Astrophysics of Galaxies
Synchrotron filaments in radio galaxies: rarity, stability, and environmental influences from LOFAR and ROSAT observations
Geoffrey Ong'alo, Martin J. Hardcastle, Willice Obonyo et al. (+2 more)
We present a systematic investigation of filamentary synchrotron structures in
radio galaxies, using deep 144 MHz observations from the LOFAR Two-Metre Sky Survey (LoTSS) in combination with archival ROSAT X-ray data. These narrow, collimated features, linking
radio lobes and often aligned with jet axes, are rare: our visual inspection of 548 cluster-associated sources identified 12 candidates (~2.2%), of which three exhibit clearly resolved filaments suitable for detailed X-ray and synchrotron minimum pressure analysis. Minimum pressures in these filaments are consistently lower than the ambient thermal pressure derived from X-ray measurements. This disparity implies a role for external confinement in filament stability, aligning with theoretical predictions of thermal pressure support and potentially toroidal
magnetic field configurations. We discuss filament formation scenarios, including relic AGN
outflows,
magnetic draping, and
plasma instabilities. Our findings highlight the utility of filamentary structures as probes of intracluster
magnetic field
topology and AGN feedback, and demonstrate the need for high-resolution, multi-frequency studies to constrain their origin and
evolution.
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All authors Geoffrey Ong'alo, Martin J. Hardcastle, Willice Obonyo, Marcus Brüggen, Paul Baki
Quantum Physics · Cross-listed from cs.LO
QisMC: A Model Checker for QISKIT Program Debugging
Aochu Dai and Mingsheng Ying
We present QisMC, the first
quantum model checker dedicated to debugging Qiskit programs. On the theoretical side, we introduce the notion of
quantum-classical transition system and a
quantum computation tree logic (qCTL) grounded in Birkhoff-von Neumann logic for modeling the behaviors and specifying the properties of Qiskit programs, respectively. On the implementation side, QisMC provides an end-to-end framework encompassing transition system generation, logical formula representation, and model checking
algorithms, and it efficiently performs image computation based on decision diagrams. These methods and design principles give QisMC advantages over previous Qiskit program debuggers, including a unified property specification
language, a fully automated and exhaustive verification process, and the ability to generate counterexamples. Extensive illustrative examples and
benchmark evaluations demonstrate the practicality, efficiency, and scalability of QisMC in verifying realistic
quantum programs.
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Nuclear Theory
Self-Consistent Determination of the Transition Temperature Between the $^{14}\mathrm{C}(n,\gamma)^{15}\mathrm{C}$ and $^{14}\mathrm{C}(p,\gamma)^{15}\mathrm{N}$ Reactions
R. Ya. Kezerashvili, N. A. Burkova, A. S. Tkachenko et al. (+1 more)
We present the first self-consistent theoretical study of the competing $^{14}\mathrm{C}(n,\gamma)^{15}\mathrm{C}$ and $^{14}\mathrm{C}(p,\gamma)^{15}\mathrm{N}$ reactions within the same modified potential cluster model (MPCM). For the $^{14}$C$(p,\gamma_{0})^{15}$N reaction, total cross sections, astrophysical $S$ factors, and reaction rates are calculated using interaction potentials constrained by the available scattering and bound-state data. The astrophysical $S$-factor is estimated as $S(0)=4.5(1)$~keV$\cdot \text{b}$. Combining these results with our recent MPCM calculations for $^{14}\mathrm{C}(n,\gamma)^{15}\mathrm{C}$, we determine the transition temperature at which
proton capture overtakes
neutron capture in the production of $^{15}\mathrm{N}$. The self-consistent comparison predicts a transition temperature $T_9^{\rm c.p.}=2.5$ under Maxwell–Boltzmann statistics, significantly higher than previous estimates. The analysis is extended to Tsallis statistics, demonstrating that deviations from thermal
equilibrium produce substantial shifts of the transition temperature. These results provide improved
nuclear-physics input for astrophysical nucleosynthesis calculations.
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All authors R. Ya. Kezerashvili, N. A. Burkova, A. S. Tkachenko, S. B. Dubovichenko
Instrumentation and Methods for Astrophysics
Quantum-optimal instruments for high-contrast imaging with multi-plane light converters
Sebastiaan Y. Haffert, Yinzi Xin and Rico Landman
Spatial Mode Demultiplexers (SPADE) are devices that split an incoming wavefront into a particular set of electric field modes. SPADEs have been shown to be
quantum-optimal for many measurement problems including coronagraphy, wavefront sensing and interferometric (nulling) beam combiners. We will show how
quantum optimal SPADEs can be implemented using Multi Plane Light Converters (MPLC). MPLCs are devices that use several phase plates in sequence to achieve arbitrary
unitary transformations. The phase plates themselves are implemented using
liquid-
crystal technology that allows us to create high-quality broadband phase plates. The accurate control of the local phase through the direct write method results in MPLCs with minimal background scatter. We will show the designs and simulated performance for each of the proposed use cases for the ELTs, HWO and LIFE and show how they improve over current concepts.
