Instrumentation and Methods for Astrophysics
Laboratory characterization of a multi-photonic lantern optical waveguide using off-axis holography
Aditya R. Sengupta, Benjamin L. Gerard, Dominic Sanchez et al. (+7 more)
Photonic lanterns (PLs) are waveguides that convert multi-mode input light to single-mode outputs. Wavefront sensing (WFS) and spectroscopy using a PL have been demonstrated, but PL simulations and experiments show significant mismatches. For the WaveDriver project, a proposed Habitable Worlds Observatory pathfinder that uses a PL for WFS as well as for integral field spectroscopy, we manufactured an optical waveguide consisting of an array of seven 19-port PLs in one device. We present laboratory characterization of the individual PLs, consisting of measurements of the principal modes at each PL input using digital off-axis holography. We compare our mode measurements to simulations to assess the variation in the PL manufacturing process. We discuss expected WFS performance in the WaveDriver configuration.
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All authors Aditya R. Sengupta, Benjamin L. Gerard, Dominic Sanchez, Matthew DeMartino, Rebecca Jensen-Clem, Kevin Bundy, Michael J. Messerly, Paul Pax, Daren Dillon, Eric Strang
Quantum Physics
su(1,1) Symmetry and Exact Solutions of the Dunkl-Klein-Gordon Equation in Higher Dimensions
M. Salazar-Ramírez, B. C. Lütfüoğlu and Jesús Alfredo Martínez-Nuño
We investigate the $d$-dimensional Dunkl–Klein–Gordon equation for a scalar particle within an algebraic framework. By employing Schrödinger factorization, we construct the generators of the $\mathfrak{su}(1,1)$
algebra and establish the associated
symmetry of the radial sector. The corresponding energy spectra are derived from
unitary irreducible representations, and the Sturmian radial bases are obtained analytically. We analyze the $d$-dimensional Dunkl–Klein–Gordon oscillator and the bound-state sector of the $d$-dimensional Dunkl–Klein–Gordon equation with a Dunkl–Coulomb-like potential. Furthermore, $\mathrm{SU}(1,1)$ coherent states are constructed and their time
evolution is analyzed, revealing a characteristic radial oscillation behavior. The results show that the Dunkl deformation modifies the spatial and spectral structure of the system and, in the oscillator sector, introduces explicit parity-dependent energy shifts while preserving the underlying radial algebraic dynamics.
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High Energy Physics (Theory)
CIPro Package: Complete Intersections in Products of Projective Spaces and Line Bundles
Lara B. Anderson, Andrei Constantin, James Gray et al. (+3 more)
CIPro is a Mathematica package for constructing and analyzing complete intersections in products of projective spaces and line bundles over such varieties. It computes properties of complete intersections, such as Chern classes,
Hilbert series, GV invariants and
symmetries, as well as properties of line bundles on complete intersections, including their
cohomology groups. The package also consolidates a number of data sets available in the literature into a single system, including the lists of complete intersection Calabi-Yau three- and four-folds. This short tutorial introduces the package, provides a brief discussion of some of the mathematical background underlying its computations, and gives a series of examples to illustrate its use. These tools are of utility for many computations in string compactifications, especially for Calabi-Yau geometries appearing in Heterotic and Type II constructions. Many tools apply beyond the Calabi-Yau context, including for example, almost Fano bases in F-theory.
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All authors Lara B. Anderson, Andrei Constantin, James Gray, Yang-Hui He, Seung-Joo Lee, Andre Lukas
Materials Science
PtyRANNOSAUR: Ptychography with Robust Artificial Neural Networks Optimized for Sub-Angstrom Accuracy and Ultrafast Reconstruction
Kieran Loehr, Rahim Raja, Xiaochuan Ding et al. (+5 more)
We present PtyRANNOSAUR, a data-driven neural network code that reconstructs atomic resolution electron ptychography data in seconds, 10-100x faster than standard methods. PtyRANNOSAUR uses convolutional autoencoders to map 4D-scanning transmission electron microscopy data to 2D phase images. Each model is trained on a large database of
crystal structures and is tailored for a range of experimental parameters, such as accelerating voltage, convergence angle, defocus, and sample thickness. This approach yields high quality reconstructions without requiring any fine-tuning of hyperparameters. In addition, the code handles spatial partial coherence, multiple scattering, and scan position errors, which are critical for state-of-the-art electron ptychography reconstructions. By testing PtyRANNOSAUR on experimental and simulated data, we show that the neural networks accurately reconstruct atomic structures of a broad range of materials systems and can achieve high resolutions of $<0.5$ Å, comparable to the best iterative reconstructions of the same data. These advances enable near-live, state-of-the-art electron ptychography reconstructions.
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All authors Kieran Loehr, Rahim Raja, Xiaochuan Ding, Jeffrey Huang, Gillian Nolan, Sang hyun Bae, Bryan K. Clark, Pinshane Y. Huang
Solar and Stellar Astrophysics
Detached Post-Algol Eclipsing Binaries Caught Between Case A and Case AB Mass Transfer
Megan G. Frank, Maxwell Moe and Nathan Smith
For sixty years,
stellar evolutionary models have predicted that intermediate-mass
stars slightly contract on the terminal-age main-sequence (TAMS) as they exhaust hydrogen in their convective cores, producing the main-sequence (MS) hook on the Hertzsprung-Russell diagram. Contraction along the TAMS has not previously been observationally verified, but an evolved eclipsing binary (EB) with a component on the TAMS can test this prediction. In a very close binary with an orbital period of less than a week, the primary
star initially fills its Roche lobe on the MS (Case A mass transfer), and the binary can invert mass ratios, producing a classical Algol. The subgiant donor then contracts on the TAMS and detaches slightly from its Roche lobe. The subgiant subsequently re-expands and refills its Roche lobe as it evolves toward the Hertzsprung Gap (Case AB mass transfer). We report the discovery of detached post-Algol EB candidates in the LMC caught between Case A and Case AB mass transfer. Their OGLE light curves feature strong reflection effects as the hot primary (former mass gainer) irradiates the cool subgiant secondary. We analyze multi-epoch echelle spectra of four post-Algol candidates taken with the MIKE spectrograph at the 6.5m Magellan-Clay
telescope. The primaries have mid-B MS atmospheres (M1 = 6 - 8 Msun). We measure dynamical masses of the subgiant secondaries to be M2 = 0.9 - 1.2 Msun. Detailed fitting of the OGLE light curves with PHOEBE reveals that the subgiants have Roche lobe fill factors of RLF F2 = 73% - 89%, consistent with binary
evolution models. Our discovery of detached post-Algol candidates provides the first empirical evidence that intermediate-mass
stars contract along the TAMS.
