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Friday 4 September

Earth and Planetary Astrophysics

Signatures of rocky debris accretion in AF-Type planet hosts

The gas-giant planet-metallicity correlation plays a fundamental role in our understanding of planet formation. We determine in a homogeneous way the metallicity and individual abundances of a sample of A and early-F stars, with and without known planetary companions, and discuss their abundance distribution and trends. We find that stars with planets generally exhibit higher abundances of both iron-peak and volatile elements compared to stars without known planets although in most cases this tendency is not statistically significant. The $\rm {C/O}$ ratio remains similar between both samples, while the $\rm {Mg/Si}$ ratio is shifted towards higher values in the general planet host sample. When the sample is limited to fully radiative stars (spectral type earlier than F5), the statistical significance of carbon overabundances vanishes. In contrast, elements such as O and Ni remain significantly overabundant. The $\rm {C/O}$ and $\rm {Mg/Si}$ ratios in this radiative subsample are statistically indistinguishable from that of the comparison sample. The persistent overabundance of O and Ni, combined with $\rm {C/O}$ and $\rm {Mg/Si}$ ratios similar to those of stars without planets in fully radiative hosts, points to the ongoing surface pollution by volatile-poor, silicate-rich rocky debris, rather than the accretion of gas giants. These findings might position early-type main-sequence stars as a crucial dynamical missing link in the chemical life-cycle of planetary systems: bridging the initial dust-trapping phase in pre-main sequence transition discs, the dilution of this superficial pollution during the fully convective red giant phase, and the eventual dynamically-driven accretion of asteroid material observed in polluted white dwarfs
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All authors J. Maldonado, I. Mendigutía, S. Barceló Forteza, G. M. Mirouh, B. Montesinos, E. Villaver

Mathematical Physics · Cross-listed from math.PR

Height fluctuation for Lozenge Tilings of Polygons

We establish Gaussian free field fluctuations for uniformly random lozenge tilings of simply connected polygonal domains with $3d$ sides whose directions cycle through the three lattice directions. More precisely, assuming that the liquid region is connected and that the boundary data do not force the height at any interior point, we prove that the fluctuations of centered height function converge to the Gaussian free field in the liquid region, confirming a prediction of Kenyon and Okounkov from 2007. We introduce a tiling action function that encodes the geometry of the limit shape through its critical points. The action function has a complex conjugate pair of critical points in the liquid region, repeated real critical points on the arctic boundary, and distinct real critical points in the frozen region. Using this tiling action function, we construct an approximation to the inverse Kasteleyn matrix in terms of explicit single-contour and double-contour integrals and prove that the approximation is uniform throughout the polygonal domain. The convergence to the Gaussian free field then follows from standard kernel computations.
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Quantum Physics

Shapley Valuation of Finite-Copy Quantum Data Depends on Physical Access

Data valuation asks how learning utility should be attributed to training data contributors. Most classical formulations begin after data have become reusable records, so the physical readout of the data is effectively fixed. Finite-copy quantum data are different: unknown states are consumable physical systems, and the same supplied states and downstream task can yield different Shapley values under different physical access models. Our framework makes this dependence explicit by treating physical access as a component of quantum data valuation itself. We establish an exact connection between physical-access advantage and contributor-level data valuation. For nested access models, we prove that the maximal downstream utility gain enabled by richer physical access exactly determines the largest symmetric Shapley ranking-reversal margin. More generally, for arbitrary access-model pairs, including non-nested ones, we derive an exact geometric characterization of the possible shifts of the full Shapley attribution vector. For fixed learning pipelines, we further obtain an operational Shapley-observable representation for finite-copy valuation. Numerical experiments demonstrate that identical quantum samples can receive different values and rankings when only the physical access model is changed. These results establish that quantum data value is not an intrinsic property of the underlying states alone, but emerges from the interaction between quantum states, physical access, and the downstream learning task.
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High Energy Astrophysical Phenomena

The angular structure of the GW170817 jet from prompt emission alone

We determine the angular structure of the GW170817 jet by the prompt emission alone, without afterglow fitting, circumburst density or microphysical parameters. We assume that GRB 090510 and GW170817 have outflows of the same kind, observed respectively on-axis and at the interferometric viewing angle of $20^\circ$. We support this assumption with independent gravitational-wave data showing compatible binary masses and radiated energies. We show that for an observer whose beaming cone is filled with outflow, the point-source Doppler scalings do not apply: $E_{\rm iso}=4\pi\epsilon(\theta_v)$, with $\epsilon$ the energy radiated per unit solid angle along the line of sight, while the peak energy follows $E_{\rm p,i}\propto\Gamma(\theta_v)$. We obtain $n={\rm d}\ln\epsilon/{\rm d}\ln\Gamma = 3.76\pm0.29$ from the ratio of the two bursts, with no free parameter and no assumed angle. This excludes four structures in common use at $4.7\sigma$ to $13\sigma$; three remain above $4\sigma$ across the full reported range of the peak energy of the GW170817 jet. Two prompt spectra fix no angular scale; supplying it with the core Lorentz factor of GRB 090510 and the viewing angle gives $\epsilon\propto\theta^{-7.4}$ outside a core of $2^\circ$–$5^\circ$, in agreement with the width inferred from $367$ short bursts, the outflow remaining relativistic at $\Gamma=33$ on the line of sight. The exponent exceeds what the Lorentz boost of a uniform comoving flow can produce, so the structure is intrinsic to the outflow and not a consequence of the boost. The same structure fixes the emission radius, which contributes $0.41$~s of the $1.74$~s delay between the gravitational-wave signal and the gamma-rays, the remainder being the launch and breakout of the jet, with no free parameters. We conclude that the faintness lies in the structure of the GW170817 jet, not in the de-beaming of a bright core.
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High Energy Astrophysical Phenomena