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Earth and Planetary Astrophysics
The Hot Neptune Initiative (HONEI) III. An ultra-hot super Neptune orbiting the metal-rich subgiant star TOI-5646: the largest host for a desert dweller
L. Mancini, F. Manni, D. Kubyshkina et al. (+25 more)
We report the confirmation of the TESS transiting-
planet candidate orbiting the metal-rich F8\,IV-V subgiant
star TOI-5646 (V=11.38 mag; T=6136 K). The planetary nature of TOI-5646b was confirmed by means of HARPS-N follow-up radial velocity measurements. We determined that the
planet has an orbital period of 2.4277 days and an orbital eccentricity compatible with zero. With a mass of 45.9 Earth masses, a radius of 6.6 Earth radii, and an
equilibrium temperature of 1935 K, it is one of the hottest super-Neptune
exoplanets ever discovered in the Neptune desert. Its density, 0.87 g cm^-3, is lower than that of most other desert dwellers, but still appears to follow the trend that the desert is populated by dense
planets than those in the ridge and savanna. The
metallicity of the parent
star ([Fe/H]=0.32) follows the trend whereby the host
stars of Neptune-sized
exoplanets in the desert and the ridge are generally richer in metal than those in the savanna. The log{g} of the parent
star (4.09) suggests that the host is an evolved
star, making this a peculiar system: TOI-5646 is the largest
star (1.8
Solar radii) ever discovered to host a Neptune-sized
planet in the desert. Internal structure modelling revealed that TOI-5646b is highly enriched in metals, with an inferred bulk
metallicity between 0.7 and 0.95. Atmospheric
evolution simulations indicate that the
planet has undergone significant mass loss (6-16%) through intense XUV irradiation from its host
star. These results indicate a peculiar formation history (potentially involving early protoplanetary disk dispersal), a planetary collision, or a late
tidal destruction event, to explain its current state as a low-density survivor in the Neptune desert.
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All authors L. Mancini, F. Manni, D. Kubyshkina, E. A. van Dijk, L. Naponiello, M. Damasso, V. D'Orazi, K. Biazzo, A. V. Bonomo, L. Fossati, Y. Miguel, J. de Leon, M. E. Everett, W. Fong, A. Fukui, D. Gandolfi, S. B. Howell, D. W. Latham, M. Lopez-Morales, P. MacQueen, F. Murgas, N. Narita, E. Palle, M. Pinamonti, T. Pugh, A. Sozzetti, S. Vissapragada, S. W. Yee
Cosmology and Nongalactic Astrophysics
A "MeerKAT-meets-LOFAR" Study of 2A 0335+096: Discovery of a Complex 500 kpc Radio Halo in a Disturbed Cool-Core Cluster
C. J. Riseley, R. J. van Weeren, L. Lovisari et al. (+9 more)
The emerging picture of
radio haloes and mini-
haloes in
galaxy clusters is more blurred and far less distinct than once thought. While both trace
cosmic ray electrons and
magnetic fields in the intracluster medium (ICM), our knowledge of the mechanisms powering these sources, their properties and their connection to cluster dynamics, is incomplete. We present new deep MeerKAT L-band (856$-$1712\,MHz) observations of the sloshing cool-core cluster 2A~0335+096, performed as part of the “MeerKAT-meets-LOFAR” mini-
halo census, as well as reprocessed LOFAR 120$-$168\,MHz LOFAR Two-metre Sky Survey data. We present highly sensitive
radio continuum images, from which we perform a spectral analysis and a comparison of the thermal and non-thermal properties using reprocessed archival XMM-Newton data. Our MeerKAT data reveal that the known mini-
halo is embedded in a large-scale
radio halo spanning up to 510\,kpc in this sloshing cluster, although only the inner mini-
halo is detected by LOFAR. We find a typical steep spectrum of $\alpha = -1.20 \pm 0.09$ for the mini-
halo; the non-detection of the larger-scale
halo by LOFAR indicates a spectral index no steeper than $-1.2$. Our results are broadly consistent with an interpretation of turbulent (re-)acceleration powered by sloshing within the cluster potential well. This work emphasises the need for using deep, high-dynamic multi-frequency
radio observations in conjunction with high-quality X-ray observations to complete our understanding of the connection between
radio halo properties and cluster dynamics.
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All authors C. J. Riseley, R. J. van Weeren, L. Lovisari, R. Timmerman, A. Botteon, A. Bonafede, A. Ignesti, N. Biava, G. Brunetti, B. Colquhoun, Y. Perrott, T. Vernstrom
Instrumentation and Methods for Astrophysics
The Photonic Lantern Nuller: from concept to laboratory and on-sky demonstrations
Yinzi Xin, Nemanja Jovanovic, Dimitri Mawet et al. (+18 more)
This thesis work presents the conceptual design and experimental characterization of the Photonic Lantern Nuller instrument, which uses a multimode-to-single-mode demultiplexing waveguide to cancel out starlight while maintaining
planet light, allowing for the direct characterization of
planets at a
telescope's diffraction limit. The PLN was experimentally characterized in the lab, where it was further enhanced using common-path wavefront sensing and control techniques, and then demonstrated on sky at the Subaru
Telescope. Highlights include measured in-lab null-depths of $\sim 10^{-4}$ in three out of four ports simultaneously and on-sky null-depths of approximately $\sim 10^{-1}$ (limited by jitter and atmospheric residuals). We provide an overview of these results and discuss avenues for future work.
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All authors Yinzi Xin, Nemanja Jovanovic, Dimitri Mawet, Daniel Echeverri, Yoo Jung Kim, Jonathan Lin, Julien Lozi, Sebastien Vievard, Olivier Guyon, Grace Piroscia, Vincent Deo, Sergio Leon-Saval, Rodrigo Amezcua-Correa, Stephanos Yerolatsitis, Sebastiaan Y. Haffert, Michael P. Fitzgerald, Pradip Gatkine, Suvinay Goyal, Barnaby Norris, Garreth Ruane, Steph Sallum
Optics
Metalens stereoscopic optical palpation for imaging cancer mechanics
Haoyi Yu, Rhys Jones, Chi Li et al. (+13 more)
Accurate intraoperative margin assessment is critical for complete resection of solid tumours. However, surgeons routinely rely on manual palpation, which is highly subjective and fundamentally limited by poor spatial resolution, and pre-operative imaging lacks real-time feedback. While emerging optical elastography techniques offer quantitative mechanical contrast, their reliance on bulky optical components necessitates cumbersome
alignment and hinders integration into miniaturised
surgical instruments. Here, we report metalens stereoscopic optical palpation (MSOP), a nanophotonic imaging platform leveraging a binocular metalens integrated with a single CMOS sensor to achieve high-fidelity, self-aligned elastography. By replacing complex bulk optics with a compact stereoscopic architecture, MSOP enables robust, high-contrast mapping of tissue surface stress. Following validation in heterogeneous silicone phantoms, we demonstrate MSOP's translational potential by characterising the mechanical signatures of malignancies in fresh mouse pancreatic cancer models, as well as excised human breast and liver specimens. By providing reliable, label-free mechanical contrast across diverse oncological landscapes, MSOP offers a compact tool for precise intraoperative margin delineation to reduce re-excision rates and improve
surgical outcomes.
