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Physics

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Wednesday 12 August

Nuclear Theory

Quasi-real photons as a probe of exotic nuclei

Takashi Nakamura and Carlos A. Bertulani

Coulomb excitation is an inelastic process in which either the target or the projectile is excited by the Coulomb interaction, which can equivalently be described as the absorption of a virtual photon. We discuss Coulomb excitation at relativistic energies, with particular emphasis on Coulomb dissociation, in which an excited projectile subsequently breaks up.
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Cosmology and Nongalactic Astrophysics

CIBER $\times$ galaxy cross-correlations reveal a bright, low-redshift NIR background

Richard M. Feder, Grigory Heaton, James J. Bock et al. (+7 more)

We perform the first tomographic analysis of near-IR extragalactic background light (EBL) anisotropies, cross-correlating CIBER 1.1 and 1.8 $\mu$m imager data with photometric galaxy catalogs from DESI Legacy Survey DR8 and Hyper-Suprime-Cam Ultra-Deep Survey. We measure significantly higher cross-power than expectations from an integrated galaxy light (IGL) model on scales $\ell < 2000$, concentrated at low redshift ($z\lesssim 0.6$). Cluster member galaxies and associated structure account for 15-20% of the large-angle cross-power, indicating that group- and galaxy-scale halos contribute the bulk of the signal. Through a parametric halo model decomposition, we detect two-halo and one-halo clustering in cross-power at high significance, with amplitudes that decline smoothly across $z=0{-}1$. The inferred one-halo cross-power is of similar amplitude between DESI-LS and the deeper HSC catalog, implying a scenario in which low-redshift EBL fluctuations are amplified by contributions from lower-mass halos with satellites and/or diffuse intra-halo light (IHL). Converting our two-halo fits into estimates of $b_I \times dI/dz$, we find that standard IGL predictions underestimate our measurements, even when assuming an intensity bias as high as 3, similar to that of large SZ clusters, suggesting that a higher $dI/dz$ is required to reconcile observed discrepancies. Lastly, we find that correlated large-scale structure (LSS) at $z<1$ accounts for a substantial fraction of the CIBER auto-power reported in earlier work. These results identify low-redshift LSS as a significant and previously unappreciated contributor to near-IR EBL fluctuation measurements, setting the stage for cross-correlation science with CIBER-2, SPHEREx and a variety of LSS tracers.
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All authors Richard M. Feder, Grigory Heaton, James J. Bock, Yun-Ting Cheng, Yi-Kuan Chiang, Phillip M. Korngut, Shuji Matsuura, Jordan Mirocha, Kohji Tsumura, Michael Zemcov

Instrumentation and Methods for Astrophysics

Updates to WFC3/UVIS Encircled Energy Values in Select Filters

Anne O'Connor, Jennifer Mack and Varun Bajaj

We present updated encircled energy (EE) curves for a subset of UVIS filters. These are derived from a reanalysis of the drizzled Point Spread Function (PSF) data underlying the current EE calibration together with new measurements from deep observations of the PSF wings. Improved centroiding and analysis techniques applied to the drizzled PSFs produce more accurate EE values at small radii ($r \le 10$ pixels), bringing the results into closer agreement with a large archival PSF study (Huynh et al. 2025). At large radii, we leverage deep observations of the PSF wings in six filters and compare the fraction of light between 2" and 6" with predictions from an optical model of the PSF (Hartig 2009). For filters with pivot wavelengths $ \gtrsim{4000} \mathrm{\mathring{A}}$, the model agrees with the empirical data, but over-estimates the EE for UV filters by $\sim0.5$% at 2". The revised EE solutions affect the UVIS zeropoints, which are derived from aperture photometry in a 0.4" (10 pixel) radius and corrected to 6" using EE tables (Calamida et al. 2022). Overall, the impact is small; the EE at 0.4" is larger by $ \gtrsim{0.5}$ % (0.005 mag) for several filters (F218W, F225W, F275W, F775W, F814W, F845M), especially for UVIS2. In contrast, the EE value is generally smaller at 0.4" for long-pass filters (F200LP, F350LP, F850LP), with F850LP differing by $\sim2 $ % (0.02 mag). Updated EE tables will be delivered together with a revised set of UVIS inverse sensitivity tables and zeropoints later in 2026. In the interim, we provide EE tables for commonly used filters in Appendix A.
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Materials Science

Beam Routing through Excitons in Transition Metal Dichalcogenide Monolayers

Yonas Lebsir, Jacob Terndrup Heiden, Jorge Barcia Rodríguez et al. (+6 more)

