amorphous, acceptor crystalline, mixed amorphous) with a very low computation time using morphology-aware descriptors of light absorption,
exciton dissociation, non-geminate recombination and free charge carrier mobilities. The method is validated against Monte Carlo and 3D drift-
diffusion simulations and applied to P3HT:PCBM and PM6:Y6 systems, shedding light on the physical compromises encountered to optimize device performance and lifetime. Finally, we show that the morphology-performance relationship is dependent on the materials system studied.
Read the full abstract ▾
All authors Yasin Ameslon, Larry Lüer, Jens Harting, Olga Wodo, Olivier J.J. Ronsin
Applied Physics · Cross-listed from quant-ph
Photolithography-Only Fabrication of Transmons Using Double-Oblique Evaporation
K. Aoyanagi, S. Abe, S. Chen et al. (+7 more)
We investigate a photolithography-only fabrication process for transmon Josephson junctions using a modified double-oblique evaporation geometry. Using a
bilayer resist process and Al shadow evaporation, we fabricate junction structures and confirm by optical and scanning electron microscopy that the resulting narrowed crossing region reaches a geometrical area on the order of $10^4~\mathrm{nm}^2$, which lies in the size range relevant to
qubit junction fabrication. Room-temperature resistance screening shows that the junction resistance falls within the target range for the present transmon design over a usable process window and exhibits a clear design dependence. We further implement fabricated junctions in transmon devices and evaluate them in a three-dimensional Al cavity at $20 \, \mathrm{mK}$, where we observe basic transmon
qubit operation with $f_{01}$=4.865 GHz, $T_1 \sim 9 \, \mu \mathrm{s}$, and $T_2^* \sim 0.4 \, \mu \mathrm{s}$. These results demonstrate the feasibility of realizing functional transmon devices in a photolithography-only process using double-oblique evaporation.
Read the full abstract ▾
All authors K. Aoyanagi, S. Abe, S. Chen, T. Inada, C. Kawai, Y. Mino, K. Nakamura, K. Nakazono, T. Nitta, K. Watanabe
Fluid Dynamics · Cross-listed from cs.LG
Physics-Informed Graph Neural Network Surrogates for Turbulent Nanoparticle Dispersion in Dental Clinical Environments
Takshak Shende and Viktor Popov
Dental aerosol procedures produce sub-50 micrometre
nuclei that can remain airborne for long periods in enclosed clinics, creating pathways for airborne pathogen transmission. Reynolds-Averaged Navier-Stokes (RANS) simulations with Euler-Lagrange particle tracking capture this transport accurately but require very long run times per scenario, which precludes real-time clinical decision support in 3D. We present the Eulerian-Lagrangian Graph Interaction Network (ELGIN), a physics-informed graph surrogate that jointly predicts carrier-flow dynamics on the OpenFOAM polyhedral mesh and the per-parcel motion of the polydisperse spray cloud. ELGIN couples a multi-head Graph
Transformer with Jacobi-preconditioned learnable pressure projection and a
turbulence-closure head to a sigmoid-gated Lagrangian Interaction Network through differentiable inverse-distance mesh-parcel coupling, and advances parcels with a
symplectic Stormer-Verlet integrator. A four-stage physics-informed curriculum stabilises 260-step autoregressive rollouts without gradient explosion. A parameter sweep with foam-extend 4.1 OpenFOAM reactingParcelFoam across clinically relevant ventilation rates and handpiece spray speeds provides CFD ground truth. This article reports a single-case demonstration in which both ELGIN and a Lagrangian-only baseline (M0) are trained and evaluated on Sweep_Case_03 of a twenty-case sweep; full 16/2/2 retraining is in progress and will replace all reported metrics. On this case, ELGIN tracks the foam-extend particle cloud much more closely than M0: mean parcel displacement error falls from 19.56% to 16.20% of room width and cloud radius-of-gyration error from 9.85% to 6.58%. A 26-second rollout completes in ~64 s on a 4 GB GPU, approximately 37x faster than the foam-extend reference pipeline, toward per-appointment infection-risk screening once the multi-case checkpoint is in place.
