General Relativity and Quantum Cosmology
Black Hole Shadow and Light Deflection in Generalized Heisenberg-Euler Nonlinear Electrodynamics
Beyhan Puliçe, Ali Övgün and Yosef Verbin
We study the optical properties of electrically charged black holes sourced by generalized Heisenberg-Euler nonlinear electrodynamics (NLED) in the second-order formalism. Using the exact parametric form of the static spherically symmetric solution, we analyze the
photon sphere, the black hole shadow, and the light deflection angle, and compare the results with those of the Reissner-Nordström and Schwarzschild cases. We find that the
photon sphere and shadow radii decrease with increasing charge and increase with black hole mass, while NLED effects become significant mainly near extremality. By confronting the dimensionless shadow radius with the Event Horizon
Telescope (EHT) bounds from Sgr A* and M87*, we derive phenomenological upper limits on the charge, with Sgr A* providing the stronger constraint. We further show that, for fixed impact parameter and charge, the deflection angle is systematically larger than in the corresponding Reissner-Nordström spacetime, and that the critical impact parameter is shifted to larger values. Our results show that NLED corrections produce observable modifications in the optical properties of charged black holes, especially close to extremality.
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Strongly Correlated Electrons
Orbital-Induced Peierls Transitions: How Orbitals Orchestrate Lattice Instability
T. Mizokawa and S.V. Streltsov
The Peierls transition is typically regarded as a phenomenon inherent to one-dimensional (1D) materials. However, orbital degrees of freedom can induce this instability even in higher dimensions. Two mechanisms are primarily responsible. First, the anisotropic shape of $p$ and $d$ orbitals can lead to effective "1D-zation" of the electronic spectrum. Second, orbital degrees of freedom can lift band degeneracy by shifting bands relative to each other via the local or band Jahn-Teller effect, thereby affecting the nesting of the
Fermi surface. The orbital-induced Peierls effect is most commonly observed when ligand octahedra surrounding transition metals share edges, and less frequently in face-sharing geometries. In this review, we discuss the underlying physical mechanisms, the materials in which this phenomenon occurs, the characteristics of the high-temperature undistorted phase, and the role of local effects such as the formation of molecular orbitals.
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Biological Physics · Cross-listed from q-bio.PE
Optimum foraging area in a three-trophic food chain
Lucas Massoni, Rafael Menezes, Marcus A. M. de Aguiar et al. (+1 more)
Organisms' foraging strategies are shaped by a trade-off between search area and local capture efficiency. This trade-off leads individuals to adapt their foraging area to an optimal value, impacting population dynamics. Here we study the effect of multiple foraging areas in a predator-prey model composed of three trophic levels. The interactions between predators and prey occur only within a limited neighborhood of the predators, where adaptation can occur over generations. We assume a trade-off where local predation efficiency is inversely proportional to the foraging area. These dynamics were implemented computationally via cellular automata and analytically via Master Equations with mean-field and pair approximations. Unlike the mean-field approximation, the pair approximation reproduced the dependence of population density on foraging area observed in the simulations. However, the simulations showed that the optimal foraging area does not maximize population density. Moreover, we found that a polymorphic population emerged, where not a single optimal strategy but a range of optimal strategies can coexist. Using the framework of Adaptive Dynamics, we confirm that the range of optimal areas is not the one that maximizes population size, but the Evolutionary Stable Strategy that can invade a population and not be invaded.
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All authors Lucas Massoni, Rafael Menezes, Marcus A. M. de Aguiar, Sabrina B.L. Araujo
High Energy Physics (Phenomenology)
Theoretical and phenomenological aspects of the Electroweak physics WG studies for the 2026 ESPPU Physics Briefing Book
Jorge de Blas, Monica Dunford, Emanuele Bagnaschi et al. (+6 more)
The 2025-2026 update of the European Strategy for Particle Physics placed renewed emphasis on quantitatively robust comparisons between future
collider projects. Within this context, the Electroweak physics working group of the Physics Preparatory Group (PPG EW WG) carried out a comprehensive assessment of the projected sensitivities of different facilities to
Higgs boson, electroweak and top-
quark observables, with particular
attention on different scenarios of theoretical uncertainties. These studies are summarized in the Physics Briefing Book. The aim of this document is to (a) provide a more detailed account of the evaluation of theoretical uncertainties, which was undertaken within the PPG EW WG, and (b) document the
collider-specific inputs used in the electroweak and Standard Model effective field theory (SMEFT) fits and discuss any needed modifications in order to harmonize assumptions between projects. In presenting the detailed theoretical uncertainty treatment and the explicit
collider inputs and assumptions, this work aims to improve the reproducibility and future extensibility of the results presented in the Physics Briefing Book.
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All authors Jorge de Blas, Monica Dunford, Emanuele Bagnaschi, Ayres Freitas, Pier Paolo Giardino, Christian Grefe, Michele Selvaggi, Angela Taliercio, Falk Bartels
General Relativity and Quantum Cosmology
Shadow and Polarized Images of Schwarzschild-MOG Black Hole Illuminated by Thick Accretion Disk
Cheng Hu, Huan Ye, Hong Lei et al. (+1 more)
Recent EHT polarimetric observations provide a powerful probe of near-horizon physics and modified
gravity. We investigate the shadow and polarization images of a static Schwarzschild-MOG black hole illuminated by geometrically thick, optically thin
accretion flows. Adopting a phenomenological model and the Hou disk model, and solving null geodesics and relativistic radiative transfer, we study how the MOG parameter, inclination angle, anisotropic synchrotron emission, and flow geometry affect the total intensity and linear polarization. It is found that the MOG parameter mainly enlarges and brightens higher-order
photon rings and broadens the shadow, while the inclination angle breaks axial
symmetry and enhances polarized emission inside the shadow. The Hou disk model suppresses off-equatorial radiative interference and localizes polarization signals within higher-order rings. Electric vector position angle (EVPA) patterns are mostly azimuthal but vary rapidly near lensed images. These results provide theoretical diagnostics for constraining MOG with EHT/ngEHT polarimetric observations.