Routing light at the nanoscale typically relies on nanostructured surfaces to imprint directionality on the emission. Using low-temperature, angle-resolved cathodoluminescence spectroscopy, we show that the intrinsic excitonic transitions of a semiconductor can themselves produce routed emission. We probe monolayers of WSe$_2$, MoSe$_2$, and MoTe$_2$ and resolve the excitonic species of monolayer WSe$_2$ – the bright exciton, the trion, and the spin-forbidden dark exciton – through their distinct angular emission profiles. While the in-plane transition dipoles of the bright exciton and trion radiate predominantly toward the surface normal, the out-of-plane dipole of the dark exciton, inaccessible under normal-incidence optical excitation, produces a directional emission channel at large angles. We further tune the balance between neutral and charged exciton emission through the local dielectric environment. Our results establish dark excitons in TMD monolayers as a platform for directional light emission in compact photonic architectures without additional nanostructuring.
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All authors Yonas Lebsir, Jacob Terndrup Heiden, Jorge Barcia Rodríguez, Maria Papadopoulou, Kenji Watanabe, Takashi Taniguchi, N. Asger Mortensen, Sergii Morozov, Nicolas Ubrig

Nuclear Experiment

Excited states of $^{148}$Nd studied via the $^{150}$Nd$(p,t){}^{148}$Nd reaction and the observation of possible low-spin two-phonon octupole states at $N=88$

A.L. Conley, M. Spieker, R. Aggarwal et al. (+15 more)

We report new data from a $^{150}$Nd$(p,t){}^{148}$Nd experiment performed at the John D. Fox Accelerator Laboratory of Florida State University. In total, 54 excited states of $^{148}$Nd were observed up to an excitation energy of 3500 keV. In this work, we focus on $0^+$ states and their band members. In contrast to previous work, the $0^+_3$ band is proposed as the candidate for the two-phonon octupole vibrational band. Supporting $spdf$ IBM-1 calculations are presented. To test the robustness of the IBM calculations, several observables were interrogated and are discussed in this publication. In addition, we make the case that neither the $0^+_2$ nor the $0^+_3$ states of the other $N=88$ isotones are likely good candidates for two-phonon octupole states. Based on our new data for $^{148}$Nd, we propose candidates in $^{150}$Sm and $^{152}$Gd. Using available $\gamma$-decay data for states with moderate spins in the yrast sequence and a comparison to IBM calculations, we also show how the staggering of the $B(E1)/B(E2)$ ratios in the yrast sequence can possibly be used to probe the appearance of bands with multiple octupole phonons.
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All authors A.L. Conley, M. Spieker, R. Aggarwal, L.T. Baby, J. Davis, J. Esparza, I. Hay, B. Kelly, T. Kirk, M.I. Khawaja, R. Mahajan, M. Mestayer, A.B. Morelock, A. Peters, A.M. Ring, J. Sheridan, V. Sitaraman, T. Stuck

High Energy Physics (Phenomenology)

Photon emission from rotating plasmas: a generalized McLerran-Toimela formula and the onset of superradiance

Kirill Tuchin

The photon emission and absorption spectra of a plasma rotating with constant angular velocity $\Omega$ are derived in terms of the spectral function of the current–current correlator. In contrast to the non-rotating case, the leading contribution arises already at one-loop order. The photon emission spectrum and its elliptic flow are calculated for a rotating quark–gluon plasma and compared with the leading two-loop result for a non-rotating plasma. The rotating plasma is found to emit significantly more soft photons than the non-rotating one. An analysis of the emission and absorption of cylindrical waves indicates that photons with energy $\omega$ and azimuthal quantum number $m$ satisfying $\omega<m\Omega$ are emitted at a higher rate than they are absorbed, thereby exhibiting the phenomenon of superradiance. It is further argued that these superradiant modes induce an instability of the magnetic field that is generated concurrently with the plasma in relativistic heavy-ion collisions.
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Materials Science

Thermoelastic Harvesting Outperforming Thermoelectric Generators Below 100 {\deg}C

Bruno Neumann, Andreas Henschke, Morik Nikolic et al. (+1 more)

Low-grade waste heat below 100 degC is one of the largest untapped opportunities in solid-state energy conversion. Three ferroic routes are candidates for recovering this resource: thermomagnetic, pyroelectric, and thermoelastic harvesters. The last has remained the most unexplored, despite decades of progress on the underlying NiTi shape-memory alloy wires. Three system-design changes close this gap: a protagonist-antagonist architecture that recovers the energy for prestraining, a continuously tunable prestrain mechanism that sets the force-strain balance, and transversal water flow that decouples cycle frequency from wire length. The resulting harvester delivers a directly measured power density of 366 mW/cm^3 with respect to the active material, about 1.7 times the next-best thermoelastic device, ahead of every reported thermomagnetic and pyroelectric generator, and outperforming the best thermoelectric generators in this temperature range also with respect to power per material cost. The system maps the parameter space directly through force and displacement measurements, without using material-property estimates, giving a quantitative picture of how the alloy responds while the device is doing work.
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All authors Bruno Neumann, Andreas Henschke, Morik Nikolic, Sebastian Fähler

Nuclear Theory

Transport properties in binary neutron star mergers: Effect of magnetic field

Pranjal Tambe and Debarati Chatterjee

In extreme environments such as binary neutron star mergers, temperatures as high as $50$ MeV and magnetic fields up to $10^{17}$ G, reach a regime where neutrino transport governs the macroscopic thermodynamic and chemical evolution. Existing merger simulations rely on zero magnetic field neutrino emissivity and opacity, potentially missing critical transport physics in highly magnetized neutron star cores. We present an exact framework for computing charged current Urca emissivity and neutrino opacity at finite temperature and magnetic field. We employ the Nucleon Width Approximation framework to account for the collisional broadening effects dominant in the high-density core. Our calculations demonstrate that extreme magnetic fields significantly enhance charged current neutrino opacity, effectively reducing the mean free path for thermal neutrinos.
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Quantum Physics