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Instrumentation and Methods for Astrophysics
Experimentally-determined performance limits for joint imaging and wavefront sensing with a photonic lantern
Aditya R. Sengupta, Vincent Chambouleyron, Rebecca Jensen-Clem et al. (+16 more)
The photonic lantern (PL) is a focal-plane wavefront sensor (WFS) that can be used for second-stage control of extreme adaptive optics (AO) systems. While the number of sensed modes and the dynamic range with respect to each mode have been relatively well characterized, little
attention has been paid to the PL's sensitivity, i.e. how measurement noise impacts the accuracy of PL wavefront reconstruction. We compute the PL's sensitivity to
photon noise as a function of spatial frequency, and compare it to existing WFSs, using simulations as well as experiments on the muirSEAL testbed. We further assess these metrics in the case where only a subset of PL ports are available for wavefront sensing. In this configuration, the remaining ports are used to spatially and spectrally reconstruct the observed scene using
algorithms such as SPADE. Using more ports for wavefront sensing enables greater aberration sensitivity but leaves less spatial information for image reconstruction. This allows us to trade off between fewer samples with smaller aberrations and more samples with larger aberrations. This work sets the stage for AO system design incorporating the PL as a joint WFS and imager.
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All authors Aditya R. Sengupta, Vincent Chambouleyron, Rebecca Jensen-Clem, Emiel Por, Benjamin L. Gerard, Jordan Diaz, Zoe Weber-Porter, Yoo Jung Kim, Steph Sallum, Matthew DeMartino, Daren Dillon, Kevin Bundy, Anna K. Gagnebin, Philip Hinz, Caleb Dobias, Tara Crowe, Stephen S. Eikenberry, Rodrigo Amezcua-Correa, Stephanos Yerolatsitis
High Energy Physics (Phenomenology)
Nature of the newly found $\Omega(2109)$
Taísa Veloso, K. P. Khemchandani, A. Martinez Torres et al. (+2 more)
We present model calculations to reveal the nature of the newly found $\Omega^-(2109)$ by the BESIII Collaboration, and show that the state has a strong correlation with the $\bar K^*(892)\Xi$ system. Our study is based on solving scattering equations in a coupled channel approach, which involves $K^-\Xi^0$, $\bar K^0\Xi^-$, $K^{*-}\Xi^0$, and $\bar K^{*0}\Xi^-$. We obtain the lowest order amplitudes for different
spin and isospin cases and find that an isoscalar state with
spin-parity $1/2^-$ is generated with precisely the same mass as $\Omega^-(2109)$. We do not find any state with total
spin 3/2, nor do we find any state in the isovector sector. We determine correlation functions to encourage such an experimental study and confirm the nature of $\Omega^-(2109)$.
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All authors Taísa Veloso, K. P. Khemchandani, A. Martinez Torres, H. Nagahiro, A. Hosaka
Quantum Physics
Vector Representation of Exact Soliton Dynamics in Multi-component Nonlinear Schrödinger Systems
Maxime Foucher, Laurent Delisle and Amine Jaouadi
Multicomponent nonlinear Schrödinger equations constitute fundamental models for coherent matter waves in multicomponent Bose–Einstein condensates, spinor
quantum fluids, and vector nonlinear optical systems. We develop a vector formulation of the Hirota bilinear formalism for the completely integrable Manakov system that treats the coupled nonlinear Schrödinger equations directly at the vector level rather than through the conventional component-wise decomposition. This framework naturally retains the intrinsic multicomponent representation of the model while providing compact analytical expressions for exact vector
soliton solutions. Within this approach, we systematically construct bright, dark, and mixed one-, two-, and three-
soliton solutions and show how the underlying vector structure provides a unified description of their nonlinear interactions. In particular, the proposed formalism makes the coupling between the different components explicit while preserving the
geometric organization of the vector system throughout the bilinearization procedure. Beyond its analytical simplicity, the framework offers a natural perspective for the study of coherent multicomponent nonlinear excitations and provides a foundation for extending vector Hirota methods to other classes of exact solutions, including rogue waves, periodic waves, and rational solutions.
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Instrumentation and Methods for Astrophysics
Searching for Extraterrestrial Intelligence with the SKA
Chenoa D. Tremblay, Alex Andersson, Joe Bright et al. (+19 more)
The search for technosignatures (also known as the Search for Extraterrestrial Intelligence or SETI) depends critically on our ability to distinguish artificial signals from the rich complexity of natural astrophysical phenomena and
radio frequency interference from anthropogenic emissions. As the search for technosignatures increasingly aligns with mainstream astrophysics, complementing the search for biosignatures, it demands not only sophisticated statistical and computational approaches, but also deep domain knowledge across the electromagnetic spectrum. The SKA will play a pivotal role in the next-generation of technosignature searches, providing an unprecedented combination of sensitivity, field of view, and spatial resolution over its wavelength range. Integrating wide-field, high-resolution observations with machine learning and multi-wavelength diagnostics will represent key steps forward. The SKA's singular capabilities will render it an indispensable instrument for the rapid identification and follow-up characterisation of promising technosignature candidates. In this chapter, we discuss the request for high temporal and spectral resolution data products with a main focus on frequency-domain SETI. Nevertheless, multiple SKA observing modes have the potential to substantially advance technosignature research.
