Plasma Physics
Integrated Observation of Isotope-Dependent Turbulence, Zonal Flow, and Turbulence-Driven Transport
Shinsuke Ohshima, Hiroyuki Okada, Shinji Kobayashi et al. (+7 more)
To address the long-standing unresolved issue of "isotope effect" in
plasma transport, this study investigates the hydrogen/deuterium (H/D) isotope dependence of a nonlinear
turbulence system. The analysis focuses on the zonal flow (ZF) activity,
turbulence properties, their nonlinear interaction, and resulting turbulent transport in a
torus plasma. ZF activity, observed in low-density electron cyclotron heating
plasmas in Heliotron J, is enhanced with increasing D gas fraction from 10 to 80 percent. While the
turbulence scale size in the edge region (rho approx 0.8) is larger in D
plasmas, the reduction and decoupling of fluctuations, associated with an enhanced ZF, results in beneficial impacts on turbulent transport, driven by an enhanced nonlinear coupling between the ZF and
turbulence in D
plasmas. These differences in the
turbulence nature lead to the significant reduction of
turbulence-induced transport observed in the D
plasma. These comprehensive observations suggest that the isotope dependence on the
turbulence system is essential for explaining the isotope effect on confinement improvement and is vital in predicting the performance of future fusion reactors.
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All authors Shinsuke Ohshima, Hiroyuki Okada, Shinji Kobayashi, Shinichiro Kado, Takashi Minami, Fumiyoshi Kin, Shigeru Inagaki, Shigeru Konoshima, Tohru Mizuuchi, Kazunobu Nagasaki
Physics and Society
Complete asymptotic type-token relationship for growing complex systems with inverse power-law count rankings
Pablo Rosillo-Rodes, Laurent Hébert-Dufresne and Peter Sheridan Dodds
The growth dynamics of complex systems often exhibit statistical regularities involving power-law relationships. For real finite complex systems formed by countable
tokens (animals, words) as instances of distinct types (species, dictionary entries), an inverse power-law scaling $S \sim r^{-\alpha}$ between type count $S$ and type rank $r$, widely known as Zipf's law, is widely observed to varying degrees of fidelity. A secondary, summary relationship is Heaps' law, which states that the number of types scales sublinearly with the total number of observed
tokens present in a growing system. Here, we propose an idealized model of a growing system that (1) deterministically produces arbitrary inverse power-law count rankings for types, and (2) allows us to determine the exact asymptotics of the type-
token relationship. Our argument improves upon and remedies earlier work. We obtain a unified asymptotic expression for all values of $\alpha$, which corrects the special cases of $\alpha = 1$ and $\alpha \gg 1$. Our approach relies solely on the form of count rankings, avoids unnecessary approximations, and does not involve any
stochastic mechanisms or sampling processes. We thereby demonstrate that a general type-
token relationship arises solely as a consequence of Zipf's law.
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Optics · Cross-listed from quant-ph
All-optical turbulence mitigation for free-space quantum key distribution using stimulated parametric down-conversion
Aaron A. Aguilar-Cardoso, Cheng Li, Tobey J.B. Luck et al. (+4 more)
In this work, we propose and demonstrate a
turbulence-resilient scheme for free-space
quantum communication. By leveraging the phase conjugation property of stimulated parametric down-conversion, our scheme enables all-optical dynamic correction of spatial-mode distortion induced by atmospheric
turbulence, thereby enhancing the secure key rate in high-dimensional
quantum key distribution. We develop a theoretical model that provides detailed guidelines for selecting the optimal basis and spatial properties needed to maximize the efficiency of the proposed scheme. Both numerical simulations and experimental results show that, even under strong
turbulence, our scheme can reduce the
quantum error rates well below the security threshold. These results highlight the potential of nonlinear optical approaches as powerful tools for robust
quantum communication in realistic free-space environments. Our work could have important implications for the practical implementation of secure
quantum channels over long free-space distances.
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All authors Aaron A. Aguilar-Cardoso, Cheng Li, Tobey J.B. Luck, Manuel F. Ferrer-Garcia, Jeremy Upham, Jeff S. Lundeen, Robert W. Boyd
Atmospheric and Oceanic Physics
Assessing the Risks of Typhoon-Induced Multi-Hazards in South Korea
Ziyue Liu and Michelle T. Bensi
Tropical cyclone-induced coastal hazards can significantly damage coastal infrastructure, and these risks may intensify under future
climate change. As a result, there is increasing interest in conducting comprehensive assessments of coastal hazards-including storm surge, storm wind, storm rainfall, and their combined impacts-associated with tropical cyclone events. Risk assessments that overlook the compounding nature of these hazards may lead to ineffective or insufficient mitigation strategies. This study seeks to identify and evaluate the available data, models, and methodologies for assessing both individual and compound typhoon-induced hazards in South Korea. Particular effort is devoted to exploring how established approaches from the North Atlantic region can be adapted, integrated, and extended for application in the South Korean context. Multiple sites across South Korea are analyzed to illustrate the strengths and limitations of these methods.
