Atmospheric and Oceanic Physics · Cross-listed from astro-ph.IM
Risk assessment of muon single-event effects for low-altitude aircraft
Zijian Qiu, Sujie Lin, Yudong Cui et al. (+2 more)
With the rapid development of low-altitude economy, the radiation environment safety of low-altitude aircraft such as drones and electric vertical take-off and landing aircraft has attracted increasing
attention. Although the dense lower atmosphere traditionally serves as an effective shield against
cosmic radiation, the shrinking feature sizes of modern integrated
circuits greatly enhance their vulnerability to single-event effects (SEEs). This study quantitatively evaluates
muon-induced SEE risks for low-altitude aircraft in various regions of China under both static
cosmic-ray background and ground-level enhancement (GLE) events, aiming to provide critical guidance for the next-generation low-altitude aviation platforms.Using city-specific atmospheric models within the CORSIKA framework, we simulate atmospheric shower processes and obtain reliable energy spectra for low-energy
muons (10-100 MeV). We also employ simulation data from other research groups to estimate
muon-induced SEE cross sections for transistors at different process nodes, including bulk, FD-SOI, and FinFET technologies. By incorporating
solar energetic particle spectra associated with GLE events, we assess
muon-induced SEE risks under both static and GLE conditions. Our results show that under static conditions, flight control systems with 1 MB
memory using advanced nodes below 45 nm and bulk transistors face non-negligible
muon-induced SEE risks in all Chinese cities. In contrast, systems with FD-SOI transistors can effectively mitigate these risks. For large-
memory systems (1 GB), redundancy or other hardening measures are essential regardless of the process technology. Regarding GLE events, we introduce the concept of
muon hazard levels to evaluate regional risk variations. During GLEs, the increase in
muon-induced SEE risk is negligible in mid-to-low latitude regions but becomes significant at high latitudes.
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All authors Zijian Qiu, Sujie Lin, Yudong Cui, Yihan Liu, Lili Yang
Fluid Dynamics · Cross-listed from quant-ph
A Scalable Approach to Solve the Carleman Linearized Burgers' Equation on a Quantum Computer
Reuben Demirdjian, Yvan Quinn, Vincent P. Su et al. (+2 more)
Efficiently solving nonlinear ordinary and partial differential equations using a
quantum computer is a major challenge due its inherent linearity. To circumvent this challenge, the Carleman linearization method has been proposed to transform a nonlinear ordinary differential equation into a linear system of equations, the primary advantage being that existing
quantum linear systems
algorithms may then be applied to obtain a solution. However, this methodology also brings forth several major challenges that must be addressed to attain a
quantum advantage. Herein, we address several of these challenges enabling us to solve the Carleman linearized one-dimensional Burgers' equation on real and simulated
quantum hardware. All simulations were performed on BlueQubit's platform allowing for
quantum circuits to be run on GPU or QPU's seamlessly. We first demonstrate that the Carleman linearized Burgers' equation can be efficiently loaded onto a
quantum computer using the linear combination of non-
unitaries method, an alternative to the linear combintaiton of
unitaries approach. Once loaded, the linear system is then solved using the variational
quantum linear solver. Since a naive implementation of this solver is hindered by the barren plateau phenomenon, we introduce a multigridding method to solve the problem in a series of stages with the solution of the previous stage acting as a warm start for the next stage. This approach is found to significantly improve the accuracy of the solution compared with a naive cold start. Finally,
circuits with a combined number of spatial and temporal discretization points totaling up to $2^{80} \approx 10^{24}$ are transpiled onto real
quantum hardware demonstrating that the proposed methodology could feasibly produce a
quantum advantage on future hardware.
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All authors Reuben Demirdjian, Yvan Quinn, Vincent P. Su, Hrant Gharibyan, Hayk Tepanyan
Geophysics
Performance and User Response of Android's Smartphone-Based Alerts in the 2025 Marmara Ereglisi Earthquake
S. Mostafa Mousavi, Patrick Robertson, Richard M. Allen et al. (+10 more)
This study presents a comprehensive evaluation of Googles Android Earthquake Alert (AEA) system during the Mw 6.2 Marmara Ereglisi, Turkiye earthquake. AEA detected the event 5.31 seconds after its initiation, alerting over 16 million users. Warning times for weak shaking (MMI III) reached up to 150 seconds, with a median of 56 seconds. While near-source warning windows were shorter, the system achieved 90% true positives and 99% precision overall. The high density of the phone network enabled faster detection than traditional stations, even for this offshore epicenter. Feedback data shows AEA recipients were highly likely to take protective actions, such as drop, cover, and hold on, or warn others. Timely alerts substantially increased user engagement, perceived usefulness, and future trust. These results highlight how crowd-sourced technology and behavioral insights can effectively enhance seismic resilience on a massive scale.
