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Physics

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Tuesday 14 July

High Energy Astrophysical Phenomena

Constraining the High-Density Equation of State with Present and Future NICER Observations Using Physics-Informed Regularized Machine Learning

Utkarsh Atul Deshmukh, Asim Kumar Saha and Ritam Mallick

The precise mass and radius measurements of neutron stars by NICER have significantly advanced our ability to constrain the properties of matter at supranuclear densities. In this work, we develop a physics-informed regularized conditional Invertible Neural Network (cINN) that bijectively maps mass–radius posterior distributions directly onto the corresponding central energy density and pressure, eliminating the need for explicit high-dimensional parameter sampling. The physics-informed regularisation guarantees that all inferred solutions satisfy causality and thermodynamic stability, ensuring physically consistent predictions without explicit forward modelling. We demonstrate that the framework accurately reconstructs central EoS posteriors for NICER-like observations while preserving the mapping between macroscopic stellar observables and the microscopic properties of dense matter. Exploiting the computational efficiency of the cINN, we perform a systematic optimisation study of 62,400 simulated mass–radius observations to identify the most informative targets for constraining the high-density EoS. We find that the constraining power depends strongly on the location of the observation in the mass–radius plane, with an optimal strategy that alternates between compact high-mass stars and extended intermediate-mass stars, reducing the uncertainty in the inferred EoS by up to $\sim 9\%-10\%$ relative to the current NICER baseline. These results establish physics-informed invertible neural networks as a powerful framework for rapid, physically consistent inference of dense-matter properties from present and future multi-messenger observations.
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Mesoscale and Nanoscale Physics

Geometric Spin-Orbit Coupling Resolves the Contradictory CISS Effect in Chiral Single Molecules

Shu-Zheng Zhou, Xi Sun, Kai-Yuan Zhang et al. (+1 more)

Some studies have reported clear chirality-induced spin selectivity (CISS) effect in four classes of chiral single molecules with remarkable spin polarization. In contrast, a recent high-precision measurement involving nearly a thousand individual tests failed to detect significant CISS signals in the same molecular systems (J. Am. Chem. Soc. 2025, 147, 25043). These conflicting results cast doubt on whether CISS truly occurs in these chiral systems at the single-molecular level. To resolve this discrepancy, we develop a theoretical framework incorporating geometric spin-orbit coupling and environmental decoherence, enabling systematic study of the CISS in four chiral single molecules with distinct geometries and sizes. Our calculations show that the CISS effect is completely suppressed in both strong-coherence and strong-decoherence regimes, but becomes pronounced in the intermediate-decoherence regime, where observable spin polarization emerges. In the strong-coherence regime, both electron-electron interaction and electron-vibration coupling enhance the CISS effect: the former is more effective in large molecules, whereas the latter plays a more significant role in smaller ones. Increasing temperature further enhances spin polarization. The proposed mechanism unifies contradictory experimental observations and reveals how the CISS effect evolves from regular helical (helical symmetric) to irregular helical (point-symmetric or axially symmetric) chirality. This framework thus provides a basis for unifying CISS phenomena across single-molecule systems, regardless of their specific molecular configurations or symmetry classes.
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All authors Shu-Zheng Zhou, Xi Sun, Kai-Yuan Zhang, Hua-Hua Fu

Instrumentation and Detectors

Influence of compaction pressure on the impedance of Gadolinium Doped Ceria electrolytes for IT-SOFCs

Renato A. N. de Oliveira, Celeste Z.A. Aquino, Magna Monteiro Schaerer et al. (+15 more)

Gadolinium doped ceria (GDC) is one promising oxygen-ion conducting ceramic electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs), due to its high ionic conductivity at reduced operating temperatures, favorable defect chemistry, and compatibility with a broad range of electrode materials [1,2]. Despite extensive understanding of its intrinsic ion transport mechanisms, the influence of ceramic processing parameters on the effective electrical behavior of polycrystalline GDC electrolytes remains an active topic for investigation [3-5]. In particular, processing steps that govern green body formation and sintering can strongly affect microstructural features such as density, grain size, grain boundary character, and residual porosity, which in turn determine the macroscopic conductivity [4-6]. In this work, dense GDC ceramic pellets were fabricated under systematically varied isostatic compaction pressures ranging from 49 to 140 MPa, followed by sintering at 1350 C for four hours under identical thermal conditions. Platinum electrodes were deposited on both sides of the pellets by electron-beam deposition, and the electrical properties were characterized by electrochemical impedance spectroscopy (EIS) over a wide temperature range. The results demonstrate a dependence of the impedance with respect to compaction pressure.
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All authors Renato A. N. de Oliveira, Celeste Z.A. Aquino, Magna Monteiro Schaerer, Rafael Galiza Yoshimura, Liliana Mogni, Maurico Arce, Diego G. Lamas, Lucia Toscani, Maria Belén Arcentales Vera, Esteban Elvis Asto Ramos, Marcia Carvalho de Abreu Fantini, Taofeeq Oladayo Bello, Tereza da Silva Martins, Danilo Waismann Losito, James Moraes de Almeida, Valeria Spolon Marangoni, Leopoldo Suescunand, Santiago Figueroa

Quantum Gases

Standard basis operator method for ground-state and temperature properties of single and two-component Bose-Hubbard model

Oliwier Urbański and Tomasz P. Polak

We formulate an improved standard basis operator (SBO) method for the single and two-component Bose-Hubbard model in three dimensions. In the first case, nonzero temperature predictions are qualitatively and quantitatively enhanced by taking into account necessary number of on-site states, not just three as in previous works. Performance of the final numerical calculations is also improved by asymptotic analysis of the self-consistent equations near the critical line. Obtained results are compared with Monte-Carlo, tensor networks, Quantum Rotor Approach and experimental data. In the two-component case, SBO generalizes rather poorly, being able to account for intra-species thermal and quantum fluctuations, but not the inter-species ones. Deeper reasons for this situation are discussed. Still however, non-trivial deformation of the phase diagrams is predicted, together with first-order phase transitions steered by the changes in chemical potential.
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High Energy Physics (Phenomenology)