Read the full abstract ▾
Plasma Physics
Resolving Conductor-to-Plasma Transition Through Low-Energy Electrical Explosion of metallic foils
Aditya Nandan Savita, Sambaran Pahari, Neraj Shiv et al. (+1 more)
Electrical explosion of metallic foils involves a rapid transition from solid-state conduction through melting and vaporization to formation of an ionized
plasma. Resolving intermediate processes is challenging because these transformations occur over strongly overlapping timescales. In this work, to examine temporal
evolution of conductor-to-
plasma transition, electrical explosion of Al foil is investigated under two controlled energy-deposition regimes. At higher energy deposition, synchronized current, voltage, and fast-framing optical measurements capture explosive destruction of foil and subsequent
plasma formation. However, underlying intermediate processes remain temporally compressed. To resolve these processes, experiments are performed at a lower energy-deposition rate while maintaining comparable
circuit timescales. Under these conditions, characteristic features in the electrical waveforms allow successive stages of heating, melting,
liquid-phase
evolution, vaporization, and vapor discharge to be delineated. Experimentally determined action integrals associated with observed transitions are compared with predictions based on the Tucker Toth specific-action model and available literature. A particularly notable observation is a sharp voltage turnaround immediately preceding current re-strike, occurring simultaneously with increasing current and reproducibly associated with
plasma formation. Although its physical origin remains unresolved, the feature suggests a rapid nonlinear reorganization during final transition from exploding conductor and metal vapor to
plasma conduction. Results demonstrate that controlled energy-deposition rate provides an effective means of temporally resolving processes otherwise compressed and offers a useful approach for investigating the dynamics preceding
plasma formation in electrically exploded foils.
Read the full abstract ▾
All authors Aditya Nandan Savita, Sambaran Pahari, Neraj Shiv, IVV Suryaprasad
Accelerator Physics
Using Longitudinal Strong Focusing Principle to Lower Particle Beam Energy Spread Locally in a Storage Ring
Xiujie Deng, Alex Chao, Wenhui Huang et al. (+3 more)
In this paper, we propose to use longitudinal strong focusing principle to lower particle beam energy spread locally in a storage ring. An example application of the proposed scheme in reversible Echo SSMB for high-power EUV radiation generation is presented. We believe strong focusing in the longitudinal dimension has a wide application potential.
Read the full abstract ▾
All authors Xiujie Deng, Alex Chao, Wenhui Huang, Zhilong Pan, Chuanxiang Tang, Jingyuan Zhao
Optics
Energy-efficient programmable integrated photonics via optimized Euler rotations
Pablo Martínez-Carrasco Romero, Andrés Macho-Ortíz, José Roberto Rausell-Campo et al. (+2 more)
Programmable integrated photonics (PIP) has emerged as a powerful on-chip platform for optical signal processing and computing, enabling the implementation of reconfigurable N$\times$N
unitary matrix transformations through meshes of tunable interferometers, which realize 2$\times$2
unitary matrices. However, the energy consumption associated with phase-shifter actuation is becoming a major limitation to the scalability of PIP platforms. Here, we introduce a
geometric framework for energy optimization in PIP
circuits by exploiting the representation of 2$\times$2
unitary matrices as concatenations of basic Euler rotations on the Bloch sphere. We show that equivalent implementations of the same N$\times$N
unitary matrix (N $\geq$ 2) can exhibit markedly different energy costs depending on the rotation trajectories on the Bloch sphere implemented by each interferometer. Leveraging this insight, we identify minimum-energy configurations by systematically selecting the shortest rotation trajectories. We experimentally and numerically validate the proposed approach in diverse silicon PIP architectures, including feedforward and multipurpose hexagonal meshes, neural network accelerators, and photonic
quantum-gate implementations. These results establish a general route toward more energy-efficient large-scale PIP processors for classical and
quantum signal processing and computing applications.