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All authors Cheng Hu, Huan Ye, Hong Lei, Zi-Chao Lin
Computational Physics
Load balancing for adaptive-precision interatomic potentials in materials science
David Immel and Godehard Sutmann
For atomistic molecular dynamics simulations, we consider a recently developed hybrid coupling between the highly accurate machine learning (ML)-based atomic cluster expansion (ACE) interaction model and a less precise (but about 1-2 orders faster) EAM potential, in order to leverage the performance bottleneck of pure ML potentials in a parallel computing environment. This spatial-temporal adaptivity has the potential for a speedup of more than an order of magnitude, that would be lost without a dynamic load-balancing strategy that becomes critical due to fluctuating potential contributions. We compare the load-balancing strategies of LAMMPS with load-balancing methods provided by the library ALL in adaptive-precision EAM-ACE simulations of a copper nanoindentation. For a regular-grid domain decomposition, the modified tensor method of the ALL library, which conserves the simplicity and transferability of the tensor method, significantly reduces the imbalance factor of the force calculation from 3.0 to 1.7 compared to the native load-balancing method of LAMMPS. A nearly perfectly balanced system with an imbalance factor close to 1.0 can be reached by load balancing an irregular grid of domains with the recursive bisectioning method of LAMMPS and with ALL's histogram method for a staggered grid of domains. Load balancing a staggered grid with ALL is found to be significantly faster than load balancing an irregular grid with the bisectioning method of LAMMPS, but the communication costs during a regular timestep are lower for the irregular grid of domains, as a lower surface-by-volume ratio of the domains is reached. Furthermore, we suggest a strategy to find the ideal load-balancing frequency for adaptive-precision simulations.
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Materials Science
Hypothesis-Driven Autonomous Materials Synthesis with Multimodal LLM Agents
Izumi Takahara, Kazunori Nishio, Akira Aiba et al. (+4 more)
Self-driving laboratories can explore synthesis conditions autonomously, but their decision-making layer is typically a black-box optimizer, and the output is a set of optimized samples, with the measurements reduced to predefined scalar objectives and the reasons behind success left unarticulated. Here we present SynAgent, a framework in which large
language model
agents operate an automated experimental system and maintain an explicit, revisable understanding of the synthesis process as the campaign's primary output. Starting with no predefined analysis pipeline, SynAgent adaptively generates analysis skills for newly acquired data and evolves this understanding through
multimodal reasoning over experimental data such as X-ray diffraction patterns and electron micrographs. The
evolution is guided by a verify-falsify scheme, in which the
agent deliberately challenges its own hypotheses by testing conditions predicted to fail as well as those predicted to succeed. In a single campaign of 18 autonomous experiments using LiCoO2 (001) thin-film deposition as a testbed, SynAgent synthesized highly crystalline films and evolved an understanding of how the substrate temperature governs crystallization, discovering an abrupt threshold and a narrow optimal growth window at 650-690 {\deg}C. These results extend autonomous experimentation beyond optimized samples to testable, human-readable understanding.
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All authors Izumi Takahara, Kazunori Nishio, Akira Aiba, Shigeru Kobayashi, Takao Nakajima, Taro Hitosugi, Teruyasu Mizoguchi
High Energy Physics (Phenomenology)
Reheating Bounds from Thermal GUT Monopole Production
Donald Liveoak, Arielle Schutz and James D. Wells
Magnetic monopoles are a generic prediction of Grand Unified Theories (GUTs) that are in tension with modern cosmological and observational bounds. In this paper, we calculate the present-day abundance of GUT monopoles produced thermally in the early Universe. We improve on previous calculations by accounting for full relativistic corrections to the thermal abundance and enhanced monopole annihilation due to the emission of radiation and scattering off massive gauge
bosons, the Standard Model
fermions and their superpartners. To obtain a present-day energy density less than that of dark matter, we show that the reheating temperature of the Universe, $T_{\rm RH}$, must be less than $0.55$ times the GUT
symmetry breaking scale $T_{\rm GUT}$ for the canonical 't Hooft-Polyakov monopole mass. Accounting for Parker bounds on the present-day
magnetic monopole abundance, the bound is tightened to $T_{\text{RH}}/T_{\text{GUT}} \lesssim 0.45$. Furthermore, experimental bounds from Super-Kamiokande require $T_{\text{RH}}/T_{\text{GUT}} \lesssim 0.35$ in our scenario.