Interpreting the Newly Observed $\Xi(1720)$ State in the Spin-$\frac{3}{2}$ $\Xi$ Spectrum

K. Azizi, Y. Sarac and H. Sundu

We analyze the low lying spin-$\frac{3}{2}$ $\Xi$ spectrum by means of the two point QCD sum rule approach. The analysis is motivated by the BESIII observation of the $\Xi(1720)$ resonance, reported with mass $1721.0\pm5.2_{\mathrm{stat.}}\pm3.4_{\mathrm{syst.}}~\mathrm{MeV}$ and favored quantum numbers $J^P=\frac{3}{2}^{+}$. In this framework, we include the $1S$, $1P$, $2S$ and $2P$ configurations as possible low lying spin-$\frac{3}{2}$ cascade states. The extracted masses are $1527.53\pm111.38~\mathrm{MeV}$, $1615.30\pm50.98~\mathrm{MeV}$, $1727.52\pm42.39~\mathrm{MeV}$ and $1803.71\pm64.50~\mathrm{MeV}$ for the $1S$, $1P$, $2S$ and $2P$ states, respectively. The mass obtained for the $2S$ configuration agrees with the BESIII value within uncertainties and favors the assignment of $\Xi(1720)$ as the first radial spin-$\frac{3}{2}$ excitation of the $\Xi$ baryon.
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Quantum Physics

Thermal Activation of Divergent Distillable Entanglement under Non-Abelian Strong Symmetry

Shuai Zeng

Heating usually destroys quantum entanglement. We show that thermalization constrained to a non-Abelian strong-symmetry sector can instead generate a distillable resource that diverges with system size. In an exactly solvable local dimer chain, entanglement across an equal bipartition is exactly zero at $T=0$, whereas every fixed $T>0$ yields $E_D=\frac12\log_2 N+C(T)+o(1)$. Measurements of the two half-chain representation labels convert thermally populated non-Abelian sectors into standard ebits. More generally, for global-singlet thermal states of finite-range, uniformly bounded, locally $SU(2)$-invariant chains, there is a nonzero high-temperature interval in which the protocol yield satisfies $Y_N=\frac12\log_2 N+O_\beta(1)$ and $E_D\geq Y_N$. For the dimer chain, the full finite-size onset is governed by a universal Bessel-function crossover with $T_*(N)=\Delta/[\ln N+O(1)]$. Exact diagonalization of a frustrated $J_1$-$J_2$ chain shows the expected finite-size signatures. Thus thermal fluctuations can create entanglement across a macroscopic cut and convert it into an unbounded operational quantum resource.
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Astrophysics of Galaxies

Perturber-Driven Dynamics of Supermassive Black Hole Binaries in Galaxy Merger

Julian Chan, Alessia Gualandris, Walter Dehnen et al. (+1 more)

The orbital eccentricity of massive black hole binaries (MBHBs) at binary formation shapes the stochastic gravitational-wave background (GWB) detectable by pulsar timing arrays (PTAs). Previous $N$-body simulations show large run-to-run scatter in this quantity, dominated by Poisson noise, raising the question of whether physical substructure adds genuine astrophysical stochasticity. We test this with high-resolution re-simulations of a major merger from IllustrisTNG100-1, evolved with the Griffin $N$-body code. A no-perturber control is compared with two matched suites in which $f_{\mathrm{target}}=0.1$ of the primary bulge mass is redistributed into equal-mass perturbers of $10^7,M_\odot$ ($\mu_{\mathrm{p}}\approx3.2\times10^{-3}$) and $10^8,M_\odot$ ($\mu_{\mathrm{p}}\approx3.2\times10^{-2}$), with four realisations per scenario. The control gives $\sigma_e\approx0.11$, consistent with the Poisson noise floor at this resolution. The $10^7,M_\odot$ case gives $\sigma_e\approx0.115$, indistinguishable from the control, whereas the $10^8,M_\odot$ case gives $\sigma_e\approx0.26$, a factor of $2.4$ above the floor, although statistically marginal given only four realisations. This excess scatter coincides with larger event-aligned residuals in orbital energy and angular momentum and stronger torque spikes, consistent with near-impulsive perturber–MBHB encounters. In binary–single scattering theory, the transition is set by the perturber–MBHB mass ratio $\mu_{\mathrm{p}}$: the $10^7,M_\odot$ case remains diffusive, whereas the $10^8,M_\odot$ case approaches the near-impulsive regime. Because the expected perturber population in massive ellipticals lies mostly below this regime, perturber-driven eccentricity randomisation is unlikely to affect GWB-relevant MBHB mergers.
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All authors Julian Chan, Alessia Gualandris, Walter Dehnen, Justin I. Read

Applied Physics

Are gate-all-around 2D CFETs the optimal architecture for the A2 node and beyond?

Fengben Xi, Gautam Gaddemane, Anshul Gupta et al. (+15 more)

As logic scaling enters the angstrom era, vertically stacked complementary field-effect transistors (CFETs) based on atomically thin two-dimensional (2D) semiconductors offer a potential route to extend device scaling beyond the A2 node. Here, we develop an A2-oriented 2D CFET integration flow with a CPP of 36 nm and Lg of 10 nm and present initial demonstrations of several key process modules. Despite their atomically thin channels, 2D GAA CFETs do not provide a contacted poly pitch scaling advantage over Si GAA CFETs at the A2 node, because contact formation constraints impose a similar minimum CPP of 36 nm. We also combine a critical assessment with a multiscale power-performance-area (PPA) evaluation framework spanning quantum transport simulations, compact-model generation, A2-targeted 2D CFET gate-all-around (GAA) integration-flow definition, parasitic extraction and circuit-level benchmarking. Our analysis, however, shows that the expected benefits of 2D GAA CFETs are strongly constrained by non-idealities, in particular high contact resistance and dominant layout-induced parasitic capacitances. Although architectural optimization can improve the Ieff/Ceff ratio, the associated rise in absolute capacitance limits circuit-level gains. Meaningful progress will require co-optimization of contacts, transport and parasitics, together with 2D-specific CFET architectures.
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All authors Fengben Xi, Gautam Gaddemane, Anshul Gupta, Sheng Yang, Aryan Afzalian, Quentin Smets, Maarten Van de Put, Kaustuv Banerjee, Tom Schram, Devin Verreck, Ward Janssens, Juergen Boemmels, Xiangyu Wu, Thomas Chiarella, Jérôme Mitard, Gouri Sankar Kar, Geert Hellings, Cesar Javier Lockhart de la Rosa