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All authors Haoyi Yu, Rhys Jones, Chi Li, Bo He, Renate Zilkens, Louise N. Winteringham, Laura Gale, Mireille Hardie, Fiona Bellamy, Saud Hamza, Christobel M. Saunders, Liver Cancer Collaborative, Stefan A. Maier, Brendan F. Kennedy, Haoran Ren, Qi Fang
Optics
Design and numerical performance analysis of efficient Ag3TaX4 (X = S, Se, Te) thin film solar cells
Md. Nahid Hasan, Tanvir Ahmed, Md. Abdur Rashid et al. (+3 more)
Silver-based ternary chalcogenides have recently emerged as promising absorber materials for thin film photovoltaics. Nevertheless, their photovoltaic performance in complete device architectures has not yet been systematically explored. In this work, three-dimensional (3D) n-CdS/p-Ag3TaX4 (X = S, Se, Te)/p+-GeS thin-film
solar cells have been designed and numerically investigated using the
Semiconductor Module of COMSOL Multiphysics. Herein, the various performance
matrices of the proposed devices have been analysed in accordance with the changing of depth, carrier, and defect concentration in each layer of the structures. The optimized Ag3TaS4-based device delivers a power conversion efficiency, PCE of 24.66%, open
circuit voltage, VOC of 1.4V, short
circuit current density, JSC of 20.68 mA/cm2, and fill factor, FF of 85.16%. The Ag3TaSe4-based
solar cell exhibits the PCE of 28.1% with VOC = 1.19V, JSC = 27.0 mA/cm2, and FF = 87.44%. The Ag3TaTe4
solar device shows a PCE of 27.56% with a VOC of 0.88 V, JSC of 36.14 mA/cm2, fill factor of 86.65%. These results provide a deeper insight into device operation and offer practical design guidelines for fabricating efficient Ag3TaX4 (X = S, Se, T e)-based novel next-generation
solar cells.
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All authors Md. Nahid Hasan, Tanvir Ahmed, Md. Abdur Rashid, Tanzina Rahman, Dinesh Pathak, Jaker Hossain
Quantum Physics
Distributed Resource Theory of Entanglement and Magic
Xiao Yuan, Wenhao Zhang, Qiming Ding et al. (+1 more)
In distributed fault-tolerant
quantum computing,
entanglement and magic are essential resources for
quantum communication and universal fault-tolerant computation, respectively. Although they are usually treated as distinct resource currencies, whether they admit a unified resource-theoretic description remains an open question. Here, we introduce the distributed resource theory of
entanglement and magic (DREAM). In this framework, the free states are convex mixtures of product local stabilizer states, and the free operations are local stabilizer
circuits assisted by classical communication (LSCC). We show that DREAM contains nontrivial resource states that are neither
entanglement nor magic, so it is strictly richer than treating the two resources independently. Surprisingly, such resources can enable the teleportation of magic states between distant parties without consuming
entanglement, revealing a counterintuitive form of resource teleportation mediated entirely by separable states. We further generalize this result to
quantum networks and investigate general
quantum-state teleportation under LSCC. We show that the shared resource under DREAM is closely related to the teleportation capability, quantified by the magic of the teleported state. Our work establish a systematic framework for studying distributed
quantum resources and uncover intrinsic relations among distinct resources within a unified resource theory.
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All authors Xiao Yuan, Wenhao Zhang, Qiming Ding, You Zhou
High Energy Astrophysical Phenomena
The First X-Ray Polarimetry of the Typical Accretion Disk Corona Source 4U 1822-37
WanYun Wu, Fei Xie and YuShan Ling
We report the first Imaging X-ray Polarimetry Explorer (IXPE) observations of the typical
accretion disk corona (ADC) source 4U 1822-37, covering 44 orbital cycles, together with simultaneous Swift-XRT data. The polarization degree (PD) of this source is found to be higher than typical low-mass X-ray binary (LMXB) values and exhibits a significant energy dependence. Within the 2–5~keV and 5–8~keV bands, PD remains constant, with average values of \(5.6\pm0.8\%\) and \(11.6\pm1.7\%\), respectively, and the difference is significant (\(>3\sigma\)). Orbital phase-resolved analysis reveals that during the companion eclipse, the PD in the 2–5~keV band drops from a significantly non-zero value to a level consistent with zero, while the polarization angle (PA) remains unchanged. In contrast, the PD in the 5–8~keV band shows a marginal rising trend, reaching \(21.3\pm6.1\%\), and the PA exhibits a periodic rotation of \(30^\circ\) before the eclipse. In addition, the PA rotates by \(40^\circ\) with increasing neutral absorption on a three-day timescale. These results suggest that the soft and hard emission in the 2–8~keV band may originate from regions with different spatial distributions, with the high PD implying a scattering contribution. The PA rotation is likely linked to scattering geometry asymmetries caused by a bulge or clumps.