Through a glass, darkly: a combined framework for estimating fast radio burst host galaxy and population properties in an era of uncertain host identification

The identification of fast radio burst (FRB) host galaxies, and subsequently their redshifts ($z$), has allowed the FRB dispersion measure (DM) to be used to probe the cosmological distribution of ionised gas, and study the properties of the FRB population itself. However, current methods cannot account for FRBs with uncertain host galaxy associations, leading to underutilisation of data, and potential biases towards nearby, bright hosts. In this work, we develop a methodology which can. We do so by combining three ingredients - the zDM code, for modelling the Macquart relation; PATH, for statistical host galaxy identification; and a set of models able to describe the intrinsic FRB host galaxy distribution - into a single formalism. We prove the fidelity of our formalism by using a synthetic set of FRB observations, with simulated hosts sampled from galaxy catalogues, and show that it reproduces intrinsic host galaxy properties even for FRB localisation uncertainties of 30", where a traditional PATH analysis produces no confidant host associations. When applied to a sample of FRBs localised by the Australian Square Kilometre Array Pathfinder, we confirm previous results showing that FRBs prefer host galaxies fainter than that predicted by star-formation, consistent with an exponential surface density scaling as $0.41^{+0.13}_{-0.09}$ times the half-light radius. We encourage the application of this formalism to data-sets from other FRB-hunting instruments.
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All authors C.W. James, B.C. Andersen, L. Marnoch, J.L. Hoffmann, N. Loudas, J.X. Prochaska, S.D. Ryder, M. Woodland

High Energy Physics (Phenomenology)

Flavor Tomography of Long-Lived Neutrino-Mass Mediators: Probing the Neutrino Mass Ordering at the HL-LHC

The neutrino mass ordering remains unresolved because long-baseline oscillation measurements are entangled with the unknown CP phase $\delta_{CP}$; a collider probe free of this degeneracy would provide a qualitatively different, complementary test. We show that when the long-lived charged particle producing a displaced-lepton signal at the High-Luminosity LHC is also the mediator responsible for Majorana neutrino masses—the shared-coupling condition—the Casas–Ibarra parametrization determines the lepton flavor ratio $N_e/N_\mu$ of time-delayed leptons in terms of Pontecorvo–Maki–Nakagawa–Sakata (PMNS) mixing parameters alone. Within the resulting shared-coupling class of models the ratio is fixed by oscillation data, independent of all beyond-Standard-Model mass and coupling parameters up to calculable corrections bounded by charged-lepton-flavor-violation data, yielding $N_e/N_\mu = 0.140$ for the Normal and $2.11$ for the Inverted Hierarchy—a separation of more than an order of magnitude between the two predictions. This prediction holds identically across the Scotogenic model, the Type-III seesaw, the inverse and linear seesaw, and lepton-portal dark matter, and is stable against oscillation-parameter uncertainties and detector-efficiency variations, which cancel in the ratio. A single efficiency-corrected decision criterion identifies the hierarchy, and explicit signal-yield estimates combined with an exact Poisson test show that $\mathcal{O}(25)$ displaced-lepton events suffice for a $3\sigma$ discrimination with the timing infrastructure already under construction at CMS and ATLAS—so that a positive long-lived-particle signal would simultaneously resolve the mass ordering, with no dependence on $\delta_{CP}$.
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Nuclear Theory

Rotational Feshbach resonances in the deformed halo nucleus $^{31}$Ne

Background: The deformed halo nucleus $^{31}$Ne exhibits unique structural properties arising from the interplay between its halo neutron and the deformation of the $^{30}$Ne core. While previous studies have established the nature of its weakly-bound ground state through reaction cross sections and inclusive breakup measurements, the structure of its excited states in the low-energy continuum, which are expected to appear as resonances, remains largely unexplored. Purpose: We investigate the structure of these resonant states and clarify their rotational nature and formation mechanism. Method: The structure of $^{31}$Ne is described using the particle rotor model (PRM), which explicitly treats the coupling between core excitation and single-particle motion in both bound and continuum states. Results: The calculations predict the emergence of unbound rotational states in the low-energy continuum of $^{31}$Ne, which form a rotational sequence built on the weakly-bound Nilsson [321 3/2] configuration. As the total angular momentum increases along the rotational band, the intrinsic Nilsson structure is largely preserved, whereas the dominant core-spin component shifts to higher spins. These resonances are stabilized through the combined effects of coupling to higher-lying closed core-excited channels and reduced effective neutron relative energies, and can therefore be interpreted as rotational Feshbach resonances. Conclusion: The present study elucidates the formation mechanism of rotational Feshbach resonances in $^{31}$Ne. This mechanism is expected to be a general feature of weakly-bound deformed nuclei. Exclusive breakup measurements with coincident detection of $\gamma$ rays from the de-exciting core will provide crucial tests of the proposed formation mechanism of rotational Feshbach resonances.
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All authors Shin Watanabe, Shoya Ogawa, Takuma Matsumoto, Kazuyuki Ogata