Astrophysics of Galaxies

Radar-Chart Analysis of Star-Formation Quenching Stages Across Circular Velocity Curve Classes in Nearby CALIFA Galaxies

Veselina Kalinova and Dario Colombo

We analyze the circular velocity curves of 215 non-active galaxies from the Calar Alto Legacy Integral Field spectroscopy Area survey. Using radar-chart analysis, we compare two classification schemes: the circular velocity curve classification and the quenching classification. We find a systematic progression from slow-rising to flat, round-peaked, and sharp-peaked curves that mirrors the transition from star-forming to fully retired systems. Star-forming galaxies are mainly slow-rising and flat, whereas fully retired galaxies are predominantly round-peaked and sharp-peaked, with intermediate stages showing a gradual shift. Overall, advanced quenching stages are associated with more centrally peaked curves and higher outer velocities (i.e., velocities along the flat part of the curve), indicating increasingly concentrated central mass distributions and more massive disks of the galaxies.
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High Energy Astrophysical Phenomena

Coupled Shock Cooling and Radioactive Heating in the Type IIb Supernova SN 2024aecx: An Extended Envelope and Rapid Optical Decline

Na Wei, Yu-Hao Zhang, Liang-Duan Liu et al. (+4 more)

SN~2024aecx is a nearby, rapidly evolving stripped-envelope supernova with a prominent double-peaked ultraviolet–optical light curve. We model its multiband evolution with an extended version of TransFit, in which the early shock-cooling emission and the subsequent radioactive heating are treated within a single time-dependent radiative diffusion calculation. To describe the stratified ejecta expected for a Type~IIb progenitor, we adopt a compact inner ejecta connected to a dilute extended outer envelope and fit the outer density slope directly from the early light curve. The model reproduces the short-lived first peak, the rise to the radioactive main peak, and the overall multiband evolution. We infer an effective outer radius of $R_0=109.6^{+6.6}_{-3.5}\,R_\odot$, an ejecta mass of $M_{\rm ej}=2.14^{+0.21}_{-0.19}\,M_\odot$, a nickel mass of $M_{\rm Ni}=0.050\pm0.002\,M_\odot$, and a steep outer density slope of $n_{\rm out}=13.33^{+0.11}_{-0.12}$. The steep outer profile favors a low-mass extended envelope, while the low ejecta mass explains the rapid evolution of the main peak. However, a control model with standard $\gamma$-ray leakage fades too slowly after maximum. We therefore introduce an effective optical-output factor to quantify the additional late-time suppression of the ultraviolet–optical luminosity. These results support the shock-cooling plus radioactive-heating interpretation of SN~2024aecx, but show that its rapid optical decline requires physics beyond the simplest radioactive-diffusion prescription.
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All authors Na Wei, Yu-Hao Zhang, Liang-Duan Liu, Guang-Lei Wu, Jing-Yao Li, Yun-Wei Yu, Ning-Chen Sun

Solar and Stellar Astrophysics

Symbiotic binaries in the Gaia data. II. Symbiotic candidates from general variability classification in DR3

Jaroslav Merc, Lionel Mulato, Joanna Mikołajewska et al. (+7 more)

We investigate the reliability of the symbiotic star class in the general variability classification of Gaia DR3 and search for new genuine symbiotic systems among the objects assigned to this category. The sample contains 649 sources, including 246 previously known symbiotic stars, 61 literature candidates, and 339 new candidates proposed by the Gaia variability pipeline. Diagnostics based on the Gaia colour-magnitude diagram, near-infrared photometry, and the pseudo-equivalent width of H$\alpha$ indicate that a large fraction of the new candidates are likely contaminants, predominantly pulsating red giants. To quantify the contamination, we constructed a Random Forest classifier trained on confirmed symbiotic stars and on Mira and semi-regular variables, using Gaia photometry, variability parameters, H$\alpha$ measurements from XP spectra, and infrared colours. The classifier reaches a balanced accuracy of $\approx$0.94 and efficiently separates most symbiotic binaries from single evolved stars, leaving only eight strong candidates among the 339 newly proposed objects. Follow-up spectroscopy confirms three new symbiotic stars through the presence of high-excitation emission lines, while several additional objects remain possible symbiotics. Our results show that the Gaia DR3 variability classification efficiently recovers known symbiotic stars but has low purity due to overlap with pulsating red giants. The small number of newly confirmed systems implies that the discrepancy between predicted and observed Galactic symbiotic populations remains unresolved, although Gaia provides a powerful basis for future searches combining variability, spectroscopic indicators, and multi-wavelength data.
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All authors Jaroslav Merc, Lionel Mulato, Joanna Mikołajewska, Paul G. Beck, Ana Escorza, Michael Abdul-Masih, Stéphane Charbonnel, Olivier Garde, Pascal Le Dû, Thomas Petit

Instrumentation and Methods for Astrophysics

Status and future development of the COSMOCal Project for absolute CMB polarization calibration

Silvia Micheli, Alessia Ritacco, Alessandro Carones et al. (+36 more)

