Fluid Dynamics
Universal mapping of drop impact spreading from wetting to Leidenfrost regimes
Shushan Hu, Nan Hu, Zirui Li et al. (+3 more)
We establish a universal mapping between the maximum spreading of a drop under wetting and Leidenfrost impact conditions from an energy-dissipation perspective, with the latter featuring a stable vapor film between the drop and the substrate. Experiments and direct numerical simulations demonstrate that the mapping remains valid over two to three orders of magnitude in the Ohnesorge and Weber numbers. This framework provides a simple route for converting established predictions for wetting impacts into their Leidenfrost counterparts, with implications for predicting and controlling droplet impact.
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All authors Shushan Hu, Nan Hu, Zirui Li, Yifei Sun, Xiang Gao, Liwu Fan
Quantum Physics
A Protocol-Guided LLM Agent for Quantum Program Synthesis and Execution
Ming-Kang Ho and Tai-Yue Li
This study evaluates a protocol-guided large
language model (LLM)
agent workflow for
quantum program synthesis and execution. A versioned YAML protocol specifies interface and
quantum-semantic requirements while leaving
circuit design to the model. The workflow combines Qiskit
circuit generation, evaluator-guided repair, and
quantum processing unit (QPU) deployment. A matched ablation evaluates four LLM endpoints using the variational
quantum eigensolver (VQE) for H$_2$, the
quantum approximate optimization
algorithm (QAOA) for MaxCut, and Fashion-MNIST
quantum-kernel classification. Across 240 trials, protocol guidance increased evaluator completion from 80.0% to 99.2%, reduced mean repairs from 2.56 to 0.75, and reduced mean
agent time from 55.70 to 30.58~s. Provider-reported
token use decreased for three of four endpoints. Completed VQE trials meeting chemical accuracy increased from 16/40 to 29/40, while valid QAOA approximation ratios remained comparable. Semantic review identified rank-one fidelity kernels, reinforcing the distinction between evaluator completion and semantic validity. A 210-run IBM QPU study evaluated the combined generation-and-selection pipelines and confirmed deployment feasibility. The results support protocol guidance as a software-reliability layer that must be complemented by
quantum-semantic validation.
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Quantum Physics
Multiparameter sensing of axion dark matter with superconducting-qubit networks
Le Bin Ho
We propose a
quantum sensor network for direct detection of
quantum chromodynamics (QCD)
axion dark matter using entangled superconducting
qubits. In the presence of a static
magnetic field, the oscillating
axion field induces a coherent
qubit rotation described by an encoding angle proportional to the
axion-
photon coupling and an unknown dark-matter phase. Treating the phase as an additional unknown parameter turns
axion detection into a two-parameter
quantum estimation problem. We formulate these signals in Cartesian coordinates, thereby avoiding the singularity that arises in the weak-signal regime and establishing a regular framework for multiparameter
quantum estimation. Using this framework, we optimize the
quantum sensor network and combine it with
Bayesian inference to reconstruct the
axion-
photon coupling. The optimized protocol accurately recovers the KSVZ and DFSZ
benchmark couplings over the mass range $m_a\in[0.1,10]~\mu{\rm eV}$, generalizes to previously unseen masses, and remains robust against realistic superconducting-
qubit decoherence and gate errors.
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Nuclear Theory
Probing Forward-Backward Multiplicity Correlations and Fluctuations Using the Strongly Intensive Observable $\Sigma$ in Pb-Pb Collisions at SPS Energies with UrQMD
Ekata Nandy and Subhasis Chattopadhyay
The strongly intensive observable $\Sigma$, constructed from charged-pion multiplicities in separated forward (F) and backward (B) pseudorapidity intervals $\Delta\eta$, is studied within the UrQMD transport model for Pb–Pb collisions at SPS energies. The dependence of $\Sigma$ on $\Delta\eta$ is investigated as a function of collision energy, centrality, and acceptance to probe the longitudinal structure of multiplicity fluctuations and correlations. For $\sqrt{s_{NN}}>6$ GeV, $\Sigma$ exhibits a non-monotonic dependence on $\Delta\eta$, increasing from values near unity at small separation, reaching a maximum at intermediate $\Delta\eta$, and decreasing towards unity at larger separation. Decomposition into scaled variance and covariance terms shows that this behavior arises from their different $\Delta\eta$ dependences. Calculations with resonance decays switched off show that resonances dominate short-range correlations, while $\Sigma>1$ at larger $\Delta\eta$ indicates fluctuations and correlations extending over broader pseudorapidity intervals. The magnitude of $\Sigma$, together with its fluctuation and covariance components, increases from central to peripheral collisions, with fluctuations dominating over covariance at large $\Delta\eta$. As the collision energy increases, the pseudorapidity interval over which $\Sigma>1$ persists becomes significantly larger, whereas at lower energies, where resonance dynamics dominate particle production, $\Sigma$ is nearly independent of $\Delta\eta$. An acceptance-scaling study reveals deviations from simple binomial scaling in regions of strong correlations. These results demonstrate the sensitivity of $\Sigma$ to the interplay between multiplicity fluctuations and forward–backward correlations in heavy-ion collisions.