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Instrumentation and Methods for Astrophysics
Demonstration of simultaneous PIAA- coronagraphy and wavefront sensing using a single metasurface-based focal-plane optic
Dhwanil Patel, Sebastiaan Y. Haffert, Skyler Palatnick et al. (+23 more)
Controlling residual wavefront aberrations downstream of an extreme adaptive optics (ExAO) system is a major challenge in high-contrast imaging. These aberrations produce quasi-static speckles due to differences between the wavefront-sensing and science paths. Highly sensitive wavefront sensors, such as Zernike wavefront sensors (ZWFSs), are used to mitigate these non-common path aberrations. High-performing coronagraphs, such as complex mask coronagraphs (CMCs), are also implemented in the focal plane. Both perform better with lossless apodization such as phase-induced amplitude apodization (PIAA) optics. Metasurfaces can have chromatic responses, allowing a single focal-plane optic to have different functionalities in different wavelength bands. We demonstrate such an optic by manufacturing a hybrid metasurface designed to function as a CMC and a ZWFS in two intermediate-band filters in the H band, each with a fractional bandwidth of approximately 1%. We show measured optical responses with phases of $\sim \pi/2$ at shorter wavelengths and $\pi$ at longer wavelengths between $1500$ and $1700,\text{nm}$. This would allow for wavefront sensing at the shorter wavelength of $\sim1500\,\text{nm}$ and coronagraphy at the longer wavelength of $\sim1700\,\text{nm}$. Additionally, we tested the mask on-sky with the MagAO-X instrument at the Magellan Clay 6.5 m
telescope at Las Campanas Observatory, Chile. On-sky results show a contrast of $\sim 10^{-1}$ at a non-ideal wavelength of $\sim 1600\,\text{nm}$. This is comparable to simulated contrast curves using the measured optical responses around that wavelength. Finally, we evaluated the wavefront-sensing performance of the metasurface using the MagAO-X internal source at $1300\,\mathrm{nm}$. The measured reconstruction error is consistent with simulations of an ideal Zernike wavefront sensor, confirming its wavefront-sensing functionality.
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All authors Dhwanil Patel, Sebastiaan Y. Haffert, Skyler Palatnick, Adam Taras, Maxwell A. Millar-Blanchaer, Matthijs Mars, Elena Tonucci, Jared R. Males, Laird M. Close, Joshua Liberman, Warren B. Foster, Kyle Van Gorkom, Olivier Guyon, Alexander D. Hedglen, Parker T. Johnson, Maggie Y. Kautz, Jay K. Kueny, Jialin Li, Joseph D. Long, Jennifer Lumbres, Eden A. McEwen, Avalon McLeod, Lauren Schatz, Katie Twitchell, Robert J. Harris, Viktoria Kutnohorsky
Cosmology and Nongalactic Astrophysics
The Effect of Slitless Spectroscopic Redshift Uncertainty and Interlopers on BAO Measurements from CSST-like Samples
Zhejie Ding, Yu Yu and Pengjie Zhang
The
baryon acoustic oscillations (BAO) is a vital probe to measure cosmological distances and constrain dark energy. The ongoing and near-future space-based
telescopes, including the Chinese Space Station Survey
Telescope (CSST), will perform
galaxy redshift surveys using slitless spectroscopy. Due to the relatively low spectral resolution and observational effects, there will be uncertainties and interloper contamination in measured
redshifts. In this study, we consider the Gaussian-distributed
redshift uncertainty and [O III]-H$\beta$ interlopers in the CSST-like slitless spectroscopic
redshift (spec-z) samples, which are simulated using the approximate $N$-body code FastPM. We study the effect of spec-z errors on BAO before and after density field reconstruction. Both the
redshift uncertainty and interlopers can damp the BAO signal, and the latter can further induce oscillations in the broadband shape of the power spectrum. We model the interloper effect on the propagator, i.e. the cross-correlation between the observed and initial density fields, as well as on the BAO power spectrum. We study the influence of the spec-z errors on the fitted anisotropic BAO parameters $\alpha_{\perp}$ and $\alpha_{\parallel}$. The resulting systematic bias on $\alpha_{\perp}$ and $\alpha_{\parallel}$ is mild, mostly within $0.1$ per cent and $0.2$ per cent, respectively. Even with the spec-z errors, BAO reconstruction can still significantly reduce the systematic bias and statistical errors on the $\alpha$ parameters. Furthermore, we vary the
redshift uncertainty and study the reconstruction performance.
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High Energy Physics (Theory)
Geometric tool kit for higher spin gravity (part III): An introduction to the general theory of connections on fibre bundles
Xavier Bekaert
These notes provides an introduction to a wide variety of notions of connection that appear in the contemporary mathematical literature. Besides the familiar Ehresmann connections on principal bundles and Koszul connections on vector bundles, there is a large zoo of perhaps less familiar notions, most notably Cartan connections on principal bundles and their avatars on tractor bundles, which may deserve more
attention for further elucidating higher-
spin interactions and
symmetries. This review is motivated both by the previous (explicit or implicit) use of these notions of connection in higher-
spin gravity and by their potential future applications in this context. Much of the material covered here is also relevant to advanced mathematical topics in
gravity, such as the rigorous treatment of conformal geometry (which is of interest for holography) and may help fill gaps left by standard textbooks (most of which typically do not address Cartan connections, tractor calculus, and related topics).