Cosmic Microwave Background (CMB) polarization measurements are pushing instrumental sensitivities to levels where calibration systematics become a dominant limitation. The large dynamic range between cosmological and Galactic emission prevents future experiments from relying only on diffuse sky measurements or standard celestial calibrators. To address this challenge, the COSmological Microwave Observations Calibrator (COSMOCal) project proposes an artificial calibration source deployed as a guest payload on a geostationary satellite, scheduled for launch by the Eutelsat group by 2030. This source will provide stable, well-characterized polarized microwave signals accessible to multiple ground-based observatories. In this work, we present the status of the project, the updated development timeline, and the refined scientific and technical requirements, defined with the observatories that plan to use this calibration source. Furthermore, we investigate the interplay between instrumental systematics and component separation in the presence of complex models of interstellar dust emission. We discuss in this paper how this can impact the recovery of the primordial signal, and whether residual calibration errors can degrade the performance of foreground cleaning algorithms.
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All authors Silvia Micheli, Alessia Ritacco, Alessandro Carones, Jonathan Aumont, Stefano Berta, Ludovico Bizzarri, François Boulanger, Andrea Catalano, Francesco Cuttaia, Anne Denis, François-Xavier Désert, Anne Laure Fontana, David González-Ovejero, Benedetta Kalemi, Nicoletta Krachmalnicoff, Samuel Leclercq, Thibaut Louis, Juan-Francisco Macías-Pérez, Bruno Maffei, Tania Mcnamara, Marina Migliaccio, Ludovic Montier, Pascal Morfin, Michel Moulin, Louise Mousset, Matteo Murgia, Ioannis Myserlis, Federico Nati, Pierluigi Ortu, Michel Pérault, Giampaolo Pisano, Tonino Pisanu, Nicolas Ponthieu, Sofia Savorgnano, Luca Terenzi, Jeanne Treuttel, Léo Vacher, Christophe Vescovi, Mario Zannoni

Astrophysics of Galaxies

Tidal Grinding of Dwarf Galaxies in Cluster Environments

Sanjaya Paudel, Suk-Jin Yoon, Tek Prasad Adhikari et al. (+4 more)

Dwarf elliptical galaxies (dEs) dominate galaxy clusters and provide key constraints on environmentally driven galaxy evolution. Here we examine whether the projected shapes of dEs retain information about their accretion and transformation histories using a homogeneous sample of 1,108 bright (m_g < 19 mag) dEs in the Virgo cluster. Based on the axis-ratio (b/a), we define flat (< 0.70) and round (> 0.74) subsamples and compare their spatial and kinematic properties. We find that flat dEs are distributed more uniformly across the cluster, whereas round dEs preferentially occupy regions of stronger tidal fields around massive (M_* > 10^{10} M_sun) galaxies. Within the central 5^\circ x 5^\circ region around the Virgo central galaxy (M87), 149 dEs have spectroscopic radial velocities compiled from public archives. In this region, the two shape classes also exhibit clear kinematic segregation: flat dEs have systematically larger line-of-sight velocity offsets from the cluster mean (median $\Delta v = 654 km/s$), whereas round dEs have smaller offsets (median $\Delta v = 414 km/s$), as expected for a more dynamically relaxed population. Flat dEs are consistent with a population that has experienced weaker tidal processing and consequently retains more flattened morphologies. By contrast, round dEs are consistent with prolonged tidal processing (“tidal grinding”) that may have transformed initially flattened systems into rounder spheroids. However, projection contamination of the round subsample may have introduced some uncertainty in the interpretation of intrinsic galaxy shapes.
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All authors Sanjaya Paudel, Suk-Jin Yoon, Tek Prasad Adhikari, Eun-Taek Gim, Myung-Hun Kim, Inhyuk Park, Nau Raj Pokhrel

Instrumentation and Methods for Astrophysics

ngVLTI: Cost and Feasibility of a Four-Telescope VLTI Expansion for Milliarcsecond-Scale Imaging

Sylvestre Lacour, Johan Kosmalski, Michael Mueller et al. (+8 more)

We assess the cost and technical feasibility of extending the Very Large Telescope Interferometer (VLTI) through the addition of four 8 m-class Unit Telescopes (UTs), an upgrade we refer to as the new generation VLTI (ngVLTI). Such an upgrade would provide a dense and homogeneous uv coverage with baselines up to 220 m, enabling true imaging at milliarcsecond angular resolution across science cases ranging from Solar System bodies to distant active galactic nuclei. Because each image is reconstructed at a single wavelength, repeating the reconstruction across the spectral channels of the instrument would deliver spectral-imaging cubes – a qualitatively new capability for the VLTI, bringing it close to the imaging power of ALMA at near-infrared wavelengths. Motivated by this scientific case, we examine a compact telescope concept consisting of a fast ($f/0.64$), segmented, parabolic primary mirror feeding a subterranean coudé focus compatible with the existing VLTI infrastructure. We summarise the optical design, which achieves diffraction-limited performance over a 1 arcmin field of view and a well-matched reimaged pupil, discuss the mechanical trade-offs behind the choice of a 60-segment, 1.2 m primary – a mirror mass of ~13.5 tons and an altitude moving mass of ~50 tons – and quantify the gravitational flexure of the telescope structure and its resulting optical sensitivity as a function of pointing elevation. We then present a back-of-the-envelope cost estimate of order 80 MEuro per telescope (2026 prices), broken down into the segmented primary, adaptive secondary, coudé train, mount, enclosure, and ancillary instrumentation. The proposed upgrade appears both cost-competitive and technically achievable, offering a long-term perspective for Paranal Observatory in the ELT era.
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All authors Sylvestre Lacour, Johan Kosmalski, Michael Mueller, Célia Desgrange, Oscar Carrión-González, Mathias Nowak, Elsa Huby, Julien Woillez, Jens Kammerer, Jean-Baptiste Le Bouquin, Jason Spyromilio

High Energy Physics (Phenomenology)

Signatures of $X_{17}$ through Coherent Elastic Solar Neutrino-Nucleus Scattering in Direct Detection Searches