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Physics and Society
The HANDY model with non-renewable resources and societal effects
Mathilde Badoual, Basil Grammaticos, Stéphane Plaszczynski et al. (+1 more)
We present an extension of the single-population Human and Nature Dynamics (HANDY) model that explicitly incorporates non-renewable resources and societal effects. The model is formulated as a system of four differential equations for which we provide a faithful discrete integrator. In the model, resource extraction and conversion is described by realistic Holling-type functional responses that capture saturation effects for both renewable and non-renewable resources, while efficiency losses are introduced to describe inherent waste. We derive analytic conditions on the model parameters, needed to ensure stable (and sustainable)
equilibria, despite population growth and depletion of resources. The different dynamical scenarios that appear in this analysis and the parametric conditions that lead to them, are illustrated by extensive numerical simulations. The societal effects we investigate include adjustable extraction and consumption rates of the resources, alongside a population-driven degradation of Nature and of its regenerative capacity. One immediate conclusion is that permanent environmental damage inevitably precipitates population collapse. In contrast, we also show that the possibility of recoverable capacities, even delayed, may lead to long-term survival and that timely late-stage interventions often succeed in averting extinction entirely.
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All authors Mathilde Badoual, Basil Grammaticos, Stéphane Plaszczynski, Ralph Willox
Quantum Physics
Transformer fault diagnosis using an efficient simulation-driven variational quantum classifier with domain-aware feature encoding
Huy Hoang Le, Ba Tu Phung, Dai Huynh et al. (+1 more)
Early
transformer fault diagnosis is challenged by nonlinear dissolved-gas interactions, overlapping fault signatures, and limited labeled data, while practical deployment further requires reliable performance under realistic computational constraints. This paper presents a simulation-driven modeling framework for dissolved gas analysis-based
transformer fault diagnosis, in which a carefully engineered variational
quantum classifier (VQC) is employed as the computational core and systematically analyzed through simulation. The framework integrates domain-aware feature modeling derived from Duval geometry with a lightweight two-
qubit quantum representation, enabling nonlinear gas-interaction effects to be captured within a shallow parameterized
circuit. A hybrid ZX-YY
quantum feature map is designed to model non-commuting feature interactions, while a full-
entanglement EfficientSU2 ansatz provides adequate expressive capacity under strict resource limits. Model behavior is evaluated using a comprehensive simulation pipeline including noise-aware
circuit emulation, cross-
dataset validation, and limited hardware-in-the-loop execution, allowing key effects of
circuit depth, noise, and optimization strategy to be examined. Simulation results on
benchmark dissolved-gas-analysis
datasets demonstrate high diagnostic accuracy, strong generalization capability, and robustness to realistic noise levels with minimal
quantum resources. The results highlight the effectiveness of simulation-informed modeling for practical
transformer diagnostic applications, offering a reproducible and resource-efficient pathway for evaluating
quantum-enhanced fault diagnosis methods.
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All authors Huy Hoang Le, Ba Tu Phung, Dai Huynh, Kim-Anh Nguyen
General Physics
Testing the Anton-Schmidt dark energy model with the DESI DR2 measurements
Himanshu Chaudhary, Salvatore Capozziello, Dhruba Jyoti Gogoi et al. (+1 more)
We present a comparative cosmological analysis of the Anton-Schmidt, $\Lambda$CDM, and CPL models using
baryon acoustic oscillation measurements from the Dark Energy Spectroscopic Instrument Data Release 2, combined with the Planck PR4 (NPIPE) CamSpec
Cosmic Microwave Background likelihoods and three Type Ia
supernova catalogues: Pantheon$+$, DES-Dovekie, and Union3. We use Markov Chain Monte Carlo analyses to constrain the parameters of the Anton-Schmidt model against each
dataset combination. We find that the Anton-Schmidt model provides a good fit to current cosmological observations. The Anton-Schmidt model provides a good fit to the current cosmological observations but does not provide a significant alleviation of either the $H_0$ or the $S_8$ tensions. The Anton-Schmidt parameter is tightly constrained to $B \simeq -0.38$, indicating that the logarithmic correction becomes relevant only at late times. The Anton-Schmidt and CPL models predict quintessence-like present-day dark-energy equations of state and shows Quintom-B
evolution, with their dark-energy equation-of-state parameters crossing the phantom divide at approximately $z \approx 0.5$. The characteristic density scale is constrained to be $\rho_\ast/\rho_{c,0}\sim4\text{--}5$, substantially smaller than the large density scales typically assumed in logotropic-inspired scenarios, indicating that the Anton-Schmidt correction mainly affects the late-time expansion history. Finally,
Bayesian evidence shows moderate-to-strong preference for the Anton-Schmidt model over the $\Lambda$CDM model and strong-to-decisive preference over the CPL parametrization. Although the Anton-Schmidt model does not alleviate the current cosmological tensions, it emerges as a statistically favored dynamical dark-energy scenario whose cosmological implications deserve further tested with forthcoming Stage-IV large-scale structure observations.
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All authors Himanshu Chaudhary, Salvatore Capozziello, Dhruba Jyoti Gogoi, G. Mustafa
Solar and Stellar Astrophysics
A quadratic balance relation for radial nonadiabatic pulsations
Jan Zalewski
Using a sesquilinear pressure - rate of volume change kernel and linear pulsation equations, we formulate a balance relation combining work integral, surface terms, norm integral and the real part of pulsation frequency (for $\exp({\omega t})$ time dependence) in terms of linear radial pulsation variables. The resulting relation is exact within the adopted radial nonadiabatic formulation. We apply the quadratic balance relation to radial pulsations in AGB envelopes and use it to check the accuracy of computation and to obtain information about mode excitation and damping. We also compare the balance relation with the classical formulation based on dissipation and kinetic energy integrals and discuss the meaning of the components made explicit by the present decomposition that appear in our balance equation and their relevance for ordinary and strange modes in AGB envelopes.