Medical Physics

BEAM3R: Beam's-eye-view architecture with Mamba-3 for implicit dose reconstruction

To enable accurate and rapid photon control point and proton beamlet dose calculation in the DoseRAD2026 challenge, we present BEAM3R, a dose estimation framework operating in beam's-eye-view (BEV). Our core innovation combines a Mamba-3 state-space depth-sequence core with physics-based transport conditioning to model long-range depth transport without expensive 3D convolutions. BEAM3R shares a 2D CNN encoder-decoder architecture for photon and proton dose tasks, processing per-plane BEV slices. Proton beamlets are conditioned on water equivalent thickness and remaining range, encoding the parameters determining Bragg peak position. Photon models use a bidirectional Mamba-3 core to capture dose contributions from materials downstream of the calculation point, while the proton model uses a forward core with learned energy-prefix tokens and a Bragg-peak refinement module. To reduce interpolation artifacts and support high spatial resolution, we introduce axial grid alignment of BEV lattices with CT slices and an implicit super-resolution representation via sub-pixel phase packing, evaluated by a differentiable Triton-accelerated resampler that reconstructs packed cubic B-spline coefficients directly in CT space. For MRI-based tasks, synthetic CTs (sCT) are generated by a patch-based conditional GAN with a SwinUNETR backbone. On the preliminary DoseRAD2026 test set, CT-to-photon and CT-to-proton models achieved 1%/1 mm local gamma pass rates of 96.8% and 96.0%, with stratified plan-level MAEs of 0.0041 and 0.0079. Substituting sCT reduced gamma pass rates to 89.7% for photon and 75.4% proton plan level doses, with stratified plan-level MAEs of 0.0093 and 0.0336. Standardised runtimes were 23.4 s and 18.4 s for CT-to-photon and CT-to-proton prediction, increasing to 39.7 s and 42.8 s for the corresponding MRI-based pipelines.
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All authors Chen Cheng, Michael Ferraro, James Grover, David E J Waddington, Emily Hewson

Cosmology and Nongalactic Astrophysics

Studies on the dark sector interaction from joint analysis of cosmological probes

We test whether constraints on the nonlinear interaction $\xi$IDE are stable under different treatments of the Type Ia supernovae absolute calibration. Fermi GRBs measurements and the Amati-relation parameters are fitted jointly with PantheonPlus SNe Ia, DESI DR2 BAO, and an updated cosmic-chronometer compilation. We compare the PantheonPlus-SH0ES route, which retains the SN absolute calibration, with the PantheonPlus-only route, in which the SN absolute magnitude is analytically marginalized. The GOLD GRB sample is adopted for the main analysis, while the FULL GRB sample is used to assess sample dependence. For the interaction parameter $\gamma\equiv\xi+3w$, where $\gamma=0$ denotes the non-interacting limit, the GOLD sample gives $\gamma=1.453^{+1.297}_{-1.597}$ for the PantheonPlus-SH0ES and $\gamma=-0.634^{+1.668}_{-2.486}$ for the PantheonPlus-only. Although the posterior medians correspond to opposite directions of energy transfer, neither route excludes $\gamma=0$ at 68% credibility, and the reconstructed interaction rate remains consistent with zero over the redshift range considered. Replacing the GOLD sample with the FULL sample produces negligible changes in the interaction constraints. Moreover, $w$CDM and CPL achieve likelihood improvements comparable to that of $\xi$IDE, while the information criteria do not consistently favor the interacting model. A redshift-bin diagnostic finds no significant redshift evolution of the Amati relation. We find no compelling evidence for a dark sector interaction that is robust to the choice of SN calibration or specifically favored over noninteracting dark energy extensions.
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All authors Jianfeng Meng, Xiaofeng Yang, Yunliang Ren, Bohao Wang, Jingze Li, Kang Jiao, Xiongwei Liu

Superconductivity

Orientation selection and superconducting properties of epitaxial Al on ferromagnetic semiconductor (In,Fe)As

Superconductor/ferromagnet heterostructures provide a versatile platform for exploring spin-dependent superconducting phenomena arising from interfacial proximity effects. In this article, we investigate the structural and superconducting properties of Al thin films grown in situ by molecular beam epitaxy on strained Fe-doped ferromagnetic semiconductor (FMS) (In,Fe)As layers. X-ray diffraction and transmission electron microscopy reveal the epitaxial growth of single-crystalline Al layers, with the growth orientation changing from (110) to (111) as the in-plane lattice constant of (In,Fe)As increases. The superconducting critical temperature of Al varies systematically with the film surface morphology and grain size. In addition, the critical magnetic field of Al exhibits an anomalous decrease below 0.5 K, possibly reflecting magnetic coupling to the underlying FMS (In,Fe)As layer. These findings provide a guideline for material design of epitaxial Al/(In,Fe)As heterostructures, which may serve as a promising platform for investigating proximity-induced superconducting and magnetic phenomena in semiconductor-based hybrid quantum devices.
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All authors Hirotaka Hara, Keita Ishihara, Masaaki Tanaka, Le Duc Anh