M. F. Mustamin, M. Demirci and M. Deniz

The $X_{17}$ particle has been proposed to explain the invariant mass anomalies observed in electron-positron pairs during nuclear transitions at the Atomki experiment. Motivated by recent observations of $^8$B solar neutrinos induced coherent elastic neutrino-nucleus scattering (CE$\nu$NS), we present the first comprehensive analysis of the hypothetical boson using data from multi-ton dark matter direct detection facilities. We consider the new particle as a light $Z'$ mediator arising from a spontaneously broken $U(1)'$ symmetry, featuring both vector and axial-vector couplings to leptons. By evaluating the latest datasets from XENONnT, PandaX-4T, and LUX-ZEPLIN, we derive stringent limits on the effective vector coupling utilizing marginalization procedures. Our global analysis provides competitive constraints that meaningfully narrow the allowed parameter space of the model, while exhibiting a clear sensitivity to the tau-flavor coupling.
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Solar and Stellar Astrophysics

Symbiotic binaries in the Gaia data. I. Known symbiotics in DR3 and FPR

Jaroslav Merc

Symbiotic stars are long-period interacting binaries composed of an evolved giant and a hot compact companion. Their complex spectra and variability make them both astrophysically valuable and observationally challenging. We investigate how known symbiotic stars are represented in Gaia DR3 and the Focused Product Release (FPR), assess the reliability of these data, and evaluate their usefulness for candidate analysis and searches for new systems. We crossmatched Gaia DR3 and the FPR with confirmed symbiotic stars from the New Online Database of Symbiotic Variables and examined their astrometric, photometric, and spectroscopic data, along with derived products such as astrophysical parameters, orbital solutions, variability properties, and emission-line classifications. Astrometric data reliably constrain the position of symbiotics in the color-magnitude diagram, aiding searches for new systems, while RUWE is generally not a reliable indicator of their binarity. Most symbiotics are variable in Gaia photometry. Mean and epoch radial velocities, as well as inferred orbital solutions, are broadly consistent with the literature, and we provide the first tentative orbital solutions for two systems. Effective temperatures and metallicities are unreliable due to contamination from nebular continuum and strong emission lines. H$\alpha$ emission is detected in nearly all symbiotics, making it a robust diagnostic. Additionally, resolved companions were identified for two systems, and one previously confirmed symbiotic star was reclassified as non-symbiotic. Gaia DR3 provides a rich dataset for the study of symbiotic binaries. The forthcoming DR4 promises a major leap forward with its longer time baseline, new data products, and epoch data.
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Applied Physics

High-frequency magnetotransport in LaMnO3 samples synthesized by microwave irradiation versus conventional heating

Y. H. Lee, M. Manikandan and R. Mahendiran

Magnetoresistance of hole-doped LaMnO3 at frequencies above a few MHz has been seldom reported compared to numerous studies on magnetoresistance measured at direct current. Here, we contrast the high-frequency magnetoresistance in the frequency range f = 0.9-3 GHz in polycrystalline LaMnO3 (LMO) synthesized by microwave irradiation of oxide precursors in a microwave furnace (MW-LMO) and by conventional heating (CH-LMO) in an electrical furnace. The structure at room temperature changed from orthorhombic in CH-LMO to rhombohedral in MW-LMO. A combination of magnetization and resistivity studies suggest that the CH-LMO sample is a canted antiferromagnetic insulator below 140 K but the MW-LMO is a ferromagnetic metal with T_C = 240 K. While the high-frequency resistance of the CH-LMO sample at 300 K decreases gradually with increasing strength of the applied dc magnetic field for all f, a peak appears at H = H_r larger than 0 gauss when f equal or greater than 1.4 GHz in the MW-LMO sample and H_r increases linearly with f. We attribute the observed features in the high-frequency magnetoresistance of MW-LMO to current-driven resonant excitation of spins in the paramagnetic state. Its absence in the CH-LMO sample highlights the need for an optimum hole density to observe this effect.
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Quantum Physics

Quantum PDE Solvers in Practice: Application-Driven Benchmarking of the Heat Equation

Mahmoud Elkarargy, Abdelaziz Rahwan, Abdelrahman Elsayed et al. (+1 more)

Quantum PDE solvers are difficult to evaluate in practice because published studies use different discretizations, output models, reconstruction rules, and hardware assumptions. We present a reproducible, application-driven benchmark for the 1-D Dirichlet heat equation that compares eleven kernels under the same problem instances and readout contract. The benchmark covers coherent linear solvers (HHL, QSVT, and QLS-Fourier), VQLS, imaginary-time methods (QITE, var-QITE, and AVQDS), real-time Hamiltonian simulation and unitary dilations (Hamiltonian simulation, Schade-Hamiltonian, and Schr"odingerisation), and the spectral quantum simulation method (QSM). We use three initial conditions, four grid sizes from $n=4$ to $7$ qubits ($N=16$ to $128$), a CFL-like ratio $r\approx0.4$, and final time $T=1$. Statevector, ideal-shot ($10^5$ shots per step), and noisy Aer backends separate algorithmic, sampling, and device-noise errors. On statevector, QSM and Schade-Hamiltonian reproduce the semi-discrete reference to floating-point precision, Schr"odingerisation reaches approximately $10^{-4}$ error, and QITE is the strongest non-transform method for smooth data. Under the fixed-shot setting, HHL degrades to approximately $0.79$ relative $\ell_2$ error, while several low-depth or postselected methods become readout-limited. A norm-mismatch ablation attributes 23–29% of the $n=7$ smooth-initial-condition error of Hamiltonian simulation, AVQDS, and QLS-Fourier to reconstruction normalization. Compact observables, including total thermal energy and individual Fourier-mode weights, require 1–3 orders of magnitude fewer shots than full-field reconstruction. The resulting public benchmark provides a practical guide for selecting quantum PDE solvers.
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All authors Mahmoud Elkarargy, Abdelaziz Rahwan, Abdelrahman Elsayed, Forat Hatem

Plasma Physics

On the transition to large fluxes and access to second stability in gyrokinetic simulations of electromagnetic turbulence in STEP

Daniel Kennedy, Yujia Zhang, Toby Adkins et al. (+6 more)

