Solar and Stellar Astrophysics
Results on young stellar clusters with the WEAVE LIFU
J. Maíz Apellániz, G. Holgado, C. Fariña et al. (+1 more)
We present the first results of two Spanish TAC programs using the WEAVE LIFU that have been obtaining data since October 2023. The first one is obtaining high-resolution multi-epoch spectroscopy of the nine
stellar clusters that contain a minimum number of 3 O-type
stars (and many more B
stars) within the field of view of the WEAVE LIFU and that are accessible from La Palma with the purpose of studying the spectroscopic multiplicity of the OB
stars. The second program is obtaining single-shot low-resolution spectroscopy of as many
stellar clusters with OB
stars as possible with the purpose of characterizing the OB-
star population in those regions that are too crowded to be properly studied with the guaranteed time SCIP program. That program has already observed 54 clusters in a wide range of environments, from H II regions to gas-free clusters, and distances, from clusters in the
solar neighbourhood to (nearby) extragalactic systems. We also present the tools developed for this program, which include a data cube processing and visualisation utility and UNWIND, a code that fits and subtracts the ISM signature in the observed spectra.
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All authors J. Maíz Apellániz, G. Holgado, C. Fariña, S. R. Berlanas
Solar and Stellar Astrophysics
Riemann Map Operator for Solar Front Diagnostics
Olena Podladchikova
Identifying a shock from a moving
solar brightness front requires relating the observed emission to changes in the
plasma state. The Riemann framework describes shocks, rarefactions and other waves as parts of a pattern connecting different states. We present the Riemann Map Operator (RMO), an inverse diagnostic framework implemented as a web application to help observers identify magnetohydrodynamic (MHD) shock families from incomplete measurements. RMO tests candidate local connections against conservation laws,
entropy requirements and characteristic conditions, while retaining observational uncertainties and model assumptions. We demonstrate the approach with five
solar examples and a complementary in-situ comparison. An event combining extreme-ultraviolet (EUV) imaging and spectroscopy admits both fast and slow shock connections within the tested conditions. For an EUV-
radio event, we derive an upstream-flow constraint that would exclude ordinary slow shocks within the adopted model, provided both diagnostics sample the same front. A
flare-loop
benchmark reproduces the published spectral profiles and recovers slow-shock ordering in the isothermal limit. The
Solar Orbiter comparison recovers an Alfvenic relation between measured velocity and
magnetic-field changes. Together, the examples show how RMO connects observations to admissible MHD interpretations and identifies the additional measurements needed to distinguish them.
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Optics
Subwavelength exceptional points in dispersive resonator arrays
Konstantinos Alexopoulos
Exceptional points provide a mechanism for producing strong spectral sensitivity in non-Hermitian wave systems. For subwavelength resonators with highly dispersive material parameters, however, the resonance problem is not a linear
eigenvalue problem in the frequency. In this paper, we use the Lippmann-Schwinger formulation and the associated volume-potential reduction to study exceptional points in dispersive resonator arrays. The reduction leads to a finite-dimensional nonlinear
matrix pencil whose entries encode both the local material response and the volume-mediated interaction between the resonators. We characterize exceptional points as defective characteristic values of this pencil and derive explicit conditions for dimers and higher-order systems. We show that passive damping and detuning can generate exceptional points without imposed gain, and we formulate an inverse-design condition for placing such degeneracies at prescribed frequencies. We also prove the corresponding Puiseux splitting laws and identify how material dispersion enters the leading sensitivity prefactor. Numerical experiments, including halide-perovskite-inspired dimers and trimers, illustrate the theory and show that the exceptional-point mechanism persists for explicit highly dispersive passive material laws.
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Strongly Correlated Electrons
Band-Saddle-Point Engineering in Mixed $A$-site $A$V$_3$Sb$_5$ Kagome Metals
Maxim Wenzel, Alexander A. Tsirlin, Andrea N. Capa Salinas et al. (+4 more)
$A$V$_3$Sb$_5$ compounds ($A$ = K, Rb, Cs) offer an experimental platform for probing the physics of kagome metals near ideal Van Hove filling. Here, we use optical spectroscopy on $A$V$_3$Sb$_5$ with mixed $A$-site compositions to reveal the effect of the alkali metal on the low-energy electronic structure. Supported by density-functional-theory calculations, we identify a band-saddle-point inversion as a chemical consequence of Cs substitution, revealing that $A$-site composition controls the orbital character of Van Hove singularities,
Fermi surface
topology, and electron-
phonon interactions while leaving the kagome layer intact.