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Quantum Physics
From Reversible Quantum Dynamics to Statistical Probability: A dynamical solution to the origin of probability and Hilbert's sixth problem
Wei-Min Zhang
Hilbert's sixth problem placed probability and mechanics at the center of the axiomatization of physics. It asks how irreversible statistical probability and thermodynamics can follow from the reversible, deterministic dynamics of a system. Building on an exact open
quantum system theory developed in the past two decades, we construct a dynamical route from the reversible
quantum dynamics to reduced statistics. For quadratic bosonic and fermionic systems bilinearly coupled to arbitrary environments, we derive the exact reduced density operator determined completely by a dissipative propagator u and a fluctuation correlation function v of the system. For continuous spectral densities with no bound-state pole, u vanishes in the long-time limit, information about the system initial states is lost completely, and the reduced density operator of systems approaches a thermal Gibbs state. Gapped spectral densities with localized bound states instead preserve long-time
memory and prevent thermalization. We then remove the usual assumption of an initially thermal, mixed environment, start from a product of pure states for the system and environment,
unitary evolution first generates system-environment
entanglement and a periodic quasi-Gibbs reduced state for a finite environment. When the number of environmental degrees of freedom tends to infinity, the spectrum becomes continuous, the recurrence disappears, the exact reduced density operator converges to a thermal Gibbs state. The total
entropy remains zero, whereas the system
entropy becomes
entanglement entropy and reaches its maximum. Probability is therefore not an additional random postulate imposed on
unitary dynamics, it is the objective statistical structure of an open system in a composite. These results provide an exact, testable dynamical solution of the determinism to statistics.
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Strongly Correlated Electrons
Optical investigation of the electronic structure of a ferromagnetic Weyl semimetal CeAlSi
Shin-ichi Kimura, Yue Pan, Hiroshi Watanabe et al. (+3 more)
To investigate electronic states during the
ferromagnetic transition in a
magnetic Weyl semimetal CeAlSi, we measured temperature-dependent optical conductivity [$\sigma_1(\omega)$] spectra and compared them with DFT+DMFT band calculations. The $\sigma_1(\omega)$ spectrum did not change significantly across the
ferromagnetic ordering temperature ($T_C$), suggesting that the Ce 4f states are almost localized. DFT+DMFT calculations with almost localized Ce 4f states successfully reproduced the spectral shape and the unchanged $\sigma_1(\omega)$ spectra across $T_C$. The dynamic effective mass evaluated from the extended Drude model is very small, which DFT+DMFT calculations also reproduce, but the scattering probability at even lower temperatures suggests
ferromagnetic fluctuations. These results suggest that the interaction intensity between the Weyl
fermions and Ce 4f states is very weak, as reproduced by DFT+DMFT calculations.
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All authors Shin-ichi Kimura, Yue Pan, Hiroshi Watanabe, Akimitsu Kirikoshi, Junya Otsuki, Hiroshi Tanida
Solar and Stellar Astrophysics
Spectral classification of OB-type stars using tree-based ensemble methods and evaluation of their explainability
J.E. Gonzales, S. Simón-Díaz, S. Cuellar et al. (+3 more)
[Abridged] The advent of large-scale spectroscopic surveys will deliver tens of thousands of spectra of blue massive
stars. This data volume renders traditional spectral classification techniques increasingly impractical. We aim to develop a robust ML framework for the automated spectral classification of massive OB
stars by assessing several tree-based ensemble
algorithms. Using a large catalog of high-quality optical spectra of OB
stars, we design 3 hierarchical experiments of increasing complexity: classification into broad SpT; fine-grained classification within the O and B domains; and joint classification of SpT and LC. We evaluate 6
algorithms, ranging from single Decision Trees to ensemble methods and gradient boosting techniques. We further analyze model consensus and probabilistic outputs, and employ SHAP value analysis to provide an interpretation of the model decisions by identifying the features that drive each classification. Models achieve excellent performance for broad SpT classification, with LGBM reaching an accuracy of 98%. For fine-grained SpT, RF provides the most robust results (89%). For the most challenging task combining SpT subtype and LC the XGB reaches a 77% accuracy. Decrease in performance is primarily driven by intrinsic degeneracies in the classical spectral classification scheme. SHAP analysis confirms that the models rely on meaningful spectral features. We also find a high level of agreement among different
algorithms, indicating that current performance limits are largely set by the intrinsic complexity of the classification problem rather than by model choice. Tree-based ensemble methods provide a reliable and interpretable framework for the automated spectral classification of OB
stars. The combination of full-spectrum modeling,
algorithm comparison, and model interpretability offers a robust approach for future large-scale spectroscopic surveys.
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All authors J.E. Gonzales, S. Simón-Díaz, S. Cuellar, J.A. Conejero, G. Holgado, A. de Burgos
Materials Science
Nonempirical Time-Dependent Density Functional Theory Framework for Nonlocal Exchange–Correlation Potentials
Zhandos A. Moldabekov, Michele Pavanello, Thomas D. Gawne et al. (+2 more)
Advanced, orbital-dependent exchange–correlation (XC) functionals can significantly improve the description of electronic structural properties, but they substantially worsen spectral properties that are computed within standard linear-response time-dependent density functional theory frameworks. This is not a failure of the underlying Kohn-Sham states, but due to a formal inconsistency in the treatment of the dynamic density response when the non-locality of the XC potential is not taken into account consistently on the level of the full off-diagonal density
matrix. To avoid these complexities, we present a non-empirical additive correction $\Delta f_\textnormal{xc}(\mathbf{q},\omega)$ to the dynamic XC kernel that re-enforces the exact f-sum rule of the non-local KS
Hamiltonian within TDDFT. Comparing our new results against a representative set of accurate experimental measurements (ambient aluminum, silicon and carbon, as well as heated and compressed aluminum) reveals a dramatic improvement in all cases without any additional computational cost. The corresponding extension to the open-source GPAW code is made freely available online. We further investigate the implications of non-local pseudopotentials and show that the non-locality has an important, physically motivated effect that is indispensable to capture the correct plasmon dispersion in lieu of full all-electron simulations. In addition to being important for the estimation of a plethora of dynamic and spectral properties, our work constitutes an important step towards a universal XC functional that can be used to estimate all kinds of observables with high accuracy. Finally, we outline the potential utility of our framework for the development of advanced non-local XC functionals, and suggest a new way to rigorously verify non-local pseudopotentials against experimental measurements of collective excitations.