This work investigates the nonlinear transition to large heat fluxes observed in local gyrokinetic simulations of electromagnetic turbulence in STEP. Using the stress-balance framework of Zhang et al. (arXiv:2606.04616, arXiv:2607.11789), we confirm that the onset of extreme transport correlates with a critical value of $q^{2}\beta_{e}$, where $q$ is the safety factor and $\beta_{e}$ is the ratio of electron thermal pressure to magnetic pressure, and relate this to a limit on the poloidal beta $\beta_{\mathrm{pol}}$. Crucially, this critical value lies below any relevant linear stability limit in the ($q$, $\beta_{e}$) space (e.g., the onset of ideal or kinetic ballooning modes). Using an extensive set of nonlinear gyrokinetic simulations, we demonstrate that the transition to large fluxes in STEP is governed by a balance between the electrostatic and magnetic-flutter stresses. We argue, and also show numerically, that larger-major-radius tokamaks reach the electromagnetic non-zonal regime at lower $\beta_{e}$, making this MHD-controlled saturation limit more accessible in reactor-scale devices than in small spherical tokamaks. We also demonstrate that access to a second-stable regime enables re-saturation at larger values of $\beta^{\prime}$. We further show that the ideal ballooning mode (IBM) threshold serves as a useful proxy for delineating this second-stable region and also as a qualitative guide for the onset of large fluxes. These results provide a predictive framework for identifying no-go zone predictions from local gyrokinetics and offer new insight into the electromagnetic saturation physics relevant to STEP and other high-$\beta_{e}$ devices.
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All authors Daniel Kennedy, Yujia Zhang, Toby Adkins, Plamen Ivanov, Francis Casson, Harry Dudding, Bhavin Patel, Colin Roach, Howard Wilson

Nuclear Theory

Role of the pre-equilibrium particle emission in the $^{249-251}$No production in the $^{204}$Pb($^{48}$Ca, xn)$^{252-x}$No reaction

Yu.L. Parfenova, M.S. Tezekbayeva, I.A. Egorova et al. (+1 more)

Experimental data on the production of $^{250}$No in its ground and isomeric states in the $^{204}$Pb($^{48}$Ca,2n)$^{250}$No reaction at $^{48}$Ca beam energies from 200 to 240 MeV are analyzed within a unified approach combining the Hauser–Feshbach statistical model and the Griffin exciton model, assuming the emission of one pre-equilibrium particle. The influence of pre-equilibrium processes on the production cross sections of the $^{249-251}$No isotopes is investigated. The inclusion of pre-equilibrium light-particle emission significantly improves the description of the measured production cross sections, particularly in the high-energy region, where differences of several orders of magnitude are obtained, and for the population of the ground and isomeric states of $^{250}$No. The proposed approach also reproduces the observed incident-energy dependence of the residual-nucleus production cross sections.
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All authors Yu.L. Parfenova, M.S. Tezekbayeva, I.A. Egorova, A.N. Ismailova

Quantum Physics

Entanglement and Optical Nonreciprocity in spontaneous Raman Scattering

Frank Schlawin

Inelastic light scattering is a central tool for sample characterization and label-free imaging across the physical and life sciences. Recent work has suggested that scattered light can also exhibit nonclassical correlations. Here, we develop a microscopic theory of Raman scattering that connects naturally to established descriptions of entangled-photon generation in three- and four-wave mixing, while capturing essential differences arising from the resonant, dissipative character of Raman scattering. Using a cumulant-expansion approach, we analyze the entanglement structure of the scattered sidebands and identify signatures that distinguish Raman-mediated correlations from those generated in conventional off-resonant nonlinear wave mixing. In particular, we show that Raman scattering induces chiral couplings between Stokes and anti-Stokes sidebands, leading to nonreciprocal amplification of coherent seed fields. These results establish a theoretical framework for Raman-based quantum photonic protocols and suggest routes toward quantum-enhanced Raman spectroscopy and imaging.
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Nuclear Theory

Thermal conductivity of dense $np\Lambda$ matter in neutron star cores

Tanay Choudhary, Athira S. and Monika Sinha

The possible presence of hyperons in the cores of massive neutron stars has important implications for their microscopic transport properties and thermal evolution. Despite recent progress in modelling core transport, a dedicated analysis regarding the thermal conductivity of a specific \(np\Lambda\) mixture remains absent from the existing literature. In this work, we investigate the thermal conductivity of dense, \(\beta \)-equilibrated \(np\Lambda\) matter within the framework of the variational linearized Boltzmann kinetic approach, employing the density-dependent DDME2 equation of state across a baryon density range of \((0.5\text{--}4.5)\,n_0\). We find that neutrons still dominate thermal transport, while the onset of \(\Lambda \) hyperons induces only a remarkably small reduction in neutron conductivity compared to pure nucleonic matter. These results suggests that the core thermal relaxation timescale remains practically unaltered in the presence of $\Lambda$ hyperons.
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Soft Condensed Matter

How Quasicrystals Remember: Hierarchical Memory Under Cyclic Shear

Edwin A. Bedolla-Montiel and Marjolein Dijkstra

Quasicrystals occupy a unique middle ground between periodically ordered crystals and disordered glasses, making them an ideal platform for examining the interplay between disorder and the emergence of mechanical memory. Using athermal quasistatic shear simulations, we show that two-dimensional dodecagonal quasicrystals encode and recover memory under cyclic driving. Above the yielding transition, the response becomes irreversible, characterized by persistent shear bands and locally transformed regions. Below yielding, cyclic shear with varying amplitudes produces a hierarchy of nested hysteresis loops in the stress-strain response characteristic of loop-return point memory. By resolving the underlying reversible plastic events, we reveal localized phason-like tile rearrangements as the elementary switching units and identify tile-switch hysterons responsible for memory in the quasicrystal. Such a microscopic identification of the fundamental switching units is considerably more challenging, and often impossible, in amorphous solids. Despite their structural diversity, these rearrangements share a compact core, sharp bistability, and an Eshelby-compatible elastic far field. In contrast, a periodic approximant of the quasicrystal lacks both the structural disorder and the bistable tile-switch rearrangements required for cyclic-shear memory, linking phason degrees of freedom to bistable hysterons.
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Physics and Society · Cross-listed from q-bio.PE

Contrasting statistical patterns in melodic and molecular evolution reveal distinctive constraints in a culturally evolving system