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Medical Physics · Cross-listed from quant-ph
Towards Continuous-variable Quantum Neural Networks for Biomedical Imaging
Daniel Alejandro Lopez, Oscar Montiel, Oscar Castillo et al. (+1 more)
Continuous-variable (CV)
quantum computing offers a promising framework for scalable
quantum machine learning, leveraging optical systems with infinite-dimensional
Hilbert spaces. While discrete-variable (DV)
quantum neural networks have shown remarkable progress in various computer
vision tasks, CV
quantum models remain comparatively underexplored. In this work, we present a feasibility study of continuous-variable
quantum neural networks (CV-QCNNs) applied to biomedical image classification. Utilizing photonic
circuit simulation frameworks, we construct CV
quantum circuits composed of Gaussian gates, such as displacement, squeezing, rotation, and beamsplitters to emulate convolutional behavior. Our experiments are conducted on the MedMNIST
dataset collection, a set of annotated medical image
benchmarks for multiple diagnostic tasks. We evaluate CV-QCNN's performance in terms of classification accuracy, model expressiveness, and resilience to Gaussian noise, comparing against classical CNNs and equivalent DV
quantum circuits. This study aims to identify trade-offs between DV and CV paradigms for
quantum-enhanced medical imaging. Our results highlight the potential of continuous-variable models and their viability for future computer-aided diagnosis systems.
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All authors Daniel Alejandro Lopez, Oscar Montiel, Oscar Castillo, Miguel Lopez-Montiel
Accelerator Physics
Experimental verification of space-charge saturation scaling laws in high-gradient photocathode RF guns
Paul Denham, David Garcia, Atharva Kulkarni et al. (+4 more)
We investigate the limits of photoemission yield in a high-gradient S-band radiofrequency photoinjector in the space-charge-dominated regime. Using an RF phase-scan technique, where the emitted charge is measured as a function of the RF-field phase in the gun, we directly monitor photoemission over a range of launch fields and
laser parameters, enabling quantitative characterization of space-charge saturation. Measurements, supported by simulations and analytic modeling, confirm the characteristic charge-field scaling laws for pancake beams and provide the first experimental verification of cigar-regime scaling in an RF photogun. These results establish a predictive framework for identifying the onset of space-charge saturation and guide the optimization of photoinjectors for ultrafast electron diffraction, microscopy, and high-brightness light sources operating at ultra-high gradients.
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All authors Paul Denham, David Garcia, Atharva Kulkarni, Brian Schaap, Ziteng Liu, Pietro Musumeci, Daniele Filippetto
Plasma Physics
Unified Model of Heated Plasma Expansion
Ritwik Sain, Lance Labun, Ou Z. Labun et al. (+1 more)
Motivated by the need to predict
plasma density and temperature distributions created in the early stages of high-intensity
laser-
plasma interactions, we develop a fluid model of
plasma expansion into
vacuum that incorporates external heating. We propose a new three-parameter family of self-similar solutions for
plasma expansion that models a wide range of spatiotemporal variations of the electron temperature. Depending on the relative scales of the heated
plasma domain $L$, the Debye length $\lambda_D$ and an emergent ion-acoustic correlation length $\lambda_s$, characterized by the parameters $\frac{\lambda_s}{\lambda_D}$ and $\frac{L}{\lambda_s}$, a spectrum of dynamical behaviors for the expanding
plasma are identified. The behavior is classified into five dynamical regimes, ranging from nearly quasineutral expansion to the formation of bare ion slabs susceptible to Coulomb explosion. Self-similar solutions with spatially uniform electron temperature with exponential time dependence are analyzed, and the dynamics in the five asymptotic limits in the parameter space are detailed. Scaling relations for the length scales and energies of the expanding
plasma are proposed. The self-similar framework is applied to
laser-
plasma interactions, specifically addressing the
plasma dynamics at a target surface as the target interacts with the rising
laser intensity envelope. The results offer insights into the expansion behavior based on the
laser-
plasma parameters, and scaling relations for optimizing
laser-
plasma schemes and guiding experimental designs in high-intensity
laser experiments.
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All authors Ritwik Sain, Lance Labun, Ou Z. Labun, Bjorn Manuel Hegelich
Atmospheric and Oceanic Physics
Computing the Full Earth System at 1 km Resolution
Daniel Klocke, Claudia Frauen, Jan Frederik Engels et al. (+24 more)
We present the first-ever global simulation of the full Earth system at 1.25 km grid spacing, achieving highest time compression with an unseen number of degrees of freedom. Our model captures the flow of energy, water, and carbon through key components of the Earth system: atmosphere, ocean, and land. To achieve this landmark simulation, we harness the power of 8192 GPUs on Alps and 20480 GPUs on JUPITER, two of the world's largest GH200 superchip installations. We use both the Grace CPUs and Hopper GPUs by carefully balancing Earth's components in a heterogeneous setup and optimizing acceleration techniques available in ICON's codebase. We show how separation of concerns can reduce the code complexity by half while increasing performance and portability. Our achieved time compression of 145.7 simulated days per day enables long studies including full interactions in the Earth system and even outperforms earlier atmosphere-only simulations at a similar resolution.