Design of monolithic microcavities for enhancing organic quantum emitters

Tim Hebenstreit, Jaime Gimeno Balaguer, Fridtjof Betz et al. (+6 more)

Single organic molecules are a well-established platform for high-quality single-photon generation: they can emit lifetime-limited photons with high purity and indistinguishability. However, their emission is accompanied by a pronounced red-shifted phonon sideband and higher-order vibrational peaks, which reduce the fraction of photons emitted into the desired narrowband zero-phonon line. The standard approach to suppressing this unwanted emission is to integrate the emitter into a monolithic photonic nanostructure that provides Purcell enhancement. However, incorporating organic materials using clean-room techniques has proven challenging, and has in fact so far prevented their integration into monolithic microcavities altogether. As a result, efficient, narrowband organic single-photon sources for applications in quantum information processing have remained elusive despite their considerable promise. Here, we propose three monolithic microcavity designs tailored to provide sufficient Purcell enhancement for organic quantum emitters. The Purcell effect induced by these cavities preferentially enhances emission into the 0-0 zero-phonon line, increasing spectral purity, photon extraction, and shortening the excited-state lifetime, which in turn relaxes the requirements for generating indistinguishable photons. The cavities have been optimized using Bayesian optimization and the adaptive Antoulas-Anderson (AAA) algorithm for rational approximation, which offer global optimization and the efficient reconstruction of spectra from scattering simulations, respectively. These structures are compatible with both standard clean-room processing and single-molecule preparation techniques. Therefore, they offer a clear route to realize high-quality, practically monochromatic organic single-photon light sources.
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All authors Tim Hebenstreit, Jaime Gimeno Balaguer, Fridtjof Betz, Felix Binkowski, Maja Colautti, Jan Renger, Costanza Toninelli, Sven Burger, Stephan Götzinger

High Energy Physics (Phenomenology)

Invisible dark-sector radiation: analytic resummation for dark photon searches

Xiangyu Deng, Rongfeng Ou, Yi Li et al. (+1 more)

We derive an analytic resummed description of the missing-mass spectrum in monophoton searches for invisible dark photons at electron–positron colliders. In a dark Abelian Higgs model with a light dark fermion, we construct the spectrum from scalar and fermionic real and virtual contributions without relying on a Monte Carlo shower implementation. Sudakov resummation method is used to deal with the collinear divergence. The analytic expressions make the dependence on the dark charges and the logarithmic structure explicit. A simplified reinterpretation of the BaBar monophoton search, accounting for its finite missing-mass resolution, shows that dark-sector radiation can modify the inferred upper limit on the kinetic-mixing parameter by $\mathcal{O}(10\%)$ in the benchmarks considered.
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All authors Xiangyu Deng, Rongfeng Ou, Yi Li, Mengchao Zhang

High Energy Physics (Experiment)

Toward a Measurement of the Higgs Boson Mass with Natural-Width Precision at FCC-ee

Jan Eysermans, Ang Li, Gregorio Bernardi et al. (+3 more)

Higgs boson mass measurements with sub-10 MeV precision enable sub-percent determinations of Higgs boson couplings and prevent the Higgs boson mass from becoming a limiting input to electroweak fits. Probing the electron Yukawa coupling through resonant Higgs boson production requires a precision comparable to the Higgs boson natural width of approximately 4 MeV. Using the leptonic ZH recoil channels, we show that FCC-ee can reach a Higgs boson mass precision of 4 MeV, including statistical and systematic uncertainties, thereby enabling this unique measurement. We identify the detector and accelerator performance required to reach this precision.
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All authors Jan Eysermans, Ang Li, Gregorio Bernardi, Christoph Paus, Emmanuel Perez, Michele Selvaggi

Instrumentation and Detectors

From Simulation to Real Scans: Anomaly Detection in Maritime Cargo with Muon Scattering Tomography

Angel Bueno Rodriguez, Christina Hrytsiuk, Maximilian Perez Prada et al. (+6 more)