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All authors Maxim Wenzel, Alexander A. Tsirlin, Andrea N. Capa Salinas, Brenden R. Ortiz, Stephen D. Wilson, Ece Uykur, Martin Dressel
Mathematical Physics · Cross-listed from math.NA
A Hybridized Staggered Discontinuous Galerkin–Mixed Finite Element Method for Strain Gradient Elasticity
Bohan Yang and Eric T. Chung
We propose a hybridized staggered discontinuous Galerkin–mixed finite element method for the strain gradient elasticity model, a fourth-order singularly perturbed problem governed by a material length scale parameter $\iota$ and the Lamé constants $\lambda$ and $\mu$. Introducing the total stress together with the scaled Cauchy and hyper stresses as auxiliary unknowns, we recast the model as a first-order system and discretize the displacement and the total stress by staggered discontinuous Galerkin spaces, the two scaled stresses by Raviart–Thomas pairs, with
symmetry imposed strongly on all three stresses. The higher-order Dirichlet boundary condition enters the variational formulation naturally, so that the scheme avoids the numerical boundary layer that limits displacement-based methods. By establishing an inf-sup condition on the symmetric subspace and a discrete Korn inequality, we prove algebraic stability and optimal convergence, both uniform in $\iota$ and $\lambda$. We further develop a hybridized scheme in which local static condensation leaves only two multipliers on the mesh skeleton as globally coupled unknowns. Numerical experiments confirm the predicted convergence rates and the parameter robustness.
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High Energy Physics (Phenomenology)
The $\gamma Z$-box correction and its impact on parity-violating deep-inelastic scattering
Balma Duch, Pere Masjuan and Hubert Spiesberger
The $\gamma Z$-box correction is an important electroweak contribution to precision parity-violation measurements, but its conventional low-energy treatment relies on an ambiguous effective
quark-mass prescription. We revisit this correction using a finite-mass calculation that provides a well-defined perturbative contribution without introducing such an auxiliary scale. Applying the result to the Jefferson Lab PVDIS measurement shifts the extracted electron-
quark couplings at the $10^{-3}$ level. We discuss the implications of this shift for precision electroweak tests and the need for a consistent separation of perturbative and non-perturbative hadronic contributions.
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General Relativity and Quantum Cosmology
Charged Black Hole Solution in Hoyle Narlikar Gravity and its Thermodynamic Properties
Aniruddha Ghosh and Ujjal Debnath
In this paper, we derive a new class of analytic black hole solutions within the framework of Hoyle–Narlikar
gravity, where the black hole is surrounded by an electric charge acting as the source. After obtaining the corresponding metric, we investigate the thermodynamic properties of the resulting black hole solutions, including the Hawking temperature and
entropy. Subsequently, we compute the specific heat and Gibbs free energy in order to analyse the thermodynamic stability of the black hole in Hoyle–Narlikar
gravity. An interesting result of our analysis is that the black hole becomes thermodynamically stable for large values of the horizon radius within this framework.
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High Energy Physics (Phenomenology)
Determination of charged pion unpolarised TMDPDFs from Drell-Yan measurements
Wen-Chen Chang, Chia-Yu Hsieh, Chung-Wen Kao et al. (+3 more)
We present an extraction of the unpolarised transverse momentum dependent (TMD) parton distribution functions (PDFs) for the valence
quarks in the pion from experimental mea- surements of the Drell-Yan process. The procedure adopted in this project relies on the framework of TMD factorisation, and the inputs of nucleon TMDPDF, pion collinear PDF, as well as the Collins-Soper kernel. The non-perturbative behaviour of the TMDPDFs is parameterised using an ansatz function that contains three unknown parameters and implements an exponential decay at large transverse distances. This work employs the most recent results in perturbation theory, and utilises a precise estimation of the nucleon TMDPDF. We perform an investigation of data used in the fit. This investigation leads to important observations regarding the effects of the kinematics and binning methods in the experimental data. Our results agree qualitatively with the previous determinations from phenomenology and a
lattice computation
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All authors Wen-Chen Chang, Chia-Yu Hsieh, Chung-Wen Kao, C.-J. David Lin, Valentin Moos, Wayne Morris
Instrumentation and Methods for Astrophysics
FOSSIL: Thermo-mechanical architecture
Valentin Sauvage, Clémence de Jabrun, Sylvain Martin et al. (+13 more)
FOSSIL (FTS fOr CMB Spectral diStortIon expLoration) is a proposed ESA M8 mission tailored to measure the spectral distortions of the
Cosmic Microwave Background (CMB) with a sensitivity three orders of magnitude beyond the COBE/FIRAS legacy measurement. Achieving this sensitivity demands an extraordinarily challenging cryogenic architecture: the scientific instrument must be maintained at the lowest achievable temperature (4.5 K), while the detector focal plane assembly operates at 50 mK. This paper presents the thermal architecture of the FOSSIL payload and instrument, from the spacecraft service module at 293 K down to the sub-kelvin detector stage. The thermal design draws on heritage from the Planck and ARIEL missions and relies on a staged passive cooling chain comprising a multi-layer insulation blanket, three V-groove radiators (operating at approximately 130 K, 90 K, and 50 K), and a 25 K actively cooled shield fed by an ESA-provided 4 K cryocooler chain. Sub-kelvin temperatures are achieved via a multi-stage adiabatic demagnetisation refrigerator (ADR) system developed for NewAthena/X-IFU, providing continuous cooling at 1.8 K and 350 mK, and 50 mK with an 80% duty cycle. The Focal Plane Assembly (FPA), which houses four Kinetic Inductance Detector (KID) arrays at 50 mK, is thermally isolated from the 4.5~K bench via a carbon-fibre reinforced
polymer (CFRP) hexapod structure with staged heat interception. We present the steady-state thermal budget across all stages, demonstrating comfortable margins at every temperature level, and discuss key thermal design drivers on the Blackbody Internal Reference (BBIR).