Atomic Physics

Analytical model for polarization transfer during gas-phase collision events in spin-exchange optical pumping: Spin-$\frac{1}{2}$ $^{129}$Xe versus spin-$\frac{3}{2}$ $^{131}$Xe

Spin-exchange optical pumping (SEOP) is a method for producing spin-hyperpolarized noble gas nuclei, such as 129Xe and 131Xe, which are used in various magnetic resonance applications from fundamental physics to quantum sensing and medical imaging. In SEOP, optically polarized alkali-metal atoms transfer their spin polarization to the noble gas nuclei in gas-phase collision events via the hyperfine coupling (HFC) between the alkali valence electron and the noble gas nucleus. While the polarization transfer physics of spin $I = 1/2$ nuclei, such as 129Xe, is relatively well understood, that of spin $I > 1/2$ nuclei, such as 131Xe ($I = 3/2$), has been far less studied, and no rigorous theoretical model has been presented to date. To this end, we derive a simple analytical model for the upper limit, neglecting relaxation, of the SEOP polarization transfer, applicable to noble gases with arbitrary nuclear spin. Analytical evaluation of the Baker-Campbell-Hausdorff expansion for the time evolution of the spin density operator $\hat{\rho}(t)$ reveals that only even-order terms in the HFC contribute to the polarization transfer, with the leading-order quadratic term being the most significant. We obtain a result similar to that derived for the spin-exchange cross section by Herman [Phys. Rev. 137, A 1062 (1965)], but in a more general framework for the time evolution of $\hat{\rho}(t)$ that is also more familiar to magnetic resonance researchers. The model is applied to understand the difference in the polarization transfer efficiency between 129Xe and 131Xe, yielding results in agreement with previous experiments. We also validate the model by comparison to detailed numerical multiscale simulations of the SEOP process, where full quantum-chemically computed spin Hamiltonians sampled from molecular dynamics simulations of the gas-phase collision events are used to propagate the spin dynamics.
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Nuclear Theory

FUSION: a skill-based research agent for publicly obtainable nuclear-physics codes

Running an unfamiliar nuclear-physics code is rarely difficult because of the physics alone. One must find and build the program, learn its input conventions, and decide whether a plausible output is actually correct. A general-purpose coding agent helps with the first two tasks but may make the last one harder: it can write an input file that runs with the wrong physical convention. FUSION addresses this problem with code-specific skills. A skill obtains the code from its public source, starts from a verified input, runs and parses the calculation, records known failure modes, and must reproduce a stated benchmark to a stated tolerance before reporting a result. The current release covers twenty codes, spanning optical models and reactions, nuclear structure, fission and statistical models, astrophysics and R-matrix analysis, and heavy-ion transport. It also includes an offline, searchable collection of 61 167 pages derived from the nucl-th literature. User notes and credentials remain outside the public repository. FUSION is available under the MIT license at https://github.com/jinleiphys/FUSION; documentation is at https://vibeinscience.com. Here I describe the design, the checks behind the current release, and one complete calculation from input to comparison with measured data.
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High Energy Physics (Theory) · Cross-listed from math.AG

q-Opers and Quantum/Classical Duality Beyond Type A

Using the language of q-opers, we propose an algebro-geometric description of the duality between Bethe Ansatz equations for quantum XXZ spin chains and many-body trigonometric Ruijsenaars-Schneider/Macdonald systems for classical groups. Upon this duality, the energy level sets of the classical B/C/D-type Hamiltonians are found to be in bijection with the set of solutions of the XXZ Bethe Ansatz equations of type A, albeit with open boundary conditions. This dictionary generalizes previous results in which a GL(N) XXZ spin chain with twisted periodic boundary conditions was dual to an N-body Ruijsenaars-Schneider system. Our construction implements a $\mathbb{Z}/2\mathbb{Z}$ folding both at the level of the (GL(N),q)-oper data as well as at the level of the N-body trigonometric Ruijsenaars-Schneider model. The nonreduced BC-type systems appear in our analysis as well.
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Plasma Physics

Activated carbon-assisted anionic dye decomposition using a dual-liquid post-double dielectric barrier discharge plasma reactor

Non-thermal Plasma (NTP) technology, including the Dielectric Barrier Discharge (DBD) reactor, has emerged as an effective advanced oxidation process (AOP) for treating persistent organic pollutants in industrial wastewater. Based on this objective, a dual-liquid dielectric-barrier-discharge plasma reactor was built and used to degrade a ternary anionic dye mixture comprising Reactive Red 120, Congo Red, and Methyl Orange in its post-discharge configuration. The adjustable length of the outer liquid electrode (grounded) provides flexibility in controlling the discharge length and cooling, thereby achieving higher degradation efficiency and greater reactor stability. The conducting-liquid high-voltage electrode (a dielectric tube filled with a conductive solution) helps mitigate metal corrosion and oxidation caused by reactive species in the discharge zone. A detailed study of the degradation of ternary anionic dye mixtures (simulated dye wastewater samples) in the presence of activated carbon (AC) was performed to explore the potential applications of post-discharge treatment. The activated carbon (granules) enhances the degradation rate of ternary anionic dye mixtures in basic solutions rather than in acidic or neutral solutions. A comparative study of the degradation reaction kinetics of the ternary anionic dye mixtures in acidic and basic solutions was conducted after analyzing UV-Vis absorption spectra. The role of other parameters, such as solution pH, the mass and size of AC particles, dye concentrations, and AC reuse, was investigated in relation to degradation efficiency. The degradation mechanism was elucidated by the formation of strong oxidizer (hydroxyl radicals) on the surface of activated carbon during post-discharge treatment. However, in acidic or neutral anionic dye solutions, the degradation mechanism was dominated by ozone.
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Quantum Physics