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All authors Zhandos A. Moldabekov, Michele Pavanello, Thomas D. Gawne, Jan Vorberger, Tobias Dornheim
Materials Science
ERAF4XRD: A multimodal agentic framework for constructing validated experimental X-ray diffraction databases from scientific literature
Afnan Mostafa, William Ratcliff, Simon J. L. Billinge et al. (+1 more)
The scientific literature contains decades of experimental measurements that remain difficult to access as structured data for modern AI and data-driven research. Much of this information is distributed across figures, captions, text, and tables, requiring experimental data and their context to be identified, connected, and verified before they can be reused. Here we introduce ERAF4XRD (Experiment Reader Agentic Framework for X-Ray Diffraction), a fully automated
multimodal (i.e., image and text), multi-
agent framework that reconstructs validated X-ray diffraction (XRD) records from scientific publications. ERAF4XRD downloads and screens documents, identifies XRD figures, extracts and links metadata to the corresponding experimental data, and validates outputs against source evidence using an independent validation
agent. On a manually curated
benchmark of 273 scientific publications containing 3,150 candidate figures, ERAF4XRD achieved up to 98.7% accuracy for XRD figure identification and generated 1,400 metadata values across 22 fields. Independent manual assessment of the final validated records yielded 98.5% precision and 90.7% recall, with no unsupported metadata observed among 443 evaluated fields. By moving beyond information extraction to the reconstruction and validation of linked experimental records, ERAF4XRD establishes an automated approach for transforming published scientific information into machine-readable experimental
datasets for AI and data-driven science.
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All authors Afnan Mostafa, William Ratcliff, Simon J. L. Billinge, Niaz Abdolrahim
Quantum Physics
Filter-Free Indistinguishable Photon Generation from Continuous-Wave-Driven Integrated Microresonators
Ruiyang Chen, Sicheng Zeng, Yuan Chen et al. (+6 more)
Quantum networks require scalable
photon sources combining narrow linewidth, high efficiency, and high indistinguishability. Microresonator
photon-pair sources are promising candidates, yet a source-only description based on the joint spectral amplitude (JSA) predicts near-zero Hong-Ou-Mandel (HOM) interference visibility between
photons generated by independent, CW-driven microresonators. In this work, we show that the observed HOM interference is not determined by the JSA alone. By combining finite-time detection with cavity-enhanced spontaneous four-wave mixing, we characterize a detector-conditioned heralded state governed by the idler-
photon detection window. We further demonstrate that independently optimizing the idler and signal detection windows allows both heralded-
photon indistinguishability and intrinsic heralding efficiency to approach unity, without spectral filtering or complex source engineering. Utilizing integrated high-$Q$ silicon nitride microresonators, we achieve HOM visibilities of 0.992(8) and 0.942(12), without background subtraction, at fourfold count rates of 4.5(3) and 12.2(6) Hz, respectively. Our work establishes CW-driven high-$Q$ microresonators as a robust and scalable platform for
quantum-network primitives.
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All authors Ruiyang Chen, Sicheng Zeng, Yuan Chen, Sanli Huang, Zeying Zhong, Zhen Chen, Xue Bai, Yi-Han Luo, Junqiu Liu
Materials Science
Thermally Desorbable InN Capping Layers for Nitride Surface Science
Mellie Lemon, Amitayush Thakur, Anthony Rice et al. (+5 more)
Group III-nitride thin films are essential for optoelectronic and power devices, where surface and interface quality critically influence performance. It is often necessary to transfer these films through atmosphere for processing or characterization steps, which can introduce significant surface contamination. Here we demonstrate a technique to protect the surface of III-N films during atmospheric exposure by capping with sacrificial InN layers. Using molecular beam epitaxy grown AlGaN films as our representative protected material, we take advantage of the lower decomposition and desorption temperatures of InN and metallic In to remove the protective cap layer in situ via thermal desorption without damaging the AlGaN film beneath. Angle-resolved photoemission spectroscopy (ARPES) measurements of the valence band dispersion in Al0.4Ga0.6N demonstrate that the film surface is recovered after InN decapping, highlighting the versatility of this process in allowing further surface-sensitive characterization of films that had been exposed to air.