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All authors Daniel Klocke, Claudia Frauen, Jan Frederik Engels, Dmitry Alexeev, René Redler, Reiner Schnur, Helmuth Haak, Luis Kornblueh, Nils Brüggemann, Fatemeh Chegini, Manoel Römmer, Lars Hoffmann, Sabine Griessbach, Mathis Bode, Jonathan Coles, Miguel Gila, William Sawyer, Alexandru Calotoiu, Yakup Budanaz, Pratyai Mazumder, Marcin Copik, Benjamin Weber, Andreas Herten, Hendryk Bockelmann, Torsten Hoefler, Cathy Hohenegger, Bjorn Stevens
Chemical Physics
Non-adiabatic perturbation theory of the exact factorisation
Matisse Wei-Yuan Tu and E.K.U. Gross
We present a novel nonadiabatic perturbation theory (NAPT) for correlated systems of electrons and
nuclei beyond the Born-Oppenheimer (BO) approximation. The essence of the method is to exploit the smallness of the electronic-to-
nuclear mass ratio by treating the electron-
nuclear correlation terms in the electronic equation of motion of the exact factorisation (EF) framework as perturbation. We prove that any finite-order truncation of the NAPT preserves the normalisation of the conditional electronic factor as well as the gauge covariance of the resulting perturbative equations of motion. We illustrate the usefulness of NAPT by obtaining nonadiabatic corrections to the BO Berry phase in Jahn–Teller systems with a conical intersection. It well captures the departure of the exact Berry phase from being topological via the lowest-order NAPT. By removing the conical intersection with a constant gap, it further yields the correct scaling of the Berry phase toward zero.
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Classical Physics · Cross-listed from cond-mat.mes-hall
Dynamical Phase Transitions Across Slow and Fast Regimes in a Two-Tone Driven Duffing Resonator
Soumya S. Kumar, Javier del Pino, Letizia Catalini et al. (+2 more)
The response of nonlinear resonators to multifrequency driving reveals rich dynamics beyond conventional single-tone theory. We study a Duffing resonator under bichromatic excitation and identify a competition between the two drives, governed by their detuning and relative amplitudes. In the slow-beating regime, where the tones are closely spaced, the secondary drive acts as a modulation that induces dynamical phase transitions between coexisting stationary states. We introduce the cycle-averaged amplitude as an order parameter and map the resulting phase diagram as a function of the drive detuning and amplitude ratio, capturing the pronounced asymmetry observed for blue versus red detuning in experiment. We devise a model to link the onset of these transitions to the resonance properties around the nonlinear stationary mode of the system. Our results provide a framework for controlling driven nonlinear systems, enabling state manipulation, and sensing in nanomechanical, optical, and superconducting
circuit platforms.
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All authors Soumya S. Kumar, Javier del Pino, Letizia Catalini, Alexander Eichler, Oded Zilberberg
Optics
Recurrent nonlinear modulational instability via down-conversion in quadratic media
Andrea Armaroli, Simone Ferraresi, Gaetano Bellanca et al. (+3 more)
We investigate the induced modulation instability in second-harmonic generation beyond the early stage of the linearized growth of the modulation. We find a regime of recurrence (quasi-periodic conversion and back-conversion between the pump and the modulation) which is genuine of the parametric conversion process in quadratic media. Such recurrence is mainly driven by a process of non-degenerate downconversion, showing no analogy to the cascading regime which mimics the cubic (Kerr) nonlinearities. We consider two different steady states, i.e., a pure second-harmonic and a mixed fundamental/second-harmonic state. Both exhibit this dynamics, which we show to be amenable to a description in terms of reduced frequency-truncated models. The comparison with full numerical simulations of the starting model prove the validity and robustness of the reduced models in characterizing in a simple and elegant way a wide range of modulationally-unstable steady states.
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All authors Andrea Armaroli, Simone Ferraresi, Gaetano Bellanca, Stefania Malaguti, Fabio Baronio, Stefano Trillo
Chemical Physics
Size-Consistent Adiabatic Connection Functionals via Orbital-Based Matrix Interpolation
Kyle Bystrom and Timothy C. Berkelbach
We introduce a size-consistent and orbital-invariant formalism for constructing correlation functionals based on the adiabatic connection for density functional theory (DFT). By constructing correlation energy
matrices for the weak and strong correlation limits in the space of occupied orbitals, our method, which we call orbital-based size-consistent
matrix interpolation (OSMI), avoids previous difficulties in the construction of size-consistent adiabatic connection functionals. We design a simple, nonempirical adiabatic connection and a one-parameter strong-interaction limit functional, and we show that the resulting method reproduces the correlation energy of the uniform electron gas over a wide range of densities. When applied to subsets of the GMTKN55 thermochemistry database, OSMI is more accurate on average than MP2 and nonempirical density functionals. Most notably, OSMI provides excellent predictions of the barrier heights we tested, with average errors of less than 2 kcal mol$^{-1}$. Finally, we find that OSMI improves the trade-off between fractional
spin and fractional charge errors for bond dissociation curves compared to DFT and MP2. The fact that OSMI provides a good description of molecular systems and the uniform electron gas, while also maintaining low self-interaction error and size-consistency, suggests that it could provide a framework for studying heterogeneous chemical systems.