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Materials Science · Cross-listed from cs.LG
BDIP-Net: Dual-Interaction Graph Learning for Property Prediction of Bilayer Materials
An Vuong, Chen Zhao, Jin Hu et al. (+2 more)
Stacked
bilayer materials exhibit rich stacking-dependent properties driven by the interplay between strong intra-layer bonding and weak inter-layer van der Waals interactions. The computational discovery of such materials is challenging because accurate structure generation typically relies on expensive DFT-based optimization, while existing machine-learning models often fail to explicitly distinguish different interaction types during property prediction. To address these challenges, we propose a machine-learning framework for efficient construction and property prediction of stacked
bilayer materials. The framework employs a MatterSim-D3-based structural optimization workflow to generate DFT-quality
bilayer structures from monolayer building blocks and stacking configurations at substantially reduced computational cost. For property prediction, we introduce BDIP-Net (
Bilayer Dual-Interaction Potential Network), a graph neural network that explicitly models intra-layer and inter-layer interactions through interaction-specific potential representations and adaptive message fusion. We evaluate the proposed framework on BiDB, HetDB, and SAMBA, encompassing homobilayers, heterobilayers, and twisted
bilayer systems. Results show that the MatterSim-D3-based workflow closely reproduces DFT-PBE-D3 optimized structures, while BDIP-Net consistently outperforms existing graph neural network and potential-based approaches for
bilayer property prediction.
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All authors An Vuong, Chen Zhao, Jin Hu, Shui-Qing Yu, Xintao Wu
High Energy Astrophysical Phenomena
Synchrotron and Inverse-Compton Signatures of Black to White Hole Explosions: Weibel-Mediated External Shocks in the Interstellar Medium
Hoang Van Quyet
We study the non-thermal electromagnetic counterpart expected when the relativistic, near-isotropic ejecta of a black-to-white hole transition sweep up the interstellar medium (ISM). Building on a photospheric model for the
prompt $\gamma$-ray emission~\cite{Villani2026}, we parametrize the kinetic energy available for an external shock, $\eiso=R_k\egprompt$, and model the resulting collisionless forward shock with a Weibel-mediated field~\cite{Weibel1959,MedvedevLoeb1999,SironiSpitkovsky2011}. We estimate the synchrotron and synchrotron self-Compton (SSC) emission from shock-accelerated electrons in a one-zone, Thomson-regime approximation, including inverse-Compton cooling, Klein-Nishina suppression, self-absorption, and $\gamma$-$\gamma$ opacity, all at order-of-magnitude or first-order accuracy. For illustrative parameters ($\egprompt\sim10^{44}$ erg, $R_k=0.1$, $\Gamma_0=100$), the electrons are slow-cooling, so for $p=2.5<3$ the synchrotron spectrum peaks at the cooling frequency $\nu_c$, in the MeV-to-GeV range and softening with time; the afterglow evolves in a fraction of a second to tens of seconds – orders of magnitude faster than a classical long-duration GRB afterglow at comparable energy, density, and Lorentz factor – with duration, peak energy, and flux depending sensitively on $R_k$, $\nism$, and $\epse,\epsB,\xie$. We identify parameter regions where a 1 keV
photon-count estimate, below the intrinsic peak, exceeds a nominal detection threshold, and discuss features – a fast, faint, roughly isotropic transient after a hard-spectrum
prompt flash, without an achromatic jet break – that may distinguish this scenario from short GRBs, magnetar
giant flares, and other fast transients, while flagging the assumptions (forward-shock-only dynamics, one-zone Thomson-regime radiation, an illustrative detectability criterion) limiting its quantitative reach.
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Atmospheric and Oceanic Physics
Projected climate memory and inherited warm-tail risk in accelerated European summer warming
Mauricio Herrera-Marín, Alex Godoy-Faúndez and Diego Rivera
European summer warming reflects interactions among background change, persistent ocean–land–circulation states, and same-season variability. We develop an empirical reduced-dynamics framework that decomposes regional summer indicators into inherited slow-state
memory, its predictable component, and contemporaneous innovation. Projection-operator theory motivates the decomposition, implemented with finite causal filters, ridge-regularised prediction, and logistic risk models. Using ERA5-derived summer indicators for 28 IPCC AR6 European sub-regions over 1950–2024, with validation on 2006–2024, we find that Mediterranean-state
memory improves mean summer-temperature prediction relative to trend-only and ARX baselines. The gain over ARX is modest, while moving-average, exponentially weighted, and tempered filters contain similar annual information, indicating that the data identify useful slow-state
memory more robustly than a unique kernel shape. Predictable-state reconstruction is ridge-sensitive and therefore treated diagnostically rather than as a
forecasting model. The strongest result concerns warm-tail risk. In parsimonious logistic models, high accumulated Mediterranean
memory raises predicted upper-tail event probability by about 8–11 percentage points for annual maximum summer temperature, warm-day frequency, and warm-spell duration at 1-, 3-, and 5-year horizons. Regional bootstrap intervals remain positive for all targets and horizons. Circular-shift placebos yield one-sided probabilities of approximately 0.05–0.14 and do not survive strict family-wise correction across nine tests, so the evidence is moderate rather than decisive. Overall, annual projected
memory is not a universal short-horizon predictor, but a physically interpretable inherited risk-loading variable identifying years and regions predisposed to warm-tail outcomes.