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All authors Valentin Sauvage, Clémence de Jabrun, Sylvain Martin, Bruno Maffei, Nabila Aghanim, Anaïs Besnard, Bruno Borgo, Ivan Charles, Xavier Coulon, Sandrine Couturier, Francesco Cuttaia, Jean-Marc Duval, Morgane Loquet Le Gall, Giorgio Savini, Luca Terenzi, Berend Winter
Earth and Planetary Astrophysics
Spectral Evolution of Ceres' Surface and Implications for Space Weathering
Qing Zhang, Jian-Yang Li, Yazhou Yang et al. (+2 more)
The surface of Ceres exposed to the space environment will be gradually altered, but the
evolution of its spectral properties remains poorly understood. Here we analyze visible and infrared spectra acquired by the Dawn mission to investigate spectral variations across different surface units. We identify local shifts of a few nm toward shorter wavelengths in the 2.7 $\mu$m band center, predominantly associated with freshly exposed slumping and impact materials. Our analysis suggests that compositional variations in Ceres' regolith are unlikely the explanation for the band center shift, and therefore it may represent a spectral
evolution within 10$^6$ years. Combining previous studies about the spectral reddening on Ceres, we propose a two-stage spectral
evolution on Ceres. The blue-shifted regions are interpreted as the youngest materials. Within 10$^6$ years after exposure, these materials become spectrally bluer, the 2.7 $\mu$m band weakens, and its center shifts toward longer wavelengths. Then the
evolution is characterized by spectral reddening and strengthening of the 2.7 $\mu$m band without the band center shift. Based on the previous laboratory work and observations on other C-complex asteroids, we suggest that the observed spectral variations may be attributed to the chemical and/or physical changes of the regolith, possibly associated with space weathering.
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All authors Qing Zhang, Jian-Yang Li, Yazhou Yang, Minge Liu, Yang Liu
General Relativity and Quantum Cosmology
Thermodynamic stability of the new black hole solution in $f(R,G,T)$ gravity
Aniruddha Ghosh and Ujjal Debnath
In this literature, we derive an approximate black hole metric within the \( f(R, G, T) \)
gravity framework, where the black hole is surrounded by an anisotropic fluid as the matter source. This approach allows us to study the influence of anisotropic pressures on the black hole structure. We then investigate the thermodynamic properties of the approximate solution, considering various types of matter fields. We analyze the thermodynamic quantities such as Wald's
entropy, Hawking temperature, and specific heat for each case. After examining the specific heat, we find that the black holes are thermodynamically stable, with positive specific heat values indicating stability. This result suggests that the black holes under these conditions do not undergo thermal instability, ensuring their long-term viability.
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High Energy Physics (Phenomenology)
Precision Sum Rule for Nucleon Isovector Polarizabilities and the Proton-Neutron Mass Difference
Xiong-Hui Cao, Ling-Yun Dai and Feng-Kun Guo
The precision of the electromagnetic
proton-
neutron mass difference $\delta m_\mathrm{QED}$ extracted from the Cottingham formula hinges on a subtraction function whose low-energy normalization $\bar S(0)$ is fixed by the isovector combination of the
proton and
neutron polarizabilities, $(\alpha_{E1}-\beta_{M1})^{p-n}$. We derive a dispersive sum rule for this combination in terms of $s$-channel photoabsorption cross sections and the product of $t$-channel $\gamma\gamma\to\pi\eta/K\bar K_{I_t=1}$ and $\pi\eta/K\bar K_{I_t=1}\to N\bar N$ amplitudes, without invoking Reggeon dominance. Combining empirical pion-photoproduction multipoles with coupled-channel Muskhelishvili-Omnès representations of the scalar-isovector $\pi\eta/K\bar K$ amplitudes, we obtain $(\alpha_{E1}-\beta_{M1})^{p-n}=-0.82(33)\times10^{-4}\,\mathrm{fm}^3$, fixing its sign and reducing the uncertainty by one order of magnitude compared with the previously known value. This result yields $\bar S(0)=-0.56(28)\,\mathrm{GeV}^{-2}$, leading to $\delta m_\mathrm{QED}=0.75^{+0.02}_{-0.04}\,\mathrm{MeV}$, substantially more precise than previous Cottingham determinations. The negative $\bar S(0)$ also provides a low-energy test of Reggeon dominance in the subtraction function.