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Physics and Society
Dynamic Estimates of Displacement in Disaster Regions: A Policy-driven framework triangulating data
Elisabetta Pietrostefani, Matt Mason, Rodgers Iradukunda et al. (+3 more)
While traditional data systems remain fundamental to humanitarian response, they often lack the real-time responsiveness and spatial precision needed to capture increasingly complex patterns of displacement. Internal displacement reached an unprecedented 83.4 million people by the end of 2024, underscoring the urgent need for innovative, data driven approaches to monitor and understand population movements. This report examines how integrating traditional data sources with emerging digital trace data, such as mobile phone GPS and social media activity, can enhance the accuracy, responsiveness, and granularity of displacement monitoring. Drawing on lessons from recent crises, including the escalation of the war in Ukraine and the 2022 floods in Pakistan, the report presents a structured pilot effort that tests the triangulation of multiple data streams to produce more robust and reliable displacement estimates. Statistical indicators derived from digital trace data are benchmarked against the International Organisation for Migration, Displacement Tracking
Matrix datasets, to assess their validity, transparency, and scalability. The findings demonstrate how triangulated data approaches can deliver real-time, high-resolution insights into population movements, improving humanitarian resource allocation and intervention planning. The report includes a scalable framework for crisis monitoring that leverages digital innovation to strengthen humanitarian data systems and support evidence-based decision-making in complex emergencies.
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All authors Elisabetta Pietrostefani, Matt Mason, Rodgers Iradukunda, Hong Tran-Jones, Iryna Loktieva, Francisco Rowe
Chemical Physics
Edge Irregularity Strength: A Complementary Descriptor to Topological Indices in QSPR and QSAR Studies
U. Vijaya Chandra Kumar, H.M. Nagesh and Narahari N
In chemical graph theory, topological indices are widely used as numerical descriptors for establishing quantitative structure-property relationships (QSPR) and quantitative structure-activity relationships (QSAR). These indices successfully correlate molecular structure with various physicochemical and biological properties. In addition to these methods, the concept of edge irregularity strength, a graph labeling measure, offers another perspective for representing structural characteristics. In this context, the edge irregularity strength concept provides a systematic way of assigning numerical labels to atoms based on specific rules. In this work, we explore the chemical applicability of the edge irregularity strength and demonstrate that it can also serve as a predictive tool for physicochemical properties, similar to topological indices. The findings show that the edge irregularity strength captures molecular features and complements existing approaches to structure-property analysis in chemical graph theory.
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Instrumentation and Detectors
Search for Double Beta Plus Decays with NuDoubt++
Stefan Schoppmann
Double beta plus decay is a rare
nuclear disintegration process. Difficulties in its measurement arise from suppressed decay probabilities, experimentally challenging decay signatures and low natural abundances of suitable candidate
nuclei. In this presentation, we propose NuDoubt++, a new detector concept to overcome these challenges. It is based on the first-time combination of hybrid and opaque scintillation detector technology paired with novel light read-out techniques. This approach is particularly suitable detecting positron (beta plus) signatures. We expect to discover two-
neutrino double beta plus decay modes within 1 tonne-week exposure and are able to probe neutrinoless double beta plus decays at several orders of magnitude improved significance compared to current experimental limits.
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Chemical Physics · Cross-listed from cs.LG
COFAP: A Universal Framework for COFs Adsorption Prediction through Designed Multi-Modal Extraction and Cross-Modal Synergy
Zihan Li, Mingyang Wan, Mingyu Gao et al. (+4 more)
Covalent organic frameworks (COFs) are promising adsorbents for gas adsorption and separation, while identifying the optimal structures among their vast design space requires efficient high-throughput screening. Conventional machine-learning predictors rely heavily on specific gas-related features. However, these features are time-consuming and limit scalability, leading to inefficiency and labor-intensive processes. Herein, a universal COFs adsorption prediction framework (COFAP) is proposed, which can extract multi-modal structural and chemical features through deep learning, and fuse these complementary features via cross-modal
attention mechanism. Without relying on explicit gas-specific thermodynamic descriptors, COFAP achieves state-of-the-art prediction performance on the hypoCOFs
dataset under the conditions investigated in this study, outperforming existing approaches. Based on COFAP, we also found that high-performing COFs for gas separation concentrate within a narrow range of pore size and surface area. A weight-adjustable prioritization scheme is also developed to enable flexible, application-specific ranking of candidate COFs for researchers. Superior efficiency and accuracy render COFAP directly deployable in crystalline porous materials.
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All authors Zihan Li, Mingyang Wan, Mingyu Gao, Xishi Tai, Zhongshan Chen, Xiangke Wang, Feifan Zhang
Optics
Topological Soliton Frequency Comb in Nanophotonic Lithium Niobate
Nicolas Englebert, Robert M. Gray, Luis Ledezma et al. (+6 more)
Frequency combs have revolutionized metrology, ranging, and optical clocks, which have motivated substantial efforts on the development of chip-scale comb sources. The on-chip comb sources are currently based on electro-optic modulation, mode-locked
lasers,
quantum cascade
lasers, or
soliton formation via Kerr nonlinearity. However, the widespread deployment of on-chip comb sources has remained elusive as they still require RF sources, high-Q resonators, or complex stabilization schemes while facing efficiency challenges. Here, we demonstrate an on-chip source of frequency comb based on the integration of a lithium niobate nanophotonic
circuit with a
semiconductor laser that can alleviate these challenges. For the first time, we show the formation of temporal topological
solitons in a on-chip nanophotonic parametric oscillator with quadratic nonlinearity and low finesse. These
solitons, independent of the dispersion regime, consist of phase defects separating two $\pi$-out-of-phase continuous wave solutions at the signal frequency, which is at half the input pump frequency. We use on-chip cross-correlation for temporal measurements and confirm formation of topological
solitons as short as 60 fs around 2 $\mu$m, in agreement with a generalized parametrically forced Ginzburg-Landau theory. Moreover, we demonstrate a proof-of-concept turn-key operation of a hybrid-integrated source of topological frequency comb. Topological
solitons offer a new paradigm for integrated comb sources, which are dispersion-sign agnostic and do not require high-Q resonators or high-speed modulators and can provide access to hard-to-access spectral regions, including mid-infrared.