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All authors S. Mostafa Mousavi, Patrick Robertson, Richard M. Allen, Alexei Barski, Robert Bosch, Nivetha Thiruverahan, Youngmin Cho, Tajinder Gadh, Steve Malkos, Boone Spooner, Greg Wimpey, Edward Shi, Marc Stogaitis
Fluid Dynamics
Self-similar Worthington jets
José M. Gordillo, Javier Rodríguez-Rodríguez and Vatsal Sanjay
When a micron-sized bubble bursts, capillary waves deform the cavity into a cone that ejects a Worthington jet. The jet is born by inertial focusing, and the local collapse follows self-similar Euler solutions set by the semiangle $\beta$. Writing $r_j$ and $v_j$ for the dimensionless jet-base radius and velocity, the local Weber number $We_j=r_j v^2_j$ measures inertia relative to capillarity. The theory, supported by accurate numerical simulations gives $r_j\propto\tau^{\alpha(\beta)}$ with $\alpha\simeq0.63$ and, hence $We_j\gg1$, with $We_j\to\infty$ as $r_j\to0$, so inertia increasingly overwhelms capillarity. In simulations, the interface collapses onto a universal shape for more than two decades in dimensionless time when lengths are scaled using our prediction for $r_j$. For water, this gives incipient radii of $\mathcal{O}(1)$ nm, predicting nanometric sea-spray aerosols.
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Fluid Dynamics · Cross-listed from astro-ph.SR
Developing Machine Learning Models of Subgrid Turbulent Transport for Quiet Sun 3D Radiative Hydrodynamic Simulations
Rimsha Hameed Syeda, Dustin Kempton, Viacheslav Sadykov et al. (+2 more)
Numerical modeling of
solar plasma dynamics is affected by the resolution of the computational grid. This often requires the estimation of subgrid processes related to the small-scale flow
turbulence, as these processes play a critical role in momentum transport and energy dissipation. In this work, we investigate the use of deep learning techniques as surrogate models for subgrid turbulent transport in realistic hydrodynamic simulations of the quiet Sun. We describe the development of a 3D Convolutional Neural Network (CNN) to capture spatial dependencies in 3D velocity fields, leveraging different activation functions, as well as different architectural designs. We specifically focus on the prediction of Reynolds stress tensor components. The resultant model integrates velocity vector components and scalar features, such as
plasma density, to enhance prediction accuracy. We compare the 3DCNN model to other types of models, such as a Multilayer Perceptron (MLP) and physics-based Gradient and Smagorinsky models, and show that the final model design reconstructs the Reynolds stress tensor components more accurately. Specifically, a 3DCNN model achieves an average improvement of ~31% on diagonal components and ~8% on the off-diagonal components of the stress tensor. Additionally, we show that applying a logarithmic data transformation of the target stress tensor components, to handle heavily skewed data, improves model performance. Results demonstrate the potential of deep learning, particularly CNNs, to approximate Reynolds stress tensor components for the upper
solar convection zone and lower atmosphere, making them a viable candidate for modeling subgrid processes and a promising alternative to traditional
turbulence models.
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All authors Rimsha Hameed Syeda, Dustin Kempton, Viacheslav Sadykov, Irina Kitiashvili, Rafal Angryk
Atmospheric and Oceanic Physics
Implications of Doppler shift for High Frequency Ocean Waves Measured Using Drifting Buoys
W. Erick Rogers, Jim Thomson and Clarence O. Collins
The advent of expendable wave buoys has greatly expanded the data available for evaluating and calibrating wave models. Ideally, the newer buoys now drifting around the world's oceans would be merged with conventional time series measurements from moored buoys to form a consistent
dataset of in situ observations. However, a comparison across several buoy types (moored Datawell, moored NDBC, and two types of drifting buoys) suggests large differences in the high frequency portion of the observed wave energy spectra (0.2 to 0.6 Hz). When binned by wind speed, the moored Datawell buoys have higher energy in the high frequency tail vs. drifting buoys, by factor 1.2 to 1.6. The moored Datawell buoys also have far better agreement with high-frequency energy levels predicted by a numerical wave model. The key to the difference appears to be the reference frame of the observations. To test this hypothesis, the spectra are adjusted from the drifting reference frame to the fixed reference frame. The adjustment is a two-step process, in which the buoy-observed frequencies are first shifted to an intrinsic reference frame, providing wavenumber at each frequency, and then the drifter-observed spectrum is Doppler shifted to the fixed reference frame. Two methods for estimation of buoy drift are tested; one is based on wind speed, and one is based on buoy positions. With this adjustment, the observations from the drifting buoys become more consistent with the moored Datawell buoys, though discrepancies still exist with the moored NDBC buoys.
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Atomic Physics · Cross-listed from nucl-th
Ab initio calculations of $^{229}$Th band-to-band internal conversion rate in $^{229}$ThO$_2$
Udeshika C. Perera, H. B. Tran Tan, H. W. T. Morgan et al. (+3 more)
We present an ab initio calculation of the band-to-band internal-conversion rate of the $\hbar\omega_{\rm nuc} \approx 8.35$ eV isomeric transition in $^{229}$ThO$_2$. Because the
nuclear transition energy exceeds the electronic band gap of ThO$_2$, the isomer can decay nonradiatively by resonantly promoting a valence electron into the conduction band. We formulate this process as a Brillouin-zone sum over vertical interband transitions weighted by local Th-centered hyperfine
matrix elements, which are evaluated directly from all-electron full-potential linearized augmented-plane-wave Bloch spinors. A finite
nuclear magnetization model is included to regularize the short-range hyperfine interaction and to account for the Bohr-Weisskopf effect. After applying scissor shifts to span the experimentally reported ThO$_2$ band gaps, we find calculated internal-conversion lifetimes in the range of $1-16~\mu{\rm s}$. The lifetime increases strongly as the band gap approaches $\omega_{\rm nuc}$ because the resonant interband phase space at the
nuclear transition energy is reduced. For the larger reported ThO$_2$ gaps, the calculated lifetime is comparable to the measured conversion-electron Mössbauer lifetime [Nature 648, 300 (2025)]. Our analysis implies that choosing solid-state hosts with band-gap values slightly lower than $\omega_{\rm nuc}$ can optimize solid-state
nuclear clock performance with internal-conversion electron readout.