Maritime cargo inspection requires imaging technologies capable of detecting concealed threats within dense, sealed containers, a role for which Muon Scattering Tomography (MST) is well suited: it images their interior through the density-dependent deflection of naturally occurring cosmic muons. However, MST remains constrained by the scarcity of labeled scans and by a cosmic muon flux that is both low and stochastic. Anomaly detection algorithms must therefore be trained on simulations, yet operate on measured scans acquired under different conditions, a sim-to-real gap that remains a central obstacle to operational deployment. We present the first end-to-end anomaly detection framework for maritime MST, from physically consistent simulations to validation on real container scans from the SilentBorder demonstration campaign. The task is cast as an out-of-distribution problem: the framework learns the spatial configurations of benign cargo and flags threats as deviations in the reconstruction error space, remaining agnostic to threat type and geometry. An attention U-Net, trained exclusively on benign synthetic scenes, preserves small-scale scattering signatures through its skip connections, and contraband consequently persists in the pixel-wise reconstruction error instead of being absorbed into the reconstructed background. A scoring function, the Homogeneity Index (HI), suppresses spatially uniform cosmic-ray statistical noise while amplifying coherent anomaly signatures: where pixel-level metrics collapse under a change of cargo configuration, HI retains its discriminative power. We evaluate three training strategies across two distinct cargo configurations under operational one-hour scan times, and test the best model on real muon cargo scans. The results for the studied scenarios indicate that the sim-to-real gap can be bridged.
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All authors Angel Bueno Rodriguez, Christina Hrytsiuk, Maximilian Perez Prada, Kaarel Tark, Felix Sattler, Jean Marco Alameddine, Madis Kiisk, Maurice Stephan, Sarah Barnes

High Energy Physics (Theory)

On Hypergraph Representation of Multipartite Quantum Systems

Adil Belhaj, Salah Eddine Ennadifi and Zakariae Ennadifi

Borrowing ideas from the link between Calabi-Yau singularities and toric geometry in string theory compactifications, a hypergraph framework for multipartite quantum systems, extending graph representations to higher-order quantum correlations, is investigated. By implementing hyperedges in many-body Hamiltonian interactions, an interplay between hypergraph states and quantum state dynamics is established. The corresponding Hamiltonian hypergraph reveals the hierarchy of all possible multipartite interactions. However, the decoherence effects impose constraints on the realization of large hypergraph states. The findings show the importance of long coherence times and strong many-body couplings for the realization of large hypergraph states.
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Lattice Field Theory

Real-time topological rate at non-zero momentum in quenched QCD

Claudio Bonanno, Massimo D'Elia, Roberto Dionisio et al. (+5 more)

We present a proof-of-concept numerical study of the real-time topological rate at non-zero momentum in quenched lattice QCD at a temperature $T\simeq 1.24 \, T_c \simeq 360$ MeV, as an important step toward the determination of this quantity in full QCD. Our strategy, already applied to compute the sphaleron rate in pure Yang–Mills and in full QCD, extracts the rate from the resolution of an appropriate inverse problem, solved applying the Hansen–Lupo–Tantalo (HLT) method to the thermal Euclidean time-correlator of the topological charge density. This method requires to control three different limits: continuum limit, limit of vanishing smearing width used in the HLT inverse problem resolution, and limit of vanishing smoothing radius used in the topological charge density correlator computation. Our lattice calculation is based on the standard Wilson discretization for the gauge action, and on three gauge ensembles with up to $N_\tau=16$ temporal points to achieve a controlled continuum limit. In all cases we employed an aspect ratio $LT=4$, which allowed us to compute the topological rate up to momenta as large as $p/T \sim 10$.
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All authors Claudio Bonanno, Massimo D'Elia, Roberto Dionisio, Giuseppe Gagliardi, Andrea Giorgieri, Francesco Sanfilippo, Alessandra Valentino, Giovanni Villadoro

Instrumentation and Detectors

Background decomposition of the CONUS+ run 1 data

N. Ackermann, H. Bonet, C. Buck et al. (+13 more)

The CONUS+ experiment is measuring the coherent elastic neutrino nucleus scattering (CE$\nu$NS) process using reactor anti-neutrinos as a source and four low energy threshold point-contact high-purity germanium spectrometers for their detection. It achieved the first measurement of coherent neutrino scattering at a nuclear reactor in run 1 of the experiment with a detection energy threshold of 160 eV$_{ee}$. This work presents the decomposition of the background spectra of the three detectors used in the run 1 analysis and the development of the corresponding background model with Geant4-based Monte Carlo simulations. The background model is used as the underlying input for the likelihood fit of the analysis. It is shown that reactor-correlated backgrounds are subdominant in all energy regions, specifically in the region of interest for CE$\nu$NS searches below 350 eV$_{ee}$ where their contribution is one order of magnitude below the expected CE$\nu$NS signal. Furthermore, cosmic ray muons and neutrons are identified as the dominant background source below 1 keV$_{ee}$ contributing approximately 75 - 90 % of the recorded background rate. The final background model predicts an average rate of (47.5 $\pm$ 3.2) d$^{-1}$ kg$^{-1}$ in reactor on measurement in the energy region between [0.4, 1.0] keV$_{ee}$, which is in excellent agreement with the average measured value of (48.0 $\pm$ 0.6) d$^{-1}$ kg$^{-1}$. Similar agreement is found in all energy regions of both reactor on and off measurements.
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All authors N. Ackermann, H. Bonet, C. Buck, J. Hakenmüller, G. Heusser, M. Lindner, W. Maneschg, S. Mertens, K. Ni, D. Piani, M. Rank, T. Rink, E. Sánchez García, I. Stalder, H. Strecker, J. Woenckhaus

Strongly Correlated Electrons

Phonon anomalies and critical scaling in the spin-$1/2$ trimer chain Na$_2$Cu$_3$Ge$_4$O$_{12}$