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All authors Chenoa D. Tremblay, Alex Andersson, Joe Bright, Bárbara Cabrales, David DeBoer, Vishal Gajjar, Michael A. Garrett, Evan F. Keane, Dong-Jin Kim, Steve Prabu, Danny C. Price, Andrew P.V. Siemion, Sofia Z. Sheikh, Cyril Tasse, Philippe Zarka, Nathalie Cabrol, Joseph R. Callingham, Steve Croft, William Diamond, Jamie Drew, Kyran Grattan, S.Peter Worden
Fluid Dynamics
Two-Dimensional Locally Adaptive Non-Hydrostatic Extension of Shallow Water Equations
Kemal Firdaus and Jörn Behrens
We introduce a two-dimensional non-hydrostatic model for shallow water wave dispersion. The model is based on a locally adapted application of a non-hydrostatic correction to the hydrostatic shallow water equations (SWE) in a predictor-corrector scheme. Applying the non-hydrostatic correction uniformly to the entire domain demands a high computational cost, since an
elliptic system of equations needs to be solved for the correction terms. We demonstrate that by determining the area where the non-hydrostatic effects are significant, and applying the correction only locally, the computational effort can be reduced by approximately 40% without sacrificing accuracy in tsunami-like scenarios. As indicators for the non-hydrostatic effect, we use the ratio between total water depth and surface elevation, as well as horizontal velocity norms. Results are shown for several well-known test cases, including wave trains over a semi-circular shoal, static, and moving bottom tsunami-like wave propagation.
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Quantum Physics · Cross-listed from cs.LG
Quantum Generative Diffusion Model for Real-World Time Series
Jack Waller, Filippo Caruso, Dimitrios Makris et al. (+2 more)
Generative models have achieved remarkable success in data synthesis, though recent advances driven by increasing model scale have introduced challenges in computational cost and efficiency.
Quantum machine learning offers a promising alternative, representing complex data distributions using compact, highly expressive models. Here, we propose QDiffusion-TS, the first
quantum generative
diffusion model for time series synthesis, and validate it on the IQM
quantum processor. The framework extends a classical
diffusion architecture by replacing feed-forward components within the denoising
transformer with
quantum neural networks, yielding a hybrid
quantum transformer that reduces the number of trainable parameters in each replaced component by nearly three orders of magnitude. Evaluated on financial time series from Apple and Amazon, the model generates synthetic data that more accurately reproduces the real distributions, reducing Wasserstein distance by approximately 44% relative to its classical counterpart across both
datasets. In a downstream
forecasting task, augmentation with the generated data improves predictive performance by up to 71% in RMSE over a baseline trained solely on real data. These results show that
quantum enhanced architectures can consistently match and frequently surpass classical performance with substantially fewer parameters, establishing a practical framework towards more efficient and scalable data-driven generative modelling.
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All authors Jack Waller, Filippo Caruso, Dimitrios Makris, Rajagopal Nilavalan, Xing Liang
Quantum Physics
Photon avalanche triggered by a single photon in a bistable nonlinear optical cavity
Asian Selvakumaran, Anna Minguzzi, Iacopo Carusotto et al. (+1 more)
We theoretically investigate the response of a coherently-driven nonlinear optical cavity to an additional incident single
photon. Using a
quantum description of the nonlinear dynamics that fully accounts for the
quantum fluctuations of the cavity field and for the discrete nature of the incident
photon, we characterize the
quantum dynamics of single-
photon-stimulated jumps from the low-
photon-number to the high-
photon-number state of the optical bistability loop. We find that the system can exhibit a
giant response to this single
quantum of excitation, rooted in the phase-transition picture of optical bistability. In addition to shedding light on the role of
quantum fluctuations in the non-
equilibrium dynamics of a nonlinear optical cavity, our results suggest a strategy for an all-optical single-
photon avalanche detector.
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All authors Asian Selvakumaran, Anna Minguzzi, Iacopo Carusotto, Maxime Richard
Chaotic Dynamics
Large post-critical dynamics of an inextensible spinning fluid-conveying pipe with pinned-roller supports: high-order Galerkin and a modified Hencky bar-chain framework
Ali Fasihi, Grzegorz Kudra, Maryam GhandchiTehrani et al. (+1 more)
This paper investigates the stability and large post-critical dynamics of an inextensible spinning fluid-conveying pipe with pinned-roller supports. Replacing the pinned-pinned support of the extensible counterpart with a sliding support removes the axial-stretching restoring mechanism and fundamentally changes the governing equations of motion. Derived here for this configuration, these equations contain a different set of nonlinear terms – arising from the inextensibility constraint and the bending
curvatures rather than the single axial-stretching term – that drives a post-critical regime with large deflections. The regime is analysed with two complementary methods. The first is a Galerkin discretisation in which the bending
curvatures are Taylor-expanded to ninth order, shown to be the lowest order resolving the post-critical amplitude; the standard cubic truncation overestimates the deflection significantly by missing the
geometric stiffening from inextensibility. The second is a modified Hencky bar-chain model with a global angular description: a closed, $n$-independent
matrix framework with exact trigonometric kinematics, directly implementable in any standard programming environment with
matrix routines and adaptable to both extensible and inextensible configurations through a single boundary-condition reduction. The linearised dynamics give an ellipse-like stability boundary in the flow-velocity–rotational-speed plane with semi-axes $U=\pi$ and $\Omega=\pi^{2}$; three damping regimes are identified, including a high-rotation instability driven by rotating damping. Close agreement between the two methods across linear-stability, bifurcation, and time-history comparisons confirms the ninth-order Galerkin truncation and establishes the modified Hencky bar-chain as a reliable general-purpose discrete framework for spinning fluid-conveying pipes.