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All authors Udeshika C. Perera, H. B. Tran Tan, H. W. T. Morgan, Eric Hudson, Daniel A. Rehn, Andrei Derevianko
Chemical Physics
Molecular Tuning of Charge-Transfer Resonance in Plasmonic Nanocavities
Hasher Irshada, Francesco Ciccarello, Konstantin Malchow et al. (+2 more)
Interfacial charge-transfer processes play a critical role in plasmon-enhanced spectroscopy, yet the energetic conditions governing charge-transfer resonance within molecule-metal nanocavities remain poorly understood. Here, plasmonic nanoparticle-on-mirror junctions incorporating systematically engineered biphenylthiol derivatives monolayers were used to investigate how frontier orbital
alignment influences chemical enhancement mechanisms. A molecular library spanning a broad range of electronically tuned acceptor states was examined using surface-enhanced Raman scattering (SERS), vibrational sum frequency generation (vSFG) spectroscopy, and density functional theory calculations. By combining different excitation wavelengths with controlled variation of substrate composition and molecular electronic structure, the energetic relationship between plasmon-enhanced charge transfer excitation and molecular orbital
alignment was quantitatively evaluated. The results reveal that charge-transfer enhancement of Raman scattering is governed by a well-defined interfacial resonance condition dependent on substrate work function and excitation energy. We further probe a subset of molecular-metal systems by nanocavity-enhanced vSFG and identify the same resonance conditions as in SERS, consistent with expectations. These findings establish an experimentally accessible framework for probing and engineering charge-transfer processes in plasmonic molecular junctions and provide mechanistic insight relevant to molecular plasmonics, charge carrier photophysics, and nanoscale interfacial spectroscopy.
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All authors Hasher Irshada, Francesco Ciccarello, Konstantin Malchow, Christophe Galland, Katrine Qvortrup
Computational Physics · Cross-listed from cond-mat.mtrl-sci
Interface-induced spin-resolved type-II band alignment and enhanced magnetic anisotropy in MSe2/WTe2 (M = V, Cr, Mn, Fe and Co) van der Waals heterobilayers
Paras Poswal, Ranjit Pati and Neeraj Shukla
Two-dimensional van der Waals heterobilayers provide an attractive platform for the development of next-generation spintronic devices. Here, first-principles calculations are performed to investigate the structural, electronic and
magnetic properties of MSe2/WTe2 (M = V, Cr, Mn, Fe, and Co) van der Waals heterobilayers. The pristine WSe2/WTe2 heterobilayer in AA'-configuration is found to be energetically favorable and exhibits type-II band
alignment with a band gap of 0.70 eV, and this provides an ideal platform for controlling carrier transport. Substituting W with 3d transition metal atoms, induces long-range
magnetic ordering and reconstructs the
spin-resolved electronic band structure. The formation of the heterointerface generates pronounced charge redistribution and an intrinsic built-in electric field, leading to interface-induced electronic reconstruction. MnSe2/WTe2 heterobilayer exhibits half-
metallicity, whereas FeSe2/WTe2 heterobilayer simultaneously exhibits half-
metallicity and
spin-resolved type-II band
alignment. Interfacial electronic reconstruction further produces a substantial perpendicular
magnetic anisotropy, driving MnSe2 from an in-plane easy axis with MAE value of 1.10 meV in the isolated monolayer to a robust out-of-plane easy axis with MAE value of 20.8 meV in the heterobilayer. Among all the structures, CoSe2/WTe2 heterobilayer exhibits maximum Curie temperature (273.87 K). The combined results establish that interface engineering makes MSe2/WTe2 heterobilayers as a promising candidates for next-generation low-dimensional spintronic applications.
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Physics Education
Teacher Leader Identity Development in a Physics Teaching Community of Practice: A Narrative Case Study
Hamideh Talafian, Maggie Mahmood, Eric Kuo et al. (+2 more)
This longitudinal narrative case study examines the leadership identity development of Kayla, a female high school physics teacher, across five years of participation in a community of practice (CoP). Drawing on multiple data sources, we trace how her participation evolved from classroom-level practice to broader institutional influence. Four interconnected dimensions of leadership identity development were identified: personal, social, practice, and institutional culture change. Findings show how CoP membership provided collective legitimacy and relational support that enabled Kayla to move beyond identity negotiation toward transformation , successfully advocating for an AP Physics course and increasing female student participation. This study contributes to teacher professional learning literature by demonstrating the value of an identity lens for understanding teacher leadership as a gradual, socially enabled process. The longitudinal design reveals transformative conditions that cross-sectional studies often obscure, highlighting narrative case study as a productive methodology for capturing teacher leadership identity development over time.