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All authors Nicolas Englebert, Robert M. Gray, Luis Ledezma, Ryoto Sekine, Thomas Zacharias, Rithvik Ramesh, Benjamin K. Gutierrez, Pedro Parra-Rivas, Alireza Marandi
Optics
Topological Expansion of Boehm's Brushes via Structured Light
Dmitry A. Pushin, Iman Salehi, Amy Chow et al. (+10 more)
We report a novel entoptic phenomenon in which the classical two-lobed Boehm's brushes are transformed into a multi-lobed structure by projecting
spin-orbit coupled light onto the human retina. These structured beams, composed of non-separable superpositions of circular polarization and orbital angular momentum (OAM), produce azimuthally modulated entoptic patterns through polarization-dependent scattering in the retina. Unlike Haidinger's brushes, which arise from dichroic absorption in the macula, the observed effect is driven by angular variations in scattering strength relative to the local polarization direction. In regions where scattering centers exhibit polarization orientations that converge toward a common point, their combined contributions reinforce one another, producing brighter and more sharply defined entoptic lobes whose number and orientation vary systematically with the
topology of the
spin-orbit stimulus. Psychophysical measurements across retinal eccentricities from 0.5$^\circ$ to 4$^\circ$ in eleven participants revealed that contrast detection thresholds decreased exponentially with eccentricity, consistent with polarization-sensitive scattering by isotropic structures in the non-foveal retinal regions. From the psychophysical fits, the mean eccentricity at which the entoptic pattern reached a 50 % threshold was $r_{50} = 1.03^\circ$ with a 95 % confidence interval of [0.72, 1.34]$^\circ$, indicating that the
spin-orbit-induced entoptic structure becomes perceptually robust at approximately 1$^\circ$ retinal eccentricity. Together, these findings demonstrate that
spin-orbit light modulates scattering-based visual phenomena in previously unrecognized ways, enabling new approaches for probing retinal structure and visual processing using topological features of light.
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All authors Dmitry A. Pushin, Iman Salehi, Amy Chow, Andrew E. Silva, Pinki Chahal, David G. Cory, Mukhit Kulmaganbetov, Gary P. Misson, Naume Shentevski, Taranjit Singh, Shelby E. Temple, Benjamin Thompson, Dusan Sarenac
Fluid Dynamics · Cross-listed from cs.LG
Towards Multi-Fidelity Scaling Laws of Neural Surrogates in CFD
Paul Setinek, Gianluca Galletti and Johannes Brandstetter
Scaling laws describe how model performance grows with data, parameters and compute. While large
datasets can usually be collected at relatively low cost in domains such as
language or
vision, scientific machine learning is often limited by the high expense of generating training data through numerical simulations. However, by adjusting modeling assumptions and approximations, simulation fidelity can be traded for computational cost, an aspect absent in other domains. We investigate this trade-off between data fidelity and cost in neural surrogates using low- and high-fidelity Reynolds-Averaged Navier-Stokes (RANS) simulations. Reformulating classical scaling laws, we decompose the
dataset axis into compute budget and
dataset composition. Our experiments reveal compute-performance scaling behavior and exhibit budget-dependent optimal fidelity mixes for the given
dataset configuration. These findings provide the first study of empirical scaling laws for multi-fidelity neural surrogate
datasets and offer practical considerations for compute-efficient
dataset generation in scientific machine learning.
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Physics and Society
The Inequity of Consumption-Based Tax Systems
Thiago Dias, José Roberto Iglesias and Sebastián Gonçalves
This study examines the lack of redistributive effectiveness of consumption-based tax systems with respect to social
fairness. Through numerical simulations, we explore the wealth exchanges among economic
agents subject to flat consumption taxes, comparing universal redistribution with optimal targeted approaches. The results demonstrate that consumption taxes exhibit inherent regressivity, disproportionately burdening the poorest 40% of households who contribute over half of total tax revenue for most tax rates. The findings challenge the equity of consumption taxes and provide quantitative insights for designing more fair fiscal policies.
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Computational Physics · Cross-listed from cond-mat.mtrl-sci
Thermal tuning of dynamic response in Ag-based nanowire networks
J.I. Diaz Schneider, C. Gomez, C. Acha et al. (+3 more)
Self-assembled networks of metallic nanowires (NWs) are being intensively explored as test benches for neuromorphic proposals. In this work, we study the electric transport properties of dense self-assembled networks of Ag-based NWs (AgNWNs) coated with a thin insulating layer, using DC and AC stimuli. The building blocks of this network are the metallic NWs and the NW-NW junctions, either metallic or memristive. In the pristine state, frequency independence of the impedance reveals an over-percolated purely resistive network. A combination of low-temperature annealing and AC stimulus is shown to drastically affect the resistivity of the sample (interpreted as a depopulation of purely metallic junctions), unveiling a rich dynamic response. This procedure triggers the achievement of a capacitive response, which is successfully rationalized using a previously introduced 'two junction model'. Thermal treatment appears to be an indirect strategy to effectively modify the humidity content at the NW-NW intersections and, consequently, enable multiple switching schemes suitable for
brain-like processing alternatives.