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All authors Ali Fasihi, Grzegorz Kudra, Maryam GhandchiTehrani, Jan Awrejcewicz
Mesoscale and Nanoscale Physics
Multiphoton Fingerprints of Altermagnetic Spin Splittings
Sayed Ali Akbar Ghorashi and Andrew M. Rappe
We systematically investigate multiphoton absorption as a polarization-resolved nonlinear optical probe of planar altermagnets (ALMs). We show that the angular harmonic of the altermagnetic
spin splitting fixes the lowest optical absorption at which a
symmetry-selective response appears: two-
photon absorption for $d$-wave order, four-
photon absorption for $g$-wave order, and six-
photon absorption for $i$-wave order. In each case, there exists a polarization channel locked to the
symmetry harmonic of the altermagnetic texture in which the direct $n$-
photon contribution to the transition
matrix element is absent. This changes the frequency scaling of the absorption rate relative to other polarization channels and provides a direct optical fingerprint of the underlying altermagnetic harmonic. Our results establish a hierarchy of nonlinear spectroscopic signatures that distinguishes $d$-, $g$-, and $i$-wave altermagnetic
spin splittings beyond linear response.
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High Energy Astrophysical Phenomena
The Astrophysics of Fast Radio Bursts
Alice P. Curtin, Marcin Gawroński, Jason Hessels et al. (+11 more)
Fast
radio bursts (FRBs) provide a glimpse of high-energy astrophysical phenomena in other
galaxies. They point the way to extreme conditions that are currently undetectable by any other known means. These coherent
radio flashes have timescales of microseconds to milliseconds, and inferred energies that are comparable to those of the most extreme bursts seen from
Galactic neutron stars. However, the nature of FRB sources remains an open question in astrophysics. Magnetically powered
neutron stars known as `magnetars' are a leading candidate for explaining the FRB phenomenon, but other plausible progenitors include magnetically interacting
neutron-
star binaries or accreting black holes. The diversity of FRB burst types and their
galactic environments hint that multiple mechanisms and progenitor types may be responsible. Here we discuss the ways in which the SKA can uncover the nature of FRBs. In particular, we focus on the key advantages of the SKA: its Southern Hemisphere location and hence overlapping sky coverage with the Vera C. Rubin Observatory, its high sensitivity compared to existing wide-field FRB surveys, its fast search timescales down to tens of $\mu$s, and its broad spectral coverage with bands from 50 MHz to 15 GHz. With these capabilities, the SKA will excel in detecting FRB sources across new frequency ranges and timescales. This will aid in a better understanding of the fundamental astrophysics behind FRBs, which will in turn also contribute to their use as cosmological probes, as explored in companion chapters.
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All authors Alice P. Curtin, Marcin Gawroński, Jason Hessels, Clancy James, Fabian Jankowski, Franz Kirsten, Benito Marcote, Harry Qiu, Robert Reischke, Mawson W. Sammons, Laura G. Spitler, Ben Stappers, Amanda Weltman, The SKA Transients SWG
High Energy Physics (Theory)
Gravitational wave scattering at $\mathcal{O}(G^4)$: Murua construction and elliptics
Yilber Fabian Bautista, Mathias Driesse, Kays Haddad et al. (+1 more)
We compute the amplitude for the scattering of a gravitational wave off of a spinless point particle at fourth order in Newton's constant, using the worldline
quantum field theory formalism. A decomposition of our master integrals incorporating Murua coefficients allows us to entirely bypass the cut subtraction needed to convert the scattering amplitude into the Magnusian, the latter mapping directly onto the scattering phase shift in partial wave space.
Elliptic functions appear in momentum space for the first time for this process at this order. To compare to the phase shift from black hole perturbation theory, we present an analytical method for performing the partial wave projection of the new
elliptic sector to any partial wave order $\ell$, and verify the equivalence of the Magnusian and the phase shift. This demonstrates that point-particle worldline
quantum field theory accurately describes Schwarzschild black holes up to $\mathcal{O}(G^4)$.
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All authors Yilber Fabian Bautista, Mathias Driesse, Kays Haddad, Gustav Uhre Jakobsen
Nuclear Theory
Single- and Double-$\Lambda$ Hypernuclear Correlations Calibrate $\Lambda\Lambda$ Interaction Energies
Shi Yuan Ding and Bao Yuan Sun
Double-$\Lambda$ hypernuclei are essential for probing the $\Lambda\Lambda$ interaction in the double-strangeness $S=-2$ sector, yet the scarcity of experimental data severely limits systematic predictions. We present an evaluation framework based on
nuclear many-body theory that exploits the intrinsic structural similarity between single-$\Lambda$ and double-$\Lambda$ systems to transfer empirical constraints from the well-mapped $S = -1$ sector to the $S = -2$ sector. By analyzing theoretical deviations of binding energies in light single- and double-$\Lambda$ hypernuclei, we identify a robust linear correlation between two sectors. This correlation enables a statistical evaluation of double-$\Lambda$ separation energies ($B_{\Lambda\Lambda}$) and $\Lambda\Lambda$ interaction energies ($\Delta B_{\Lambda\Lambda}$) for heavier double-$\Lambda$ hypernuclei, by drawing on a wealth of empirical data from the single-$\Lambda$ sector with quantified uncertainties. Our results show that evaluated $\Delta B_{\Lambda\Lambda}$ values, while consistent with existing data, are systematically larger than direct relativistic density functional predictions constrained only by the NAGARA event. This discrepancy suggests that standard mean-field-based extrapolations may underestimate $\Lambda\Lambda$ correlations and other many-body effects, motivating an evaluation-based correction that offers crucial
benchmarks for future $S = -2$ experiments at facilities such as HIAF and J-PARC.