P. Srikanth Patnaik, A. K. Bera, Srishti Bhardwaj et al. (+4 more)

Low-dimensional quantum magnets provide an ideal platform to explore spin-lattice coupling-mediated quantum correlations, which give rise to emergent quasiparticle excitations. The antiferromagnetically coupled spin-1/2 trimer chain of copper ions in Na$_2$Cu$_3$Ge$_4$O$_{12}$ (NCGO) hosts high-energy spin excitations of different species, whose energy scales overlap with those of lattice vibrations. Here, we report a comprehensive temperature-dependent Raman spectroscopic study performed between 80 and 400 K. The dynamic spin susceptibility, as obtained from the analysis of the broad spectral background, reveals the emergence of quasiparticle excitations below 170 K. We further identify an unusual crossover of phonon dynamics when the material transits from a normal paramagnetic state to a correlated quantum magnetic state. A power law dependence of the integrated Raman susceptibility of the phonon modes, $I_{\chi^{\prime\prime}}^{i}\sim|T-T_{c}|^\beta$, is observed with the critical temperature $T_c$=167$\pm$1 K, and critical exponent $\beta = 0.24\pm 0.02$. The combined results obtained from the broad spectral background and sharp phonon peaks further indicate that the phonon renormalization observed across the crossover is driven by dynamic spin states. Additionally, statistical correlations among phonon energy eigenvalues, quantified through matrix-norm and power-test analyses of 200 spectra recorded at 80 K, reveal an unexpected linear correlation among phonon modes, also indicating that the collective lattice response is governed by spin correlations. These findings establish NCGO as a model system for investigating cooperative spin-lattice coupling and critical scaling behavior of phonon dynamics in low-dimensional magnetic materials.
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All authors P. Srikanth Patnaik, A. K. Bera, Srishti Bhardwaj, Tulika Maitra, Buddhananda Banerjee, Anushree Roy, S.M. Yusuf

Quantum Physics · Cross-listed from math.NA

Numerical methods for the simulation of quantum walks and quantum annealing

Asa Hopkins and Viv Kendon

It is known that Chebyshev based polynomial approximation gives a near-optimal rate of convergence for calculating a function of a Hermitian matrix. However, previous work has not discussed the option of true minimax approximation, nor the specifics of writing a high performance implementation with a rigorous analysis of errors. This work provides such an analysis and an open-source implementation of three approximation methods in C++.
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Quantum Physics

Enhancing the power of a quantum heat engine via control of the system–reservoir coupling

Sabrina Burgardt, Julian Feß, Silvia Hiebel et al. (+2 more)

The non-equilibrium properties of open quantum systems are determined by the microscopic laws governing energy exchange with their environment. In particular, an enhancement of the performance of quantum heat engines has been predicted by speeding up the dynamics through control of the system–bath interaction. However, direct microscopic control of heat transfer between the machine and the reservoir has remained elusive so far. Here, we experimentally demonstrate such control in a quantum Otto engine realized with ultracold Cs-133 atoms coupled to an atomic reservoir of ultracold Rb-87 atoms. Heat exchange between the two is mediated by inelastic s-wave collisions whose energy-dependent scattering cross sections lead to an asymmetric equilibration dynamics in the isochoric heating and cooling strokes. By tuning the kinetic temperature of the atomic reservoir, we modify the associated microscopic scattering rates, and thereby the heat transfer law, giving control over the time allocation within the engine cycle through control over the microscopic, multi-exponential relaxation dynamics. This enables power output optimization at fixed efficiency. Our results establish microscopic control of system-reservoir interactions as a tool for manipulating heat flow at the nanoscale and engineering the finite-time performance of quantum thermal machines.
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All authors Sabrina Burgardt, Julian Feß, Silvia Hiebel, Eric Lutz, Artur Widera

Fluid Dynamics

Strain-coupled one-dimensional turbulence: a single-line closure, its limits, and the consequence for leading-edge noise

Sparsh Sharma and Alan R. Kerstein

Turbulence approaching a solid surface is strained before it arrives, and the distortion of its spectrum is often what governs the downstream response; yet reduced-order predictions, leading-edge-noise theory among them, still take the incoming spectrum as frozen. We develop a strain-coupled formulation of one-dimensional turbulence (ODT) that evolves strained turbulence with full spatial resolution at a cost compatible with parametric study, carrying the rapid distortion and the nonlinear relaxation together. The obstacle is that the rapid pressure-strain is non-local and three-dimensional while an ODT line resolves only the flow state along its own coordinate. Splitting the distortion physics by structure captures the phenomenology: the off-axis production and a spectrally closed rapid operator enter as continuous-in-time forcing along the model coordinate, while `eddy events' capture the on-line production and the turbulence-driven relaxation. Carried through to leading-edge noise, the evolved inflow shifts the predicted level by 5-20 dB at the energy-containing scales relative to the conventional frozen-spectrum assumption.
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Mathematical Physics

Model-Consistent Structured-Hankel Matrix Completion for 3D Sparse Multi-frequency Electromagnetic Source Reconstruction