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Materials Science
Evaluating Predicted Densities, Hamiltonians, and Density Matrices as Periodic SCF Initializers
Pin Chen, Jiang Li and Yutong Lu
Learned electronic states are usually evaluated by prediction error, even though their intended use is to accelerate the self-consistent-field (SCF) loop of density functional theory (DFT). We ask whether lower offline error actually yields a better SCF initializer. We construct $\rho$HD-43K, a 43,851-
crystal DFT corpus with aligned charge-density,
Hamiltonian, and density-
matrix labels, and extend the solver workflow to inject all three predicted states. The closed-loop
benchmark compares direct converged-state prediction against residual prediction from solver-native references on a frozen test set of non-
magnetic crystals, using paired convergence, iteration, and SCF-loop timing measurements. Injecting the exact converged density
matrix or
Hamiltonian as an oracle upper bound cuts the median SCF count from 16 to one, revealing substantial acceleration headroom. Among learned inputs, direct charge-density prediction (Charge3Net-E3) accelerates about 91% of paired
crystals, saves a median of three SCF iterations, and yields a $1.18\times$ SCF-loop speedup. In contrast, the tested residual-density and
matrix initializers do not consistently improve over the standard superposition-of-atomic-densities baseline. These results establish that target-space accuracy alone is insufficient: a learned initializer must also be compatible with the nonlinear solver trajectory, and its utility must be measured in the loop.
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General Relativity and Quantum Cosmology
Dynamical Structure of Einasto Dark Matter Wormholes: Thin-Shell Stability and Particle Transitions
M. Yousaf, Faisal Javed, Gulzoda Rakhimova et al. (+2 more)
In this manuscript, we develop topologically charged static and spherically symmetric wormhole (WH) configurations in Einstein
gravity by employing the Einasto dark matter profile to construct an analytic shape function. The resulting spacetime satisfies the fundamental traversability conditions, while the matter sector exhibits localized violations of energy conditions near the throat, indicating confined exotic matter content. We analyze
equilibrium through the TOV framework, revealing a non-
equilibrium force competition in which hydrostatic and anisotropic contributions self-organize to sustain static configurations within specific parameter domains. Stability is examined via the anisotropy parameter and further extended to linearized radial perturbations of the surrounding shell, uncovering parameter-dependent stability windows that characterize the system's nonlinear response. A detailed dynamical analysis shows that the monopole charge parameter significantly restructures the effective potential landscape, modifying
curvature and inducing qualitative transitions in particle motion. The coupled interplay between monopole charge, angular momentum, and particle energy governs a nonlinear transition from tightly wound quasi-bound states to unbounded scattering trajectories. This transition reflects an emergent dynamical phase structure in the WH spacetime. Furthermore, the complexity factor exhibits strong localization near the throat and vanishes asymptotically, indicating that structural complexity is confined to the inner nonlinear regime, whereas a volume integral quantifier is employed to estimate the total exotic matter content required to sustain the configuration.
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All authors M. Yousaf, Faisal Javed, Gulzoda Rakhimova, Farkhod Botirov, Farruh Atamurotov
Quantum Physics
A train–prune–readout–rewrite workflow for interpretable quantum learning
Siran Zhang, Shuming Cheng, Xiang Li et al. (+1 more)
AI for Science aims not only to predict complex physical systems from data, but also to extract mathematical structure and physically testable representations from learned models. Here, a train–prune–readout–rewrite workflow is developed that separates physical-domain grounding from three increasingly stringent analysis claims: algebraically equivalent readout of a trained predictor, compact teacher-faithful symbolic rewriting on the sampled physical domain, and transformation-based tests of learned internal representations. The workflow is implemented with complex-valued Kolmogorov–Arnold networks, whose explicit edge functions enable post-
pruning analytic readout of the retained computation. In analytically controlled single-
qubit tasks, rewriting recovered the quadratic structure of purity, whereas von Neumann
entropy yielded only a domain-bounded symbolic surrogate; physics-aligned variable grouping preserved symbolic fidelity. For two-
qubit entanglement-related tasks, shared learning exposed a common internal representation whose physical content was interrogated directly. Local-
unitary transformations rejected a direct invariant-coordinate interpretation, while fixed-decoder transfer showed that the shared activation carries Pauli-correlation information in a transformation-consistent form. Task-related invariant spectral features were subsequently recovered through low-order nonlinear readouts. Separate predictive tests retained high accuracy for three-
qubit classification and controlled ten-
qubit purity regression with over one million complex inputs. These results establish an evidence-resolved framework for distinguishing physical grounding, readable computation, faithful symbolic compression and transformation-tested physical structure in constrained complex-valued scientific learning.