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All authors Hamideh Talafian, Maggie Mahmood, Eric Kuo, Morten Lundsgaard, Tim Stelzer
Optics
Seeing inside a Plasmonic Nanogap: Few-molecule Orientation and Preferential Adsorption
Francesco Ciccarello, Nobuaki Oyamada, Thwahira Shirin Alampara et al. (+2 more)
Molecule-surface interactions are central to many research and technological areas, spanning from heterogeneous catalysis and
polymer science to electrochemistry. Of particular relevance are metallic nanogaps used in molecular electronics and near-field spectroscopy. Due to the buried nature of these double interfaces, few methods exist to monitor side-specific interactions and relative molecular orientation inside the gap. In this work, we introduce plasmon-enhanced nonlinear vibrational spectroscopy as an efficient tool to investigate surface molecular adsorption within metallic nanojunctions. By exploiting simultaneous vibrational sum- and difference-frequency generation in dual-resonant nanocavities, we resolve molecular orientation and preferential binding to one of the two gold surfaces, with few-molecule sensitivity. We also discover that the non-resonant (electronic) second-order nonlinear response is not an intrinsic property of the metal surface, but is instead governed by the molecule-surface interaction. Our findings provide a powerful analytical tool, easily implementable as an add-on to Raman spectroscopy, thanks to commercially available mid-infrared
quantum cascade
lasers.
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All authors Francesco Ciccarello, Nobuaki Oyamada, Thwahira Shirin Alampara, Konstantin Malchow, Christophe Galland
Fluid Dynamics
Wall-bounded turbulence needs not be long
Carlos Martinez Lopez and Javier Jimenez
Experiments on the regeneration of long streaks in flows in which they had originally been damped show that their initial growth is due to the interaction of the mean shear with long cross-flow velocities (rollers) that remain even when the streaks are damped. More surprisingly,
turbulence also persists in simulations in which only the long rollers are damped while long streaks remain, and these flows are also able to recover when the damping is removed. Finally, simulations are presented in which both streaks and rollers longer than $\lambda_x^+ \approx 600$ are damped. They survive and regenerate, and an interpretation in terms of their energy balance is provided. In contraposition to the classical minimal channels, which include infinitely long structures, these new flows do not contain features longer than the damping wavelength, and support a model in which wall
turbulence only depends on processes for which the
geometric aspect ratio is of order unity.
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Applied Physics · Cross-listed from astro-ph.IM
Lessons learned from ongoing coordination between NRAO/GBO and LEO NGSO satellite constellations
Bang D. Nhan, Christopher G. De Pree, Sheldon Wasik et al. (+3 more)
With the increased demand for spectrum usage in recent years, particularly with the expansion of NGSO satellite systems for broadband internet and cellular services,
radio astronomy observatories located at remote sites have been faced with the challenge of increasingly detrimental RFI exposure from ubiquitous satellite downlinks. With the help of the U.S. NSF, NRAO and the
radio astronomy community have spearheaded collaboration efforts with the commercial NGSO operators to develop different coordination techniques to alleviate the impacts of these downlink signals in
radio astronomy scientific observations. This paper summarizes the ongoing coordination efforts, spectrum interference avoidance schemes, and a case study on community participation of the Operational Data Sharing (ODS) system between RAS and NGSO operators. We highlight some of the essential lessons learned from these collaborations and potential application of the ODS system to other potential spectrum stakeholders.
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All authors Bang D. Nhan, Christopher G. De Pree, Sheldon Wasik, Aaron Lawson, Daniel Bautista, Frank Schinzel
Fluid Dynamics
A Splitting Scheme for Dispersive Shallow Moment Equations
Ullika Scholz, Robin Paar and Manuel Torrilhon
The well-known Shallow Water Equations (SWE) are used for modeling incompressible free-surface flows whenever the shallowness allows for a vertical-averaging; i.e., vertical effects are negligible in comparison to horizontal ones. But vertical averaging comes with the price of losing information along the vertical axis. Moment models for shallow flow contain information on the vertical velocity and pressure profile despite being dimensionally reduced. A class of these models incorporating a non-hydrostatic pressure have been introduced before as Dispersive Shallow Moment Models (DSM). However, no method for solving the non-stationary equations has been presented yet, mainly because it was unclear how to compute the pressure equation in the form of the divergence-free constraint. We rewrite the pressure equations of the DSM models in the form of a Poisson-like problem to enable their solution with a projection-type splitting scheme. For the linear equations, we present the calculations for the generalized model and discuss the non-linear case. We state the first two linear models and the corresponding nonlinear counterparts. Finally, we introduce a hybrid Finite-Volume Finite-Difference method and discuss the non-stationary numerical results for an experiment with periodic boundary and uneven bottom topography.