John M McBride and W Tecumseh Fitch

Evolved sequences can be used to infer the rules of evolution. Orally transmitted folk melodies are evolved sequences whose similarity to protein sequences (one-dimensional, drawn from a limited alphabet) invites application of bioinformatics methods to study cultural evolution. A major obstacle is that melodies encode rhythm, which breaks some assumptions of standard sequence-alignment algorithms. We develop a rhythm-aware alignment method and apply it to \num{40000} Irish dance tune variants, enabling the first large-scale automated melodic alignment. Four canonical bioinformatics analyses – mutability, substitution matrices, positional conservation, and covariance – reveal patterns distinct from those of molecular evolution, revealing the forces that shape each domain: biochemical and biophysical constraints for proteins; memory, motor, and social biases for melodies. Together the results show that bioinformatics provides a powerful framework – conceptual as much as algorithmic – for studying cultural evolution. Although the cultural transmission of music has been discussed for centuries, here we show how to analyze it at large scale.
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Materials Science

Emergent exchange bias in ultra-thin La0.67Sr0.33MnO3 films driven by ferro-antiferromagnetic phase coexistence

Inés García-Manuz, Gabriel Caballero, Jose Luis F. Cunado et al. (+7 more)

Ultra-thin La0.67Sr0.33MnO3 (LSMO) films are generally regarded as single-phase ferromagnets, yet their reduced dimensionality enhances the impact of oxygen stoichiometry and local structural distortions. Here we demonstrate that LSMO layers with thicknesses between 3 and 17 nm develop a robust and thickness-independent exchange bias (EB) despite the absence of an engineered ferromagnetic-antiferromagnetic (FM-AFM) interface. Angular magneto-optical Kerr effect measurements reveal a reproducible hysteresis-loop shift that reverses sign upon 180-degree rotation, confirming its intrinsic origin. X-ray photoelectron spectroscopy shows a thickness-independent Mn2+ fraction (about 20 percent), indicating the presence of oxygen-deficient reduced regions embedded within the Mn3+/Mn4+ ferromagnetic matrix. A simple interfacial-exchange model suggests that only a sub-percent fraction of antiferromagnetic (or frustrated spin-ice-like) regions is required to generate the observed EB. These results demonstrate that ultra-thin LSMO can spontaneously host internal FM-AFM interfaces driven by oxygen deficiency, revealing an emergent route to exchange bias in nominally single-phase manganite films.
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All authors Inés García-Manuz, Gabriel Caballero, Jose Luis F. Cunado, Miguel Romera, Mariela Menghini, Carlos León, Jacobo Santamaría, Julio Camarero, Paolo Perna, Fernando Ajejas

Optics

Collective-State Preparation in a Subwavelength Triangular Trimer Using SUPER Excitation

Thomas Nunner, Johannes Kerber, Helmut Ritsch et al. (+1 more)

The Swing-UP of quantum EmitteR population (SUPER) scheme has recently been proposed as a deterministic method for the preparation of collective radiative states in two strongly dipole-coupled quantum emitters (Phys. Rev. Res. 8, 013179 (2026)). Here, we apply this approach to an equilateral subwavelength triangular trimer of dipole-coupled two-level quantum emitters (QEs), loosely inspired by biological light-harvesting ring geometries, and demonstrate that tailored, time-overlapping, red-detuned ultrashort SUPER pulses can selectively prepare collective states in a $C_3$-symmetric system, including energetically degenerate eigenstates that are resolved through site-dependent optical phases. We find that both the state selectivity and the preparation efficiency depend strongly on the inter-emitter spacing. In particular, at deep-subwavelength separations, the symmetric collective state can be deterministically prepared with near-unity efficiency (approximately $94\%$), whereas the inversion efficiency and state selectivity are significantly lower at larger inter-emitter separations. Furthermore, this state preparation technique inherits a certain degree of robustness against reasonable static position imperfections and on-site frequency inhomogeneities of the individual QEs. Our results demonstrate that deep-subwavelength triangular trimers and, more broadly, highly compact ring geometries are excellent candidates for the deterministic preparation of collective radiative states via SUPER excitation. These predictions could be realized with solid-state emitters and molecules. Our findings offer a route toward the direct probing of the `pure' electromagnetic layer of interaction in biological and bio-inspired synthetic nanophotonic ring configurations, with possible relevance in photonics, quantum information processing, and metrology.
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All authors Thomas Nunner, Johannes Kerber, Helmut Ritsch, Arpita Pal