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All authors J.I. Diaz Schneider, C. Gomez, C. Acha, P.E. Levy, E.D. Martínez, C.P. Quinteros
Fluid Dynamics · Cross-listed from cond-mat.soft
Capillary and priming pressures control the penetration of yield-stress fluids through non-wetting 2D meshes
Manon Bourgade, Nicolas Bain, Loïc Vanel et al. (+2 more)
Forcing hydrophilic fluids through hydrophobic porous solids is a recurrent industrial challenge. If the penetrating fluid is Newtonian, the imposed pressure has to overcome the capillary pressure at the fluid-air interface in a pore. The presence of a yield-stress, however, makes the pressure transfer and the penetration significantly more complex. In this study, we experimentally investigate the forced penetration of a water based yield-stress fluid through a regular hydrophobic mesh under quasi-static conditions, combining quantitative pressure measurements and direct visualisation of the penetration process. We reveal that the penetration is controlled by a competition between the yield-stress and two distinct pressures. The capillary pressure, that dictates the threshold at which the yield-stress fluid penetrates the hydrophobic mesh, and a priming pressure, that controls how the fluid advances through it. The latter corresponds to a pressure drop ensuing a local capillary instability, never reported before. Our findings shine a new light on forced imbibition processes, with direct implications on their fundamental understanding and practical engineering.
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All authors Manon Bourgade, Nicolas Bain, Loïc Vanel, Mathieu Leocmach, Catherine Barentin
Atmospheric and Oceanic Physics
Towards a Unified Data-Driven Boundary Layer Momentum Flux Parameterization for Ocean and Atmosphere
Renaud Falga, Sara Shamekh and Laure Zanna
Boundary layer
turbulence, particularly the vertical fluxes of momentum, shapes the
evolution of winds and currents and plays a critical role in weather,
climate, and biogeochemical processes. In this work, a unified, data-driven parameterization of turbulent momentum fluxes is introduced for both the oceanic and atmospheric convective boundary layers. An artificial neural network (ANN) is trained offline on coarse-grained large-eddy simulation (LES) data representing a wide range of turbulent regimes in both fluids. By normalizing momentum flux profiles with their surface values, we exploit a self-similar structure across regimes and fluids, enabling joint training. The ANN learns to predict vertical profiles of subgrid momentum fluxes from mean wind or current profiles, capturing key physical features such as upgradient fluxes that are inaccessible to traditional first-order closure schemes. When implemented online in the Single Column Atmospheric Model (SCAM), the ANN parameterization consistently outperforms the SCAM baseline parameterization in replicating the
evolution of the boundary layer wind profiles from the LES, especially under convective conditions, with errors reduced by a factor of 2-3 across regimes. ANN performance remains robust even when the surface momentum flux is biased up to 30%, and generalization is confirmed by testing on LES cases excluded from the training
dataset. This work demonstrates the potential of machine learning to create unified and physically consistent parameterizations across boundary layer systems in
climate models.
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Applied Physics · Cross-listed from cond-mat.mtrl-sci
Comparison between first-principles supercell calculations of polarons and the ab initio polaron equations
Zhenbang Dai, Donghwan Kim, Jon Lafuente-Bartolome et al. (+1 more)
Polarons are composite quasiparticles formed by excess charges and the accompanying
lattice distortions in solids, and play a critical role in transport, optical, and catalytic properties of
semiconductors and
insulators. The standard approach for calculating polarons from first principles relies on density functional theory and periodic supercells. An alternative approach consists of recasting the calculation of polaron wavefunction,
lattice distortion, and energy as a coupled nonlinear
eigenvalue problem, using the band structure,
phonon dispersions, and the electron-
phonon matrix elements as obtained from density functional perturbation theory. Here, we revisit the formal connection between these two approaches, with an emphasis on the handling of self-interaction correction, and we establish a compact formal link between them. We perform a quantitative comparison of these methods for the case of small polarons in the prototypical
insulators TiO2, MgO, and LiF. We find that the polaron wavefunctions and
lattice distortions obtained from these methods are nearly indistinguishable in all cases, and the formation energies are in good (TiO2) to fair (MgO) agreement. We show that the residual deviations can be ascribed to the neglect of higher-order electron-
phonon couplings in the density functional perturbation theory approach.