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All authors Mellie Lemon, Amitayush Thakur, Anthony Rice, Glenn Teeter, Michelle Smeaton, Renae Gannon, Jessica L. McChesney, M. Brooks Tellekamp
Mesoscale and Nanoscale Physics
Layer-Dependent Vibrational and Optical Properties of $\mathrm{Mo}{0.58}\mathrm{W}{0.42}\mathrm{Se}_2$ Alloy
Szymon Socha, Tomasz Wozniak, Elena Blundo et al. (+7 more)
Semiconducting Mo$_x$W$_{1-x}$Se$_2$
alloys provide a versatile platform for tailoring the optical properties of two-dimensional materials through both composition and layer thickness. Here, we systematically investigate mechanically exfoliated Mo$_{0.58}$W$_{0.42}$Se$_2$ flakes ranging from monolayer (1L) to nine layers by combining Raman scattering (RS), photoluminescence (PL), reflectance contrast (RC) spectroscopy, and first-principles
phonon calculations. Thirteen RS peaks are identified, including the low-frequency interlayer shear mode, whose thickness dependence is well described by a linear-chain model, yielding an interlayer force constant of $K_s=(2.996\pm0.015)\times10^{19}$ N m$^{-3}$. PL measurements reveal a crossover from the direct-bandgap 1L to indirect-bandgap multilayers. The thickness
evolution of the indirect optical transition is quantitatively reproduced using a
quantum-confinement model, yielding an out-of-plane reduced effective mass of $\mu_\perp=0.75 m_0$. RC spectroscopy reveals four excitonic resonances. While the A and B
excitons associated with the $K^\pm$ valleys remain nearly independent of layer thickness, the higher-energy C and D resonances originating from the band-nesting regions exhibit pronounced
redshifts, reflecting substantial thickness-induced modifications of the electronic band structure. These results establish comprehensive spectroscopic fingerprints of flake thickness, interlayer coupling, and electronic structure in Mo$_x$W$_{1-x}$Se$_2$
alloys and provide a reliable, non-destructive framework for their optical characterization.
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All authors Szymon Socha, Tomasz Wozniak, Elena Blundo, Malgorzata Brzoska, Grzegorz Krasucki, Piotr Wrobel, Antonio Polimeni, Adam Babinski, Maciej R. Molas, Katarzyna Olkowska-Pucko
Quantum Physics
Catalytic Activation of Genuine Multipartite Entanglement and Nonlocality
Eliot Donnadieu, Pavel Sekatski, Nicolas Brunner et al. (+1 more)
We demonstrate the possibility to activate genuine multipartite
entanglement (GME), the strongest form of
entanglement for multipartite states, within the framework of
quantum catalysis. Specifically, we show that any biseparable state (i.e. not GME) that is not partition separable can be deterministically transformed into a GME state via the help of a catalyst and local operations, without any classical communication. In turn, we construct a catalytic protocol tailored to the multipartite case. The protocol is termed "sum-to-product", as it transforms a mixture of states into their tensor product in a heralded manner. We apply this protocol to random network entangled states, which are biseparable by construction, and demonstrate catalytic activation of both GME and genuine multipartite Bell nonlocality.
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All authors Eliot Donnadieu, Pavel Sekatski, Nicolas Brunner, Victor Barizien
Quantum Physics
Spectral Optimization for Absolutely PPT States: Purity, Entropy, and Volume Decay
Anh T. Tran
We study maximum purity and minimum von Neumann
entropy of absolutely positive partial transpose (APPT) states, together with the relative volume of their spectral sets. A consequence of Hildebrand's criterion gives an explicit outer spectral polytope, whose vertices we classify. Optimizing purity over this polytope, together with the Song–Chen result for the $2\otimes3$ system, yields, for every $mn\ge6$, an explicit upper bound on the purity of APPT states that is asymptotic to $4/(3mn)$. This improves the previous $2/(mn)$ upper bound for absolutely separable states. The new bound applies to every APPT state, a class containing all absolutely separable states, and is sharp for every $2\otimes n$ system with $n\ge3$. For every $3\otimes n$ system with $n\ge3$, however, the unique outer-polytope maximizer is not APPT, so the bound is strict and disproves the Dũng–Khôi qutrit–qudit
conjecture. The polytope also gives an explicit
entropy lower bound in arbitrary bipartite dimensions and, together with the Song–Chen extreme-point classification, the exact minimum
entropy for every $2\otimes n$ system. Finally, exact formulas for the relative volumes of an inner polytope and the outer spectral polytope give explicit two-sided bounds on the
qubit–qudit relative spectral volume $a_n$ whose ratio is less than $4$ and tends to $3$. Consequently, $a_n=\Theta\!\left(\sqrt n(4/27)^n\right)$, and the relative volume of the
qubit–qudit APPT spectral set (equivalently, the absolutely separable spectral set) has exact exponential decay rate $\ln(27/4)$.
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Instrumentation and Detectors
Terahertz Radar Inversion for Range-Resolved Solids Concentration Profiling in Gas–Solid Flows
Philip Kjaer Jepsen, Albert Monteith, Diana Carolina Guío-Pérez et al. (+4 more)
A stable inversion method is developed to reconstruct millimeter-scale solids-concentration profiles in particulate suspensions from monostatic sub-terahertz frequency-modulated continuous-wave (FMCW) radar measurements. In industrial particulate flows, cumulative attenuation renders the direct inversion of the path-integrated volume-scattering radar equation ill-conditioned. The method resolves this by an ensemble-averaged Mie-scattering closure coupled to a stable backward-integration scheme, yielding an analytical solution for the range-resolved solids concentration without case-specific parameter fitting against reference concentration measurements. The required range-dependent system response is determined by absolute near- and far-field calibration via external substitution with an electrically large metallic sphere. The method was evaluated against solids-volume-fraction estimates derived from differential-pressure measurements in a 3.1 m-tall circulating fluidized-bed riser operated with ambient air and copper powder (median diameter 32.6 $\mu$m, density 8920 kg m$^{-3}$). The radar-derived and pressure-derived profiles agreed well across three superficial gas velocities producing distinct axial solids distributions, and the radar indicates sensitivity down to solids volume fractions of order $10^{-6}$.