Read the full abstract ▾
All authors Pablo Martínez-Carrasco Romero, Andrés Macho-Ortíz, José Roberto Rausell-Campo, Francisco Javier Fraile-Peláez, José Capmany Francoy
Fluid Dynamics
HiLiftAeroML: A High-Fidelity Computational Fluid Dynamics Dataset for High-Lift Aircraft Aerodynamics
Neil Ashton, Adam Clark, Konrad Goc et al. (+11 more)
HiLiftAeroML is, to our knowledge, the first open high-fidelity computational fluid dynamics
dataset dedicated to high-lift aircraft aerodynamics. It contains 1,800 simulations spanning 180 variants of the NASA Common Research Model high-lift configuration and ten angles of attack from $4^\circ$ to $22^\circ$. Each case was generated with a GPU-accelerated explicit wall-modeled large-eddy simulation approach on solution-adapted grids of 300–500 million
cells, covering attached, separated, and post-stall flow conditions. Comparisons with wind-tunnel measurements for reference landing configurations show good agreement in integrated loads and sectional pressures, with grid adaptation substantially improving drag and pitching-moment predictions. The CC-BY-4.0 release includes geometries, time-averaged surface and volume fields, integrated loads, validation material, and deterministic
benchmark splits. Initial GeoTransolver and Transolver baselines, evaluated on the complete native surface and volume support of every held-out case rather than on a sampled subset, reconstruct the fields well for several interpolation and held-out-geometry tests, while high-angle separated flow, limited-data training, and out-of-distribution flow-regime shifts remain substantially harder. The
dataset and baselines provide a common resource for developing and assessing data-driven models for realistic high-lift aerodynamics.
Read the full abstract ▾
All authors Neil Ashton, Adam Clark, Konrad Goc, Liam Heidt, Christopher Ivey, Rahul Agrawal, Sanjeeb T Bose, Corey Adams, Peter Sharpe, Daniel Leibovici, Semih Akkurt, Sheel Nidhan, Rishi Ranade, Jean Kossaifi
Classical Physics
Automated Discovery of Metainterfaces with Tailored Friction Laws
Li Fu, Djibril Gabriel Kashala, D. Dalmas et al. (+1 more)
Providing dry solid contacts with on-demand macroscale frictional behaviour remains a formidable challenge in tribology, haptics or robotics. Metainterfaces created from surfaces with engineered asperity-based topographies can achieve such friction control. However, only few friction behaviours were demonstrated because suitable topographies were identified based on human intuition. Here, we introduce a numerical-optimisation-based inverse design framework to automatically discover new metainterfaces satisfying specified relationships between friction and normal forces (friction law). To illustrate the framework's versatility, we first expand the range of achievable friction coefficients at a constant material pair; we next unlock power-law friction laws with arbitrary exponents between 2/3 and 1.35; we then achieve bilinear laws with a smaller slope in the second segment than in the first. We validate relevant cases experimentally. By enabling systematic exploration of large parameter spaces, not limited to topography but potentially incorporating the individual asperities' bulk material or surface physicochemistry, our automated framework offers design solutions for any physically possible friction law. It also provides new insights into the elusive relationship between local interfacial properties and macroscopic friction.