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Fluid Dynamics
The multifractal nature of turbulent energy dissipation
Charles Meneveau and K.R. Sreenivasan
The intermittency of the rate of turbulent energy dissipation ${\epsilon}$ is investigated experimentally, with special emphasis on its scale-similar facets. This is done using a general formulation in terms of multifractals, and by interpreting measurements in that light. The concept of multiplicative processes in
turbulence is (heuristically) shown to lead to multifractal distributions, whose formalism is described in some detail. To prepare proper ground for the interpretation of experimental results, a variety of cascade models is reviewed and their physical contents are analysed qualitatively. Point-probe measurements of ${\epsilon}$ are made in several laboratory flows and in the atmospheric surface layer, using Taylor's frozen-flow hypothesis. The multifractal spectrum $f({\alpha})$ of ${\epsilon}$ is measured using different averaging techniques, and the results are shown to be in essential agreement among themselves and with our earlier ones. Also, long data sets obtained in two laboratory flows are used to obtain the latent part of the $f({\alpha})$ curve, confirming Mandelbrot's idea that it can in principle be obtained from linear cuts through a three-dimensional distribution. The tails of distributions of box-averaged dissipation are found to be of the square-root exponential type, and the implications of this finding for the $f({\alpha})$ distribution are discussed. A comparison of the results to a variety of cascade models shows that binomial models give the simplest possible mechanism that reproduces most of the observations. Generalizations to multinomial models are discussed.
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Earth and Planetary Astrophysics
JWST/MIRI Finds ISM-like Amorphous Silicates in Interstellar Comet 3I/ATLAS
Matthew Belyakov, Ian Wong, Carey M. Lisse et al. (+7 more)
We present the first spectroscopic mineralogical analysis of the
dust coma of an interstellar object (ISO) from JWST mid-infrared spectroscopy of 3I/ATLAS (3I). 3I exhibits a strong 9- to 11-micron emissivity feature due to Si-O vibrational stretching modes that is commonly seen in asteroids, comets, disks, and the interstellar medium. Characterization of this 10-micron emissivity maximum reveals that 3I's
dust composition is dominated by amorphous silicates, and that 3I is unlike
Solar System comets, which show significant crystalline silicate
dust. Instead, 3I's
dust composition is more similar to circumstellar transition disks and the interstellar medium. We suggest 3I may have formed in a distant part of its home system out of interstellar medium-like material, without substantial incorporation of silicates condensed near its host
star, unlike the mixing scenarios commonly suggested for the
Solar System. Alternatively, 3I's original crystalline silicates may have been amorphized during its Gyr-long journey, although we find this alternative less likely due to 3I's mass loss rate and distinct 10-micron feature as compared to observed
Solar System comets.
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All authors Matthew Belyakov, Ian Wong, Carey M. Lisse, M. Ryleigh Davis, Bryce T. Bolin, Audrey Martin, Klaus M. Pontoppidan, Geoffrey A. Blake, Christine Chen, Michael E. Brown
Medical Physics
Ridge-filter crosstalk in conformal proton FLASH planning: dependence on beamlet pitch and iterative mitigation
Zongsheng Hu, Yuting Li, Henry Meyer et al. (+5 more)
Objective: Patient-specific ridge filters (PSRFs) can enable conformal single-energy
proton FLASH delivery without energy switching. However, converting optimized spot-based dose distributions into physically adjacent ridge-filter structures may introduce inter-beamlet modulation errors not captured by conventional isolated-spot optimization. This study characterized ridge-filter (RF) crosstalk, evaluated its dependence on the beam-width-to-pitch relationship, and developed an iterative mitigation strategy. Approach: A Monte Carlo dose influence
matrix was generated for monoenergetic
proton beamlets passing through RFs of varying thickness. A baseline spot-weighted IMPT plan was optimized to meet dose constraints and converted into PSRF geometries. PSRF dose distributions were calculated by explicitly modeling the PSRF in the scanned beam path. RF crosstalk was quantified by comparing PSRF and baseline IMPT plans. Lateral beamlet spacings of 8, 10, 12, and 15 mm were evaluated using gamma analysis, DVH metrics, and mean relative dose difference. An iterative re-optimization method was tested in water-phantom and patient CT geometries. Results: RF crosstalk produced hot and cold spots, reducing agreement between PSRF and baseline IMPT plans. For the same spot size and target geometry, crosstalk increased as beamlet spacing decreased. Iterative re-optimization substantially reduced dose discrepancies, lowering the mean relative dose difference in the target from 8.9% to 3.4% in water and from 3.7% to 1.8% in CT. Significance: RF crosstalk is an important source of dose inconsistency in ridge-filter-based conformal
proton FLASH planning. Its dependence on the beam-width-to-pitch relationship and mitigation through iterative re-optimization provide a practical framework for improving the accuracy and robustness of patient-specific single-energy
proton FLASH delivery.