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Mathematical Physics · Cross-listed from math.AP
Intrinsic Structure of Elasticity in Hilbert Space
Cristian G. Gebhardt, Johannes Lankeit and Marc C. Steinbach
Mathematical elasticity has a long history and a huge body of literature. Surprisingly, at its heart elasticity exhibits a rich and transparent structure that, to our knowledge, is rarely presented in an explicit and unified form. Using standard tools from functional analysis, this article reveals four orthogonal decompositions of
Hilbert spaces that characterize the static
equilibrium of an elastic body at small deformations, universally for arbitrary spatial dimension, arbitrary boundary conditions, and classical as well as data-driven formulations. Regarding data-driven continuum mechanics, it highlights the intrinsic structure that remains unchanged when constitutive laws are replaced by material data sets.
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Mathematical Physics
Boundary Free Energies, Quenched Mixing, and Gibbs-State Selection in Disordered Ising Models
Mauris Chueng, Hexiang Wang and Keheng Zhu
We study boundary free energies and half-space responses in nearest-neighbor disordered Ising models. First, we prove the existence of fixed-depth tangential pressure and identify its derivative almost everywhere with the limiting boundary response. Second, under quenched exponential boundary-response mixing, we prove Gibbs-state selection independence and exponential convergence of finite-depth pressures. We further show that uniform one-
spin mixing yields DLR uniqueness and Gaussian normal localization, and verify the required mixing conditions whenever $(2d-1)\mathbb E\tanh(\beta\vert{}J\vert{})<1$. Finally, we establish an all-face surface limit in the bounded Dobrushin regime and provide counterexamples that delimit general surface and stiffness claims.
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Strongly Correlated Electrons
Critical bifurcation and deconfined quantum criticality in an interacting cluster Ising chain
Sourabh, Bachana Beradze, Mikheil Tsitsishvili et al. (+2 more)
We investigate the cluster Ising chain with an additional nearest-neighbor interaction using tensor-network methods and a weak-coupling field theory. Without the interaction, the Jordan-Wigner transformation decomposes the model into a triplet of identical Majorana chains related by an exact $O(3)$
flavor symmetry. Their common mass vanishes at the $SU(2)_2$ Wess-Zumino-Novikov-Witten critical point with central charge $c = 3/2$ separating the
symmetry-protected topological cluster phase from a ferromagnet. The interaction reduces $O(3)$ to its cyclic subgroup $C_3$, splitting the triplet into a singlet and a doublet whose gaps close separately, producing a critical bifurcation into Ising ($c = 1/2$) and Gaussian ($c = 1$) critical lines. A second
ferromagnetic phase opens between these critical lines for repulsive interactions and a disordered phase for attractive ones. The Gaussian line then separates two Landau-incompatible ferromagnets, realizing a deconfined
quantum critical line with emergent $O(2)$
symmetry, along which our independently extracted exponents vary continuously yet satisfy the parameter-free relation $\beta = (2\nu - 1)/4$ of the eight-vertex weak universality class. At stronger repulsion this line opens into an extended gapless floating phase with incommensurate algebraic correlations, entered through Berezinskii-Kosterlitz-Thouless transitions. All of these phases and the transitions between them are captured by the weak-coupling theory. Beyond its regime of validity, our simulations reveal a translation-
symmetry-breaking antiferromagnet reached through first-order transitions.
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All authors Sourabh, Bachana Beradze, Mikheil Tsitsishvili, Alexander Nersesyan, Titas Chanda
Quantum Physics
Three-slit interference with a which-path memory ancilla: A bright-dark state formulation
Ajay Kumar, Guruprasad Kadam and Anirban Pathak
In this paper, we study the effect of a which-path
memory ancilla on the three-slit interference pattern within the framework of the bright–dark state description [Phys. Rev. Lett. 134, 133603 (2025)]. Whereas two slits give one bright mode, a photonic mode that couples to the detector atoms, and one dark mode, which does not couple to the detector atoms, three slits lead to one detector-coupled bright mode and a two-dimensional dark-mode subspace in the three-dimensional path space. We first discuss the classical three-slit interference pattern in terms of probability leakage into the dark subspace. We then study the von Neumann
entropy $S_D$ of the dark subspace and the coherence measures of the reduced photonic state obtained by tracing out the
memory: dark-sector coherence $C_D$ and bright–dark coherence $C_{BD}$. These quantities bring out the internal
quantum structure of the two-dimensional dark subspace. We show that, whereas $C_D$ is not by itself a basis-independent physical observable, $C_{BD}$ is basis-invariant. We establish that, for two paths, $C_{BD}$ is fixed entirely by the populations and the single pairwise coherence, whereas for multiple paths, $M\geq 3$, it acquires a genuinely multipath contribution generated by asymmetry among the pairwise which-path overlaps. Finally, we distinguish the part of the path-coherence loss that is recoverable through a suitable measurement of the
memory from the irreducible coherence deficit imposed by an uncontrolled environment.
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Medical Physics
Validation of HRV Studio: A Transparent and Quality-Control-Aware Platform for Heart Rate Variability Analysis
Cyrus Mexon Evrard Djindot, Faliang Liu, Sylvain Laborde et al. (+6 more)
Reproducibility of heart rate variability (HRV) analysis is limited by differences in preprocessing and computational conventions across software platforms. We developed HRV Studio, an open-source PyQt6-based desktop application integrating transparent HRV analysis with automated quality-control (QC) diagnostics. Validation included large-scale agreement with NeuroKit2, targeted Kubios benchmarking, spectral-method comparison, synthetic perturbation testing, recording-duration sensitivity analysis, and arrhythmia-focused QC stress testing. HRV Studio showed near-identical agreement for the widely used time-domain indices RMSSD and SDNN under matched conditions. In the primary five-minute NeuroKit2 comparison, frequency-domain median relative errors were 1.35% for LF, 0.18% for HF, and 1.41% for LF/HF, while VLF remained more convention-sensitive (37.79%). Nonlinear Poincaré indices also demonstrated high consistency. Sequence-harmonized Kubios benchmarking confirmed near-identical agreement for time-domain and nonlinear indices and strong agreement for most frequency-domain measures. Extended ten-minute analyses reproduced the same overall pattern with lower disagreement for some convention-sensitive spectral outputs. Synthetic and arrhythmia stress tests maintained 100% numerical stability while consistently triggering QC warnings. Overall, HRV Studio provides a transparent and reproducible platform for HRV research, with strong cross-platform consistency when NN sequences, preprocessing, and analytical conventions are harmonized. Stress-test results indicate computational robustness rather than clinical validation.