Astrophysics of Galaxies

Discovery of a star sensitive to the spin of Sgr A*

K. Abd El Dayem, R. Abuter, N. Aimar et al. (+85 more)

Residing in the center of the Milky Way, Sgr A* is the closest massive black hole (MBH). Its vicinity has allowed measuring individual stellar orbits around it. The stars act as test particles and probe the gravitational potential around the $4.3 \times 10^6 M_\odot$ MBH. These observations have determined the central mass to sub-percent precision, and the mildly relativistic motions of stars have given access to the dominant relativistic corrections, the gravitational redshift, the transverse Doppler effect, and the prograde precession imposed by the Schwarzschild metric nature of the potential. These effects are of order $\beta^2 = (v/c)^2$ (for velocity $v$ and speed of light $c$). The Kerr metric for a rotating black hole leads to corrections of order $\beta^3$. Here, we report the discovery of a faint main-sequence star ($m_K = 19.3$), S301, on a 8.7-year orbit and with small enough a pericenter distance, such that the star's peak velocity reaches $25000\,$km/s. Within the measurement capabilities of current near-infrared interferometry and future spectroscopy on an extremely large telescope, S301's motion is directly sensitive to the spin of Sgr A*. The high eccentricity of S301 suggests that it is the captured component of a binary that was torn apart via the Hills mechanism.
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All authors K. Abd El Dayem, R. Abuter, N. Aimar, P. Amaro-Seoane, A. Berdeu, J.-P. Berger, G. Bourdarot, W. Brandner, A. Burkert, D. Calderon, C. Correia, J. Cuadra, R. Davies, D. Defrere, L. Delit, A. Drescher, F. Eisenhauer, L. Esteras Otal, M. Fabricius, H. Feuchtgruber, N.M. Foerster Schreiber, A. Foschi, P. Garcia, R. Garcia Lopez, A. Generozov, R. Genzel, S. Gillessen, F. Gonte, X. Haubois, S.F. Hoenig, M. Houlle, S. Joharle, A. Kaufer, J. Kammerer, P. Kervella, J. Kolb, L. Kreidberg, L. Labadie, S. Lacour, O. Lai, R. Laugier, J.-B. Le Bouquin, J. Leftley, B. Lopez, D. Lutz, F. Mang, A. Merand, F. Millour, M. Montarges, N. Morujao, H. Nowacki, M. Nowak, S. Oberti, J. Osorno, T. Ott, T. Paumard, C. Paladini, H.B. Perets, K. Perraut, G. Perrin, R. Petrov, P.O. Petrucci, T. Piran, N. Pourre, S. Rabien, D.C. Ribeiro, S. Robbe-Dubois, M. Sadun Bordoni, J. Sanchez Bermudez, D. Santos, R. Sari, J. Sauter, S. Scheithauer, J. Scigliuto, J. Shangguan, T.T. Shimizu, F. Soulez, J. Stadler, C. Straubmeier, E. Sturm, M. Subroweit, C. Sykes, L.J. Tacconi, P. Thevenet, I. Urso, F. Vincent, J. Woillez, G. Zins

General Relativity and Quantum Cosmology

Two-fluid $f$-mode oscillations of dark-matter-admixed neutron stars

Zi-Yue Zheng, Ting-Ting Sun, Huan Chen et al. (+4 more)

We study quadrupolar $f$-mode oscillations of dark-matter-admixed neutron stars (DANSs) in full general relativity (GR). The ordinary component is described by microscopic Brueckner-Hartree-Fock matter matched to the Shen2020 crust, while the dark matter (DM) component is treated as a cold self-interacting fermion fluid coupled to ordinary matter only by gravity. For fixed-DM-fraction sequences we solve the polar two-fluid perturbation equations with an outgoing gravitational-wave (GW) boundary condition, obtaining complex eigenfrequencies rather than only real mode frequencies. The spectrum contains two principal $f$-like sequences. Their local character can be ordinary-matter-led, DM-led, or mixed, and is diagnosed using the component kinetic energies, the displacement overlap, and the cancellation of the matter quadrupole. A main result is that, for intermediate DM fractions, one of the two-fluid branches can become weakly radiating, with damping times enhanced by several orders of magnitude. The same calculation gives the outgoing Zerilli amplitude and the GW damping time, which we use to estimate the GW energy required to reach a prescribed detector threshold. Thus the analysis extends previous two-fluid Cowling studies by retaining metric perturbations and the radiative boundary condition.
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All authors Zi-Yue Zheng, Ting-Ting Sun, Huan Chen, Xiao-Ping Zheng, Jin-Biao Wei, G. F. Burgio, H.-J. Schulze

Nuclear Theory

Harmonic-dependent geometry-to-flow transfer in AMPT Ru+Ru and Zr+Zr isobar collisions

Murad Badshah and Muhammad Ajaz

We present a fixed-$N_{\rm part}$ study of geometry-to-flow transfer in string-melting AMPT simulations of $^{96}{\rm Ru}+^{96}{\rm Ru}$ and $^{96}{\rm Zr}+^{96}{\rm Zr}$ collisions at $\sqrt{s_{NN}}=200$ GeV. Four nuclear configurations are considered: deformation-only Ru+Ru, deformation-only Zr+Zr, deformation plus neutron skin Ru+Ru and deformation plus neutron skin Zr+Zr. The AMPT/HIJING initialization is modified to include deformed Woods–Saxon densities and, when enabled, separate proton and neutron Woods–Saxon radii and diffuseness parameters (neutron skin effect). We introduce an eccentricity-normalized isobar response double ratio, $D_n=(v_n^{\rm Ru}/v_n^{\rm Zr})/(\varepsilon_n^{\rm Ru}/\varepsilon_n^{\rm Zr})$, evaluated in common participant-number intervals. This observable eliminates the initial-geometry eccentricity ratio, and investigates whether the final-state flow ratio is fully determined by the initial-geometry ratio. We find that the elliptic double ratio is nearly unity, and the triangular double ratio is consistently greater than unity for the two deformation-only and deformation-plus-skin configurations. The positive $D_3-1$ pattern is maintained when varying the $N_{\rm part}$ binning, peripheral-bin treatment, flow $p_T$ range and rapidity/pseudorapidity acceptance. The result identifies a harmonic-dependent AMPT response: Ru/Zr elliptic flow follows leading eccentricity scaling to high accuracy, whereas triangular flow retains a residual response component after the triangularity ratio is divided out.
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Quantum Physics

Quantum metrology with undetected mid-infrared photons for applied non-destructive testing

Paul Gattinger, Andreas W. Schell, Maja Buchegger et al. (+2 more)

Metrology with undetected photons is an emerging technique that leverages quantum effects and photon correlations (entanglement) to retrieve valuable information in a target spectral range (e.g., mid-infrared, mid-IR) using measurements in an easily accessible domain (e.g., visible, near-IR). The underlying quantum process of spontaneous parametric down-conversion (SPDC) is utilized to generate non-degenerate correlated signal and idler photons to serve as detection and probing photons, respectively. Sensing with undetected photons enables important advantages, such as ultra-low probe powers, room-temperature operation, and shot-noise-limited detection. In this contribution, we apply a quantum nonlinear interferometer based on an SPDC source to perform applied mid-IR spectroscopy, mid-IR microscopy, and mid-IR optical coherence tomography (OCT) as among the most promising techniques for quantum-based routine non-destructive testing. Moreover, we characterize the system, benchmark it against classical systems, and provide a prospective outlook for this new technology.
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All authors Paul Gattinger, Andreas W. Schell, Maja Buchegger, Markus Brandstetter, Ivan Zorin