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Physics and Society · Cross-listed from cs.CY
The queer Hero versus the Fool bias of the queer trait: An archetypometric analysis of the collective portrayal of queerness in fictional stories
Ashley M. A. Fehr, Calla Glavin Beauregard, Julia Witte Zimmerman et al. (+4 more)
Visibility in media is pivotal for identity development and for broadening societal views of gender and sexuality. Queer representation has increased in recent years, yet damaging stereotypes and tropes persist. Here, we focus on queer portrayal and its perception by audiences in fictional stories (television, film, and literature) by studying characters by their quantified archetypes which are operationalizations of common conceptions such as Hero, Diva, and Outcast. We use the archetypometrics and Fandom's LGBTQIA+
datasets to study samples of fictional characters along the trait differential spanning straight to queer. We find, quantify, and explain a seeming paradox. The characters with the highest queer score present positive primary archetypes and are typically Heroes rather than Fools, Angels rather than Demons, and Adventurers rather than Traditionalists. But evaluation across many stories for the straight-queer trait itself reveals a strong collective-writing bias towards Fool (away from Hero) and no meaningful loading for the other two dimensions. Our analysis offers a population-scale view of the complexities of queer portrayal, while also pointing to risks in blindly training on many-authored story corpora.
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All authors Ashley M. A. Fehr, Calla Glavin Beauregard, Julia Witte Zimmerman, Danny Benett, Timothy R. Tangherlini, Christopher M. Danforth, Peter Sheridan Dodds
Physics and Society
Self-similarity of mobility networks
Ying-Yue Lyu, Xiao-Yong Yan, Bin Jia et al. (+3 more)
Mobility systems of people and goods are inherently multi-scale, spanning levels of organization from individual cities to regions and nations. Understanding whether mobility networks exhibit similar patterns across these scales is important. Such similarity would point to common organizing principles, enabling insights gained at one scale to inform planning and management at others. Despite growing efforts to analyze mobility at multiple scales, such cross-scale similarity remains poorly understood, and renormalization provides a natural framework for addressing this question. Here, we propose a Neighbor-Limited Box Covering method to renormalize undirected weighted mobility networks. This method iteratively selects box centers in descending order of node strength, merges each center with a fixed number of its highest-weight neighbors to form a renormalized node, and aggregates edge weights between renormalized nodes to generate the network at the next scale. We apply this technique to uncover multi-scale structures of real-world inter-city human mobility and freight trip networks in China and find that the topological structures, weighted structural features, and dynamic processes all exhibit self-similarity across these multi-scale mobility networks. Moreover, we find that the constituent nodes in most renormalized nodes show a strong spatial cohesion, and the boundaries of them closely follow existing political and socio-economic borders, even though the method does not explicitly incorporate any spatial information. Our study not only reveals the consistency of multi-scale inter-city mobility patterns, but also provides important insights into their spatial organization. Furthermore, our method is applicable to mobility networks of different sizes and has potential as a powerful tool for the multi-scale analysis of various other real-world complex systems.
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All authors Ying-Yue Lyu, Xiao-Yong Yan, Bin Jia, Jobst Heitzig, Ziyou Gao, Jürgen Kurths
Chemical Physics · Cross-listed from cond-mat.soft
A strong-coupling theory for polarizable symmetrically charged walls with counterions only
Ladislav Šamaj, Alexandre P. dos Santos and Emmanuel Trizac
A pair of parallel polarizable planar walls at distance d is considered. The walls are symmetrically charged with a uniform surface charge density, neutralized by mobile point counterions moving between them. The case of repulsive particle images is studied in the strong-coupling (SC) regime. Of interest is the dependence of the effective inter-wall interaction (pressure), mediated by the mobile counterions, as a function of the distance d. It is shown that previous virial SC single-particle theories work well at small d when the dielectric jump is small; for intermediate and large dielectric jumps they are inadequate even in the SC region. Here, we propose a Wigner-type SC theory based on harmonic deviations of particles from their ground-state monolayer or
bilayer Wigner structures formed inside the space between the dielectric walls. Our Monte-Carlo simulations are in very good agreement with the Wigner SC predictions, even down to moderate coupling constants ($\Xi > 10$).
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Computational Physics · Cross-listed from math.NA
An Explicit Higher-Order Dual Basis for a Multiplicatively Calderón Preconditioned Electric Field Integral Equation
Bernd Hofmann, Thomas F. Eibert, Francesco P. Andriulli et al. (+1 more)
One of the most effective means to precondition the electric field integral equation (EFIE) discretized with Rao-Wilton-Glisson (RWG) functions is the multiplicative Calderón preconditioner employing Buffa-Christiansen (BC) functions as a basis dual to the RWG basis. It results in a formulation that is free from the dense-discretization and the low-frequency breakdown. To generalize the multiplicative Calderón preconditioner from the low-order BC and RWG basis to higher orders, we utilize B-spline-based basis functions and establish the first explicit high-order dual basis. It can be regarded as a generalization of the BC functions to arbitrary
polynomial degrees and constitutes a fundamental building block for other approaches that rely on a dual basis. Numerical results for the obtained preconditioner demonstrate a low and constant number of generalized minimum residual (GMRES) iterations independent of the number of unknonws and the
polynomial degree for canonical and realistic perfectly electrically conducting (PEC) scatterers; a key to enable the full potential of higher-order bases.
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All authors Bernd Hofmann, Thomas F. Eibert, Francesco P. Andriulli, Simon B. Adrian
Computational Physics · Cross-listed from hep-ph
Optimal-Transport-Based Cell Resampling for Negative and Pathological Event Weights
Regan Doherty, Lauren Hay, Rishabh Jain et al. (+4 more)
Negative and pathologically large Monte Carlo event weights strain the computing budgets of experiments at the Large
Hadron Collider.