Nitrogen Vacancy Centers in Diamond for Quantum Biosensing: Magnetometry Techniques, Platforms and Applications

Quantum sensing using nitrogen-vacancy (NV) centers in diamond has emerged as a powerful platform for detecting ultra-low magnetic fields under ambient conditions. Owing to their long spin coherence times, optical addressability, and compatibility with aqueous environments, it has found widespread applications in biosensing and bio-imaging. This review presents the fundamental principles and recent advances in NV-based quantum magnetometry for biosensing applications, with a particular focus on measurements in aqueous medium and at cellular and molecular length scales. We discuss the underlying spin physics of NV centers and highlight two primary detection modalities: optically detected magnetic resonance (ODMR) and T1 relaxometry-based sensing and how these approaches aids in the detection of both static magnetic fields and dynamic magnetic noise arising from biological processes. The review explores key application areas, including nanoscale nuclear magnetic resonance (NMR), monitoring of neural activity, detection of abnormal or rogue cells using NV-based platforms etc. In addition, strategies for enhancing sensitivity, such as surface functionalization of nanodiamonds, femtosecond (fs) laser-written photonic structures, and integration with microfluidic and lab-on-chip systems have also been discussed in depth. We also address the critical challenges, including surface-induced decoherence, charge-state instability, and signal-to-noise limitations in biofluids associated with NV-based biosensing applications. Finally, we outline future prospects, highlighting how NV-based magnetic biosensing provides a promising pathway for translating quantum sensing technologies into practical biomedical applications.
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All authors Sirsendu Ghosal, Umakant Prajapati, Sachin Negi, Saifian Farooq Bhat, Thejas B, Vibhav Bharadwaj

Statistical Mechanics

Thermodynamic learning

We discuss the possibility to train a thermodynamic system, whose micro-variables are fully determined through the Hamiltonian by the usual statistical mechanical rules, to perform tasks such as memorization and generalization. Training is achieved by the application of suitable external fields, playing the role of data. At variance with conventional machine learning, no other logical or algorithmic rules are introduced. The system is amenable, in principle, to exact analytical calculations. We specialize this general approach to a prototypical Ising system with annealed dichotomous couplings and study its learning ability. Results indicate excellent memorization and good generalization capacity already for small systems, and a tendency to improve with system size.
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All authors F. Corberi, S. dello Russo, G. Messuti, S. Scarpetta, L. Smaldone

High Energy Astrophysical Phenomena

Evidence of Orbital Evolution of Gigahertz-Peaked Spectra in Binary Millisecond Pulsar

We present the first systematic investigation of the continuous orbital evolution of the Gigahertz-Peaked Spectum turnover frequency ($\nu_{peak}$) in the binary millisecond pulsar, PSR J2144$-$5237. Using approximately 50 hours of densely sampled observations spanning the $\sim10$-day orbit with the Parkes Ultra-Wideband Low frequency receiver, we obtained continuous frequency coverage from 704 MHz to 4 GHz, enabling robust measurements of the spectral evolution throughout the binary orbit. We detect a clear and systematic modulation of the turnover frequency with orbital phase for both the $1^{st}$ pulse and $2^{nd}$ pulse components, with both emission components exhibiting remarkably similar evolutionary trends despite originating from distinct emission regions within the pulsar magnetosphere. The correlated evolution of the two pulse components strongly suggests that the observed spectral variability is governed by propagation through the intra-binary environment. The large orbital modulation of turnover frequency can be explained by cyclotron resonance absorption in magnetized plasma associated with the companion, while alternative absorption mechanisms are unable to reproduce the observed behaviour. Modelling the orbital evolution of the turnover frequency within the cyclotron absorption framework, can constrain the electron density distribution in the pulsar wind, estimate the magnetic field strength of the companion, and place limits on the geometry of the absorbing plasma and the binary system. This study establish orbital evolution of the Gigahertz Peaked Spectum as a powerful new diagnostic of the magnetized intra-binary medium and provide a hitherto unexplored probe of pulsar wind-companion interactions in eclipsing millisecond pulsar binaries.
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Quantum Physics

One Bit of Collective Information Is Worth N ln 2 Bits of Local Information in a Many-Body Quantum Battery