Shujaat Khan and Abdul Wahab

Reconstruction of 3D electromagnetic currents from sparse, multi-frequency, far-field radiation data is severely ill-posed because sparse sampling masks specific current Fourier modes and the missing spectrum enlarges the null space of the forward operator. Although structured-Hankel completion can recover missing spectrum by exploiting the finite rate of innovations structure of a compactly supported geometrically sparse source, it treats current components independently without guaranteeing compatibility with the model. This often renders non-physical solutions that violate model consistency. To resolve this, we propose a training-free Maxwell-model-consistent 3D structured-Hankel framework (MC-Hankel) that alternates joint low-rank Hankel completion with an exact, closed-form projection onto the true Maxwell synthesis subspace while enforcing conjugate symmetry and noise-aware data fidelity. Across tests on two source models, three sparse sampling rates (30%, 40%, and 50% of a Nyquist-sampled grid), and clean versus noisy (10 dB SNR additive white Gaussian noise) conditions, MC-Hankel consistently outperforms sub-sampled Fourier inversion, scale-normalized $\ell_1$-compressed sensing baseline, and the standard joint 3D annihilating filter-based low-rank Hankel matrix completion approach (ALOHA). Across all considered source-noise-sampling configurations, MC-Hankel improves mean peak SNR (PSNR) by 0.65-4.22 dB and tri-planer structural similarity (3D SSIM) by $0.0266$-$0.0703$, reduces relative full-volume $\ell_2$ reconstruction error by $7.4\%$-$38.9\%$, and brings non-physical model residuals down to machine precision over standard joint 3D ALOHA with merely 17% computational overhead. Exact signed-rank tests are underpowered for five paired trials, so statistical conclusions are reported together with paired bootstrap intervals, effect sizes, and small-sample limitations.
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Cosmology and Nongalactic Astrophysics

MeerKAT Reveals Evidence of a Radio Megahalo at GHz Frequency

Swarna Chatterjee and Kenda Knowles

Radio megahalos are recently discovered large-scale diffuse synchrotron sources identified through LOFAR observations. We present MeerKAT L-band observations of the massive galaxy cluster RXC~J0528.9$-$3927, that reveals faint emission surrounding its central radio halo. At 1.28 GHz, the known $\sim1.14$ Mpc halo is embedded within previously unreported low-surface-brightness emission extending to $\sim2$ Mpc. The surface-brightness profile of the emission shows a distinct flattening beyond $\sim0.55R_{500}$, suggesting that the outer emission forms an additional component. These properties make the cluster a candidate megahalo system and potentially the first detected at GHz frequencies, although deeper multi-frequency observations are required for confirmation.
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Optics

Spatial and energetic correlations of ultrashort two electron pulses

Stefan Meier, Jonas Heimerl, Felix López Hoffmann et al. (+3 more)

When two electrons are emitted from a metallic needle tip into a nanometric volume on femtosecond timescales, strong Coulomb correlations arise. While longitudinal correlations, manifested as energy shifts, have been observed both from bare tips and in electron microscopes, transverse correlations remain hardly explored. Here, we present the first complete experimental characterization of such 3D correlations from needle tips. We find that electron pairs of small transversal spatial separation exhibit a pronounced energy gap of 3.3 eV width, while electrons of small longitudinal energy separation show strong transverse repulsion, increasing their average mutual divergence angle by a substantial 34.5%. The measurements are in excellent agreement with semiclassical point-particle simulations. These reveal that the maximal energy-gap magnitude is primarily determined by the laser pulse duration, whereas the maximal spatial separation is governed by the tip radius. The latter can be exploited in a remarkably simple method to generate strongly sub-Poissonian electron beams: A mere aperture, notably present in most electron-optical setups anyway, can act as an electron number sensitive filter. In combination with energy filtering we find an unprecedented suppression of multi-electron pulses reaching g(2) = 0.02 when keeping 3% of the electron beam. These results provide a foundation for future studies of electron entanglement, correlated electron microscopy, and the design of ultrafast electron-optical instruments.
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All authors Stefan Meier, Jonas Heimerl, Felix López Hoffmann, Tobias Volk, Marco Knipfer, Peter Hommelhoff

Instrumentation and Methods for Astrophysics

Automation and Modernisation of Legacy BiSON Solar Observatories with the BiSON:NG Platform

S. J. Hale, E.Murray, W. J. Chaplin et al. (+4 more)

The Birmingham Solar Oscillations Network (BiSON) provides long-term, high-precision Sun-as-a-star radial-velocity observations for helioseismology. While most BiSON sites operate autonomously, two observatories at Observatorio del Teide, Tenerife, and at Mount Wilson Observatory, USA, have historically required daily on-site operation. We present the automation of these sites using the BiSON:NG next-generation observing platform, incorporating compact fibre-fed instrumentation and a modular, microservice-based control and data acquisition architecture. At both locations, new automated optical feeds and a common software framework have been deployed, enabling autonomous operation of the observing subsystems, including guiding, data acquisition, and instrument control, despite markedly different physical and operational constraints. The upgrades demonstrate that modern automation can be successfully integrated within existing and historic observatory infrastructure. Adoption of the BiSON:NG architecture reduces operational overhead, mitigates risks associated with hardware and software obsolescence, and supports sustainable operation of the network over the multi-decade timescales required for helioseismic studies. The flexibility of the architecture also provides a pathway for future deployment of additional small-footprint observatories.
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All authors S. J. Hale, E.Murray, W. J. Chaplin, Y. P. Elsworth, R. Howe, P. L. Pallé, E. J. Rhodes Jr