Cell resampling
algorithms locally redistribute event weights among nearby events in a metric space. We study the performance of metrics defined in terms of Optimal Transport, namely the Energy Mover's Distance and a spectral variant, in the context of such
algorithms. As these metrics are insensitive to the addition of soft and collinear radiation, they may be applied directly to particles at any stage of event generation. When applied to samples simulated at next-to-leading-order in
quantum chromodynamics, this approach reduces the observed bias relative to other
cell resampling techniques presented in the literature. We also study the Cross-Section Mover's Distance as an unbinned, broadly-applicable figure of merit for quantifying the bias introduced by any full-phase-space reweighting.
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All authors Regan Doherty, Lauren Hay, Rishabh Jain, Matt LeBlanc, Julia Marrinan, Camille Mauceri, Jennifer Roloff
Optics
Asymmetric high-harmonic generation from subwavelength bianisotropic resonators
Albert Mathew, Piyush Jangid, Rebecca Aschwanden et al. (+3 more)
High-harmonic generation (HHG) enables attosecond light pulses and table-top sources of coherent extreme-ultraviolet and soft X-ray radiation. Although HHG has long been associated with gases and
plasma, nanostructured solids are emerging as new alternative sources enabling both the enhancement and control of HHG. Here, we experimentally demonstrate and theoretically describe that a single dielectric subwavelength resonator can act as a direction-selective high-harmonic source, enabling control over multiple harmonic orders through the excitation and hybridization of Mie modes. The resonator's geometrical volume is $0.12 \lambda^3$, and its optical mode volume is $0.03 \lambda^3$ at its pump wavelength. Structural asymmetry of the resonator along the propagation direction translates into different mode coupling under opposite illumination directions, resulting in pronounced forward-backward asymmetry in the generation of the third, fifth, and seventh harmonics. These results establish bianisotropic subwavelength resonators as a platform for flexible asymmetric generation of high harmonics, expanding the toolbox for controlling strong-field light-matter interactions with Mie-resonant nanophotonics.
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All authors Albert Mathew, Piyush Jangid, Rebecca Aschwanden, Yves Köppeler, Thomas Zentgraf, Sergey Kruk
Chemical Physics · Cross-listed from astro-ph.GA
Detection of the Polycyclic Aromatic Hydrocarbon Phenalene (C$_{13}$H$_{10}$) in the Very Low Luminosity Object (VeLLO) MC27/L1521F
Gabi Wenzel, Thomas H. Speak, Ci Xue et al. (+12 more)
To date, 14 polycyclic aromatic hydrocarbons (PAHs) ranging in size from two to seven (including five- and six-membered) carbon rings have been detected in the starless dense core TMC-1 CP within the Taurus molecular cloud. Their detection raises questions about the distribution of PAHs in the cold interstellar medium (ISM) and their
evolution during
star formation. Here, we present the first interstellar detection of a three-ring PAH outside of TMC-1 CP. We detect phenalene (C$_{13}$H$_{10}$), a compact, peri-fused PAH, in the dense core MC27/L1521F, a molecular cloud in Taurus containing a very low-luminosity object (VeLLO). We compare the abundances of phenalene in the two sources with respect to the single-ring aromatic benzonitrile, and find that it is enhanced by a factor of four in MC27/L1521F. We discuss the implications for possible formation and destruction pathways in the two sources. These findings further support the widespread abundance of PAHs throughout the cold ISM and are consistent with survival, inheritance, or replenishment during the earliest stages of
star formation.
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All authors Gabi Wenzel, Thomas H. Speak, Ci Xue, Edwin A. Bergin, Andrew M. Burkhardt, Martin A. Cordiner, Miya Duffy, Zachary T. P. Fried, Andrew Lipnicky, Christopher N. Shingledecker, Reace H. J. Willis, Anthony J. Remijan, Michael C. McCarthy, Brett A. McGuire, Ilsa R. Cooke
Physics and Society
Dynastic dynamics: Modelling powerful naming choices with stochastic prestige
Pablo Rosillo-Rodes, Santiago Lamata-Otín, David Soriano-Paños et al. (+2 more)
The naming choices of powerful rulers encode millennia of cultural, political, and institutional influences. Consequently, the long-term onomastic dynamics within some of the most powerful dynasties cannot be explained by simple mechanisms such as frequency-dependent reinforcement or random name reuse. Here, we propose a minimal model that encapsulates these influences in a single highly
stochastic variable, prestige, and assume that name selection is driven by the prestige accumulated by previous rulers bearing the same name within each dynasty. Using an extensive
dataset spanning ten dynasties, we show that the model reproduces the pronounced inequalities in name frequencies, the long-term persistence of dominant names, and the abrupt rises in popularity observed in historical records. Our results suggest that the naming traditions of powerful rulers preserve institutional
memory through reinforcement while remaining sensitive to rare historical events that can reshape the hierarchy of names across generations.