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Geophysics
A Spatial Persistence Gradient in European Warming Consistent with North Atlantic Cold-Blob Influence
Mauricio Herrera-Marín, Alex Godoy-Faúndez and Diego Rivera
Europe is warming faster than the global mean, yet the spatial organisation of this acceleration remains incompletely understood. Using ERA5 reanalysis for 1950–2024 across 28 IPCC AR6 European sub-regions, we identify two connected empirical results. First, the DFA1 Hurst exponent of interannual temperature residuals is strongly and negatively associated with the 1996–2024 warming rate ($r=-0.792$, $p=5.1\times10^{-7}$). High-persistence, mainly Atlantic-proximal regions warm more slowly, whereas low-persistence continental regions warm faster. This relationship is robust to five residualisation schemes, three
memory estimators, leave-one-region-out analysis, and five null-test families, including spatial block permutation. It also persists across warming windows ($r=-0.550$ for 1981–2024, $-0.792$ for 1996–2024, and $-0.875$ for 2000–2024), but vanishes under DFA2, indicating that the signal lies in low-frequency interannual-to-decadal persistence rather than trend
curvature. The pattern is consistent with, but does not prove, North Atlantic cold-blob and thermohaline influence on European land temperatures. Second, under a strict 2006–2024 holdout, contemporaneous Mediterranean SST reduces mean annual temperature RMSE by 43% (from $0.787$ to $0.449,^{\circ}\mathrm{C}$). A causal lag-weight predictor based on prior-year Mediterranean and Atlantic SST also outperforms AR(2) ($0.578$ versus $0.695,^{\circ}\mathrm{C}$) and remains informative after removing NAO, AO, and PNA effects. Similar skill from five-year moving-average and exponentially weighted predictors shows that short Mediterranean SST persistence at 1–5-year lags is the key predictive ingredient. Together, the results support a two-regime interpretation: Atlantic-proximal regions exhibit stronger
memory and oceanic buffering, while continental interiors show faster warming and weaker interannual persistence.
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Quantum Physics
Is the H Atom Surrounded by A Cloud of Virtual Quanta Due to the Lamb Shift?
G. Jordan Maclay
\abstract{The Lamb shift, one of the most fundamental interactions in atomic physics, arises from the interaction of H atoms with the electromagnetic fluctuations of the
quantum vacuum. The energy shift has been computed in a variety of ways. The energy shift, as Feynman and Power demonstrated, equals the change in the
vacuum energy in the volume containing the H atoms due to the change in the index of refraction arising from the presence of the H atoms. By using this result and a group theoretical calculation of the contribution to the Lamb shift from each frequency of the
vacuum fluctuations, we can obtain an expression for the size of the region of
vacuum energy for each frequency \texorpdfstring{$\omega$}{{\omega}} around the H atom due to the Lamb shift. The ground state atom is surrounded by a region of positive
vacuum energy that extends well beyond the atom for low frequencies. This region can be described as a steady state cloud of virtual quanta. For energies \texorpdfstring{$E=\hbar\omega$}{E=hbar omega} eV less than 1 eV, the radius of the positive energy region is approximately 14. 4/E Angstroms. For a
vacuum fluctuation of wavelength \texorpdfstring{$\lambda$}{lambda} the radius is \texorpdfstring{$(\alpha/2\pi)\lambda$}{(alpha/2pi) lambda}. Thus, for long wavelengths, the region has macroscopic dimensions. The energy-time Uncertainty Relation predicts a maximum possible radius that is larger than this by a factor of \texorpdfstring{$1/ 4\alpha$}{1/(4 alpha)}.} \keyword{Bethe; radiative shift; shift spectral density; spectral volume;
vacuum fluctuations;
vacuum field; Lamb shift; QED; energy field, renormalization, zero point fluctuations; hydrogen atom}.
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Instrumentation and Methods for Astrophysics
Co-design of ground-based gravitational wave detector networks
Daniel Lanchares, Lysiane Mornas, Luigi Toffolatti et al. (+1 more)
Discussions around the design philosophy and location of the next generation of ground-based gravitational wave detectors are still underway. In this context, we propose IfoScout, an innovative methodology for detector co-design based on state-of-the-art machine-learning (ML) techniques. As a simple demonstration, we present a two-stage simulation of a network of fictional L-shaped interferometers whose sensitivity is optimized within physical and geographical constraints, indirectly resulting in reducing the costs. To achieve this, we gather publicly available data for two
token locations and establish the length and orientation with reinforcement learning (RL). Next, we optimize the internal detector parameters related to cavity stability to achieve the best possible sensitivity by means of differential programming (DP). We make the case that pipelines such as IfoScout could have a positive impact on the final design of new generation detectors (e.g. the Einstein
Telescope, the
Cosmic Explorer, etc.), given precise data and detailed, realistic simulations of the interferometers.