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All authors Zongsheng Hu, Yuting Li, Henry Meyer, Xiaochun Wang, Susan L. McGovern, Emil Scheueler, Radhe Mohan, Uwe Titt
General Relativity and Quantum Cosmology
Geodesic Focusing Conditions in $f(Q)$ Gravity
Chao-Qiang Geng, Chunhui Liu, Ling-Wei Luo et al. (+1 more)
We study the geodesic deviation equation in symmetric teleparallel geometry (STG), where the relative acceleration is defined with respect to the STG connection. We analyze the modified Raychaudhuri equation along a geodesic congruence in $f(Q)$
gravity under the Weyl-type ansatz, together with an additional assumption under which the metric variation term along the congruence is converted into a disformation-induced acceleration term. In contrast to the purely geometrical Raychaudhuri equation obtained in general metric-affine settings, the equation derived here contains matter-source contributions through the trace equation of $f(Q)$
gravity. Different from general relativity, focusing in $f(Q)$
gravity is not automatic, and one must impose an appropriate focusing condition. We collect the model-dependent terms in the modified Raychaudhuri equation into an effective energy-momentum trace $T_{\text{eff}}$, so that the focusing condition can be written as the inequality $T\leq T_{\text{eff}}$, where $T$ is the trace of the matter energy-momentum tensor. We also apply this condition to the flat Friedmann–Lemaître–Robertson–Walker (FLRW) background. The homogeneous and isotropic STG connection admits three branches, each characterized by a single connection function $\gamma_i$, with $i=1,2,3$. Only the first branch with the coincident gauge is compatible with the Weyl-type ansatz. We obtain the resulting effective trace $T_{\text{eff}}=T$ for any form of $f(Q)$ satisfying $f_Q>0$ in the flat FLRW universe. The focusing inequality is saturated and imposes no additional constraint on the matter content.
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All authors Chao-Qiang Geng, Chunhui Liu, Ling-Wei Luo, Jianhui Qiu
Astrophysics of Galaxies
A Definitive Determination of the Interstellar Carbon Abundance toward rho Ophiuchi A and B
Adam M. Ritchey, S. R. Federman, Daniel E. Welty et al. (+1 more)
We present the results of an effort to derive interstellar gas-phase C II abundances along the lines of sight toward rho Oph A and B. Our analysis is based on high-resolution NUV and FUV archival spectra acquired with the Space
Telescope Imaging Spectrograph on the Hubble Space
Telescope. Column densities of C II are derived both from fits to the weak C II] 2325 intersystem transition and from fits to the damping wings of the strong C II 1334 line. We find that the results from the weak-line and strong-line determinations agree with each other remarkably well for both sight lines, demonstrating the reliability of the f-values of the C II transitions. Furthermore, the gas-phase C abundance that we obtain for rho Oph A is in very good agreement with previous determinations of interstellar C abundances from measurements of the weak C II] 2325 line. By demonstrating the reliability of the damping wing fitting technique for the C II 1334 line, our analysis opens the door to future surveys of interstellar C abundances using the same methodology.
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All authors Adam M. Ritchey, S. R. Federman, Daniel E. Welty, Adolf N. Witt
General Relativity and Quantum Cosmology
Dynamics of Relativistic Binaries in Structured and Stochastic Environments: A Lagrange-Fourier-Hansen Framework
Lorenz Zwick, Conor Dyson, Brian C. Seymour et al. (+2 more)
We develop a general framework to characterize non-
vacuum perturbations to relativistic binaries in the gravitational-wave (GW) driven regime, for use in GW parameter estimation studies. The effect of smooth, structured and
stochastic perturbations to the binary's motion is reduced to a resonant spectral projection defined on a rolling averaging window, with weights given by Hansen coefficients. This is combined with practical criteria for identifying and evaluating the corresponding dynamical response to perturbations, starting from either analytical models or numerical simulations of binaries in environments. The result is a set of coupled ODEs for the orbital elements that capture epi-cyclic, apsidal and nodal resonances, consistently incorporate feedback from radiation reaction and can be solved efficiently on a coarse time grid. We demonstrate the practical application of the framework in two representative astrophysical scenarios: a compact binary in a variable
tidal field and an extreme-mass-ratio inspiral in an
accretion disk. We propose the Lagrange-
Fourier-Hansen framework as a unified tool for modeling environmental effects in GW templates for eccentric and precessing binary sources, and particularly for bridging the gap between phenomenological prescriptions and realistic models of binaries in environments.
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All authors Lorenz Zwick, Conor Dyson, Brian C. Seymour, János Takátsy, Johan Samsing
Geophysics
Quantitative interpretation of Brookfield DV3TLV measurements: shear rate conversion, correction factors, and applicability limits
A. E. Vasiliev, A. S. Besov and D. O. Andreev
The flow behavior and hydrodynamic characteristics of fluids in rotational viscometry systems are investigated using the Brookfield DV3TLV viscometer, with emphasis on measurement reliability and applicability limits of different measuring geometries. The results are compared and validated using the high-precision MCR 302 rheometer manufactured by the Austrian company Anton Paar. Both Newtonian (water and glycerol) and non-Newtonian fluids (guar-based gels), exhibiting fundamentally different viscosity-shear rate behavior, were included in the study. Based on the comparison of measurements obtained with the Brookfield DV3TLV viscometer and the MCR 302 rheometer, empirical coefficients were determined that relate the spindle rotational speed to the shear rate, taking into account the geometry of the measuring systems. Analysis of the Reynolds number range showed that laminar flow conditions were maintained for all measurement systems, which justifies the application of quasi-static models that neglect possible flow
turbulence within them. Comparison with high-precision measurements performed on the MCR 302 rheometer showed that, with appropriate interpretation, the data obtained using the Brookfield instrument can be used to estimate the real viscosity of process fluids with an accuracy specific to each geometry and its operating conditions. The proposed methodology enables reliable characterization of flow properties in rotational systems and can be applied in engineering practice and laboratory analysis of complex fluids, especially at oil and food production facilities where high-end rheometers are unavailable or impractical to use. The study is formulated within the framework of experimental fluid mechanics and non-Newtonian flow characterization.