Charging a quantum battery through a collective non-adiabatic stroke stores energy in a shared bosonic mode, but part remains locked in correlations with the collective spin and is inaccessible to cyclic unitaries acting on the mode alone. A demon holding one bit can unlock this energy, quantified by the daemonic ergotropy. We investigate the value of one bit and its dependence on where the information is obtained. Two protocols are compared at matched stored energy and matched information, using balanced two-outcome measurements carrying exactly one bit. We find that one bit about the collective coordinate unlocks N ln(2) times as much work as one bit about a single ion. For three stored-energy settings and N = 4-24, the measured scaling exponent is 0.990 +/- 0.043, while double extrapolation gives a prefactor of 0.69298 +/- 0.00044, within 0.02% of ln(2). To leading order, the daemonic gain equals nu mu^2 times the between-outcome variance of Jx, verified numerically to 1.3%. A balanced single-ion measurement resolves 1/4 of this variance, whereas a balanced collective split resolves (ln(2)/4)N. The microscopic origin of the prefactor remains open; a Gaussian median-split estimate of 1/(2pi) is excluded by 9%. One bit recovers a constant fraction of the locked energy independent of N and yields roughly twice as much work per bit as a complete readout, indicating strong diminishing returns. We also show that unnormalized gain comparisons can reverse the conclusion and that the break-even ion number does not collapse onto the Dicke superradiant threshold when the mode frequency is varied.
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Mesoscale and Nanoscale Physics

Interlayer Exciton Condensate Stiffness Is Non-Monotonic in Quantum Metric

Identifying the origin of the superfluid stiffness of electron-electron and electron-hole pair condensates is an important issue in flat-band physics. Here, we study the stiffness of bilayer exciton condensates using exact diagonalization and realistic Coulomb interactions across a wide variety of flat Chern band systems, including Landau levels, mixed Landau levels, and moiré bands. We find that stiffness is non-monotonic in the trace of the quantum metric and that it develops peaks when the band wavefunctions are engineered to be similar to those of Landau levels. The stiffness predicted by mean-field theory agrees quantitatively with exact diagonalization in these optimal cases, but systematically overestimates it otherwise. Flat bands with identical quantum geometry tensors can exhibit substantial differences in stiffness. The stiffness of condensates formed between moiré flat bands, which typically have strong variations in Berry curvature and quantum metric across their Brillouin zones, tends to be larger when the bands have non-zero Chern numbers and can be larger than that of Landau levels. Our results reveal a behavior that is richer than that suggested by simple geometric bounds and provide new guiding principles for the design of robust flat-band condensates with large superfluid stiffness.
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All authors Bo Zou, Yitong Zhang, Siddhartha Sarkar, Shi-Zeng Lin, Allan H. MacDonald, Kai Sun

Instrumentation and Methods for Astrophysics

Validating the SCALES DRP: A Performance Study of the Medium-Resolution IFS Mode

We present a performance verification of the medium-resolution integral field spectrograph (IFS) mode of the SCALES Data Reduction Pipeline (SCALES-DRP) using data obtained during recent cryogenic cooldown testing. SCALES (Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy), scheduled for deployment on the Keck II Telescope in late 2026, will be the first facility-class high-contrast thermal-infrared IFS, operating over the 2-5 micrometer wavelength range. The SCALES-DRP, developed within the Keck Data Reduction Pipeline Framework and implemented in Python, converts raw detector reads into calibrated three-dimensional datacubes using rectification matrices derived from position-dependent monochromatic lenslet point-spread functions, and supports both optimal and chi-sqaure-based spectral extraction to maximize signal-to-noise and extraction fidelity. We present laboratory verification results for the medium-resolution IFS mode, which combines a 0.34x0.36 arcsec lenslet subarray with an image slicer to achieve spectral resolutions of R ~ 2,000 - 5,000, focusing on the performance of the rectification matrices and the robustness of the extraction algorithms. These results demonstrate the readiness of the SCALES-DRP for instrument commissioning and early science operations. The pipeline is publicly available on GitHub.
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All authors Athira Unni, Steph Sallum, Max Brodheim, Rosalie McGurk, Andy Skemer, Matthew Brown, Peyton Benac, Michael P. Fitzgerald, Deno Stelter, Dusty Reichwein, Aaron Hunter, William T. S. Deich, Isabel Kain, Mackenzie Lach

General Relativity and Quantum Cosmology

Naked Singularities beyond Spherical Symmetry: Instability of $\kappa$-Self-Similar Solutions via an Iteration Scheme

This paper provides the instability counterpart to our recent construction of nonspherically symmetric approximating $\kappa$-self-similar naked-singularity solutions for the Einstein–scalar field system. These singular solutions contain pervasive nonspherical borderline terms, and to prove instability the delicate renormalization procedure developed in [2] does not extend to the more singular setting considered here. To overcome these difficulties, we introduce a new iteration scheme adapted to singular backgrounds whose leading-order geometry depends on the angular variables. At each step, the nonlinear coefficients are frozen using the preceding double-null geometry, and the resulting equations are solved in a triangular order. In this way, the nonspherical borderline terms are incorporated into the approximate geometry rather than treated as perturbative errors, yielding successively sharper estimates. After sufficiently many iterations, the scheme controls the singular angular structure and produces an approximate spacetime whose difference from the exact solution satisfies the required bounds. In particular, these bounds provide an existence region large enough to carry out the instability argument. We further prove that anisotropic perturbations of the outgoing data, arbitrarily small in a scale-critical norm, lead to the formation of a trapped surface. We also formulate and verify a matter-focusing condition under which a parabolic flow argument guarantees the existence of a corresponding marginally outer trapped surface (MOTS). Together, these results establish the nonlinear instability of $\kappa$-self-similar naked singularities beyond spherical symmetry in the Einstein–scalar field system and introduce a framework for applications across Einstein systems.
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Mathematical Physics · Cross-listed from math.PR