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All authors Daniel Lanchares, Lysiane Mornas, Luigi Toffolatti, Pietro Vischia
High Energy Physics (Phenomenology)
A Material Frame: Hard Recoils from Slow Force Carriers
Francesco Serra
We modify the Standard Model by making the longitudinal component of the
photon physical, propagating with small speed $c_L \ll 1$. This modification breaks gauge invariance and Lorentz
symmetry, defining a preferred reference frame. No new fields or scales are introduced, and the
photon mass is protected by a Galilean higher-form
symmetry. The theory has a smooth $c_L\to0$ limit: the new modes decouple from standard matter and ordinary gauge theory predictions are recovered. Experimental constraints are severe. Charged particles Cherenkov-emit these slow modes, experiencing hard
recoils against the preferred frame. The
recoil rate decreases with $c_L$, but the momentum transfer remains of the order of the particle's momentum. Dark matter detectors, sensitive to keV-scale
nuclear recoils, imply an order-of-magnitude bound $c_L \lesssim 10^{-60}$, tens of orders of magnitude stronger than speed-difference bounds. At such values, $c_L$ is better understood as a
recoil-rate factor rather than a physically relevant speed. The slow modes, practically fixed in space, make the reference frame a material medium capable of absorbing momentum from charged particles.
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Quantum Physics
Designing tight frames for quantum computing
Luis Quezada
The aim of this thesis is to explore the implementation of a special kind of
quantum measurements, so called harmonic tight frames. To achieve this goal, representation theory is addressed, emphasizing its construction from irreducible representations and the relations they satisfy. These tools simplify the study due to the existence of
symmetries, leading to the concept of group frames, defined as orbits under the
unitary action of a group and characterized by their
symmetry groups. Among the various groups, the simplest are the abelian ones, giving rise to harmonic frames, which are analyzed through the classification
theorem of abelian groups and the characters of their irreducible representations. In the
quantum mechanics context, the frame elements can be interpreted as pure states of a system. Therefore, the necessary and sufficient conditions for separability are explored, as separable states are easier to implement due to their local nature. Alternatively, when viewing frames as measurements, the concept of POVMs and Naimark's
theorem are studied as key tools for designing measurements in
quantum computers. Using this knowledge, a characterization of the harmonic frames is given from the abelian group structure
theorem, which allows obtaining a necessary and sufficient condition for their separability. The conditions of maximum
entanglement of these states for bipartite systems are also studied, obtaining a necessary condition on the dimensions of the subsystems. Finally, a
quantum circuit is obtained that allows implementing the harmonic frames associated to cyclic groups as POVMs using a
Fourier matrix and a permutation
matrix. We conclude by giving simple examples where the results are applied to
quantum computers and proposing future avenues of research that could serve to improve the
circuit design and extend it to the case of all harmonic frames.
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Solar and Stellar Astrophysics
Three-dimensional Magnetic Field Structure of a Quiet-Sun Region Revealed by Sunrise III/SCIP
Masahito Kubo, Yukio Katsukawa, Yusuke Kawabata et al. (+38 more)
The balloon-borne stratospheric
solar observatory Sunrise III successfully completed 6.5 days of observations in July 2024. One of its focal-plane instruments, the Sunrise Chromospheric Infrared spectroPolarimeter (SCIP), is a slit-scanning spectropolarimeter that simultaneously measures full Stokes profiles of multiple spectral lines in the 850 nm and 770 nm bands. SCIP obtained an unprecedented data set of a quiet-sun region near disk center, covering a $58'' \times 58''$ field of view. With an integration time of 10 s per slit position, the scan was completed in 107 minutes without interruption, achieving remarkably stable polarimetric precision of 0.03-0.04% (1$\sigma$) of the continuum level. The multi-wavelength SCIP observations reveal that the chromospheric line-of-sight (LOS)
magnetic field exhibits thread-like, elongated structures over the internetwork regions, with no obvious photospheric counterpart directly below. These threads are typically narrower than $1''$ and are embedded within the canopy fields extending from the network regions. Their LOS field strengths derived from the weak-field approximation are typically 10-20 G weaker than the surrounding canopy. In particularly clear cases, the
magnetic polarity of the threads is opposite to that of the adjacent canopy. These findings suggest that the canopy field is not simply an expanding structure originating from network regions, but instead has a complex three-dimensional configuration containing numerous localized substructures. These observations provide new constraints on the quiet-sun
magnetic topology from the photosphere to the chromosphere.