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Materials Science
A BRAVE Alloy Design Campaign (Bayesian Risk-aware Alloy discoVery and Exploration)
Mrinalini Mulukutla, Danial Khatamsaz, Trevor Hastings et al. (+23 more)
In constrained
alloy optimization, the compositions with the highest performance potential often reside at the boundary of phase stability – where the risk of experimental failure is also highest. This work demonstrates this principle through a risk-aware
Bayesian optimization campaign on single-phase FCC high-
entropy alloys in the Al-V-Cr-Mn-Fe-Co-Ni-Cu system. A learned feasibility classifier, integrated directly into the multi-objective acquisition function, probabilistically penalizes candidates likely to produce failed experiments while preserving access to high-performing boundary compositions. From approximately 27,000 CALPHAD-screened candidates, 48
alloys were synthesized over three closed-loop iterations targeting five objectives (yield strength, UTS/YS ratio, strain at UTS, dynamic-to-quasi-static hardness ratio, and simulated depth of penetration), exploring 0.12% of the feasible space. Two compositional regimes emerged: a V-rich, Ni-rich high-strength regime (UTS up to ${\sim}1480$~MPa at 50% elongation) and a Mn-containing high-ductility regime (UTS/YS up to 4.20 at $>$50% elongation). Among feasible
alloys, vanadium simultaneously drives yield strength ($r = 0.84$) and sigma-phase formation ($r = 0.54$ with infeasibility); at V = 24~at.%, the three strongest
alloys and three sigma failures share the same compositional point. Additionally, the strongest performing
alloys cluster in a narrow region of compositional space (V $\geq$ 20 at.%, Ni $\geq$ 36 at.%), representing ${\sim}100$ of $27,074$ feasible candidates – a probability of $P \approx 6.5 \times 10^{-6}$ under random sampling. This dual role – consistent with the KKT prediction that constrained optima lie on active constraint boundaries – required feasibility-aware acquisition to access; hard filtering would have excluded this region entirely.
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All authors Mrinalini Mulukutla, Danial Khatamsaz, Trevor Hastings, Wenle Xu, Daniel Salas, Joydeep Kundu, Vasanth C. Shunmugasamy, Daniel Lewis, Jacob Hempel, Clinton Strosser, Alexandra Salinas, Brent Vela, Nicolas Flores, Sina Hossein Zadeh, Ali Rachidi, David Elbert, Brady Butler, James Paramore, Dimitris Lagoudas, Justin Wilkerson, George Pharr, Douglas Allaire, Vahid Attari, Ibrahim Karaman, Ankit Srivastava, Raymundo Arróyave
Astrophysics of Galaxies
Discovery of an extremely narrow trail-like feature crossing the Veil Supernova Remnant in deep amateur observations
David Martinez-Delgado, Jan-Niklas Pippert, Miguel A. Perez-Torres et al. (+9 more)
We report the discovery of an extremely narrow and highly collimated gaseous trail-like structure crossing the eastern region of the Veil Nebula (Cygnus Loop). The feature was first identified in deep narrow-band H-alpha images obtained by a small
telescope and was confirmed in more than a dozen publicly available amateur and professional images in the last two decades, rejecting the possibility of being an artifact (e.g., artificial satellite trail). To characterize its structural and luminosity parameters, we applied a model-fitting code originally developed for the analysis of extragalactic
stellar tidal streams. The structure is only detected in H-alpha emission, with no detectable counterpart in [SII] or in visible observations, and shows an almost constant brightness and width along its extension. It exhibits a surface brightness of 22.32+/- 0.13 H-alpha mag arcsec^2. Model fitting yields a median width of 1.63", which corresponds to a physical scale of approximately 1200 UA, assuming it is at the same distance (2400 light-years) as the Veil Nebula remnant. We discuss several potential scenarios for the origin of this feature: a Herbig-Haro-like jet, the trail of a high-velocity object, or a non-radiative shock associated with the
supernova remnant. We rule out the Herbig-Haro scenario, given the absence of a driving
stellar source and the lack of [S II] emission. A high-velocity-object wake cannot yet be excluded, particularly if the driver is a compact remnant, but the absence of an obvious source or bow-shock apex and the extremely small, nearly constant width of the structure make a normal runaway-
star origin unlikely. The current evidence instead favours a Balmer-dominated non-radiative shock associated with the Cygnus Loop, generated as the SNR blast wave encounters a dense material layer or
magnetic structure viewed nearly edge-on.
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All authors David Martinez-Delgado, Jan-Niklas Pippert, Miguel A. Perez-Torres, Malte Busmann, Emilio J. Alfaro, Mark Hanson, Giuseppe Donatiello, Alexander Zaytsev, Claudia Toci, Claus Gossl, Michael Schmidt, Christoph Ries
Geophysics · Cross-listed from cs.LG
Boundary condition fidelity for bottom-hole pressure and CO2 plume prediction in geological carbon storage
Romal Ramadhan, Seyyed A. Hosseini and Larry W. Lake
Accurate prediction of bottom-hole pressure (BHP) and CO2 plume migration is essential for safe geological carbon storage, yet practical simulations often rely on truncated domains where artificial boundaries distort pressure
diffusion and CO2 saturation footprints. In this study, we evaluate how boundary-condition fidelity affects BHP and CO2 plume prediction by comparing ten reduced-domain boundary treatments against full-domain reference simulations in homogeneous and heterogeneous reservoirs. We test uniform pore-volume multipliers, transmissibility modifiers, corner-adjusted pore-volume corrections, layered corrections, and gradual modifiers using BHP RMSE, NRMSE, peak pressure deviation, and plume Intersection over Union (IoU) as performance metrics. Our results show that conserving corner pore volume is the most important requirement for truncated-domain modeling. We find that uniform treatments which neglect corner storage generate large pressure errors, with BHP RMSE of 362 to 382 psi in the homogeneous model and 250 to 304 psi in the heterogeneous model, and yield plume IoU values near 0.80 to 0.84, indicating roughly 16 to 20% of the combined plume area is misrepresented. Corner-adjusted scenarios substantially reduce pressure errors and raise plume IoU above 0.94, but we observe that transmissibility correction is not universally beneficial. In homogeneous reservoirs, uniform transmissibility adjustment improves pressure fidelity; in heterogeneous reservoirs, it can over-restrict flow across variable-permeability boundary faces, increasing BHP error and contracting the predicted plume. We find the gradual modifier with transmissibility correction provides the most consistent performance, achieving BHP NRMSE below 3.7% and plume IoU above 0.97 in both reservoir types.