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All authors Zhenbang Dai, Donghwan Kim, Jon Lafuente-Bartolome, Feliciano Giustino
Optics · Cross-listed from quant-ph
Non-Gaussianity and security of entanglement-based QKD
Mariia Gumberidze and Vladyslav C. Usenko
We theoretically analyse the relation between non-Gaussianity and security of
entanglement-based
quantum key distribution (QKD) protocols, namely device-independent (DI) and
entanglement-based BB$84$. A similar analysis has already been made for prepare-and-measure (P&M) protocols \cite{Lasota2017}. In addition, we consider imperfect detection with dark counts and limited efficiency. We assume a perfect source of entangled Bell states as produced by
quantum-dot type sources, depolarisation in the channel and different noise statistics, namely thermal and Poissonian. We consider single-
photon avalanche photodiodes (SPAD) and
photon number resolving detectors (PNRD) and use their respective criteria for non-Gaussianity. The results show cross-regions for both security and non-Gaussianity, hence, the possibility to conclude about the suitability of a given channel for secret key distribution. Our results can be useful as a pre-check for the implementation of QKD protocols.
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Chemical Physics
Volumetric and viscosity data of 1-iodonaphthalene + n-alkanes mixture at (288.15-308.15) K
Luis Felipe Sanz Juan Antonio González, Fernando Hevia, Daniel Lozano-Martín et al. (+4 more)
Density and viscosity measurements have been performed for the systems 1-iodonaphthalene + heptane, or + decane, or + dodecane, or + tetradecane over the temperature range (288.15-308.15) K and atmospheric pressure. At this end, a densitometer Anton-Paar DMA 602 and a Ubbelohde viscosimeter were used. Excess molar volumes are large and negative and decrease when the temperature is increased, which reveals that the main contribution to the excess molar volume arises from structural effects. The values of the deviations of dynamic viscosity from linear dependence on mole fraction are also large and negative, indicating that n-alkanes are good breakers of the interactions between 1-iodonaphthalene molecules. Different models were applied for describing viscosity data. McAllister's equation correlates well with kinematic viscosities. Results are similar when dynamic viscosities are correlated with the Grunberg-Nissan or Fang-He equations. This means that size effects are not relevant to the mentioned data. The adjustable parameter of the Grunberg-Nissan equation is negative for all the systems at any temperature, a typical feature of systems where dispersive interactions are dominant. This is in agreement with findings obtained in previous studies on similar n-alkane mixtures involving C$_6$H$_5$X (X = Cl, Br, I) or 1,2,4-trichlorobenzene or 1-chloronaphthalene. Free volume effects have little influence on the present dynamic viscosity results, well represented by the absolute rate model using residual molar Gibbs energies obtained from the DISQUAC model.
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All authors Luis Felipe Sanz Juan Antonio González, Fernando Hevia, Daniel Lozano-Martín, João Victor Alves-Laurentino, Fatemeh Pazoki, Isaías García de la Fuente, José Carlos Cobos
Instrumentation and Detectors · Cross-listed from hep-ex
First results of the NEXT-100 detector using $^{83m}$Kr decays
NEXT Collaboration: G. Martínez-Lema, C. Hervés Carrete, S. Torelli et al. (+112 more)
The NEXT collaboration is investigating the double beta decay of $^{136}$Xe using high-pressure gas electroluminescent time projection chambers, which provide excellent energy resolution together with a robust topological signature. Operating at the Laboratorio Subterráneo de Canfranc (LSC) and building on the success of the NEXT-White detector, the NEXT-100 apparatus began commissioning in May 2024 and started operation with xenon at a pressure of 4 bar in October 2024. We report here the first results obtained with NEXT-100 using low-energy calibration data from $^{83m}$Kr decays, which allow mapping of the detector response in the active volume and monitoring of its stability over time. After homogenizing the light response, we achieve an energy resolution of 4.37% FWHM at 41.5 keV for $^{83m}$Kr point-like energy deposits contained in a radius of 425 mm. In a fiducial region representing the operating conditions of NEXT-100 at 10 bar we obtain an improved energy resolution of 4.16% FWHM. These results are in good agreement with that obtained in NEXT-White, and an $E^{-1/2}$ extrapolation to $Q_{\beta\beta}$ yields an energy resolution close to 0.5% FWHM, well below the 1% FWHM design target.