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All authors Cyrus Mexon Evrard Djindot, Faliang Liu, Sylvain Laborde, Yinjia Zhang, Jessie Chen, Ming Li, Congrong Wang, Weixiong Rao, Qinpei Zhao
Materials Science
Off-stoichiometric variable doping for exceptional power factors in L2$_1$ Fe$_2$VAlM$_x$ (M=Ti, W) epitaxial thin films
Jose María Domínguez-Vázquez, Miguel Angel Tenaguillo, Ketan Lohani et al. (+7 more)
We show that the addition of Ti or W to stoichiometric L2$_1$ Fe$_2$VAl thin films by sputter codeposition produces off stoichiometric thin film
alloys with superior thermoelectric properties than their stoichiometric counterparts. Ti incorporation induces p-type semiconducting behavior, while W incorporation shifts the material toward n-type, hereby enabling simultaneous tuning of both carrier types within a single parent (Fe$_2$VAl) material system, making it highly desirable for thermoelectric devices. The introduction of both Ti and W partly substitutes V in the stoichiometric compound. The partial substitution of V in the stoichiometric
alloy allows fine-tuning the band structure of the system and transport properties. With this approach we obtain exceptional maximum power factor values for p and n-type films of 1300 $\mu$W/m$\cdot$K$^2$ and 2100 $\mu$W/m$\cdot$K$^2$ ,respectively, yielding maximum figures of merit zT of 0.07 and 0.14, respectively.
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All authors Jose María Domínguez-Vázquez, Miguel Angel Tenaguillo, Ketan Lohani, Jose J. Plata, Antonio M. Marquez, Olga Caballero-Calero, Alfonso Cebollada, Andrés Conca, Ernst Bauer, Marisol Martín-González
Earth and Planetary Astrophysics
Nitrogen- and nitrogen-oxygen-bearing organic molecules in comet 67P/Churyumov-Gerasimenko: An untargeted investigation
N. Hänni, K. Altwegg, D. Baklouti et al. (+6 more)
Comets provide a unique window into the history of the
Solar System as they carry some of the best-preserved material and make it available to in situ exploration. A milestone in comet studies was the European Space Agency's Rosetta mission, which, for the first time, rendezvoused with a comet, namely 67P/Churyumov-Gerasimenko (67P), and studied it from a close range for two years. Amongst other unexpected insights, data from this mission show that comets contain a surprisingly large portion of organics, both in the refractory and the icy phases. For this work, we evaluated high-resolution mass spectra collected in comet 67P's inner coma by Rosetta's ROSINA-Double Focusing Mass Spectrometer (DFMS). In unprecedented detail, we investigated the N- and NO-bearing cometary complex organic molecules (COMs) of the general sum formula CnHmN and CnHmNO, where n and m are the stoichiometric coefficients of carbon and hydrogen. Our discussion-driven approach combines the empirical concept of Occam's razor with knowledge from studies of relevant astrophysical environments and constraints expected from naive bottom-up assembly of molecules. We present an exemplary minimal and non-unique set of molecules needed to explain the DFMS observations. While this set might not capture the full organic diversity, but rather its lower limit, it identifies many N- and NO-bearing COMs with reasonable certainty, while excluding others, potentially informing future observational campaigns, and hence contributes to the exploration of the origin and
evolution of organic complexity in space. Among the key results is strong evidence for an abundant presence of heterocycles as well as substantial alkylation of both cyclic and acyclic species. These findings align well with reports on soluble organic matter in meteorites and asteroids and ...
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All authors N. Hänni, K. Altwegg, D. Baklouti, M. Combi, S. A. Fuselier, J. De Keyser, D. R. Müller, M. Rubin, S. F. Wampfler
Materials Science
Influence of Interface Energy Anisotropy on the Solid-state Instability in Ni-based Superalloy: A Multiscale Study
Sourav Ghosh, Christian Brandl and Rajdip Mukherjee
The microstructural stability of nickel-based superalloys critically depends on the morphology and
evolution of $\gamma'$-precipitates, which is governed by elastic and interfacial anisotropies at the atomic scale. Here, we present a novel quantitative multiscale framework that, for the first time, directly incorporates atomistically computed interface energy anisotropy into mesoscale phase-field simulations to elucidate morphological selection and instability in the Ni–Al system. We employ density functional theory (DFT) to accurately predict the orientation-dependent $\gamma/\gamma'$ interface energies for key crystallographic planes. A rigorous analytic mapping is then developed to systematically reduce the three-dimensional (3D) interface anisotropy landscape to the two-dimensional (2D) simulation plane. This enables quantitative transfer of DFT-informed anisotropy parameters into a continuum phase-field model that also accounts for elastic inhomogeneity and eigenstrain. Our simulations demonstrate that the explicit inclusion of DFT-based interface energy anisotropy fundamentally alters precipitate morphological
evolution, robustly suppressing instability and faceting phenomena otherwise promoted by supersaturation and elastic effects. The framework bridges atomic- to mesoscale modeling, enabling predictive control of precipitate shapes and providing new insights into the interplay of elastic and interfacial contributions in Ni-based superalloys. This approach paves the way for quantitative microstructural design in advanced high-temperature
alloys via first-principles-guided multiscale simulation.