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Physics and Society
Toward a Hybrid Digital Twin of Society: Quantifying Cognitive-Spatial Linkages Through Online-Offline Feedback Networks
Rafiazka Hilman and Julia Koltai
Digital platforms increasingly shape how people experience and navigate cities, linking virtual information seeking with physical mobility. Despite this interdependence, online and offline activities are often studied separately in urban mobility research. This paper introduces the Feedback Network, a computational framework that captures interactions between cognitive activity in digital environments and behavior in physical space. Using Google Search and Location History data from the same individuals, collected through a data donation framework in Budapest, Hungary, between 2018 and 2022, we examine how online search patterns and offline visitation behavior co-evolve. We combine semantic and spatial analytical approaches. Radius of gyration is adapted to measure variation in geographic mobility and semantic exploration, enabling comparison between physical movement and online cognitive dispersion. A Feedback Network models transitions between search-related and location-related activity clusters and is evaluated using Concentration
Entropy, which measures whether behavioral flows are concentrated around routine pathways or distributed across exploratory transitions. The results show that online exploration is more concentrated than offline mobility, suggesting narrower and more repetitive semantic interests, while physical movement remains relatively diverse. Persistent linkages between search and visitation activities related to retail and business services indicate stable cognitive-spatial behavioral loops. The COVID-19 pandemic disrupted spatial routines more strongly than cognitive exploration, widening the gap between digital engagement and realized movement. The findings demonstrate that urban mobility depends on the interaction between informational exposure and spatial encounter and provide a foundation for Hybrid Digital Twins of Society.
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Materials Science
Mapping the Growth of Two-Dimensional $\pi$-Conjugated Polymers on Au(111): Organometallic Intermediates and Edge Terminations
Simon W. Briesenick, Wyatt A. Behn, Manuel González Lastre et al. (+6 more)
Kagome
lattices provide an exciting space for the exploration of
graphene-like $\pi$-conjugated molecular systems with flat bands. Using heterotriangulene-derived precursors, along with an on-surface Ullmann coupling process, makes growing
polymers with Kagome
lattices accessible and straightforward. Here, we use scanning tunneling microscopy alongside high-resolution atomic force microscopy to examine the
evolution of tribromotrioxaazatriangulene on Au(111) into ordered, covalent films. Using density functional theory and scanning probe methods, we find previously unreported organometallic intermediate states involving Au adatoms incorporated within the growing
polymer lattice. We also find that a majority of
polymer edges remain brominated up to 250 $^{\circ}$C and a large number of edges bonded to Au adatoms coordinated to an adjacent bromine atom. These observations suggest that residual bromine could play a role in stabilizing the
polymer edges to Au adatoms and thereby influence the growth pathways that lead to ordered Kagome
polymer lattices.
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All authors Simon W. Briesenick, Wyatt A. Behn, Manuel González Lastre, Chang Wan Kang, Pablo Pou, Ekaterina D. Ulyanov, Rubén Pérez, Dmytro F. Perepichka, Peter Grutter
Quantum Physics
I-QMapper: Error-Aware Layout Optimization and Device Diagnostics for NISQ Hardware
Milana Bazayeva and Kenneth Merz
Achieving high-fidelity execution on noisy intermediate-scale
quantum (NISQ) hardware requires careful selection of physical
qubit layouts, as gate errors, readout errors, and coherence times vary across the device and drift over time. Currently,
qubit mapping is performed either through manual inspection of device calibration data or through automated layout pipelines, neither of which provides integrated, interactive layout visualization combined with calibration analytics. In this work, we present the Interactive
Quantum Mapper (I-QMapper), a Jupyter-based, open-source tool for noise-aware layout selection, visualization, and analysis on superconducting
quantum hardware. I-QMapper offers two operating modes: a general-purpose mode for arbitrary
circuits, and a dedicated mode for
quantum-chemistry applications, specifically tailored to the Local
Unitary Cluster Jastrow (LUCJ) ansatz. Within each mode, a Design panel supports interactive layout construction, while an Error panel provides calibration analytics through four temporal viewing modes (Live, Snapshot, Intraday, and Multi-day range) together with threshold filtering and delta-mode comparison for drift identification. Each layout receives a Layout-Quality Score (LQS) that aggregates the readout and two-
qubit gate errors of the layout into a single quality value. Starting from the automatic LUCJ
circuit-generation provided by IBM
Quantum, we extend it to a multi-programming setting in which multiple
circuits are mapped onto a single
quantum processing unit (QPU). I-QMapper further supports side-by-side visualization of two
quantum backends and layout comparison, and session export for experimental reproducibility. By combining interactive exploration with calibration analytics, I-QMapper aims to support both rapid layout prototyping and informed noise-aware experimental design on NISQ devices.
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