Superconductivity
Quasiclassical theory of nonlinear response in d-wave superconductors
Aidan Steineman, Samuel Awelewa and Maxim Dzero
We use a self-consistent Keldysh–Nambu quasiclassical theory to study two related nonlinear phenomena in clean d-wave
superconductors: the photo-induced static correction to the order parameter – the Eliashberg effect – and third-harmonic generation. Both follow from a systematic perturbative solution of the out-of-
equilibrium Eilenberger equation for the Keldysh propagator. For the steady-state correction to the pairing amplitude we find that at temperatures close to the critical temperature and to leading order in the gap magnitude $\Delta$, the photo-induced change of the order parameter is zero at all drive frequencies: in contrast to s-wave
superconductors, a clean d-wave
superconductor exhibits no Eliashberg enhancement at this order. The gap-enhancing quasiparticle-redistribution channel that drives the effect in the s-wave case is suppressed by an additional power of $\Delta$ in the d-wave case. For third-harmonic generation we find that the charge-density-fluctuation (particle–hole) channel significantly dominates the Schmid–
Higgs amplitude-mode contribution over a broad frequency range, the two becoming comparable only in a narrow window near the resonance frequency $\omega\approx 2\sqrt{2}\,\Delta$ if one neglects the diamagnetic part of the current in the normal state. We trace this to the nonequilibrium dynamics of nodal quasiparticles, which must be retained explicitly and which also makes the response sensitive to the orientation of the driving field.
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Optics
High order harmonic Optical Reconstruction by delayed time-depeNdent Ellipticity perturbaTion: HORNET
Lucas Perez, Corentin Picot, Stefan Skupin et al. (+2 more)
We present and demonstrate an all-optical in situ method for temporal characterisation of high-order harmonics generated in gas with a linearly polarised intense infrared (IR)
laser. By using a delayed cross-polarised replica of the IR pulse with a lower amplitude, we introduce a weak and time-dependent ellipticity in the IR driving field. Since the XUV emission is very sensitive to the ellipticity of the driving field, it is perturbed precisely at the times when ellipticity is significant. The detected emission is then reduced only if the unperturbed XUV emission is substantial at these times. Perturbed XUV spectra are recorded for several delays and exhibit changes both in amplitude and in their spectral content. An iterative ptychographic
algorithm is used to retrieve the electric field of individual harmonics in a very robust way. Experimental measurements are in good agreement with simulations. The reconstructed temporal profiles show a steady
evolution of the XUV pulse duration and chirp with the harmonic order. The highest harmonics exhibit a positive chirp and are emitted in the rising front of the IR driving pulse, while the lowest ones exhibit a negative chirp and are emitted throughout the entire pulse.
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All authors Lucas Perez, Corentin Picot, Stefan Skupin, Fabrice Catoire, Eric Constant
Fluid Dynamics
Influence of Park's Two-Temperature Model Control Temperature on the Flow Properties in Hypersonic Reentry Conditions
Gibson De Marchi Poltronieri, Farney C. Moreira and João Luiz F. Azevedo
Numerical simulations of reactive hypersonic flows under thermochemical non-
equilibrium conditions are presented for the FIRE II and Mars Pathfinder capsules. An 11-species chemical model is employed to simulate Earth's atmosphere, while an 8-species chemical model simulates Mars' atmosphere. The current formulation uses Park's two-temperature model to account for the non-
equilibrium phenomena. The present work analyzes the impact of different sets of weight factors used in Park's model to calculate the control temperature. The code used to simulate the hypersonic flow addressed in this work solves the Navier-Stokes equations for reacting gas flows. The findings are depicted in terms of the Mach number, temperature modes, and mass fraction distributions along the stagnation streamline in a region closer to the shock wave. The study also includes results regarding the stagnation point convective heat flux. The results presented are encouraging and show that the weight factors significantly impact the FIRE II test cases while having little impact on the Mars Pathfinder flows. In all cases, it is possible to observe some effect of the weight factor selection on property distributions. In summary, the weight factors influence the flow behavior with varying intensities depending on the flow conditions.
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Instrumentation and Methods for Astrophysics
Cascade adaptive optics with a second stage based on a Zernike wavefront sensor for exoplanet observations II. Validation in broadband light on the ESO/GHOST testbed
A. Rahim, M. N'Diaye, A. Vigan et al. (+10 more)
Current high-contrast facilities on the ground use extreme adaptive optics (XAO) systems to achieve contrasts down to $10^{-6}$ at 200\,mas for
exoplanet observations. This performance is mainly limited by the XAO residuals due to the temporal errors in the XAO control loop. To overcome this issue, a promising solution consists in using cascade adaptive optics with a fast second stage. This approach was recently validated for a control loop based on a Zernike wavefront sensor (ZWFS) in monochromatic light. As wavefront sensors operate in broadband light to maximise
photon sensitivity, this work aims to validate the ZWFS-based control loop in polychromatic light and assess its performance over a wide range of seeings, wind speeds, and
stellar fluxes. Experiments were conducted on the ESO's GPU-based High-order adaptive OpticS Testbench (GHOST) testbed to probe our scheme in polychromatic light. Residual aberrations from a first-stage XAO system were simulated and our approach was evaluated in narrowband and broadband light through contrast in Lyot coronagraphic images. Closing the ZWFS-based control loop consistently improves contrast within its correction region in most tested conditions. After subtraction of quasi-static aberrations, our loop reaches a contrast gain up to one order of magnitude, independently of bandwidth and
turbulence strength. The broadband and narrowband cases match in performance for bright sources, while narrowband remains slightly preferable for faint targets. These results demonstrate the feasibility of broadband ZWFS-based control loop and underline promising avenues with achromatic masks and an accurate calibration of quasi-static aberrations for future high-contrast imaging on Extremely Large
Telescopes.