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All authors Masahito Kubo, Yukio Katsukawa, Yusuke Kawabata, Takayoshi Oba, Hirohisa Hara, Toshifumi Shimizu, Ryohtaroh T. Ishikawa, Takuma Matsumoto, Yoshihiro Naito, Fumihiro Uraguchi, Toshihiro Tsuzuki, Kazuya Shinoda, Tomonori Tamura, Yoshinori Suematsu, Jose Carlos del Toro Iniesta, David Orozco Suárez, Maria Balaguer Jiménez, Carlos Quintero Noda, Sami K. Solanki, Andreas Lagg, Achim Gandorfer, Pietro Bernasconi, Thomas Berkefeld, Alex Feller, Tino L. Riethmüller, Alberto Álvarez-Herrero, H. N. Smitha, Bianca Grauf, Michael Carpenter, Alexander Bell, Valentín Martínez Pillet, Francisco Javier Bailén, Julian Blanco Rodríguez, Juan Sebastián Castellanos Durán, Edvarda Harnes, Johannes Hölken, Francisco A. Iglesias, Azaymi L. Siu-Tapia, Hanna Strecker, Dušan Vukadinović, Patrick A. Ondratschek
Quantum Physics
On $R$-parastatistics I: Foundation
Zhiyuan Wang and Kaden R. A. Hazzard
Parastatistics is an exotic type of exchange statistics beyond
fermions and
bosons. Paraparticles transform in higher dimensional representations of the exchange
symmetry group, analogous to non-Abelian anyons, yet consistently defined in any dimension. Although paraparticles have long been proposed, they were widely believed to be physically equivalent to
fermions or
bosons. Nevertheless, a recent paper proposed a different theory, called $R$-parastatistics, and demonstrated that nontrivial $R$-paraparticles can emerge as quasiparticles in condensed matter systems, and are observably distinct from both
fermions and
bosons. This paper develops the theoretical foundation and several extensions of $R$-parastatistics, with particular emphasis on its observable consequences. Central to this paper is a general theory of local observables extending the basic family introduced before. First, we define local observables that distinguish particle types. Second, we formulate local observables at special point defects that probe the internal indices of $R$-paraparticles, crucial for observing $R$-parastatistics and for the proposed applications in
quantum information. Third, we introduce local observables that create or annihilate particle-antiparticle pairs, important for building a relativistic
quantum field theory for $R$-paraparticles. We further introduce generalized hidden
symmetries that act on internal indices of $R$-paraparticles while preserving the local observable
algebra, providing a basis for proving local indistinguishability and for connecting to a categorical description of $R$-paraparticles. This work sets a solid theoretical foundation for understanding the fundamental physical properties of $R$-paraparticles and pave the way for finding them in nature.
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Quantum Physics
Hardware-Aware QUBO Reformulation of Constrained Binary Optimization via the Walsh-Fourier Transform
Loong Kuan Lee, Harsha Nagarajan, Thore Gerlach et al. (+3 more)
We present a novel slack-free, penalty-based framework for reformulating constrained binary optimization as Quadratic Unconstrained Binary Optimization (QUBO) on near-term
quantum annealing hardware. Given a user-chosen penalty function that most naturally captures a constraint—typically non-quadratic, such as a Heaviside-function surrogate—and a target probability measure over the Boolean hypercube, our method returns the weighted least-squares projection of the chosen penalty function onto the subspace spanned by linear and quadratic Walsh–
Fourier characters that correspond to physically realizable couplings on the target hardware graph. Within this restricted family, the resulting quadratic surrogate is uniquely and optimally determined by the normal equations: unlike state-of-the-art approaches, it introduces no per-constraint penalty coefficients to tune and avoids dense all-pairs couplings by construction. Two practical consequences follow. First, the projected penalty respects device connectivity, reducing chain lengths and physical-
qubit overhead after minor
embedding. Second, we show empirically that this hardware-native surrogate can outperform denser full-pairwise projections, despite being drawn from a strictly smaller approximation space. This advantage widens once the QUBO is embedded and sampled on
quantum annealers, yielding samples with the lowest worst-case and mean objective gaps compared to unbalanced penalization and a hardware-blind projection onto all quadratic terms.
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All authors Loong Kuan Lee, Harsha Nagarajan, Thore Gerlach, Sascha Mücke, Ragavi Krishnamoorthy, Nico Piatkowski
Astrophysics of Galaxies
Stellar Population Astrophysics (SPA) with the TNG. Beyond the iron peak: Galactic evolution of molybdenum, ruthenium and zirconium through open clusters
Natalia Alvarez-Baena, Valentina D'Orazi, Christopher Sneden et al. (+11 more)
Context: Open clusters serve as key laboratories for studying the chemical
evolution of the Milky Way. In particular, leveraging these coeval groups of
stars to study elements beyond the iron peak provides insights into heavy-element nucleosynthesis, whose origins remain uncertain. Aims: This work aims to determine the Mo, Ru, and Zr abundances for 81
stars across 30 open clusters. We compare these new chemical patterns with those of key reference elements (Y, Sr, Eu), which were previously derived by our group. This comparison seeks to disentangle the distinct contributions from various nucleosynthetic processes. Methods: Using the high-resolution spectra acquired within the
Stellar Population Astrophysics programme using the HARPS-N echelle spectrograph at the Telescopio Nazionale Galileo, we estimate chemical abundances through spectral synthesis with TSFitPy under local thermodynamic
equilibrium (LTE) conditions. Results: This study provides the first Ru abundances for a large open cluster sample, alongside new measurements for Mo and Zr. We observe tight correlations between Mo, Ru, and other s-process elements (Sr, Y, Zr), with slopes near unity, suggesting common enrichment timescales. Conversely, relations with the r-process element Eu show significant deviations, implying additional nucleosynthetic contributions. Crucially, chemical planes involving [Mo/Ru] and [s/Mo] ratios suggest systematic offsets when compared to theoretical s-process predictions.