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All authors Philip Kjaer Jepsen, Albert Monteith, Diana Carolina Guío-Pérez, Lars Ulander, Tomas Bryllert, Henrik Ström, David Pallarès
High Energy Physics (Theory)
Deep learning emergent spacetime from fermionic spectral functions in holography
Koji Hashimoto, Hyun-Sik Jeong, Keun-Young Kim et al. (+2 more)
We present a physics-informed machine learning framework based on Neural Ordinary Differential Equations that solves the
holographic inverse problem: reconstructing the bulk spacetime and gauge field of a charged AdS black hole directly from boundary fermionic spectral functions. Encoding the UV asymptotics, horizon regularity, and zero temperature extremality as hard constraints in the neural network architecture, our framework reliably reconstructs the extremal Reissner-Nordström AdS geometry across three
quantum critical regimes set by the $U(1)$ probe charge—non-
Fermi liquid, marginal
Fermi liquid (strange metal), and
Fermi-
liquid-like states—and can jointly infer the probe charge itself to sub-percent accuracy. Relaxing the near-AdS boundary constraint uncovers a geometrical degeneracy: bulk profiles that differ throughout the radial direction but share the same near-horizon $AdS_2 \times \mathbb{R}^2$ data reproduce identical spectral functions near the
Fermi surface. This isospectral non-uniqueness is precisely the bulk degeneracy expected on general
holographic grounds at zero temperature, and its spontaneous emergence across independent training runs shows that the network isolates the IR CFT universality rather than overfitting a single UV completion.
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All authors Koji Hashimoto, Hyun-Sik Jeong, Keun-Young Kim, Daichi Takeda, Kwan Yun
Quantum Physics
Julian Hager, Michael Kölle, Gerhard Stenzel et al. (+3 more)
We propose a compact NISQ-compatible
quantum transformer architecture for synthetic QNLP sequence modelling. The model preserves the autoregressive next-
token interface of a classical
transformer, but replaces
attention and feed-forward sublayers with variational
quantum encoder blocks, connector
circuits, decoder blocks and a direct two-
qubit measurement readout.
Token contexts are angle-encoded into small
quantum registers, processed by parallel variational heads and encoder integration
circuits and conditioned through decoder ancillae to produce a distribution over a four-
token vocabulary. We evaluate several architecture variants on deterministic and lexicographic grammar-generation tasks against a compact classical
transformer baseline. The
quantum models are trainable end-to-end and learn nontrivial grammar structure, including perfect deterministic generation in individual runs and high lexicographic validity in the strongest variant. The classical baseline remains more accurate and stable and the
quantum models are sensitive to initialization. The contribution is therefore not a claim of
quantum advantage, but a concrete architecture and evaluation of
transformer-inspired QNLP sequence modelling under near-term
quantum constraints.
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All authors Julian Hager, Michael Kölle, Gerhard Stenzel, Tobias Rohe, Jonas Stein, Claudia Linnhoff-Popien
High Energy Physics (Phenomenology)
Asymmetric Inelastic Dark Matter and the LUX-ZEPLIN event
Natsumi Nagata and Tsutomu T. Yanagida
The recent LUX-ZEPLIN (LZ) search at high
nuclear-
recoil energies reported an intriguing candidate event near 250 keV, motivating interpretations in terms of inelastic dark matter. A simple realization with Higgsino dark matter, however, is strongly constrained by capture and subsequent annihilation in the Sun, which would produce a high-energy
neutrino flux excluded by IceCube. We propose an asymmetric inelastic dark-matter scenario that naturally avoids this tension. The dark matter is a predominantly Standard-Model-singlet Dirac
fermion that mixes weakly with a nearly degenerate electroweak doublet. Its
primordial asymmetry is generated by CP-violating out-of-
equilibrium decays of heavy Majorana
fermions produced nonthermally from inflaton decays, while the symmetric component is efficiently depleted through dark-sector interactions. The absence of an appreciable antiparticle abundance then suppresses dark-matter annihilation in the Sun and eliminates the associated IceCube constraint. The singlet-doublet structure simultaneously yields an off-diagonal Z-
boson coupling proportional to the mixing angle, whereas the diagonal coupling is suppressed by its square. Consequently, an observable inelastic scattering rate can coexist with stringent limits on elastic scattering. We find that the LZ event can be accommodated for dark-matter masses of a few hundred GeV to 1 TeV, with mass splittings of a few hundred keV and mixing angles below O$(10^{-2})$. Since the relic abundance is set by the
primordial asymmetry rather than thermal freeze-out, lighter dark matter is also viable and can alleviate the potential tension with the absence of events in the LZ high-energy sideband. This framework predicts correlated elastic and inelastic direct-detection signals, together with complementary signatures at
collider and precision experiments.
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Quantum Physics
Extensibly Causally Separable Processes Admit Realizations as Quantum Circuits with Classical Control of Causal Order
Wenjie Wei and Shengshi Pang
Indefinite causal order extends the conventional
circuit paradigm by allowing local
quantum operations to be connected without a predetermined global order. Within the process-
matrix framework, it is characterized by causal nonseparability, whereas extensible causal separability (ECS) requires that, under arbitrary input-ancilla extensions, a process admit a recursive decomposition into components, each compatible with a particular operation acting first.