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Quantum Physics
A Theory of Finite-Noise Optima and Generalization in Quantum Machine Learning
Ziyu Zhang, Zikang Jia, Xiaosong Li et al. (+1 more)
Quantum noise is expected to degrade
quantum machine learning by driving
circuits away from their noiseless implementations. Yet recent studies show moderate noise can reduce testing error, a behavior unexplained by weak-noise perturbative error accumulation or strong-noise trainability collapse. Here we develop a statistical learning theory connecting microscopic noise processes to macroscopic learning performance. At its heart is a noise-order purity parameter, derived from a surrogate model analysis, that predicts the noise-induced reduction in model complexity and the consequent reduction in the generalization gap. Noise simultaneously increases prediction bias. Their competition explains the intermediate-noise regime left open between these limits. It produces a finite-noise optimum whose location depends on the learning setup and can disappear in the large-sample limit. Numerical experiments validate these predictions. Noise programming can move a model towards this optimum. These results make the non-monotonic effect of noise predictable and provide a route to harness it.
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All authors Ziyu Zhang, Zikang Jia, Xiaosong Li, Yulong Dong
Materials Science
Two Microscopic Mechanisms of Piezomagnetism in CoF$_2$ from First-Principles Calculations
Hiroshi Katsumoto, Tamio Oguchi and Kunihiko Yamauchi
Rutile-structured CoF$_2$ has long been recognized as a prototypical piezomagnetic material. Recently, it has attracted renewed interest as an altermagnet, exhibiting
spin-split electronic bands even in the absence of
spin-orbit coupling. Although the piezomagnetic response of CoF$_2$ has been extensively discussed from the viewpoint of
magnetic symmetry, its microscopic origin has remained elusive. First-principles calculations reveal two distinct microscopic mechanisms of piezomagnetism in CoF$_2$. Under $xy$ shear strain, the local volumes of the CoF$_6$ octahedra surrounding the two Co sites become different, leading to unequal
magnetic moments on the two sublattices and hence a net magnetization. In contrast, under $yz$ shear strain, the piezomagnetic response originates from
spin canting induced by the Dzyaloshinskii–Moriya interaction through
spin-orbit coupling. The presence of two distinct microscopic mechanisms may be a general feature of piezomagnetic antiferromagnets.
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Astrophysics of Galaxies
An HI study of a large sample of ultra-diffuse galaxies
Ruilei Zhou, Ming Zhu, Chuan-Peng Zhang et al. (+5 more)
By cross-matching the SMUDGes catalog with the FASHI and ALFALFA HI surveys, we construct an HI-detected sample of 112 ultra-diffuse
galaxies (UDGs) and 48 low-surface-brightness (LSB)
galaxies, providing HI-based
redshifts for 76
galaxies for the first time. Using DESI DR1
redshifts, we assemble an HI-non-detected sample of 168
galaxies for stacking analysis, with detections in two
stellar mass bins below 10^{8.5} M_sun. Combining optical, UV, and HI data, we investigate
stellar masses,
star formation rates, gas fractions, and kinematics. We present a systematic analysis of the HI mass–optical size relation for UDGs and LSBs, showing both populations follow a mass–optical size scaling similar to normal
galaxies, suggesting an average HI surface density, under the assumption that the optical size traces the extent of the HI distribution. Their
stellar mass–size relation indicates nearly constant
stellar surface densities for
galaxies with central surface brightness mu_{0,g}>~24mag arcsec^{-2}, independent of UDG or LSB classification. Many UDGs and LSB
galaxies are systematically offset from the baryonic Tully–Fisher relation toward higher baryonic masses at a given velocity, consistent with trends found in UDGs with resolved HI kinematics. Both populations exhibit low
star formation efficiencies and long gas depletion times, supporting multiple formation pathways for UDGs.
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All authors Ruilei Zhou, Ming Zhu, Chuan-Peng Zhang, Lin Du, Cheng Cheng, Qi Guo, Tian-Wen Cao, Wenzhe Xi
Materials Science
Excitonic fingerprints of magnetic configurations and switching in multilayer CrSBr
Lukas Krelle, Ryan Tan, Jakob Conradi et al. (+6 more)
The coupling between electronic states and magnetism provides a route towards optical readout and control of
magnetic information. In the
magnetic semiconductor CrSBr,
excitons are coupled to
magnetic order, making their optical response sensitive to the underlying magnetization. Here, we show that the energy and oscillator strength of bulk and surface
excitons provide distinct spectroscopic fingerprints of
magnetic configurations and switching pathways. We distinguish domain-wall-mediated magnetization reversal, manifested by continuous spectral
evolution as a domain wall traverses the optical spot, from abrupt, large-area magnetization reversal. Using the resulting excitonic fingerprints, we reconstruct successive
magnetic configurations in 4- and 5-layer CrSBr during the transition from
ferromagnetic to
antiferromagnetic order. We further find that the sensitivity to
magnetic order is strongly
exciton-dependent: low-energy
excitons resolve intermediate and surface-related configurations, whereas a higher-energy
exciton predominantly exhibits a transfer of oscillator strength between
ferromagnetic and
antiferromagnetic resonances. These results establish excitonic spectroscopy as a sensitive probe of layer-dependent
magnetic configurations and their switching pathways in layered
magnetic semiconductors.