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All authors Pablo Rosillo-Rodes, Santiago Lamata-Otín, David Soriano-Paños, Laurent Hébert-Dufresne, Peter Sheridan Dodds
Optics · Cross-listed from quant-ph
Low-latency FPGA-based electronic control system for fast preparation of defect-free atom arrays
Ya-Dong Hu, Dong-Qi Ma, Tian-Yang Zhang et al. (+13 more)
The scalability of neutral atom
quantum computing demands integrated electronic control systems with low latency, modular architecture, and real-time feedback capability. Here, we present an FPGA-based electronic control system that eliminates the PC from the feedback loop, integrating
photon counting, real-time decision-making, and waveform generation within a unified PXIe architecture. The system achieves a total feedback latency of $282\,\mathrm{\mu s}$ and is validated in practical experiments by assembling defect-free atom arrays from 24 stochastically loaded optical tweezers. A single-round rearrangement achieves a filling fraction of $\sim96\%$, while feedback-controlled iterative rearrangement over five rounds boosts the success probability for generating a 10-atom defect-free array from $65.7\%$ to $95.4\%$. This system establishes the electronic infrastructure necessary for mid-
circuit measurement and real-time
quantum error correction on neutral-atom platforms.
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All authors Ya-Dong Hu, Dong-Qi Ma, Tian-Yang Zhang, Liang Chen, Yi-Chen Zhang, Xiao-Kang Zhong, Wen-Yi Zhu, Hong-Jie Fan, Qing-Xuan Jie, Yan-Lei Zhang, Gang Li, Xi-Feng Ren, Xu-Liang Zhang, Guang-Can Guo, Zhu-Bo Wang, Chang-Ling Zou
Plasma Physics
Precision mapping of laser-driven magnetic fields and their evolution in high-energy-density plasmas
Lan Gao, PM Nilson, IV Igumenshchev et al. (+4 more)
Magnetic fields generated by the Rayleigh-Taylor instability were measured in
laser-accelerated planar foils using ultrafast
proton radiography. Thin plastic foils were irradiated with $\sim$4-kJ, 2.5-ns
laser pulses focused to an intensity of $\sim$10$^{14}$ W$/$cm$^{2}$ on the OMEGA EP
Laser System. Target modulations were seeded by
laser nonuniformities and amplified during target acceleration by the Rayleigh-Taylor instability. The experimental data show the hydrodynamic
evolution of the target and MG-level
magnetic fields generated in the broken foil. The experimental data are in good agreement with predictions from 2-D magnetohydrodynamic simulations.
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All authors Lan Gao, PM Nilson, IV Igumenshchev, MG Haines, DH Froula, R Betti, DD Meyerhofer
Fluid Dynamics
Drift of interfaces in forced stably-stratified turbulence and the role of vertically-sheared helical structures
Niccolò Cocciaglia, Luca Biferale, Fabio Bonaccorso et al. (+1 more)
Experimental investigations of forced stably stratified
turbulence (SST) have shown that the step-like density profile, made of well-mixed density layers and sharp interfaces alternating along the
gravity direction, undergo a slow coarsening dynamics with either decay or merging of interfaces. In this Letter, we focus on the coarsening dynamics phenomenon, by means of Direct Numerical Simulations of forced SST at moderate resolutions, and very long temporal integration. We show that the vertical drift and merging of interfaces is associated to the emergence of spatially-uniform, vertically-sheared helical structures that break the mirror-
symmetry of the system. When these are absent, interfaces decay is observed instead. %how the kinetic energy excursions observed at $Fr=0.076$, occurring in parallel to vertical drift of interfaces, are due to the emergence of spatially-uniform, vertically-sheared helical structures that break the mirror-
symmetry of the system. This is absent at larger $Fr=0.22$, where interface decay is observed instead. A dynamical correspondence between helicity dissipation rate by buoyancy effects and the vertical buoyancy flux allows to establish a (causal) connection between the
chiral structures and the vertical movement of interfaces leading to merging.
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All authors Niccolò Cocciaglia, Luca Biferale, Fabio Bonaccorso, Alessandra S. Lanotte
Fluid Dynamics
Inverse Transfer and Coherence in Rotating Stratified Flow with Clouds and Phase Transitions
Yeyu Zhang, Yingshuo Peng and Leslie M. Smith
Inverse energy transfer to large-scale coherent structures in idealized models of geophysical flows has been of interest for over four decades. Extensive knowledge exists regarding inverse transfer in rotating and stratified dry dynamics, characterized by the Rossby number and a single dry Froude number. The current study includes effects of water and phase changes, with dynamics characterized by the Rossby number and two Froude numbers for unsaturated and saturated environments. Using numerical computations with random forcing, inverse energy transfer is examined for a model with a Boussinesq dynamical core, incorporating water vapor and
liquid water in the limit of asymptotically-fast cloud microphysics. Besides kinetic energy, total energy includes buoyant potential energies from each phase, and latent moist energy responsible for potential energy transfer at phase boundaries. The rotation and stratification terms are large and comparable, such that the dry version of the
evolution equations is dominated by inverse transfer of pseudo potential vorticity(PV). For fixed Rossby and dry (unsaturated) Froude numbers, compared to dry dynamics, there is a reduction in energy transfer rate, associated with the larger Froude number of saturated regions. The upscale transfer to moist PV is influenced by nonlinear waves at lowest order resulting from nonlinear buoyancy near phase interfaces. These nonlinear waves lead to coherent updrafts and downdrafts roughly aligned with fuzzy, large-scale phase boundaries identified by the time average of a cloud indicator function. Statistical relationships between phase boundaries, updrafts/downdrafts and moist PV are explored in flow regions dominated by moist PV-
vortices.