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All authors A. Rahim, M. N'Diaye, A. Vigan, M. Kasper, J. Nousiainen, B. Engler, K. Dohlen, S. Leveratto, J. Floriot, M. Marcos, C. Bailet, P. Bristow, E. S. Douglas
High Energy Physics (Theory)
The Sharp Edges of Calabi-Yau Manifolds: Designing Symmetric Models for Ricci-flat Metrics
Viktor Mirjanić and Challenger Mishra
Computing
Ricci-flat metrics on Calabi-Yau
manifolds is challenging since no closed-form solutions are known. However, these computations are needed in order to make physical predictions in heterotic string theory, such as the masses of
quarks and Yukawa couplings. In this manuscript, we present an overview of relevant literature for learning about Calabi-Yau
manifolds, as ML researchers often face a steep learning curve when entering the field. Furthermore, we survey the impact of the
manifold's
symmetries on machine learning approximations to these flat metrics. We also characterise the isometries of
Ricci-flat metrics, a result frequently omitted or used without proof. Then, we address
symmetry breaking in point sampling and introduce a novel formula for computing volume ratios on general CICY
manifolds. We conclude by presenting a new
symmetry-aware model built using graph neural networks that avoids pathological behaviour witnessed in some other models.
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High Energy Astrophysical Phenomena
Supernova remnants in the new radio astronomy era
A. Ingallinera, M. Arias, G. Castelletti et al. (+25 more)
Supernova remnants (SNRs) are what is left after
stellar explosions, when the
stellar ejecta, the explosion shock and the circumstellar medium interact. Despite being among the first objects studied in
radio astronomy, observational difficulties have so far prevented a definitive characterisation, which would help answer open questions related to these sources. It is debated which is the contribution of SNRs to
Galactic cosmic rays, or how the interaction with the surrounding environments influences the particle energetics. The SKA precursors are providing valuable and unexpected discoveries on SNRs, thanks to their unique capabilities to probe spatial scales from a few arcseconds to a few degrees with a sensitivity of tens of microjansky. Accurate integrated flux density measurements and arcsecond-scale spectral-index maps are now possible for tens of SNRs, substantially expanding the small subset of remnants traditionally studied in great detail. SKA will markedly enhance current observations by providing: higher sensitivity, enabling the detection of fainter SNRs also in polarisation, revealing diffuse structures and the underlying
magnetic field configuration; higher angular resolution, allowing detailed mapping of compact remnants and reducing depolarisation in fine structures, tracing filaments and shocks fronts; wider frequency coverage to probe unexplored spectral windows, where spectral turnovers and breaks or cut-off may occur, establishing a direct connection to X-ray and {\gamma}-ray emission that constrains the electron population, and enabling accurate modelling of the non-thermal emission across the electromagnetic spectrum; improved image fidelity for more reliable cross-matching with other wavelengths, leading to a better understanding of the SNR-interstellar medium interplay.
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All authors A. Ingallinera, M. Arias, G. Castelletti, C. Bordiu, F. Bufano, G. Cosentino, M. D. Filipović, D. Liu, S. Loru, S. Orlando, O. Petruk, Z. Smeaton, A. Traficante, C. Trigilio, G. Umana, G. Anderson, F. Bocchino, C. Buemi, F. Cavallaro, E. Egron, N. Hurley-Walker, R. Kothes, P. Leto, S. Mantovanini, M. Miceli, G. Morlino, A. Pellizoni, M. Sasaki
Quantum Physics
Francisco Javier del Arco Santos and Jakob S. Kottmann
Quantum chemistry is one of the major potential applications in
quantum computation. Currently there is a considerable focus on relatively small active spaces as a consequence of hardware noise and exponential bottlenecks in simulations. In the long run, there will be an increasing demand in reliable approximations for larger systems – both, as initial states for projective
algorithms like the
quantum phase estimation or for the evaluation of dynamical properties. While numerous approaches to select active spaces and extrapolate basis set accuracy exist, there is currently no consistent approach that results in a single
quantum circuit for the total system. In this work, we combine hybrid Fermionic-Bosonic encodings with the structured approach of
Quantum Valence Bond Theory to directly construct
quantum circuits for comparably large molecular systems. With this approach we are able to push simulability barrier of variational
quantum eigensolvers towards chemically relevant systems and demonstrate
circuit designs that outperform active space counterparts and achieve good approximations with respect to the exact solutions.