Read the full abstract ▾
All authors Li Fu, Djibril Gabriel Kashala, D. Dalmas, J Scheibert
Medical Physics
On the Hyperelastic Behavior of the Boar Diaphragmatic Tendon Membrane by Inflation Tests and Modeling
R. Anwar, J. Vasquez-Villegas, S. Le Floc'h et al. (+3 more)
Background: Despite the large variety of materials used to repair congenital diaphragmatic hernia (CDH), none has proven ideal due to complications and risk of recurrence. Understanding the mechanical behavior of the diaphragm's central tendon is essential for developing biomimetic prostheses. Objective: This study aims to characterize the hyperelastic behavior of the porcine diaphragmatic tendon under biaxial loading conditions. Methods: Biaxial hyperelastic response of the porcine diaphragmatic central tendon was characterized using bulge inflation tests combined with full-field stereo digital image correlation (3D-DIC). Principal stretches were extracted from the reconstructed three-dimensional geometry using a spherical-cap approximation, with corrections for clamping-induced pre-deformation. Several incompressible isotropic hyperelastic models (Neo-Hookean, Mooney-Rivlin, Yeoh and Fung) were first evaluated as phenomenological baselines. To account for the anisotropic mechanical signature of the tendon, a transversely isotropic hyperelastic formulation of the Humphrey-Yin type was implemented. This model represents an effective anisotropic response associated with the lamellar and collagen-rich structure of the tissue through its thickness, while assuming isotropy within the membrane plane. Results: The diaphragm tissue exhibited an exponential mechanical response. Neo-Hookean and Mooney-Rivlin models failed to capture the observed behavior, while the Yeoh model slightly overestimated nonlinearity. The Fung model provided the closest fit to the nonlinear pressure-stretch response, yet failed to reproduce the directional differences observed between meridional and circumferential stretches. The Humphrey-Yin model provided a markedly improved description of the experimental data over the full inflation range. Parameter identification revealed that the transversely isotropic contribution dominated the strain-energy response, highlighting the limitations of isotropic constitutive laws for modeling diaphragmatic tendon mechanics, even under macroscopically axisymmetric inflation. Despite specimen-to-specimen variability, no significant differences were observed between left and right diaphragm samples. Conclusion: Overall, this work demonstrates that effective anisotropic hyperelastic formulations are required to describe the biaxial mechanical behavior of the diaphragmatic central tendon under inflation loading. The proposed experimental-numerical framework provides a robust basis for biomechanical modeling and constitutes a first step toward the development of biomimetic prosthetic materials for diaphragmatic repair.
Read the full abstract ▾
All authors R. Anwar, J. Vasquez-Villegas, S. Le Floc'h, P. Royer, N. Bahlouli, Christiane Wagner-Kocher
Instrumentation and Detectors
The measurement of late-pulses and after-pulses in the large area Hamamatsu R7081 photomultiplier with improved quantum-efficiency photocathode
S. Aiello, M. Anghinolfi, A. Balbi et al. (+9 more)
In recent years, large
underwater telescopes have been designed and realized to measure high energy
neutrinos from astrophysical objects.
Muon tracks produced by the
neutrino interaction in the surrounding medium are reconstructed from the arrival time and the number of photo-electrons of the Cherenkov light measured by the Photomultiplier tubes (PMT) array of the detector. For a correct reconstruction procedure, both the scattering of the light in the water and the late and after pulses produced in the PMTs must be considered. In this paper we report on this latter effect which has been measured in our laboratory using a
laser in the single photoelectron mode (SPE) on a Hamamatsu R7081MOD 10" PMT with a high
quantum efficiency photocathode. The PMT voltage supply was set to provide the 1 photo-electron peak at 10 pC as during normal operation: in this condition we find that the late-pulse contribution is small but not negligible.