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All authors NEXT Collaboration: G. Martínez-Lema, C. Hervés Carrete, S. Torelli, M. Cid Laso, P. Vázquez Cabaleiro, B. Palmeiro, J.A. Hernando Morata, J.J. Gómez-Cadenas, C. Adams, H. Almazán, V. Álvarez, A.I. Aranburu, L. Arazi, I.J. Arnquist, F. Auria-Luna, S. Ayet, Y. Ayyad, C.D.R. Azevedo, K. Bailey, F. Ballester, J.E. Barcelon, M. del Barrio-Torregrosa, A. Bayo, J.M. Benlloch-Rodríguez, F.I.G.M. Borges, A. Brodoline, N. Byrnes, A. Castillo, E. Church, L. Cid, X. Cid, C.A.N. Conde, C. Cortes-Parra, F.P. Cossío, R. Coupe, E. Dey, P. Dietz, C. Echeverria, M. Elorza, R. Esteve, R. Felkai, L.M.P. Fernandes, P. Ferrario, F.W. Foss, Z. Freixa, J. García-Barrena, J.W.R. Grocott, R. Guenette, J. Hauptman, C.A.O. Henriques, P. Herrero-Gómez, V. Herrero, Y. Ifergan, A.F.B. Isabel, B.J.P. Jones, F. Kellerer, L. Larizgoitia, A. Larumbe, P. Lebrun, F. Lopez, N. López-March, R. Madigan, R.D.P. Mano, A. Marauri, A.P. Marques, J. Martín-Albo, A. Martínez, M. Martínez-Vara, R.L. Miller, K. Mistry, J. Molina-Canteras, F. Monrabal, C.M.B. Monteiro, F.J. Mora, K.E. Navarro, P. Novella, D.R. Nygren, E. Oblak, J. Palacio, A. Para, I. Parmaksiz, A. Pazos, J. Pelegrin, M. Pérez Maneiro, M. Querol, J. Renner, I. Rivilla, C. Rogero, L. Rogers, B. Romeo, C. Romo-Luque, E. Ruiz-Chóliz, P. Saharia, F.P. Santos, J.M.F. dos Santos, M. Seemann, I. Shomroni, A.L.M. Silva, P.A.O.C. Silva, A. Simón, S.R. Soleti, M. Sorel, J. Soto-Oton, J.M.R. Teixeira, S. Teruel-Pardo, J.F. Toledo, C. Tonnelé, J. Torrent, A. Trettin, P.R.G. Valle, M. Vanga, J.F.C.A. Veloso, J.D. Villamil, J. Waiton, A. Yubero-Navarro
Applied Physics
A Compact Model for Polar Multiple-Channel Field Effect Transistors: A Case Study in III-V Nitride Semiconductors
Aias Asteris, Thai-Son Nguyen, Huili Grace Xing et al. (+1 more)
A compact analytical model is developed for the mobile charge density of polar multiple channel field effect transistors. Two dimensional electron and hole gases can be potentially induced by spontaneous and piezoelectric polarization in polar
heterostructures. Focusing on the active region of devices that employ a multiple
quantum-well layout, the total electron and hole populations are estimated from fundamental electrostatic and
quantum mechanical principles. Hole gas depletion techniques, revolving around intentional donor doping, are modeled and evaluated, culminating in a generalized closed-form equation for the mobile carrier density across the doping schemes examined. The utility of this model is illustrated for the III-Nitride material system, exploring AlGaN/GaN, AlInN/GaN and AlScN/GaN
heterostructures. The compact framework provided herein considerably elucidates and enhances the efficiency of multi-layered transistor design.
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All authors Aias Asteris, Thai-Son Nguyen, Huili Grace Xing, Debdeep Jena
Applied Physics
Path-Optimized Fast Quasi-Adiabatic Driving in Coupled Elastic Waveguides
Dong Liu, Yiran Hao and Jensen Li
Fast quasi-adiabatic driving (FAQUAD) is a central technique in shortcuts to adiabaticity (STA), enabling accelerated adiabatic
evolution by optimizing the rate of change of a single control parameter. However, many realistic systems are governed by multiple coupled parameters, where the adiabatic condition depends not only on the local rate of change but also on the path through parameter space. Here, we introduce an enhanced FAQUAD framework that incorporates path optimization in addition to conventional velocity optimization, extending STA control to two-dimensional parameter spaces. We implement this concept in a coupled elastic-waveguide system, where the synthetic parameters-detuning and coupling-are controlled by the thicknesses of the waveguides and connecting bridges. Using scanning
laser Doppler vibrometry, we directly map the flexural-wave field and observe adiabatic energy transfer along the optimized path in parameter space. This elastic-wave platform provides a versatile classical analogue for exploring multidimensional adiabatic control, demonstrating efficient and compact implementation of shortcut-to-adiabaticity protocols.
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Geophysics
A multi-scale assessment for managing coastal geomorphic changes in southwestern Lake Michigan
Boyuan Lu, Wei Wang, Nick Jordan et al. (+4 more)
Understanding coastal geomorphic change is essential for advancing the United Nations Sustainable Development Goals (SDGs) through a multi-scale coastal management framework. In particular, characterization of coastal geomorphic change across multiple spatial and temporal scales can provide essential insights and context-specific knowledge that can inform and empower local communities. In this study, we present a multi-scale assessment of coastal geomorphic change in southwestern Lake Michigan in the Laurentian Great Lakes. Three spatial scales: county, reach, and transect and two temporal scales: long-term and short-term were examined using nine sets of historical aerial imagery spanning 1937 to 2020. The site-averaged long-term (1937-2020) change rates for the bluff crest, bluff toe, and shoreline were -0.22, -0.17, and -0.16 m/year, respectively. In the short term (1995-2020), the corresponding rates were -0.22, -0.15, and -0.32 m/year, indicating an increasing shoreline erosion in recent years. The coastal geomorphic changes at county, reach, and transect scales were further characterized, showing regional and localized distributions of coastal erosion in our study sites. The mechanisms driving coastal change,particularly wave impacts, were also examined to assess their correlation with coastal geomorphic change across different spatial scales. The results indicate that wave impacts influence coastal environments at certain scales more strongly than at others. Several erosion "hotspots" were examined to identify local factors contributing to severe site-specific erosion. Lastly, the spatial uniformity of coastal geomorphology was examined between the county and reach scales. Overall, the findings suggest that multi-scale analyses provide a valuable insight for effective management of coastal geomorphology.
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All authors Boyuan Lu, Wei Wang, Nick Jordan, Daniel Wright, Adam Bechle, Lucas Zoet, Chin Wu