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High Energy Astrophysical Phenomena
The Emerging Population of High-energy Emitting Radio Galaxies
G. Bruni, V. S. Paliya, D. J. Saikia et al. (+22 more)
High-energy emission from
radio galaxies provides a unique laboratory to study the connection between
accretion, jet formation, and particle acceleration in active
galactic nuclei (AGN). The recent detection of $\gamma$-ray emission from misaligned
radio galaxies - including Compact Symmetric Objects (CSOs), FR0, FRI/II, and even
Giant Radio Galaxies (GRGs) - has shown that efficient particle acceleration is not limited to blazars, but occurs throughout the full
radio-loud AGN population. This finding supports a unifying framework where leptonic synchrotron, synchrotron self-Compton (SSC), and external inverse-Compton (EIC) processes coexist across multiple spatial scales, from the inner jet and corona to the extended lobes, possibly with a hadronic contribution in dense environments. The Square Kilometre Array (SKA) will be pivotal in advancing this field. SKA1-Low will detect and characterize diffuse, low-surface-brightness emission tracing aged
plasma and jet duty cycles. SKA1-Mid will enable high-resolution spectral and polarimetric studies of compact jets and
nuclear regions, while SKA-VLBI will connect parsec- to kiloparsec-scale structures, identifying the exact sites of high-energy dissipation. In synergy with forthcoming high-energy missions such as NewAthena and CTAO, SKA will provide the first spatially resolved, multi-scale view of particle acceleration and energy release in misaligned AGN, unveiling the physical link between the central engine and its large-scale feedback on the host
galaxy evolution.
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All authors G. Bruni, V. S. Paliya, D. J. Saikia, L. Bassani, R. D. Baldi, E. Bronzini, F. D'Ammando, S. del Palacio, M. Kadler, Y. Y. Kovalev, D. V. Lal, G. Migliori, B. Mingo, J. Moldon, L. Ostorero, F. Panessa, M. Persic, I. Prandoni, L. Ricci, T. Savolainen, F. Shankar, F. Tavecchio, E. Traianou, F. Ubertosi, T. Venturi
Instrumentation and Detectors
HERETIX: A Hermetic, Enriched, Rare-Event Time Projection Chamber in Xenon
L. Althueser, N. Hargittai, J. Pienaar et al. (+4 more)
Xenon-based time projection chambers have established themselves as one of the most powerful technologies for rare-event searches. HERETIX is a proposed multi-tonne
liquid xenon observatory featuring two nested time projection chambers that enable the simultaneous optimisation of searches for weakly interacting massive particles and neutrinoless double beta decay ($0\nu\beta\beta$) of $^{136}$Xe. A hermetically sealed sapphire vessel containing xenon enriched to 90% $^{136}$Xe forms the inner detector, providing an ultra-low-background environment for $0\nu\beta\beta$ searches. Monte Carlo studies indicate that material-induced backgrounds can be effectively eliminated, yielding a projected $0\nu\beta\beta$ half-life sensitivity of $3.2 \times 10^{28} \, \mathrm{years}$ at 90% confidence level after a 10-year exposure, while the surrounding xenon volume, depleted in $^{136}$Xe, preserves the excellent dark matter sensitivity of large
liquid xenon detectors. HERETIX therefore offers a unified experimental approach capable of delivering leading sensitivity to two of the most compelling questions in fundamental physics.
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All authors L. Althueser, N. Hargittai, J. Pienaar, R. Braun, H. Landsman, C. Weinheimer, R. Budnik
Quantum Physics
Scalable Message-Passing Quantum Graph Neural Networks in the Weisfeiler-Leman Hierarchy
Snehal Raj, Brian Coyle, Léo Monbroussou et al. (+3 more)
Graphs provide a natural
language for relational data in chemistry, biology and optimisation. Graph neural networks (GNNs) have driven much of the recent progress in learning from such data through message passing, a single primitive that generalises convolution and
attention.
Quantum counterparts have been proposed, but with limited connection to message passing and few guarantees on performance or scalability. More broadly, the trainability of variational
quantum circuits is a recognised bottleneck for their wide applicability, and pre-training has emerged as one way to address it. Yet for a
quantum model to be useful, it must offer expressivity guarantees along with demonstrable scalability. Here we show how a
quantum graph neural network can be built to perform message passing, to be permutation equivariant, and to sit at a chosen level of the Weisfeiler-Leman hierarchy, the standard measure of how finely a model can tell graphs apart. We show that, as for classical GNNs, the training can be done first on small graph instances, allowing for a pre-training that can mitigate usual training issues, and its output can be read out at a cost that stays low as the graph grows. We validate the framework in large-scale simulations of up to 56
qubits across three
datasets, on synthetic graphs that ordinary message passing cannot separate, on molecular property prediction, and on the travelling salesperson problem. Our framework opens a path for near-term
quantum algorithms with theoretical guarantees and practical scalability, bringing the principles of graph learning into
quantum circuit design.