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All authors Natalia Alvarez-Baena, Valentina D'Orazi, Christopher Sneden, Athanasios Psaltis, Frédéric Thévenin, Angela Bragaglia, Tamara Mishenina, Shilpa Bijavara Seshashayana, Ricardo Carrera, Laia Casamiquela, Marina Dal Ponte, Henrik Jönsson, Antonino Nunnari, Marco Pignatari
High Energy Physics (Theory)
D-branes and nonlinear interactions in the $AdS$ pure spinor string
Brenno Carlini Vallilo
We develop a coordinate-independent algebraic description of zero-field boundary conditions for the pure spinor string on $AdS_5\times S^5$ in the closed-string channel. The construction is organized by involutive
automorphisms of $\mathfrak{psu}(2,2|4)$ that exchange the odd sectors of the $\mathbb Z_4$ grading. Their fixed subalgebras provide candidate half-BPS, Lorentzian D-brane geometries with vanishing background world-volume flux, consistent with the standard $AdS_2$, $AdS_3\times S^1$, $AdS_4\times S^2$, and related
embeddings. Together, the seven representatives realize the Lorentzian zero-flux D1, D3, D5, and D7 probe sectors considered here. We then construct a local ansatz for the matter and ghost boundary interactions and derive a system of consistency equations for the tangential superconnection, transverse
embedding, and four ghost-gluing couplings. The resulting system is a set of Dirac-Born-Infeld-like equations of motion on the brane world-volume.
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Earth and Planetary Astrophysics
Dynamical evolution and surface accretion of DART impact ejecta in the (65803) Didymos system
Xiaoyu Fu, Nicolo Stronati, Stefania Soldini et al. (+6 more)
The DART spacecraft impacted Dimorphos, the small moonlet of Didymos binary system, on 26 September 2022. The impact ejected
dust, fragments, and boulders into the near-binary environment. In November 2026, ESA's Hera mission is expected to arrive at the binary system to characterise both asteroids and investigate the post-impact consequences in detail. In this research, we aim to investigate the dynamical
evolution of DART-generated impact ejecta and to quantify their surface
accretion patterns within the Didymos binary system. High-fidelity ejecta dynamics, including polyhedron asteroid
gravity and
solar radiation pressure with combined occultations, are constructed. The ejecta initial conditions are generated from the observation-constrained velocity-size distribution and ejecta-cone geometry. In total, 20 million trajectories are integrated to characterise the ejecta
evolution and surface
accretion. More than 93.5% of DART-generated ejecta particles escape from the system within two years, while only approximately 0.002% remain in the near-binary environment. The deposited layer on Dimorphos reaches the order of 1.5 mm at mid-to-low latitudes. On Didymos, the accreted layer is mostly thinner than 0.3 mm, but may reach 3-11.5 mm in a localised high-density region. The results indicate that, most DART-generated ejecta are removed from the binary system, while a small but dynamically meaningful subset remains near the system or accretes onto the asteroid surfaces. The surface
accretion distribution is strongly controlled by the initial ejecta-cone geometry, especially the cone-axis direction.
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All authors Xiaoyu Fu, Nicolo Stronati, Stefania Soldini, Fabio Ferrari, Carmine Giordano, Paolo Panicucci, Alessandro Rossi, Adriano Campo Bagatin, Michael Kueppers
Mathematical Physics · Cross-listed from math.NA
A Cartesian Grid Method for Advection-Diffusion Equations with Robin Boundary Conditions on Moving Domains
Han Zhou, Yoichiro Mori and Lingxing Yao
We develop a Cartesian grid method for advection–
diffusion equations with Robin boundary conditions on moving domains. The moving-domain problem is reformulated as an interface problem on a box, with an unknown density introduced on the moving interface to enforce the Robin condition. The bulk equation is discretized by a
cell-centered finite-difference scheme on the Cartesian grid, while interface corrections are obtained from local problems in a narrow band around the interface. The resulting method requires only modest computational geometry, avoids remeshing and cut
cells, and is compatible with
geometric multigrid and
matrix-free GMRES. The GMRES iteration count is essentially independent of the mesh size, and the computational cost scales linearly with the number of bulk degrees of freedom. For the one-dimensional scheme, first-order convergence in time and second-order convergence in space are proved. Numerical examples in one and two dimensions, including manufactured solutions and an active transport problem without an exact solution, demonstrate the accuracy and efficiency of the method.
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Solar and Stellar Astrophysics
Ultracool and Brown Dwarf Candidates Identified via CatWISE-2MASS-Gaia DR3
Daniel Majaess, Dante Minniti, Matias Gomez et al. (+2 more)
Ultracool and brown
dwarf candidates ($d_{\odot}\lesssim 125$ pc, $|b|>8^{\circ}$) were identified via multiband and astrometric data from CatWISE ($W_1W_2$), 2MASS ($JHK_s$), and
Gaia DR3 ($G$, $G_{RP}$, $\pi$, $\mu_{\alpha}$, $\mu_{\delta}$). $N\approx 11.8 \times 10^3$ candidates emerged once simultaneously constrained by color and absolute magnitude criteria (e.g., $G-W_2 \ge 1.75(G-J)-2.25$), whereby $\simeq 350$ sources are absent from the
Gaia Ultracool
Dwarf (UCD) catalog. Spectral types were approximated using a hybrid $M_G-M_{W_1}$ sigmoid that offers additional temperature coverage in certain cases. Subsequent efforts may focus on extending sampling to the deeper NIR VVVX footprint that partly encompasses the
Galactic plane, and over the long-term spectroscopically (in)validating candidates missing from the
Gaia UCD database.