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All authors Siran Zhang, Shuming Cheng, Xiang Li, Jinyi Liu
High Energy Physics (Phenomenology)
Heavy-quark expansion at leading power for local QCD operators in gradient flow
Yun-Han Gui, Xin-Qiang Li, Xiang-Peng Wang et al. (+1 more)
Gradient flow provides finite-flow-time QCD operators, whose
matrix elements can be computed on the
lattice and related to renormalized QCD operators through perturbative matching. We develop a matching framework that relates local flowed-QCD operators to the corresponding operators in heavy-
quark effective theory (HQET) at leading power in the heavy-
quark expansion. By combining the flowed-QCD-to-HQET matching relation with conventional QCD-to-HQET matching, we obtain a mass-dependent conversion relation between flowed-QCD operators and renormalized QCD operators. As a first application, we calculate the one-loop matching coefficients for heavy-light currents and derive the corresponding conversion coefficients. We find that heavy-
quark mass effects in the matching and conversion coefficients can be numerically important when the flow scale is not much larger than the heavy-
quark mass scale, highlighting the need for mass-dependent matching in precision
lattice applications of gradient flow to heavy-
quark observables.
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All authors Yun-Han Gui, Xin-Qiang Li, Xiang-Peng Wang, Ya-Dong Yang
Materials Science
Navigating Sparse Singlet Fission Chemical Space: An Intelligent Generative-Predictive Paradigm
Longfei Lv, Li Fu, Si Zhou et al. (+2 more)
Singlet fission (SF) offers a promising route to surpass the Shockley-Queisser limit by converting a photoexcited singlet
exciton into two triplet
excitons, thereby enhancing photovoltaic energy conversion efficiency. However, realizing efficient SF process requires stringent energetic requirements among low-lying excited states that render SF molecules intrinsically rare within the vast chemical space. This extreme sparsity presents a grand challenge for molecular discovery. Due to low hit rates and trial-and-error computational waste on nonviable structures, conventional high-throughput virtual screening faces significant constraints, even when accelerated by machine learning models. Here, we establish a synergistic generative-predictive framework for the targeted inverse design of SF molecules by integrating a structure generator, a properties predictor and a multi-criteria validation workflow. By continuously coupling generative exploration with SF predictive models, the framework progressively enriches SF species and achieves a success rate of approximately 90% in generating molecules that satisfy the target SF energetic criteria. High-throughput evaluation of about 100 million generated structures with time-dependent density functional theory (TDDFT) validation of just a random 1% subset confirmed a 90.8% success rate for SF candidates. All together, we constructed an SF database of 283,559 candidates with favorable energetics of excited states and synthetic accessibility. From it, we identified a key fragment strongly associated with the requirements for SF, namely, CN([O])N(C)[O]. These findings establish an efficient route for overcoming the sparsity difficulty in SF molecular discovery and provide interpretable design principles for the development of novel excited-state functional materials.
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All authors Longfei Lv, Li Fu, Si Zhou, Lingzhi Zhao, Jijun Zhao
Materials Science
Demonstrate of High-Performance Top-Gate ALD Crystalline In2O3 Transistor Enabled by Lattice-Matched HfO2 and In2O3 Heterostructure
Kai Jiang, Chen Wang, Ziheng Wang et al. (+2 more)
In this work, we demonstrate high-mobility top-gate (TG) atomic-layer-deposited (ALD) crystalline In2O3 transistors through simultaneous interface and crystallinity engineering. First, a HfO2/In2O3/HfO2 stack is employed, enabling epitaxial-like crystallization of the ultrathin In2O3 channel, because of the
lattice matching between monoclinic phase HfO2 and cubic phase In2O3. Second, an oxygen-rich gate
insulator process is applied using high-dose O3 precursor and elevated deposition temperature, effectively suppressing oxygen scavenging during gate dielectric deposition, significantly reducing interfacial defect formation. Third, the homogeneous In-O bonding network in crystalline In2O3 exhibits substantially enhanced resistance to oxygen scavenging by source/drain contacts, which significantly improves the immunity to threshold voltage (VTH) roll-off at short channel length compared to amorphous In2O3. As a result, high-performance TG long-channel In2O3 transistors are achieved with a high mobility of 163 cm2/V s and a steep subthreshold slope of 64 mV/dec. High-performance TG short-channel In2O3 transistors with high ION of 1650 {\mu}A/{\mu}m at VD of 1 V, large on/off ratio over 1010 and VTH of -0.27 V are demonstrated. These results establish
lattice-engineered crystalline In2O3 as an effective strategy for high-mobility, aggressively scaled TG
oxide transistors suitable for BEOL-compatible applications.