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All authors Snehal Raj, Brian Coyle, Léo Monbroussou, André J. Ferreira-Martins, Renato M. S. Farias, Elham Kashefi
Mesoscale and Nanoscale Physics
Rashba Spin Demons in Two-Dimensional d-Wave Altermagnets and their Electrostatic Contro
Muhammad Irfan Sarwar, Mohsin Raza and Kashif Sabeeh
Spin demons in d-wave altermagnets are acoustic collective excitations produced by nearly out-ofphase motion of
spin-split quasiparticle populations. We identify a new mode, Rashba
spin demon mode, in 2D d-wave altermagnets in the presence of Rashba
Spin-Orbit Coupling (RSOC). The pristine
spin demon mode in altermagnets, without RSOC, is a charge-dark excitation which is invisible to charge-sensitive probes. We show that Rashba
spin demon mode is a
spin-dominated acoustic mode that is distinct from the pristine mode and has a finite charge density spectral weight. RSOC rotates the quasiparticle
spin texture in momentum space, generating mixed charge-
spin coherence factors that give the longitudinal
spin pole a charge residue. We also show that a nearby metallic gate provides a complementary electrostatic knob by screening the Coulomb interaction and tuning the pole dispersion and linewidth. Within a charge-
spin random-phase approximation, we identify regimes where the Rashba mode is underdamped, charge visible, and still predominantly longitudinal-
spin-like. Our results establish RSOC and electrostatic screening as complementary controls for tuning the
spin and charge character of altermagnetic
spin demons and making them accessible to charge probes without destroying their
spin-dominated character.
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Quantum Physics
Dissipation-Induced Deviations from Kibble-Zurek Scaling in Non-Hermitian Quantum Annealing
H. Najafzadeh, S. Sadeghizade, R. Jafari et al. (+1 more)
We revisit the
quantum annealing problem in the non-Hermitian transverse-field Ising model. We determine, both analytically and numerically, the intrinsic transition probabilities and the resulting defect density. Our results reveal that, unlike the Hermitian case where defect production is dominated by modes near the gap-closing point, the non-Hermitian dynamics involve significant contributions from broad momentum sectors. We find that, depending on the dissipation strength, the defect density exhibits standard Kibble-Zurek scaling, anti-Kibble-Zurek behavior, and a suppression faster than the Kibble-Zurek prediction. We demonstrate that these deviations from the standard Kibble-Zurek scaling can be understood in terms of the underlying excitation probabilities. Specifically, the fast decay of the defect density originates from a vanishing excitation probability spanning a range of annealing times across all allowed modes, even at the gap-closing points. In contrast, the anti-Kibble-Zurek behavior arises from supplementary excitations facilitated by dissipation over a broad range of allowed modes, particularly those situated away from the gap-closing region.
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All authors H. Najafzadeh, S. Sadeghizade, R. Jafari, A. Langari
General Relativity and Quantum Cosmology
Ai-chen Li, Han-Qing Shi and Keyun Wu
We use a
primordial Majorana field as a fermionic probe of
quantum correlations during inflation. Working in a torsion-free FLRW spacetime, we derive the two-component Majorana mode equations in an
axion-inflation background and construct the corresponding quadratic
Hamiltonian in the paired momentum basis.
Hamiltonian diagonalization and the fermionic squeezing formalism are shown to give the same Bogoliubov transformation, providing a direct map from the Majorana mode functions to the instantaneous occupation number and to the two-mode state of each $(\boldsymbol{k},-\boldsymbol{k})$ pair. Because
Fermi statistics restricts each helicity sector to the
vacuum and one-pair states, the resulting
Hilbert space is finite and the bipartite
quantum-information measures can be evaluated explicitly. We compute the von Neumann
entropy of the reduced mode and the logarithmic negativity of the Majorana pair. Both diagnostics indicate that sufficiently light Majorana modes can retain enhanced super-horizon bipartite quantumness, with the logarithmic negativity making the residual inseparability especially explicit. Our result does not by itself constitute an observational Bell test or a complete decoherence analysis; rather, it identifies a Pauli-bounded matter sector in which horizon exit alone is not sufficient to erase the
quantum signature encoded in the two-mode state, thereby motivating an open-system study of how reheating and inflaton-induced interactions classicalize
primordial fermionic probes.
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Physics and Society
Human adaptive variability stabilises collective traffic dynamics
Shirui Zhou, Ching Jin, Junfang Tian et al. (+5 more)
Automated systems are often designed on the assumption that replacing human behavioural variability with precise, uniform algorithmic control improves collective performance. In automotive traffic, this principle underlies commercial adaptive cruise control (ACC). Using two large-scale human-driving experiments comprising 2.95 million car-following observations, a 25-vehicle platoon experiment and a controlled 11-driver protocol, cross-validated with 0.77 million observations from the NGSIM
dataset and data from 22 production ACC systems, together with empirically calibrated ACC simulations, we show the opposite: rigid algorithmic uniformity creates systemic fragility. Commercial rule-based controllers amplify small local perturbations into severe stop-and-go waves, increasing fuel consumption and carbon emissions by approximately 2.7- to 5.0-fold across scenarios. Human-driven platoons, by contrast, progressively dissipate disturbances and maintain smoother flow. We identify the behavioural mechanism behind this advantage: human car-following does not follow a fixed proportional spacing rule. Drivers continuously reshape their time-headway distributions across speed regimes, exhibiting a non-monotonic shift from efficiency-oriented to risk-sensitive regulation. This speed-dependent variability generates nonlinear damping that suppresses the synchronisation and propagation of local errors. Our findings challenge the view that human variability is merely suboptimal noise to be eliminated. More broadly, they suggest that robust large-scale interactive AI systems should embed adaptive, human-inspired behavioural flexibility rather than rely on rigid uniformity.