Read the full abstract ▾
All authors S. Aiello, M. Anghinolfi, A. Balbi, M. Brunoldi, K. Gracheva, A. Grimaldi, V. Kulikovskiy, E. Leonora, G. Ottonello, D. Sciliberto, M. Taiuti, Y. Yakovenko
Optics
Near-Field Vibrational Energy Transfer for Mid-Infrared Upconversion in Plasmonic Nanogaps
Avisekh Pal, Anju Sajan, Christopher Sumner et al. (+3 more)
Förster energy transfer underpins modern photonics, yet establishing an analogous vibrational pathway in the mid-infrared (MIR) remains highly challenging, as sub-picosecond intramolecular vibrational redistribution (IVR) suppresses intermolecular coupling. Here we demonstrate vibrational donor–acceptor transfer in the MIR and subsequent upconversion to visible luminescence enabled by sub-2 nm plasmonic nanogaps. The extreme lateral field confinement in metal–molecule–metal ring cavities defined by self-assembled molecular spacers couples efficiently to in-plane molecular dipoles. Continuous-wave MIR excitation selectively populates $-\mathrm{C}\equiv\mathrm{N}$ vibrational donors, and plasmon-enhanced near-field coupling transfers this energy to nearby electronic acceptors, generating anti-Stokes visible emission under low power densities. Upconversion efficiencies exceeding $0.3\%$ are observed, limited by competition between the plasmon-mediated transfer rate and IVR. These results show that extreme plasmonic confinement can redirect molecular vibrational relaxation pathways, opening a route toward vibrational nanophotonics, intermolecular interactions for bioimaging, and room-temperature MIR detection based on molecular degrees of freedom.
Read the full abstract ▾
All authors Avisekh Pal, Anju Sajan, Christopher Sumner, Eman Alharbi, Wolfgang Theis, Rohit Chikkaraddy
Data Analysis and Statistics · Cross-listed from astro-ph.IM
Methodological Synergies between Technosignature and UHE Neutrino Searches
Paramita Dasgupta
Radio technosignature searches and
radio-based ultra-high energy (UHE)
neutrino experiments address different scientific questions, but share a closely related data analysis problem: identifying rare signals of unknown morphology within large
datasets dominated by thermal noise and anthropogenic
radio-frequency interference (RFI). UHE
neutrino radio experiments (including ARA, RNO-G, ANITA, and PUEO) have developed advanced methodologies for continuous-wave (CW) mitigation and background characterization. This invited contribution makes that connection concrete through three points. First, we demonstrate that catalog-based time-domain sine subtraction – the CW mitigation technique used in ANITA and ARA – can be adapted for technosignature pipelines by restricting subtraction to documented persistent contaminants, improving broadband transient visibility while preserving uncataloged narrowband candidates. Second, we identify a structural equivalence between spatiotemporal clustering used in UHE
neutrino experiments and direction/cadence-based RFI rejection in
radio SETI, proposing a joint feature space incorporating direction, time, frequency, bandwidth, duration, and polarization. Third, we argue that background-only anomaly ranking is the natural second stage of this workflow, providing morphology-agnostic candidate triage. Together, these ideas motivate a 'preserve-then-rank' workflow for commensal rare-event discovery, opening a near-term path toward cross-community collaboration.
Read the full abstract ▾
Fluid Dynamics
Optimal airfoils in the intermediate Reynolds number range
Gleb Zhdanko and Dmitry Kolomenskiy
We revisit a classical airfoil design problem: the search for shapes that maximize aerodynamic performance metrics, targeting the underexplored intermediate Reynolds-number regime between 1 and 3000, relevant to small animals and miniature vehicles. The problem is formally stated as the glide ratio or the endurance factor maximization for Joukowski airfoil profiles and for more general airfoil shapes with adjustable position of the maximum camber, under steady inflow. It is solved numerically by a hybrid approach combining
stochastic search and direct parameter sweep, and using a steady laminar Navier–Stokes solver based on conformal mapping and second-order finite-difference discretization. Zero-thickness cambered airfoils are found to be globally optimal, within the Joukowski family, across the entire Reynolds-number range considered. The optimal angle of attack decreases monotonically with $Re$, whereas the optimal camber varies non-monotonically, reaching a pronounced maximum near $Re \approx 40-50$ before declining at higher $Re$. At low Reynolds numbers ($Re \lesssim 100$), a broad family of cambered shapes performs within a few per cent of the optimum, indicating weak sensitivity to geometrical parameters. In contrast, for $Re \gtrsim 1000$, the performance landscape becomes sharply localized around a single preferred design, for which
geometric refinement is critical.