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All authors Kai Jiang, Chen Wang, Ziheng Wang, Zhiyu Lin, Mengwei Si
Astrophysics of Galaxies
A comparative analysis of the long-term optical variability characteristics of narrow and broad-line Seyfert 1 galaxies at z > 0.8
Aratrika Dey, Stalin C.S., Akshith S. et al. (+1 more)
We present the results on a comparative analysis of the long-term optical variability characteristics of high-
redshift narrow-line Seyfert 1 (NLSy1)
galaxies and broad-line Seyfert 1 (BLSy1)
galaxies. Our sample spanning the
redshift range of $0.8 < z < 2.6$, comprises 2490 NLSy1 and 2490 BLSy1
galaxies matched in the optical brightness$-$
redshift plane. We used V-band data from the Catalina Real-Time Transient Survey covering a baseline of 5$-$9 years, and g, r, and i-band data from the Zwicky Transient Facility spanning 5 to 6 years. To characterise variability we estimated the amplitude of variability ($\sigma_m$). We found that NLSy1
galaxies generally exhibit lower $\sigma_m$ compared to BLSy1
galaxies. In both the NLSy1 and BLSy1
galaxy samples, we observed a wavelength dependent variability using data from Zwicky Transient Facility, with $\sigma_m$ gradually increasing towards shorter wavelengths. We found an anti-correlation between $\sigma_m$ and Eddington ratio in the g, r, and i bands for BLSy1
galaxies, whereas this anti-correlation is observed only in the r and i bands for NLSy1
galaxies. For both NLSy1 and BLSy1
galaxies, we found no correlation between $\sigma_m$ in g, r, and i bands and black hole mass. In both the samples, we found that $\sim$90% of the sources showed a bluer when brighter trend. We found no significant time lag between variations in g and r bands in both BLSy1 and NLSy1
galaxies. The observed long-term trends in the optical light curves of our high
redshift sample of BLSy1 and NLSy1
galaxies could be driven by variations in the
accretion disk.
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All authors Aratrika Dey, Stalin C.S., Akshith S., Suvendu Rakshit
Plasma Physics
Two-length spatial correlation function of turbulence in TCV
Olivier Panico, Pascale Hennequin, Sascha Rienäcker et al. (+4 more)
Spatial correlation functions of density fluctuations are measured in the Tokamak à Configuration Variable (TCV) using a dual-channel Doppler backscattering (DBS) diagnostic. In certain cases, the spatial correlation function exhibits two characteristic length scales. By analogy with nonlinear reduced simulations, the presence of two correlation lengths may be indicative of avalanche-like transport. The correlation functions obtained from DBS are compared with those from short-pulse reflectometry measurements and show reasonable agreement. Both short- and long-range correlations are measured in the same
plasma geometry for different heating powers. Short-scale correlation lengths are found to be on the order of 3-5 Larmor radii, while large-scale correlations extend over approximately 5-15 Larmor radii. The correlations are found to decrease towards the very edge of electron cyclotron heated discharges, coinciding with a narrow Er well.
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All authors Olivier Panico, Pascale Hennequin, Sascha Rienäcker, Oleg Krutkin, Benoit Labit, Yanick Sarazin, the TCV team
Physics Education
Data-driven modeling in the introductory physics laboratory: Scaling analysis and data collapse in the specific heat of water experiment
Kazumasa Kushida, Tomohiro Oda and Koji Yamaguchi
We present a data-driven redesign of the classic specific-heat-of-water experiment that uses scaling analysis and data collapse for model construction rather than beginning with a previously established thermodynamic formula. The activity combines structured experimental and analytical guidance with instructor-mediated questioning, while the thermodynamic description is deliberately postponed. Students collect temperature-time data under different conditions and obtain a collapsed relation between the mass-normalized energy input and temperature rise through successive rescaling. They formulate an empirical model from this relation and test it using additional data not included in its construction. In the post-experimental discussion, the thermodynamic description shows that the fitted empirical constant characterizes the combined response of the water and calorimeter and approximates a quantity that depends weakly on water mass. Reanalysis of the mass-dependent data separates the two contributions, with limited precision over the available water-mass range. The copper cup is an intentional feature of the instructional design: its contribution is large enough to require physical interpretation but varies little enough over the explored mass range for the data to collapse approximately onto a single relation. The same apparatus thereby supports empirical model construction, thermodynamic interpretation, and separation of the component contributions.
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General Relativity and Quantum Cosmology
Inspiral waveforms of charged compact binaries and observational constraints
Zi-Han Zhang, Wen-Hong Ruan, Tan Liu et al. (+1 more)
Electric charges carried by compact objects can affect binary dynamics and imprint characteristic signatures on gravitational-wave signals. We derive next-to-leading-order post-Newtonian frequency-domain waveforms for charged compact binaries in both the gravitational-quadrupole and electric-dipole dominated regimes, including electromagnetic corrections beyond leading-order electric-dipole radiation that reduce the degeneracy between the component charge-to-mass ratios. Using gravitational wave events from GWTC-5.0, we place constraints on the charge-to-mass ratio and mass of each component of the binary system.