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All authors Lukas Krelle, Ryan Tan, Jakob Conradi, Priyanka Mondal, Wenze Lan, Kseniia Mosina, Regine von Klitzing, Zdenek Sofer, Bernhard Urbaszek
Mathematical Physics · Cross-listed from math.CA
Optimal Hardy Inequalities for Random Walks on $\mathbb{Z}^2$
Philipp Hake, Matthias Keller and Felix Pogorzelski
We prove an optimal Hardy inequality for every aperiodic, symmetric random walk in $\mathbb{Z}^2$ with finite variance. In particular, we verify null-criticality, and thus, optimality of the underlying Hardy weight. Under suitable moment conditions, we use fine asymptotics of the potential kernel due to Fukai and Uchiyama in order to derive the asymptotics of the weight. For the standard
Laplacian, we recover the expected first order term in the asymptotics but also show that next order term is negative. Thus, our result shows that the constant in the Hardy inequality proven by Kapitanski and Laptev cannot be larger than $1/4$, which is the optimal constant in the continuum. The proof of null-criticality rests on a new criterion for general graphs beyond the locally finite case. We also recover the situation of $\mathbb{Z}^d$ with $d \geq 3$ which can also be also treated by our new method.
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Astrophysics of Galaxies
SDSS-IV MaNGA: Star Formation Cessation in Low-redshift Galaxies. III. Dependence on Quenching Criteria
Zhuo Cheng, Tao Jing, Cheng Li et al. (+1 more)
This paper is the third in a series of studies investigating
star formation cessation in nearby
galaxies on kiloparsec scales. Using the final SDSS-IV MaNGA data release, we ask how the inferred importance of global, local, and environmental properties depends on the operational definition of quenched regions. We classify spaxels as
star-forming, reliably quenched, or potentially quenched by accounting for measurement uncertainties, and train random forest classifiers with a parameter set chosen for direct comparison with previous work. For reliably quenched regions, the local
stellar mass surface density $\Sigma_\ast$ consistently has the highest feature importance, independent of quenching definition. By contrast, the high importance of central velocity dispersion $\sigma_c$, previously interpreted as evidence for
galaxy-wide AGN feedback, is recovered mainly when potentially quenched regions are included. The leading parameter also varies with
stellar mass: $\Sigma_{\rm 1kpc}$ is most important below $\sim10^{10.2}\,\textrm{M}_{\odot}$, whereas local quantities such as $\Sigma_\ast$ and $\sigma_\ast$ become more prominent at high masses. These results show that quenching criteria and uncertainty treatment can reconcile apparently discrepant feature-importance studies. AGN-related processes may contribute to ambiguous regions, but the reliably quenched population is most tightly linked to high local
stellar density.
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All authors Zhuo Cheng, Tao Jing, Cheng Li, Renbin Yan
Statistical Mechanics
A Minimal Thermodynamically Consistent Chemical Oscillator
Benedikt Remlein, Luca Monari, Beatrice Bartolomei et al. (+3 more)
Inspired by the chemical reaction network considered as the smallest system featuring a
Hopf bifurcation and its reversible extension, we introduce an even more minimal reaction network that is thermodynamically consistent and exhibits autonomous oscillations under nonequilibrium driving. The model combines three features that are rarely realized simultaneously in compact oscillator networks: a chemically plausible structure restricted to uni- and bimolecular reactions, reversibility of such reactions, and analytical tractability. The system consists of three internal species coupled to two chemostatted species and still undergoes a supercritical
Hopf bifurcation when a chemostat concentration is varied. To analyze the dynamics and thermodynamics near the onset of oscillations, we employ the mathematical technique of normal-form reduction, which allows obtaining a controlled irreversible approximation that preserves the leading phase-space structure of the full reversible network while enabling explicit calculations. This framework provides analytical access to the bifurcation structure and the leading contributions governing thermodynamic observables. Within this setting, we use the onset of oscillations to characterize the thermodynamic response of the system. In particular, we offer an analytical description of key thermodynamic quantities such as the semi-grand Gibbs free energy and the non-conservative work rate, which exhibit a kink-like discontinuity at the
Hopf bifurcation. We thus provide an analytical description of a phenomenon previously characterized only through numerical simulations of more complex networks.
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All authors Benedikt Remlein, Luca Monari, Beatrice Bartolomei, Giulio Ragazzon, Massimiliano Esposito, Emanuele Penocchio
Solar and Stellar Astrophysics
Flare waiting time as a novel proxy of stellar magnetic activity
Henggeng Han, Song Wang, Chuanjie Zheng et al. (+3 more)
Stellar flares have long served as
stellar magnetic activity tracers. The
flare waiting time, defined as the interval between two consecutive
flares, provides a valuable diagnostic for probing underlying mechanisms of energy storage and release in
stellar atmospheres. In this work, utilizing flaring M
dwarfs observed by the Kepler satellite, we establish a simple yet effective activity proxy, i.e., median
flare waiting time ($t_{\rm{w, med}}$). Our results show that the $t_{\rm{w, med}}$ can trace long-term activity levels similar to the
flare rate. However, $t_{\rm{w, med}}$ corresponding to different waiting time percentiles may encode richer physical insights than
flare rate. In addition, for the first time we construct a clear relation between $t_{\rm{w, med}}$ and
stellar rotation period, which is quite similar to the canonical activity–rotation relation. More intriguingly, this relation exhibits a more notable supersaturation effect (i.e., below a critical rotation period, $t_{\rm{w, med}}$ begins to increase instead of keeping constant) compared to other activity proxies. The filling factor–rotation period relation favors poleward migration of active regions as the explanation for supersaturation, rather than coronal stripping. With the dramatic increase in
stellar flares detected by missions like TESS and the upcoming Earth 2.0 satellite, $t_{\rm{w, med}}$ will become a powerful diagnostic for probing
stellar magnetic activity and underlying physics.
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All authors Henggeng Han, Song Wang, Chuanjie Zheng, Cunshi Wang, Xue Li, Jifeng Liu