Fluid Dynamics

A transport geometry of acoustic analogies:exact holonomy of source re-attribution and its observable consequences

Sparsh Sharma

The source term of an acoustic analogy is not unique: different rearrangements of the Navier-Stokes equations attribute the same radiated sound to different apparent sources. Although this non-uniqueness has long been recognised, it has never been given a quantitative structure. We provide one by organising acoustic analogies into a fibre-like family over the space of effective media and defining transport between analogies through unique frequency-preserving, rotation-free linear space-time maps. Three exact results follow. First, the classical family of convected analogies is not closed under transport: successive uniform-flow regaugings generate effective media with anisotropic sound-speed tensors, recovering the generalised media introduced by Goldstein. Second, the discrete holonomy of analogy transport is obtained in closed form. It consists of an exact spectral dilation and a rotation that vanishes to fourth order in Mach number; transport becomes singular on a sonic horizon in analogy space. Third, in the continuum limit the boost sector is flat, while curvature is confined to anisotropy directions and is given by the commutator of sound-speed-tensor increments. The geometry does not imply any change in the physical sound field: all exact analogies yield the same far field. Its significance is operational. When an approximate source model is transported between analogies, as commonly occurs in hybrid prediction methods, the resulting far-field predictions acquire an exact, parameter-free bias consisting of a rigid spectral dilation and directivity rotation. An exact far-field law for anisotropic media extends these results to open transport paths. All identities are verified symbolically and numerically.
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Astrophysics of Galaxies

Search for a Globular Cluster whose Passage through the Galactic Disk could Trigger the Radcliffe Wave

V. V. Bobylev and A. T. Bajkova

Using a catalog of 152 globular clusters (GCs), their orbits were constructed to determine their intersections with the Galaxy's plane of symmetry. Young open star clusters (OSCs) were selected from the selection zone characteristic of the Radcliffe wave. The Hunt and Reffert catalog served as the source of data on these OSCs. A grouping of 17 OSCs with an average age of 32.7 million years was found. It is compact in coordinate, velocity, and age space. This grouping is shown to be a good candidate for the hypothesis that the Radcliffe wave is generated by the passage of an impactor through the Galaxy's plane of symmetry, with the impactor being the GC NGC~4372. The last time it crossed the galactic plane was 55.5 million years ago, and 22.2 million years later, a burst of star formation occurred at this location, forming a whole group of open-clustered stars, and possibly the Radcliffe wave as a whole.
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Other Condensed Matter

Formally Verified Lock-Free Software Transactional Memory for Scientific Measurement

Kentaro Kitagawa

Automated measurement of condensed-matter experiments requires instrument-control, data-acquisition, and user-interface threads to access shared, naturally hierarchical state concurrently. Coarse-grained locking can delay acquisition and cause sample loss, whereas fine-grained locking requires deadlock-prone lock ordering across instruments. Instead, we describe the lock-free software transactional memory (STM) that has been at the core of an open-source measurement platform for 16 years, in nuclear magnetic resonance experiments and, more recently, in optically detected magnetic resonance experiments. The STM organizes this state as a tree and provides atomic subtree updates and consistent subtree snapshots. After initial bundling, an unchanged subtree snapshot is acquired in $O(1)$ time through a custom lock-free atomic shared pointer. Within each bounded TLA+ configuration, TLC exhaustively checks the state space, establishing the safety and livelock-freedom properties specified for that configuration. Bounded executions of the atomic shared-pointer implementation are separately checked under the C11 weak-memory model. The same Snapshot and Transaction interfaces are exposed to Python scripting and AI-assisted automation.
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Physics and Society

Sectoral inter-dependencies drive the loss of structural balance in signed financial networks

Kartik Dahake and Abhijit Chakraborty

Signed graphs provide an effective architecture for portraying a system in which cooperation and conflict coexist. Emerging from the concept of balance in psychological sciences, they have found applications across several domains. Financial markets are one such example that can be modeled using signed networks, where assets exhibit correlations in price movements. During periods of systemic risk, such a signed financial network shows a loss of balance, which has been consistently demonstrated. Here, we explore how this structural imbalance is distributed across scales within the financial network, revealing its mesoscopic origin. Adopting the framework of structural balance theory, we use a measure of polarization based on triadic motifs to investigate the distribution of structural imbalance across varying sectoral scales. We analyze the temporal evolution of global polarization and its sectoral constituents using longitudinal data derived from the S&P 500 index. By decomposing global polarization into intra-sectoral and inter-sectoral constituents, we show that structural imbalance arises predominantly from interactions between sectors rather than within them during periods marked by systemic risk. We employ randomization protocols to confirm that observed imbalance configurations are statistically significant and not artifacts of lower-order interactions. We derive a regression equation demonstrating that the variance in global polarization is well explained by macroeconomic variables, indicating that low levels of global polarization during economic crises are driven by compounding pressures from supply chain disruptions and inflation uncertainty. Collectively, these findings provide a quantitative framework for understanding how localized sectoral conflicts propagate across the financial network and contribute to large-scale structural instability during periods of economic crisis.
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Quantum Physics