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All authors Shirui Zhou, Ching Jin, Junfang Tian, Shiteng Zheng, Rui Jiang, Shiquan Zhong, Shoufeng Ma, Vittorio Loreto
Quantum Physics · Cross-listed from math.AP
Quantum Physics-Informed Neural Networks for Solving Integro and Fractional PDEs
Deepak Gupta and Ratikanta Behera
Quantum neural networks have emerged as powerful models for approximating nonlinear functions. Yet their use in solving integro-differential equations (IDEs) and fractional integro-partial differential equations (FIPDEs), which involve inherently nonlocal operators, remains unexplored. This work introduces a
quantum physics-informed neural network (QPINN) framework that combines a
quantum neural network with the governing equations of general nonlinear IDEs and FIPDEs. The proposed
quantum network uses an affine feature map and variational
quantum circuits to produce trial solutions with explicit trigonometric structure. We prove a quantitative $L^{2}(\mu)$ universal approximation
theorem for this architecture, achieving a convergence rate of $\mathcal{O}(n^{-1/2})$. This extends classical
Fourier approximation theory to
quantum circuits for physics-informed learning. We propose two QPINN variants: the numerical-quadrature QPINN (N-QPINN), which handles nonlocal integrals and fractional operators via high-order numerical quadrature while computing local derivatives through automatic differentiation of
quantum trial solutions; and the auxiliary-function QPINN (A-QPINN), which eliminates numerical quadrature by introducing auxiliary variables that reformulate each integro-differential equation as an equivalent coupled system of partial differential equations, enabling a multi-output
quantum neural network to simultaneously represent the solution and its associated variables. A series of numerical experiments demonstrates that the proposed QPINN framework accurately captures the behavior of nonlinear IDEs and FIPDEs and outperforms classical physics-informed neural networks.
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High Energy Physics (Experiment)
Projected sensitivity of the ANUBIS detector to heavy neutral leptons
Martin Bauer, Rachel Bentham, Oleg Brandt et al. (+5 more)
Long-Lived Particles (LLPs) are a common feature in various extensions to the Standard Model (SM) that seek to address known limitations. The ANUBIS detector has been proposed to extend the sensitivity of the ATLAS experiment at the LHC to LLPs by instrumenting the ceiling of the ATLAS detector cavern. This article presents the projected sensitivity of ANUBIS to Heavy Neutral
Leptons (HNLs). For a minimal Majorana HNL model that only couples to a single flavour of
lepton ($e$ or $\mu$) ANUBIS reaches a maximum sensitivity of $|V_{1e}|^2=1.8\times10^{-8}$ and $|V_{1\mu}|^2=1.9\times10^{-8}$ for a HNL mass of $m_{N_1}=6.4$ GeV and 6.3 GeV respectively. This provides complementary coverage to other proposed LLP experiments in the HNL parameter-space, with potential for significant improvement during ANUBIS data-taking through advances in analysis strategies. The results are obtained with SET-ANUBIS, a flexible framework to evaluate the sensitivity of ANUBIS to a variety of LLP models.
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All authors Martin Bauer, Rachel Bentham, Oleg Brandt, Sofie Nordahl Erner, Anna Mullin, David Peng, Theo Reymermier, Paul Swallow
Optics
Low-Threshold Degenerate Optical Parametric Oscillations in Bichromatically-Pumped Normal-Dispersion Photonic-Crystal Microresonator
Valery E. Lobanov, Nadezhda S. Tatarinova, Artem E. Shitikov et al. (+3 more)
The process of excitation of degenerate optical parametric oscillations via bichromatic pump is studied numerically in normal-dispersion photonic-
crystal microresonator. It is demonstrated that the photonic-
crystal structure with two split modes placed symmetrically at the particular interval from the pumped modes provides significant reduction in pump power threshold for the considered process. The parameter range for this phenomenon is determined. Introduction of mode splitting at the signal mode located in the center between pumped modes leads to an increase in the generation threshold.
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All authors Valery E. Lobanov, Nadezhda S. Tatarinova, Artem E. Shitikov, Olga V. Borovkova, Igor A. Bilenko, Dmitry A. Chermoshentsev
High Energy Physics (Experiment)
Calibration and Performance of proANUBIS: A proof-of-concept detector for the ANUBIS experiment
Giulio Aielli, Oleg Brandt, Jude Burling et al. (+12 more)
Long-lived particles with lifetimes $\tau>10$~ps are predicted by many extensions of the Standard Model with viable dark matter candidates. The ANUBIS experiment proposes to extend the experimental sensitivity to long-lived particles by instrumenting the ceiling of the ATLAS cavern with Resistive Plate Chamber detectors in order to reconstruct vertices from long-lived particle decays in the air-filled volume above the ATLAS detector. The proANUBIS detector has been installed in the ATLAS cavern to validate the detector technology planned for ANUBIS and to take in-situ measurements of
muon and
hadron fluxes inside the ATLAS cavern using $pp$ collision data from the LHC. In this paper, the data collected, reconstruction techniques used, and performance of the \proanubis detector are discussed. The detection efficiency and timing resolution are found to be consistent with expectations and to meet the performance requirements of ANUBIS.