Annealed Survival Probability of Random Walk in an Inhomogeneous Poisson Environment of Mobile Traps

We study the annealed survival probability of a random walk in an inhomogeneous Poisson environment of mobile traps on $\mathbb{Z}^d$. In dimensions $d=1,2$, we determine the asymptotics for the annealed survival probability of the walker under suitable assumptions on the average trap intensity and study how inhomogeneity in the initial trap configuration affects these asymptotics. Our results extend the asymptotics proved for the homogeneous setting in \cite{DGRS2012}. We also establish a law of large numbers, central limit theorem and large deviation principle for the inhomogeneous Poisson trap environment in $d\ge 1$, generalising the corresponding results proved for the homogeneous case considered in \cite{CG1984}. We present a class of examples of inhomogeneous trap environments where the decay rate of survival probability can be identified and also instances where it does not decay with time.
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Statistical Mechanics

Scaling laws and energy dissipation in the dynamics of SLE curve as a 1D turbulence model

In this study, we demonstrate the characteristics of the stochastic Loewner evolution (SLE) as a one-dimensional (1D) turbulence model. First, we show that the diffusion process $x(t)$ obtained by the time coordinate change in the SLE becomes the time dependent diffusion process that satisfies Richardson's law of turbulence.Subsequently, we derive the condition on the diffusivity parameter $\kappa$ such that the diffusion process $x(t)$ satisfies Kolmogorov's 4/5th law, which determines the relation between the mean energy dissipation and velocity in the particles of turbulence. Further mathematical analysis showed that this condition is seen as the condition on Loewner entropy $S_{\mathrm{Loew}}$, which includes the white Gaussian noise term $W_{s}$ in the Loewner driving function of the present model. In addition, the numerical simulations were performed to verify the scaling relations of this 1D turbulence model. These results suggest that the standard SLE becomes a beneficial model of 1D turbulence by introducing an appropriate time coordinate change and imposing the conditions on $\kappa$ and $S_{\mathrm{Loew}}$.
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Statistical Mechanics

Mean-field theory for quantum spin chains

Mean-field theory is a widely used approximation for describing phase transitions, particularly effective above the upper critical dimension. Its origins can be traced back to the van der Waals theory of the liquid-gas transition and Weiss's molecular field theory of the paramagnetic-ferromagnetic transition. However, it was Lev D. Landau who provided a unifying and general framework applicable to a broad class of physical systems. The mean-field approach typically involves neglecting thermal fluctuations, which is a reasonable assumption in many classical contexts. However, its application to quantum phase transitions at zero temperature is less common. The aim of this short pedagogical paper is to explore and clarify the use of the mean-field approach in the less familiar domain of quantum phase transitions. We specifically consider the Ising model and the Blume-Capel model.
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All authors Mylène Martirosyan, Astrid Monin-Baroille, Leïla Moueddene, Mohammed M. Shabat, Bertrand Berche

Physics Education · Cross-listed from cs.SE

Building a research-software catalog with a coding agent: from hackathon prototype to public deployment

Generative AI and coding agents can accelerate research software development, but they also increase the need for efficient software discovery and maintenance. We developed a repository catalog during a three-day hackathon and subsequently examined the engineering required to make it suitable for public deployment, including adversarial review, data-quality checks, browser-level validation, and publication safeguards. We then explored whether the lessons learned from this prototype could be transferred to a much larger, human-curated portal, through a retrieval agent under development for MateriApps that combines curated portal metadata, external documentation, vector search, and local language-model generation. Implementation with coding agents was rapid, but achieving reliable operation required substantial additional engineering: the most consequential problems were not crashes but silent failures that produced plausible yet incomplete or incorrect outputs, arising from incomplete data acquisition, misleading assessments, and retrieval or preprocessing failures. These observations suggest that AI-assisted software portals require explicit validation, monitoring, and repeated review, and that curated metadata and maintained documentation remain essential. The MateriApps work is exploratory and remains under active development, so the observations reported for it are preliminary; a comparable combination of curated metadata, automatically collected documentation, and retrieval-based assistance may nevertheless be useful for extending other research-software portals.
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Quantum Physics

Strong-Drive Limits in Josephson Circuits: From Chaos to an Unbound-Resonance Threshold