Quantum circuits with classical control of causal order (QC-CC), in which previous outcomes dynamically determine which operation acts next, are known to generate ECS processes, but whether every ECS process admits such a realization has remained a longstanding open problem. We settle it through a generalized teleportation construction that realizes every multipartite ECS process as a QC-CC. We further establish consistency between ECS definitions for trivial and nontrivial global past and future systems. These results provide ECS with an exact operational interpretation and identify QC-CC as the complete
circuit structure underlying this class of processes.
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Quantum Physics
Information Geometry of Four-Parameter Single-Qutrit States: From Quantum to Semiclassical Geometric Tensors
Xue-xiang Xu, Kai-xu Cai, Xue-feng Zhan et al. (+1 more)
The gap between the classical and
quantum Fisher information
matrices (CFIM and QFIM) separates what is operationally accessible through measurements from what is intrinsic to a
quantum state. In the multiparameter setting, this
quantum obstruction is generically not saturable. Motivated by the recently introduced semiclassical
geometric tensor (SCGT), we perform an explicit information-
geometric study for a class of pure four-parameter single-qutrit states (FPSQSs). These states are probed by a one-parameter family of measurements that interpolates between an uninformative POVM and a sharp projective measurement. We derive closed-form expressions for the CFIM, the
quantum geometric tensor (QGT), and the SCGT. We show that the SCGT reproduces the QGT in the projective limit and vanishes in the trivial limit. The real part of the SCGT splits into two terms: the CFIM and an additional nonnegative measurement-transmitted metric in the phase sector. Its imaginary part provides a semiclassical Berry
curvature. Its loss relative to the QGT is quantified by a measurement-dependent gap. Our results provide an exactly solvable four-parameter platform for the semiclassical
geometric framework. They also clarify how realistic measurements read out the
geometric content of
quantum states, and how they partially degrade it.
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All authors Xue-xiang Xu, Kai-xu Cai, Xue-feng Zhan, Hong-chun Yuan
Astrophysics of Galaxies
Signatures of dark subhaloes in dwarf spheroidal galaxies: II. Transient and localised kinematic features
Eduardo Vitral, Jorge Penarrubia, Roeland P. van der Marel et al. (+1 more)
We use controlled N-body simulations to investigate whether dark matter subhaloes leave detectable signatures in the internal kinematics of
dwarf spheroidal
galaxies. At each snapshot, we fit a velocity distribution function to
stellar line-of-sight velocities and proper motions, construct normalised residual fields for the projected velocity components, and analyse their power-spectra. We show that subhalo encounters generate a plethora of kinematic features. Amongst the most prominent are rotation-like signals, which arise in our models even though the
stellar component is initialised without intrinsic rotation. In line-of-sight velocity alone, several snapshots resemble the classical blueshift–
redshift pattern associated with stationary rotation. The plane-of-sky components, however, bring complexity, with alternating regions of expansion and contraction, as well as clockwise and anticlockwise streaming. Although we observe coherent streaming globally, these structures depart from typical
equilibrium configurations, while their residual power-spectra quantify the characteristic spatial scales involved. This signal strengthens in models containing more massive subhaloes and becomes difficult to recover for small
stellar samples: robust power-spectrum recovery of the full velocity-space signature usually requires O(10^{4}) tracers, although a rotation signal alone can be recovered with considerably smaller samples. These results suggest that
dwarf spheroidal velocity fields can retain signatures of subhalo heating. Future spectroscopy, improved
Gaia astrometry, and chemo-dynamical information should turn these diagnostics into population-level probes of dark matter substructure.
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All authors Eduardo Vitral, Jorge Penarrubia, Roeland P. van der Marel, Matthew G. Walker
Atmospheric and Oceanic Physics
Disentangled Fingerprints suggest no historical weakening of Atlantic Overturning and Subpolar Gyre
Bahar Emirzade, Jade Ajagun-Brauns, Maya Ben-Yami et al. (+4 more)
The AMOC and the Subpolar Gyre are key components of the Earth's
climate system, both potentially prone to destabilization and abrupt shifts under anthropogenic forcing.Given the strong influence of the AMOC and the SPG on global
climate, detecting changes in their stability is of high importance, yet is hindered by the limited length of observational records.In the absence of long-term direct AMOC observations, several observation-based fingerprints of the AMOC have been proposed.However, existing fingerprints do not clearly distinguish between SPG and AMOC variability, instead reflecting an opaque mixture of dynamics from both systems.Here, we assess the performance of widely used AMOC fingerprints across CMIP6 models and compare them with statistically optimal fingerprints that we derive from sea surface temperature and salinity.We show that traditional AMOC fingerprints exhibit weak correlations with both AMOC and SPG strength.In contrast, our statistically optimal fingerprints, trained on pre-industrial control simulations, consistently outperform existing approaches across independent segments of piControl simulations and historical experiments.These fingerprints accurately reconstruct AMOC and SPG variability while minimizing overlap, enabling a clear separation between the two systems.Our results provide the first tailored observational fingerprints that robustly distinguish AMOC and SPG, demonstrating the potential of statistically optimized approaches to improve detection and attribution of changes in Atlantic circulation, including precursor signals of potential tipping behavior.Applying our approach to sea surface temperature observations, we find that our optimized fingerprints do not confirm the substantial AMOC weakening in the recent decades as suggested by traditional fingerprints, but also do not rule out a loss of stability.