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All authors Giulio Aielli, Oleg Brandt, Jude Burling, Patrick Collins, Jonas Dej, Cayetano Fernandez Ruiz, Christopher Lester, Kaijia Liu, Luca Pizzimento, Ludovico Pontecorvo, Theo Reymermier, Michael Revering, Aashaq Shah, Tom Spencer, Paul Swallow
Space Physics
Excursion-set structure factor of the auroral electric field
Magnus F Ivarsen, Kaili Song, Jean-Pierre St-Maurice et al. (+1 more)
A spacecraft crossing the aurora cannot tell whether structures in the field-aligned currents are short-lived or merely small. However, by tracking clusters of coherent radar echoes from aurorae and
Fourier-transforming motion-shifted echo pairs across radar snapshots, we can calculate the dynamic structure factor of the point-clouds, thereby quantifying the auroral electric field's spatial power and its persistence from 5 to 40 km, in regions where the radar look-direction is perpendicular to the geomagnetic field. This follows from the fact that coherent E-region radar echoes appear only where the ionospheric electric field exceeds the Farley-Buneman instability threshold, and so a point-target imaging radar naturally samples the field's excursion set; the field's spatiotemporal correlations are discernible from that point process. We find that the echo pattern moves with its cluster: large-scale structures persist for tens of seconds, but scales under 10 km renew within seconds, and conjunctions with Swarm satellite pairs replicate the same scale dependence in field-aligned currents. Coherent radar can thus quantify multi-scale variability in the auroral electric field on Alfvénic timescales.
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All authors Magnus F Ivarsen, Kaili Song, Jean-Pierre St-Maurice, Glenn C Hussey
General Relativity and Quantum Cosmology
Conservation law of super-Lorentz charges across spatial infinity
Geoffrey Compère and Sébastien Robert
Under assumptions compatible with generic gravitational scattering, the
vacuum relativistic gravitational field is entirely determined at leading order in the large radius expansion at spatial infinity by its supermomentum, its dual supermomentum and its global supertranslation frame. At subleading order, the gravitational field is determined by three additional sets of charges: the super-Lorentz charges, the leading mixed tail/ peeling-breaking charges and the leading peeling-breaking charges. In this work we provide a proper-supertranslation-invariant definition of these charges in terms of asymptotic Bondi-Sachs fields as well as a corresponding proper supertranslation and logarithmic translation invariant definition of these charges in terms of Beig-Schmidt fields. Using the properties of homogeneous and inhomogeneous solutions to relevant wave equations over the boundary de Sitter spacetime at spatial infinity, we derive the conservation law of super-Lorentz charges between the future and past of spatial infinity. We obtain that the super-Lorentz aspects are non-locally defined from the Bondi-Sachs fields.
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Adaptation and Self-Organizing Systems
Data-driven inference of Hopf normal form representations from oscillatory time series
Shinsuke Koyama and Ryota Kobayashi
We introduce a data-driven framework that maps noisy oscillatory time series directly onto the
Hopf normal form, enabling inference of underlying dynamics without knowledge of governing equations. By
embedding the normal form in a probabilistic state-space model, the method jointly infers latent states and system parameters, yielding robust estimates of the natural frequency, Floquet exponent, and asymptotic phase even far from the bifurcation point and under strong noise. Combined with complex Gaussian process regression, the approach further reconstructs phase and amplitude sensitivity functions from data.
Benchmarks on the van der Pol oscillator demonstrate substantially improved accuracy and noise robustness compared with existing phase-based and regression methods. This work establishes a direct bridge between normal-form theory and statistical inference, providing a general and practical route to low-dimensional descriptions of oscillatory dynamics in complex systems.
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Optics
Taming the single-cylinder scattering through time-modulation – The role of the modulation phase
J. Yan, I. Katsantonis, M. Mostafa et al. (+2 more)
Dielectric particles with time-modulated electromagnetic properties exhibit intriguing scattering phenomena, entailing unique response and possibilities in meta-structures made of such particles. In this work, we investigate the scattering properties of an infinitely-long cylinder with periodically time-modulated permittivity. We demonstrate parametric scattering amplification, depending on the strength of the modulation, as well as controllable angular scattering pattern, ranging from enhanced forward to enhanced backward, or even scattering cancellation. This angular tunability is achieved through appropriate control of the modulation phase, highlighting its critical role in multi-modal time-modulated scattering systems.
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All authors J. Yan, I. Katsantonis, M. Mostafa, V. Asadchy, M. Kafesaki
Materials Science
HF Etching and Silanization: Evidence for the Role of Surface Hydroxyl Groups in Silicon Nitride Resonator Loss
Ariane Giesriegl, Nicola Cavalleri, Robert West et al. (+4 more)
Silicon nitride $SiN_x$ nanomechanical resonators are central to sensing,
quantum technologies, and fundamental physics experiments due to their exceptional mechanical quality factors (Q). However, as resonator thickness approaches the nano-scale, surface-related dissipation limits performance. Here, we investigate the role of surface chemistry in low-stress Si-rich SiNx membranes through a combination of hydrofluoric acid (HF) etching and trimethylchlorosilane (TMCS) silanization, correlated with surface characterization and mechanical measurements. Preliminary analysis by TEM-EELS, XPS, RBS/ERDA, and XRR reveals a native
oxide surface layer (1-2 nm). Surface modification by HF and TMCS was subsequently evaluated using XPS, photothermal FTIR, contact-angle measurements, and intrinsic quality factor ($Q_{int}$) characterization. While HF etching effectively removes the native
oxide and TMCS introduces hydrophobic $Si-(CH_3)_3$ termination, neither
oxide thickness nor surface energy correlates with mechanical dissipation. TMCS treatments produce the largest enhancements, increasing $Q_{int}$ by up to 50%, whereas HF etching alone yields lower gains of 20-25%. These findings suggest surface hydroxyl groups as a key contributor to energy loss in $SiN_x$ resonators and demonstrate that chemical functionalization can substantially suppress surface dissipation.