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All authors Zi-Han Zhang, Wen-Hong Ruan, Tan Liu, Zong-Kuan Guo
High Energy Physics (Phenomenology)
Did LZ see modified gravity?
Basabendu Barman
We investigate whether the recently reported high-energy
nuclear recoil event by the LUX-ZEPLIN (LZ) collaboration can be interpreted as a signal of freeze-in dark matter (DM) in a non-standard cosmological history. We consider DM production from the Standard Model thermal bath during an era of modified expansion preceding Big Bang nucleosynthesis. Requiring consistency with the observed DM abundance, cosmological and
collider constraints, we identify viable parameter regions that can accommodate the LZ event. Our results demonstrate the potential of direct detection experiments to probe non-standard cosmological histories and, more broadly, alternative theories of
gravity.
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Optics
Enhanced Spin-Orbit Interaction of Light through Complex Fresnel Reflection
Dileep Kumar Upadhyay and Nirmal K. Viswanathan
Spin-orbit interaction (SOI) of light manifests as the generation of a
spin-dependent
vortex beam and the
spin-
Hall effect when a
spin-polarized beam interacts with an optical interface at normal and oblique incidence, respectively. The weak SOI limits its widespread use for quantifying physical quantities in various applications. We demonstrate a significantly enhanced SOI effect, approaching the strong-coupling regime, by retroreflecting a nonparaxial focused beam of light at a multilayer dielectric mirror. The large difference in angle-of-incidence-dependent Fresnel reflection coefficients (r-TE, r-TM ) introduced by the mirror simultaneously enhances the
spin-orbit-converted
vortex-beam amplitude and the
spin-
Hall effect in the reflected beam. Near-field superposition of the orthogonal polarization components in the reflected beam yields a spatially nonuniform beam field with C-, V-, and L- polarization singularities. These topological features are mapped and are used to demonstrate the transverse and 3D
spin-
Hall effect in the focal region. The superposition of enhanced optical near-fields and the lossless broadband nature of the mirror reflectivity are expected to enable a variety of polarization
topologies and to tailor their features via designed mirror reflectivities.
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Materials Science
Ionic-Radius Mismatch as a Structural Lever for Tuning Phase Transitions and Luminescent Thermometry
A. Javaid, M. Szymczak, A. Sieradzki et al. (+1 more)
The widespread implementation of luminescence thermometers requires a comprehensive understanding of the structural factors governing their thermometric performance. Establishing such structure-property relationships is essential for the rational design of sensing materials with application-tailored characteristics. This is particularly relevant for phase-transition-based luminescence thermometers, which offer exceptionally high relative sensitivities. The systematic analysis of K3Lu(PO4)2:Eu3+ demonstrates that introducing co-dopant ions with a controlled ionic-radius mismatch provides an effective strategy for tailoring phase-transition characteristics. This approach enables both the phase-transition temperature and thermal operating range to be controlled. Specifically, the transition temperature shifts from 210 K for K3Lu(PO4)2:Eu3+ to 310 K for K3Lu(PO4)2:Eu3+,10%La3+, while the operating range broadens from 30 to 60 K. Importantly, linear correlations between the ionic-radius mismatch parameter, {\Omega}, and the phase-transition temperature, enthalpy, and
entropy provide a quantitative framework for controlling the thermodynamics of the transition through compositional engineering. Beyond luminescence thermometry, these relationships establish a general strategy for designing materials exhibiting first-order phase transitions with tailored thermodynamic characteristics, opening opportunities for their optimization across a broad range of functional applications.
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All authors A. Javaid, M. Szymczak, A. Sieradzki, L. Marciniak
Instrumentation and Methods for Astrophysics
Nii-MALA: A Fast Metropolis-Adjusted Langevin Sampler with Radial Velocity Benchmarks
Jian Jiao, Sheng Jin, Wenxin Jiang et al. (+1 more)
Markov chain Monte Carlo is widely used for model assessment and parameter fitting in astronomy and astrophysics, leading to numerous ready-to-use packages implementing various sampling techniques. For large-scale analyses involving many individual targets, computational efficiency becomes paramount, as it dictates the overall runtime. We introduce Nii-MALA, a high-performance C implementation of the Metropolis-Adjusted Langevin
Algorithm, which leverages Message Passing Interface for parallelization and incorporates automatic differentiation backends for gradient evaluation. The code offers flexible control via a configuration file, allowing users to specify the proposal step sizes for all model parameters across parallel chains. We validate its effectiveness on 15- and 30-dimensional Gaussian distributions and a bimodal distribution, and further
benchmark it against several other codes using radial velocity data from 51 Pegasi b. Our
benchmarks confirm the efficiency of Langevin sampling over random-walk sampling in obtaining the effective sample size, particularly as the dimensionality of the target function increases. This algorithmic advantage can be effectively leveraged when paired with an efficient automatic differentiation library. However, for complex functions commonly encountered in astronomy—such as radial velocity orbital fitting—the derivative-dependent Langevin sampler shows lower efficiency than parallel tempering or alternative sampling approaches, as revealed by effective sample size analysis.