Strong microwave drives enable fast measurement and parametric control in superconducting circuits but can induce transitions out of the intended low-energy manifold. We develop a unified description of strong-drive limits in flux- and charge-driven Josephson circuits across drive frequency and dc flux bias. Using classical phase-space analysis and Floquet–Markov simulations, we identify distinct low- and high-frequency mechanisms. At low frequency, we characterize bound-state resonances and separatrix chaos and find that the flux-drive chaos threshold depends strongly on dc flux bias. At high frequency, these mechanisms are suppressed, and the dissipative steady state transfers from the central bound-state sector to outer resonances formed by above-barrier running trajectories. The resulting unbound-resonance threshold is nearly independent of drive frequency and circuit parameters over the regime studied and is controlled primarily by dc flux bias. Coherent simulations show that parametric operation persists beyond this threshold, but at a reduced rate, setting an effective upper bound on the achievable operation speed. We derive analytical criteria for both thresholds, validate them numerically, and experimentally confirm the predicted dc-bias dependence of the low-frequency threshold in a flux-driven SQUID. We also determine the timescales for transfer into the unbound-resonance regime and relaxation back to the bound-state manifold after the drive is removed. Finally, we relate the stability limits to a complementary picture based on the junction critical current and extend the framework to multitone drives and inductively shunted circuits. Together, these results identify the mechanisms limiting strong driving and suggest routes to extend the stable operating range of Josephson circuits.
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Chemical Physics

Voltage-embedded equivariant machine learning potential for open system simulations

Modeling electrochemical interfaces under operational non-equilibrium conditions is vital for energy technologies but remains bottlenecked by the expensive cost of ab initio methods. Current machine learning potentials, largely designed for closed systems under homogeneous electric fields, are limited in open quantum transport applications. To overcome this, we present an E(3)-equivariant graph neural network that embeds voltage bias for open-system simulations. Our approach decouples the system energy and forces into zero-bias and bias-dependent contributions, assigning distinct vector encodings to electrode and scattering-region atoms to capture non-equilibrium conditions. Trained on limited discrete bias data, the model achieves high predictive accuracy and robust extrapolation transferability. When applied to a lithium/water interface, our model successfully captures the field-induced dynamic reorientation of water molecules and reproduces asymmetric electrochemical behavior at different electrodes.
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All authors Yiming Guan, Rongzhi Gao, ChiYung Yam, GuanHua Chen, Ziyang Hu

High Energy Astrophysical Phenomena

A Differentiable Neural Surrogate for Photon Propagation in Neutrino Telescopes

Large-volume neutrino telescopes infer neutrino properties from Cherenkov light, but simulating the transport of billions of photons through highly scattering ice or water is computationally costly. We introduce candela, a differentiable SIREN neural field that learns the photon Green's function of the IceCube Neutrino Observatory, a cubic-kilometer detector embedded in Antarctic glacial ice. Given a point-like energy deposit and sensor, it predicts the expected photon yield and full arrival-time distribution at the sensor. Complete events are simulated by decomposing charged-particle energy deposits into point-like sources and superposing their predicted sensor responses. Trained on Monte-Carlo simulations, candela generates events $50$–$100\times$ faster than existing methods, with cost scaling only weakly with neutrino energy. It keeps median yields within $2\%$ of the MC expectation and timing distributions at the MC statistical floor across six photon-count decades. The model also provides end-to-end gradients with respect to event parameters and opens a path toward optimizing scattering-medium properties, which often dominate systematic uncertainties in neutrino telescopes.
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All authors Felix J. Yu, Berthy T. Feng, Nicholas Kamp, Carlos A. Argüelles

Physics and Society

Low-Dimensional Phase Diagram of Higher-Order Networked Systems

Higher-order networks exhibit rich critical phenomena that cannot be captured by traditional pairwise models. Here, we develop an analytical dimension-reduction framework that maps higher-order networked dynamics onto an effective low-dimensional system, allowing accurate prediction of tipping boundaries, bistability regions, and the nature of phase transitions. We demonstrate the power of this framework across a range of dynamical processes, revealing distinct effects of higher-order interactions on transition continuity and hysteresis. Furthermore, we find that system resilience exhibits a profound dependence on the alignment between pairwise and higher-order connectivity, with assortative mixing enhancing tipping toward active states. Our findings establish a general theory for understanding the critical transitions in higher-order networks, offering new insights for anticipating and managing systemic risk in complex systems.
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All authors Jia-Jie Qin, Jack Murdoch Moore, Xiaozhu Zhang, Gang Yan

Exactly Solvable and Integrable Systems

Complex singularities for Burgers' equation with piecewise-continuous initial conditions

There is a body of research devoted to understanding how complex singularities of solutions of nonlinear partial differential equations (pdes) spontaneously emerge at $t=0^+$ and propagate for $t>0$, and how their behaviour affects the solution on the real axis. Despite the importance of the small-time limit in these studies, there is still a lack of understanding of how complex singularities are born at $t=0^+$, including for initial conditions that are not analytic functions of the spatial variable. In this paper, we use Burgers' equation as a prototype nonlinear pde and study the complex-plane singularities for initial conditions that are piecewise smooth. Using matched asymptotic expansions, we show how infinitely many singularities emerge from points of discontinuity in a pattern that can be described using branches of the Lambert-$W$ function. For various initial conditions, we observe how these singularities rearrange themselves to align with the appropriate exactly-described long-time behaviour, including sigmoid-shaped travelling waves, constant-area (triangular wave) similarity solutions and $N$-wave solutions. In terms of Burgers' equation, our small-time asymptotic analysis of the singularity propagation for piecewise-continuous initial conditions illustrates the types of generic behaviours that arise for inner regions when diffusion dominates advection. More generally, this work is a step towards understanding complex-plane behaviour of solutions of nonlinear partial differential equations with non-analytic initial conditions.
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