Efficient Assembly of a Defect-Free Quantum Register of 1024 Neutral-Atom Qubits

Lukas Sturm, Marcel Mittenbuehler, Tim Gollerthan et al. (+2 more)

Low-entropy arrays of atomic quantum systems in optical tweezers offer unique prospects for fundamental research on few- and many-body systems as well as for extended applications in quantum technology. The significance of this approach relies on the achievable system size, its uniformity, and the rate of qubit allocation. We propel the neutral-atom quantum-technology platform by the rapid assembly of a regular two-dimensional quantum register of up to 1024 atomic qubits, enabled by a novel implementation of intensity-homogenized tweezer arrays and parallelized atom transport. Our highly efficient microoptical architecture modularizes intensity equalization and tweezer patterning in separate functional units, eliminating restrictions that arise for high-power, high-resolution, and large-scale light-field control within a single device. Arrays of precise grid structure, trap depth, and vibrational frequency with more than 3500 sites are demonstrated. Individual sites are interconnected by up to 50 parallelized transport tweezers with intensity and position control in real-time for swift qubit relocation. Multi-tweezer transport enables the operation of target patterns of up to 32 x 32 sites with sustained near-unity filling fraction. These results boost neutral-atom quantum information science above the kiloqubit level.
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All authors Lukas Sturm, Marcel Mittenbuehler, Tim Gollerthan, Malte Schlosser, Gerhard Birkl

Materials Science

Energy-Dependent Dechanneling in Cu: Insights from Monte Carlo Channeling Simulations

Przemyslaw Jozwik, Cyprian Mieszczynski, Renata Ratajczak et al. (+1 more)

Ion channeling and backscattering techniques are powerful tools for studying crystal lattice disorders and defect structures in crystalline materials. However, the accurate interpretation of channeling phenomena necessitates the utilization of simulation models that account for the intricate interactions between point defects, dislocations, and extended defect clusters. The present paper introduces a Monte Carlo method that reproduces experimental spectra over a wide range of analyzing beam energies and enables quantitative identification of defect types and distributions. The simulations reveal characteristic energy dependencies that distinguish point defects from extended defects, offering a novel perspective on disturbances caused, for example, by ion implantation in metals and semiconductors. To this end, the McChasy code has been developed as a flexible and accessible tool for scientists, enabling the modeling of various crystal systems, including complex semiconductors, multilayer epitaxial films, and oxide crystals. The program's integration of experimental data on ion channeling with defect modeling establishes a robust framework for defect analysis in materials science. The present article expounds upon the simulation capabilities of the program by reproducing the characteristic "elbows" in channeling spectra that were previously observed in experiments conducted on Cu crystals.
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All authors Przemyslaw Jozwik, Cyprian Mieszczynski, Renata Ratajczak, Andrzej Turos

High Energy Astrophysical Phenomena

Constraining the gamma-ray efficiency of LINER outflows with Fermi-LAT and MEGARA

Alberto Domínguez, Alejandra León, Adithiya Dinesh et al. (+1 more)

Low-Ionization Nuclear Emission-line Regions (LINERs) commonly host ionized gas outflows, but their role as high-energy particle accelerators remains debated, particularly following the very-high-energy $\gamma$-ray detection of NGC 4278, which implied extreme radiative efficiencies. We empirically determine the $\gamma$-ray radiative efficiency of a local sample of LINERs to test whether their high-energy emission can be powered by extended ionized outflows or requires compact nuclear jets. We combine spatially resolved optical integral-field kinematics from the Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía at the Gran Telescopio de Canarias, yielding ionized-outflow kinetic powers, with 17 years of Fermi-Large Area Telescope observations to derive 0.05–500 GeV luminosities or 95% confidence upper limits. We place the sample in an optical/$\gamma$-ray diagram alongside archetypal starbursts and radio galaxies. We present the first empirical upper limits on the $\gamma$-ray radiative efficiency of LINER outflows as a population. No LINER is formally detected ($TS \geq 16$). The strongest constraint is obtained for the radio-loud LINER NGC 1052, with $\eta < 41%$. For the remaining sources, the Fermi-LAT limits generally lie well above the outflow kinetic powers ($\eta \gg 100%$), while three sources show marginal hints of emission ($9 < TS < 16$). We conclude that extended ionized outflows in LINERs are highly inefficient high-energy particle accelerators, analogous to starburst superwinds. These constraints disfavor the outflows as the sole origin of extreme $\gamma$-ray efficiencies and favor compact nuclear jets for the most efficient $\gamma$-ray-emitting LINERs.
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All authors Alberto Domínguez, Alejandra León, Adithiya Dinesh, Armando Gil de Paz