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All authors Jian Jiao, Sheng Jin, Wenxin Jiang, Dong-Hong Wu
High Energy Physics (Theory)
Hyperbolic monopole-type solutions in $SU(3)$ Yang-Mills theory
Yuki Amari
We construct $S^1$-invariant solutions of the $SU(3)$ pure Yang-Mills theory on four-dimensional Euclidean space using the Cho-Faddeev-Niemi decomposition and a harmonic map from $S^2$ into the flag
manifold $F_3=SU(3)/U(1)^2$. The resulting ansatz reduces the full Yang-Mills equations to coupled radial equations. Solving the coupled equations, we derive two types of solutions: analytic self-dual solutions interpreted as noninteracting clusters of
hyperbolic monopoles and non-self-dual numerical solutions that can be interpreted as
hyperbolic monopole-antimonopole bound states. In the large-mass limit of the
hyperbolic monopole-antimonopole bound states, their normalized action approaches the energy of the corresponding non-Bogomolny $SU(3)$ monopole in flat space.
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High Energy Astrophysical Phenomena
Hardware-aware quantum attention for fast radio burst identification
Li He, Xuan Yang, Feng Xiong et al. (+10 more)
Fast
radio bursts (FRBs) are millisecond-duration extragalactic pulses whose discovery requires searches over large signal-parameter spaces and the rejection of candidate sets dominated by
radio-frequency interference and noise. Integrating
quantum processors into FRB searches requires a workflow connecting telescop data to hardware-compatible models. Here we develop a pipeline that converts raw search-mode PSRFITS data into dynamic-spectrum segments and identifies FRB-like signals using a hybrid
Quantum Vision Transformer (QViT). On labelled FAST data, the selected QViT achieves a mean accuracy of 94.00% and recall of 98.30%, with similar performance to a compact classical
Vision Transformer. Recall reaches 97.11% on an FRB source excluded from training and model selection. Real-device execution on 82 segments yields a mean simulator-hardware Hellinger fidelity of 0.9161 +/- 0.0074. The workflow connects raw
telescope data to
quantum-assisted identification and provides an experimental basis for assessing the measurement requirements that must be addressed before survey-scale deployment.
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All authors Li He, Xuan Yang, Feng Xiong, Songbo Zhang, Qiuhao Chen, Yuchen He, Yunxiang Yang, Jun Lu, Claudio Furtado, Amilcar R. Queiroz, Xinping Deng, Yang Wu, Xuefeng Wu
General Relativity and Quantum Cosmology
Interior gravitational perturbations to naked singularities of a scalar field
Junbin Li and Tingting Li
For the $k$-self-similar naked singularity solutions of Einstein–scalar field equations constructed by Christodoulou, we construct a family of interior gravitational perturbations leading to trapped surface formation that remain large but finite at the threshold Hölder regularity, while converging to zero in all regularities below the threshold. This extends the interior spherically symmetric result below the threshold in \cite{Li25} to non-spherically symmetric setting. We further construct a genuinely localized family of perturbations whose angular support shrinks to a single point, with smooth convergence to zero away from that point. This exploits the additional angular freedom available beyond spherical
symmetry. Moreover, when measured instead in Sobolev regularity, such genuinely localized family of perturbations still converges to zero in all regularities below the same threshold.
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Materials Science
Re4+ Luminescence as a Highly Sensitive Alternative to Ruby for Optical Pressure Sensing
Yeshan Wu, Maja Szymczak, Lukasz Marciniak et al. (+5 more)
Luminescence-based remote pressure sensing provides a powerful approach for pressure determination under conditions where conventional contact methods are difficult to implement. Although ruby remains the undisputed gold standard among luminescent pressure indicators, its relatively low pressure sensitivity and susceptibility to temperature variations represent important limitations. Therefore, in this work, Cs2HfCl6:Re4+ is proposed as an alternative luminescent pressure indicator exhibiting a 15-fold higher pressure sensitivity (6.93 nm GPa-1) than ruby while maintaining a comparable thermal sensitivity, making it a particularly attractive material for optical manometry. Furthermore, Cs2HfCl6:Re4+ enables ratiometric pressure readout, providing a high relative pressure sensitivity reaching 175.1% GPa-1. To the best of our knowledge, this work represents the first demonstration of Re4+ luminescence for pressure sensing, introducing a new class of luminescent pressure indicators and opening new opportunities for the development of highly sensitive optical manometers based on Re4+-activated materials.
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All authors Yeshan Wu, Maja Szymczak, Lukasz Marciniak, Yifei Yu, Shuailing Ma, Tian Cui, Laihui Luo, Peng Du