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All authors Ariane Giesriegl, Nicola Cavalleri, Robert West, Antonius Armanious, Markus Sauer, Thomas Schachinger, Silvan Schmid
Materials Science
A Hybrid Quantum Mechanics Machine Learning Forcefield (QM/ML) Framework for Accurate Solute-Dislocation Interaction Simulations
Junting Zhang, Colleen Reynolds, Ryan S. Stroud et al. (+4 more)
Solute-dislocation interactions play a central role in controlling microstructural
evolution and mechanical behaviour of structural materials, yet conventional atomistic modelling approaches struggle to combine the chemical accuracy with computational scalability. In the
nuclear industry, these challenges become particularly acute, as experiments reveal strong correlations between solute segregation and irradiation-induced dislocation loops. However, theoretical insight remains limited because density functional theory (DFT) simulations are prohibitively expensive at relevant length scales, while traditional semi-empirical interatomic potentials lack the chemical fidelity required for predictive solute-defect calculations. Here, we introduce a hybrid
quantum-mechanics/machine-learning (QM/ML) simulation framework that couples DFT with neural-network machine learning interatomic potentials (MLIPs), enabling accurate atomistic dislocation simulations at reduced computational cost. We demonstrate the QM/ML framework's capability by reproducing the experimentally observed Sn and Fe segregation to dislocation loops in Zr and investigating magnetically complex solute-dislocation interactions in steel. These results establish the approach as a transferable, high-fidelity tool for modelling irradiation-induced defect structures and benchmarking emerging MLIPs.
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All authors Junting Zhang, Colleen Reynolds, Ryan S. Stroud, Jana Smutna, Daniel J. M. King, Andrew P. Horsfield, Mark R. Wenman
Astrophysics of Galaxies
Theoretical determination of the binding energies of methanol and related species onto amorphous solid water ice
Aneesa Ahmad, Catherine Walsh, Stefan Vogt-Geisse et al. (+2 more)
The formation and survival of complex organic molecules (COMs) in cold interstellar environments depends on their interactions with icy
dust grain surfaces. Methanol, a key COM detected in cold cores and protoplanetary disks, is believed to form on amorphous solid water (ASW) through surface reactions and reside there until it is desorbed into the gas phase. We present a theoretical study of the binding energies (BEs) of methanol and its photolysis-derived species on ASW clusters by means of dispersion-corrected density functional theory (DFT) using a refined protocol implemented in the Binding Energy Evaluation Platform (BEEP). Molecules capable of hydrogen bonding, such as H2O, CH3OH, HCOOH, and OH, exhibit high BEs and broad BE distributions that reflect the structural heterogeneity of the ASW surface. In contrast, weakly interacting volatiles including CO, CO2, CH4, and CH3 display narrower distributions dominated by dispersion interactions. Open-shell radicals such as CH2OH and OH bind more strongly than HCO and CH3 due to their ability to form directional hydrogen bonds. Incorporation of our BEs into an astrochemical model, in conjunction with a recalculation of the pre-exponential factor using transition state theory, demonstrates the sensitivity of model results to the method of calculation of the grain-surface reaction rates. The new approach generally predicts a higher abundance of radicals on the ice that are key reactants for the formation of COMs when surface
diffusion is assumed to be efficient. These findings emphasize the importance of incorporating BEs that have been determined in a self-consistent manner into astrochemical models, and provide reliable theoretical
benchmarks for species with limited experimental data.
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All authors Aneesa Ahmad, Catherine Walsh, Stefan Vogt-Geisse, Gabriela Silva-Vera, Felix Sainsbury-Martinez
High Energy Physics (Experiment)
Precision luminosity measurement in proton-proton collisions at a center-of-mass energy of 13 TeV with the CMS detector at the Large Hadron Collider
CMS Collaboration
Discovering new fundamental physics requires spotting subtle deviations between theoretical predictions and experimental data. This delicate comparison hinges on the precise knowledge of the integrated luminosity, the measure of how many particle interactions were actually delivered by the
collider. Here, we report a landmark measurement of the integrated luminosity by the Compact
Muon Solenoid (CMS) experiment for
proton-
proton collisions at a center-of-mass energy of 13 TeV at the CERN Large
Hadron Collider (LHC). By calibrating multiple independent monitors through specialized beam-separation techniques and rigorously validating their long-term stability against well-understood Z
boson production rates, we comprehensively map and minimize systematic uncertainties. Combining the findings yields a total integrated luminosity precision of 0.73% for the entire data set. This marks the most precise luminosity measurement ever achieved at a bunched-beam
hadron collider. Crossing the sub-percent precision threshold per data taking year fundamentally sharpens our ability to test the standard model and establishes a vital baseline for the upcoming High-Luminosity LHC era.