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Physics and Society
Statistical inference of dynamical processes on networks
Javier Ureña-Carrion, Tiago P. Peixoto and Gerardo Iñiguez
Mechanisms of interaction in spreading models are central to our quantitative understanding of networked contagion processes, from disease transmission to opinion dynamics. Yet, while empirical data can reveal who interacts with whom, they rarely provide direct information about how interactions drive spreading, leaving the underlying mechanism to be inferred from observed dynamics, and selected among competing hypotheses. We propose a general framework for model selection in binary-state spreading processes on networks and show that asymptotic approximations in the thermodynamic limit can accurately predict inference outcomes in finite systems. By systematically exploring a broad parameter space, we characterize the detectability of six archetypal spreading mechanisms commonly used in the literature and find that accuracy generally increases in sparse networks, which are prevalent in real-world systems, and near phase transitions, such as the epidemic threshold of simple contagion processes. We further assess the prevalence of these mechanisms across a diverse set of empirical
datasets, highlighting the impact of data preprocessing on model recovery. Our results show that statistical model selection can fail under common conditions and suggest new directions for overcoming these limitations.
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Applied Physics · Cross-listed from cond-mat.mtrl-sci
Microwave Studies of Single Crystal TeO2 at Cryogenic Temperatures
Timothy Holt, Maxim Goryachev, William Campbell et al. (+1 more)
We use whispering-gallery-mode analysis to characterise the microwave dielectric properties of single-
crystal TeO$_2$ at cryogenic temperatures and compare its loss performance with other low-loss dielectric materials. Finite-element modelling is combined with measurements at room temperature, 4 K, and 20 mK to develop accurate cryogenic simulations and extract the anisotropic dielectric permittivities, giving $\varepsilon_\parallel=25.75\pm0.08$ and $\varepsilon_\perp=20.90\pm0.07$. Loss measurements reveal quality factors as high as $9\times10^6$ and minimum loss tangents approaching $3\times10^{-8}$, placing TeO$_2$ among promising low-loss dielectrics for cryogenic microwave applications. Electron-
spin-resonance spectroscopy further indicates a clean
spin environment, while identifying distinct
spin systems consistent with the known properties of the
crystal.
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All authors Timothy Holt, Maxim Goryachev, William Campbell, Michael E. Tobar
Biological Physics
Acceleration-based clustering reveals frequent gait switching in sprint sled dogs
Benjamin Seleb and Saad Bhamla
Continuous
video is difficult to obtain during field studies of sprint sled dogs, limiting analysis of stride-to-stride variation during load-pulling gallop. We developed an acceleration-based pipeline to identify recurrent stride states from harness-mounted tri-axial accelerometers without manual gait labels. Using multivariate dynamic time warping,
manifold embedding, and density-based clustering, we analyzed more than 20,000 strides from a 10-dog team and identified recurrent, dog-specific stride states. In one previously annotated individual, acceleration-derived states were broadly consistent with manually labeled gallop patterns. Across dogs, transitions between stride states were frequent, with substantial inter-individual variation and limited evidence of strong team-level coordination. A simple logistic model based on local tugline-force timing and magnitude had weak predictive power for transition events. These results suggest that sprint sled dog gallop occupies a variable set of nearby stride states and that local tugline-force fluctuations alone do not explain the observed switching.
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Instrumentation and Detectors
A Novel Hadronic Calorimeter With A Direct Neutron Readout
I. Giomataris, F. Jeanneau, T. Papaevangelou et al. (+2 more)
A
neutron-sensitive sampling calorimeter based on alternating lead absorber and gadolinium-loaded
liquid scintillator layers is investigated using detailed Geant4 Monte Carlo simulations. In addition to the conventional
prompt calorimetric signal, the proposed detector records delayed energy from
neutron moderation and capture, providing direct information on the
neutron component of hadronic showers. A six-layer Pb/LAB-Gd calorimeter exposed to 10~GeV
protons is studied to characterize its
neutron response and evaluate its impact on calorimetric performance. The delayed deposited energy is found to be almost perfectly proportional to the
neutron-capture multiplicity, providing a direct calibration of the
neutron-sensitive signal. Event-by-event analyses further reveal a clear relationship between the
prompt calorimetric response and the delayed
neutron observable, demonstrating that the latter contains substantial information on the invisible hadronic energy. Exploiting this correlation through a simple nonlinear event-by-event correction improves the
prompt-energy resolution from 21.8% to 13.3% without rejecting events. Furthermore, the analysis of events with similar
neutron multiplicities indicates that
neutron-production fluctuations constitute a major contribution to the overall hadronic energy resolution. These results demonstrate the potential of gadolinium-loaded sampling calorimeters to recover part of the invisible hadronic energy and significantly improve hadronic energy reconstruction and energy resolution.
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All authors I. Giomataris, F. Jeanneau, T. Papaevangelou, G. Tsiledakis, M. Vandenbroucke