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All authors Daniel Majaess, Dante Minniti, Matias Gomez, Roberto K. Saito, Maria G. Navarro
Mathematical Physics
Quantum Turing Patterns
Kazuki Ikeda
We construct
quantum Turing patterns in Lindblad
lattice dynamics and establish a rigorous theory of their nonlinear order and
quantum fluctuations. For an explicit family of completely positive
lattice generators with finite-range couplings, the first-moment equations undergo a supercritical instability at a nonzero wave number and admit analytic site- and bond-centered commensurate stripe branches. These branches are locally asymptotically stable in their reflection-fixed period-
cell spaces, and projected coherent states exhibit extensive Bragg order on every bounded time interval in the semiclassical limit. We prove $O(N^{-1/2})$ convergence of microscopic covariances to a nonautonomous Gaussian Lyapunov flow, transferring strict partial-transpose uncertainty violations to sufficiently large $N$. In the homogeneous Gaussian sector, a single dimensionless ratio controls both the Turing stability determinant and the logarithmic negativity of opposite momenta, relating wavelength selection directly to
quantum entanglement. Differential transport shifts the strongest opposite-momentum correlations from the infrared to the selected Turing scale. Numerical continuation and two-dimensional simulations display stripe, spot, and labyrinth morphologies whose
Fourier modes and fluctuation spectra concentrate at the same selected wave numbers.
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Astrophysics of Galaxies
Automated Computer Vision Cluster Identification in the Fireworks Galaxy
Debby Tran, Benjamin F. Williams, Emily M. Levesque et al. (+5 more)
We present the integrated photometry, radii, and spatial distribution of young ($\leq$ 25 Myr)
star cluster candidates in NGC 6946. NGC 6946, also known as the Fireworks
Galaxy, is a highly
star-forming
galaxy with numerous young massive clusters. We have developed a modified computer
vision algorithm using photometry from images taken with Hubble Space
Telescope (HST) Wide Field Camera 3 Ultraviolet channel (WFC3/UVIS) F275W and F336W filters to identify and outline candidate clusters. We describe our technique in detail, including extensive testing with artificial clusters, where the
algorithm recovers 60.7% of synthetic clusters and has a conservative false positive rate of 27.3% down to luminosities of M$_{F336W} \sim -6$. We identify 6410 cluster candidates down to much fainter magnitudes (M$_{F336W} \sim -4$) via the aforementioned
algorithm which are more difficult to verify, but are still of interest as the luminosity function of these candidates is consistent with a standard power law with a slope of $\sim$2.
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All authors Debby Tran, Benjamin F. Williams, Emily M. Levesque, Tobin M. Wainer, Emerson Bowles, Bo-Eun Choi, L. Clifton Johnson, Anil C. Seth
Earth and Planetary Astrophysics
Nanoscale Storage of Incompatible Elements at Olivine Grain Boundaries in Natural Basalts
Wenhao Zhao, Reid Cooper, Stephen Parman et al. (+2 more)
Grain boundaries are pervasive in polycrystalline olivine, yet their structure and trace-element chemistry remain poorly constrained. We characterize boundaries in undeformed olivine aggregates from Piton de la Fournaise (La Reunion) and Mauna Loa (Hawaii) by correlating electron backscatter diffraction, transmission electron microscopy, and atom probe
tomography. The boundaries are crystalline, with a structural width of about 1 nm and no continuous glassy film resolved. Ca, Al, P, Na, and Ti are selectively enriched, whereas Mg, Fe, Ni, and Mn remain homogeneous. Several enriched mass windows coincide with nominal rare-earth-element ion positions, but unresolved isobars and the lack of a diagnostic isotope envelope preclude secure assignments. Divalent-cation segregation follows an ionic-size-misfit trend, while aliovalent departures require unconstrained contributions. The Ca interfacial excess is 2.94-2.97 atoms per square nanometer, equivalent to 0.327-0.330 monolayers, and lies near the upper published 1523 K
equilibrium segregation isotherm of Hiraga et al. (2004), within the range of basaltic olivine crystallization temperatures. This supports boundary formation during
crystal growth, although synneusis followed by high-temperature residence could produce a similar signature. Ca chemical widths are about 6-9 nm, and those of the most strongly enriched elements reach about 10-15 nm, demonstrating decoupling between the narrow structural core and broader chemical segregation. Compared with published atom-probe data on deformed olivine, these boundaries preserve broader
halos, although analytical differences make the contrast tentative. Olivine grain boundaries therefore constitute a distinct nanoscale reservoir that should be included alongside
crystal interiors and residual melt in trace-element mass balances of olivine-rich aggregates.
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All authors Wenhao Zhao, Reid Cooper, Stephen Parman, Austin Akey, Greg Hirth
Mesoscale and Nanoscale Physics
On the static dielectric constant of thin dielectrics in extremely scaled silicon nanosheet transistors
Massimo V. Fischetti, Dallin O. Nielsen and Edward Chen
We argue that the static dielectric constant of small (thin and/or narrow)
semiconductor and
insulator nanostructures depends strongly on the their environment. We do so by considering the electronic response simply reviewing, briefly but critically, the existing literature. Regarding the ionic response, in addition to reviewing the literature, we use a simple model to account for the confinement of optical
phonons in thin films and show that the reduction of their density of states has a negligible effect on the dielectric constant, in contrast to some claims found in the literature. In general, we argue that in realistic structures, such as double-gated Si nanosheets, the use of the bulk dielectric constants for both the channel and the gate
insulators, is justified.
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