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Cosmology and Nongalactic Astrophysics
Distance-Ladder Measurements of the Hubble Constant: Recent Progress, Systematics, and Prospects
Xiaodian Chen and Shu Wang
The Hubble constant, \(H_0\), links the nearby distance scale to the present
cosmic expansion rate. Local distance-ladder measurements now reach percent-level precision and remain more than \(5\sigma\) higher than the value inferred from
cosmic microwave background (CMB) observations in base-\(\Lambda\)CDM, making the reliability of the local ladder a central issue in the Hubble tension. We describe the ladder as a covariance network connecting level-0
geometric anchors, level-1
stellar distance indicators, and level-2 Hubble-flow probes. The Cepheid–Type Ia
supernova (SN Ia) route remains the most precise single local ladder, but independent indicators including the tip of the red
giant branch (TRGB), J-region asymptotic
giant branch (JAGB)
stars, Mira variables, surface-brightness fluctuations (SBF), the Tully–Fisher relation, and Type II
supernovae (SNe II) now test shared and method-specific systematics. In a compact seven-route covariance summary, combining the Cepheid–SN Ia route with three level-1 alternatives (TRGB, JAGB, and Mira) and three level-2 alternatives (SBF, Tully–Fisher, and SNe II) gives \(H_0=73.30\pm0.92~{\rm km~s^{-1}~Mpc^{-1}}\), still \(5.6\sigma\) above Planck base-\(\Lambda\)CDM. JWST has already tested Cepheid crowding and is making independent TRGB-based \(H_0\) measurements increasingly feasible. Over the next five years, a reliable one-percent local \(H_0\) requires larger calibrator samples, cross-validated level-1 zero points, explicit covariance propagation, and AI-assisted, reproducible, pre-specified selection criteria for distance-indicator measurements.
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Computational Physics
pyDOF: a Python library for the design of discrete forward and inverse filters
Z. Nikolaou, P. Domingo, L. Vervisch et al. (+1 more)
In this work, we present pyDOF, a Python-based software library which provides a domain-specific framework for the design of symmetric, physical-space, forward as well as inverse discrete filters. pyDOF is based on a constrained optimisation framework developed in our previous work [1, 2]. This framework allows the user to impose a wide range of constraints on the discrete filter transfer-function such as monotonicity, positivity, value-fixing, gradient-smoothing etc. amongst many others. pyDOF additionally includes an adaptive filter stencil selection option, and a van Cittert-based inverse-filter design with a user-controlled reconstruction order. The filter coefficients are computed automatically, and saved to a plain text file which can be readily parsed by any programming
language. pyDOF can be used to design a wide range of low-pass, high-pass, multi band-pass/band-stop etc. discrete filters. In addition, due to its generality and abstraction, pyDOF can be used to design specific filters for user-defined target filter transfer functions. Although developed primarily for application to computational fluid dynamics simulations, pyDOF can be used to design discrete filters for a wide range of signal processing applications.
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All authors Z. Nikolaou, P. Domingo, L. Vervisch, D. Drikakis
Astrophysics of Galaxies
Probing outflow physics through CH$_3$CN and CH$_3$OH chemistry
L. Giani, D. Zaremba, M. De Simone et al. (+4 more)
Chemical correlations between molecules provide powerful diagnostics to probe the physical conditions of protostellar
outflows. In particular, the relationship between methanol (CH$_3$OH) and methyl cyanide (CH$_3$CN) offers a promising tool to investigate the chemistry and irradiation environment of shocked gas. In this Letter, we use the CH$_3$OH/CH$_3$CN abundance ratio to constrain the physical properties of the
outflow driven by the Class 0 protostar S68N using ALMA Band 3 and Band 6 observations. Assuming local thermodynamic
equilibrium (LTE), we derive excitation temperatures of 50-60 K and column densities of 2-3$\times$10$^{13}$ cm$^{-2}$ for CH$_3$CN and 3-5$\times$10$^{15}$ cm$^{-2}$ for CH$_3$OH. The resulting CH$_3$OH/CH$_3$CN abundance ratio is nearly constant along the
outflow, with values of $\sim$100-200, similar to those found in other protostellar environments. Using an up-to-date astrochemical model, we test whether gas-phase formation of CH$_3$CN can account for the observed ratios. We find that they are reproduced only by assuming enhanced
cosmic-ray ionization rates $\zeta_{\rm CR}$ up to $\sim$10$^{-14}$ s$^{-1}$. These results suggest that the CH$_3$OH-CH$_3$CN correlation can be used as a probe of the irradiation conditions in protostellar
outflows. Further studies are required to explore the possible contribution of grain-surface formation of CH$_3$CN which could lead to a lower $\zeta_{\rm CR}$ and to extend the analysis to a larger sample of sources.
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All authors L. Giani, D. Zaremba, M. De Simone, L. Tychoniec, L. Podio, C. Codella, A. Somigliana
Mathematical Physics · Cross-listed from math.AP
Quantitative uniform resolvent estimates
Piero D'Ancona, Jérémy Faupin and David Krejcirik
We derive quantitative uniform resolvent estimates for Schrödinger operators on the half-line with inverse-square potentials, which provide a sharp behaviour in the limit of large coupling. Our approach is based on a
matrix representation of the boundary value of a weighted resolvent. The partial wave decomposition then turns these one-dimensional channel estimates into explicit weighted resolvent estimates for the
Laplacian, its inverse-square potential perturbations and for the
magnetic Laplacian with an Aharonov–Bohm potential. We also obtain exact Simon-type identities for the imaginary parts of the weighted resolvents of these operators.
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