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All authors Bahar Emirzade, Jade Ajagun-Brauns, Maya Ben-Yami, Sebastian Bathiany, Yechul Shin, Jong-Seong Kug, Niklas Boers
Mathematical Physics
Some Considerations on the Fluid-Dynamical Limit of Particle Systems
Mario Pulvirenti and Sergio Simonella
In this note we review and compare mathematical procedures aimed at rigorously deriving fluid-dynamic descriptions of classical particle systems in the large-scale limit of
Hamiltonian dynamics. Despite the longstanding nature of this program, its fundamental problems remain open, with only a few notable exceptions that we briefly highlight.
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Quantum Physics
Giant-atom-mediated photon blockade
C. Cui, W. Y. Hu, Y. Q. Ji et al. (+3 more)
Photon blockade is a phenomenon where the presence of system nonlinearity causes the output to consist of single
photons, which has been extensively studied in point atom systems, but it is barely explored in
giant atom ones. In this paper, we propose
giant atom-mediated
photon blockade scheme based on two cavities and three cavities systems with driving field applied to the first cavity. We show that simultaneous unconventional
photon blockades (UPBs) can not occur in the point atom system (the atom coupling only to the leftmost cavity) due to there always existing a cavity to have a single path. In contrast, the spatially extended nature of
giant atom enables coupling to multiple cavities and allows for the introduction of a phase and coupling strength. Consequently, simultaneous UPBs in multiple cavities can be obtained due to the multipath destructive interference. Moreover, by manipulating the detuning, we observe simultaneous conventional
photon blockades (CPBs) in multiple cavities. Finally, we study simultaneous two-
photon blockades (2PBs) in point atom multiple cavities system.
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All authors C. Cui, W. Y. Hu, Y. Q. Ji, H. T. Cui, Yan-Hui Zhou, H. Z. Shen
Computational Physics
Braided endovascular implants for intracranial aneurysms: mechanics, hemodynamics, and clinical translation
Ratnadeep Pramanik, Duygu Dengiz, Mariya S. Pravdivtseva et al. (+9 more)
Endovascular implants prevent intracranial aneurysm rupture by altering the mechanical and hemodynamic environment at the aneurysm neck. Yet many in silico workflows prescribe or reconstruct the post-deployment geometry before computing flow, leaving unresolved the mechanics that create the clinically relevant interface. Here we review braided intraluminal flow diverters, intrasaccular devices, and emerging flow-disruption concepts across deployment mechanics, inter-wire and wire-wall contact, superelasticity, wall apposition, pore geometry, computational fluid dynamics, and fluid-structure interaction. We connect these modeling choices to neck coverage, malapposition, migration, deformation, and durability, and distinguish established evidence from mechanistic inference and prospective hypotheses. We argue that model fidelity should match the clinical question: prescribed or fast placement may support screening, whereas questions of coverage, apposition, compaction, and migration benefit from mechanically plausible deployment states. An interface-resolved mechanics-to-flow framework, supported by measurable validation targets and standardized reporting, could improve device design and enable more reliable patient-specific treatment planning.
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All authors Ratnadeep Pramanik, Duygu Dengiz, Mariya S. Pravdivtseva, Martin Frank, Ivo Steinbrecher, Prasanth Velvaluri, Matthias Mayr, Philipp Berg, Sylvia Saalfeld, Naomi Larsen, Olav Jansen, Alexander Popp
Astrophysics of Galaxies
Challenging the archetypal intermittent radio galaxy J0111+3906. New insights from optical GTC/OSIRIS and radio VLA and LOFAR observations
M. Orienti, J.A. Acosta-Pulido, E. De Rubeis et al. (+5 more)
We present results on new optical Gran Telescopio CANARIAS OSIRIS+ spectroscopy and
radio Very Large Array (VLA) observations at 360 MHz of the optical object behind the
radio emission 20 arcseconds east of the archetypal restarted compact symmetric object (CSO) J0111+3906. The optical counterpart is a post-starburst
galaxy at
redshift $z$ = 1.042, ruling out any physical relation between this object and the CSO
radio galaxy J0111+3906 at
redshift $z$ = 0.668. The
radio emission is therefore not the remnant of a past activity of the CSO J0111+3906 that took place around 10$^7$ years ago. When observed with the high angular resolution of VLA and the International LOw Frequency ARray
telescope the East
radio source is resolved in a compact component with spectral index 0.7, centred on the optical
galaxy, surrounded by diffuse emission with a slightly steeper spectrum. The upper limit to the radiative age of the East
radio source is a few million years. If the trigger of the
radio emission and the recent burst of
star formation observed in the East
radio source are causally connected, there must be a long time gap between the two phenomena. The multi-frequency analysis of the CSO
radio galaxy J0111+3906 pointed out excess flux density at 150 MHz, which may indicate the presence of fossil
plasma confined within the host
galaxy. In this scenario, the past activity of the CSO J0111+3906 switched off not long after its trigger, suggesting a duty cycle of about 10$^4$ yr.
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All authors M. Orienti, J.A. Acosta-Pulido, E. De Rubeis, C. Stanghellini, M. Bondi, F. D'Ammando, L. Coccato, I. Alemán-Martín