Read the full abstract ▾
Atomic Physics
Precision probing of ionic-core transitions in alkaline-earth Rydberg atoms
Mitsuki Odahara and Shinsuke Haze
We report precision spectroscopy of ionic-core transitions in alkaline-earth Rydberg atoms. We demonstrate high-resolution measurements of isotope shifts and hyperfine splitting of dipole transitions in ionic cores which have not been explored so far. A key element of this work is the reduction of the linewidth by more than two orders of magnitude enabled by dynamical control of Rydberg electron's orbit which significantly enhances the spectral resolution. Furthermore, to unambiguously identify the frequency shift, we directly compare core ion's spectrum with a signal from a single trapped ion serving as an ultimate frequency reference. This work provides an important foundation for
quantum control of inner-core transitions, which offer an useful tool in manipulating Rydberg atom as well as a sensitive probe for electron-core interactions in atomic and molecular systems.
Read the full abstract ▾
Computational Physics · Cross-listed from nlin.CD
Task-specific programming of chaos in neural circuits
Jungyoon Kim, Kyuho Kim, Kunwoo Park et al. (+2 more)
Chaotic dynamics have emerged as a versatile resource for neuromorphic and probabilistic computing, enabling high-dimensional nonlinear processing and classical analogues of
quantum randomness. Exploiting chaos for computation requires task-dependent control over complexity, as demonstrated in reservoir computing, random-number generation, and probabilistic inference. Existing approaches have focused on tuning element-level parameters, leaving the collective, many-body origin of chaos largely unexplored as a design freedom. Here, we demonstrate programmable chaotic dynamics for task-specific reservoir computing. Using a continuous-time neural-
circuit model, we show that tuning network
topology drives an ordered-to-chaotic transition, accompanied by transitions in correlation timescales, stability characteristics, and signal propagation. By jointly controlling element-level properties and network
topology, we establish a unified chaos-latency phase diagram, revealing that small-world connectivity enables low-latency on-off switching of chaos via edge rewiring. Supported by distinct reservoir-computing
benchmarks across various topological regimes, our results demonstrate that network
topology serves as a reconfigurable parameter for task-specific computation and tunable randomness.
Read the full abstract ▾
All authors Jungyoon Kim, Kyuho Kim, Kunwoo Park, Namkyoo Park, Sunkyu Yu
Optics
Wide-angle high-performance photodetector empowered by angle-insensitive Tamm plasmon polariton
Yurii V. Konov, Rashid G. Bikbaev, Feng Wu et al. (+1 more)
Tamm plasmon-polaritons (TPPs) - optical modes localized at the interface between a metal and a photonic
crystal (PhC) - offer a versatile platform for confining light in planar optoelectronic devices. However, their implementation in angle-sensitive applications such as photodetectors and
solar cells is hindered by strong angular dispersion of light. In this work, we propose a strategy to overcome this limitation by tailoring the dispersive properties of a PhC through the integration of
hyperbolic metamaterials (HMMs). Using the transfer
matrix method and effective medium theory, we demonstrate that the HMM exhibits type-I
hyperbolic dispersion in the telecommunication wavelength range. This enables a photonic bandgap whose angular dependence compensates for the intrinsic blue shift of the TPP mode, effectively anchoring the resonance at 1550 nm over a broad range of incidence angles. Device performance is evaluated using the Fowler internal photoemission model, yielding a normal-incidence responsivity of 17.5 mA/W. Notably, for TM-polarized light, the responsivity decreases by only 10% at a 60 degree incidence angle - a substantial improvement over conventional all-dielectric PhC structures, which exhibit a degradation exceeding 86%. Our findings establish HMM-engineered TPPs as a promising platform for wide-angle high-performance photodetectors and open new directions for dispersion engineering in active plasmonic and optoelectronic devices.
Read the full abstract ▾
All authors Yurii V. Konov, Rashid G. Bikbaev, Feng Wu, Ivan V. Timofeev