Quantum Physics
Efficiency-Induced Freezing in Quantum-State Purification
Jiaxin Liu, Zuoxian Wang, Feng Li et al. (+1 more)
Any nonzero detection loss qualitatively changes feedback-controlled purification under diffusive monitoring. In every finite dimension, we prove a sharp, dimension-independent ceiling on the decay of trajectory-averaged
impurity moments, uniformly over admissible predictable feedback protocols.Below unit efficiency, this ceiling becomes independent of moment order above a critical value and is attained on extremal rank-two
quantum-nondemolition (QND) faces. For generic observable spectra, a determinant-root law precludes every full-rank state from attaining this boundary rate over an explicit moment-order interval. For
qubits at $0<\eta<1$, the frozen rate is the exact optimum, set by rare, persistently mixed trajectories. Parameter-free finite-action scaling functions resolve both the rounded QND moment-order transition and the near-unit QND–always-unbiased crossover.
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All authors Jiaxin Liu, Zuoxian Wang, Feng Li, Danyue Ma
Fluid Dynamics
An improved fully one-sided diffuse-interface immersed boundary method with target-value reconstruction for compressible flows
Qian Mao, Song Zhao, Pierre Boivin et al. (+1 more)
Although one-sided spreading has been shown to improve the near-wall accuracy of diffuse-interface immersed boundary methods (DIBMs), the effect of its asymmetric kernel support on the effective boundary location remains insufficiently understood. In this work, a detailed analysis of the one-sided spreading operator reveals an inward displacement of the effective boundary relative to the
geometric boundary. To compensate for this displacement, a target-value reconstruction strategy is developed to ensure consistency between the values imposed at the effective boundary and the prescribed conditions at the
geometric boundary. The strategy is incorporated into the fully one-sided diffuse-interface immersed boundary method (FODIBM) and applies to both Dirichlet and Neumann boundary conditions. Although confined to the target-value evaluation step, the modification substantially improves boundary-condition enforcement with negligible additional computational cost. Coupled with a hybrid
lattice Boltzmann solver, the improved method consistently reduces L_2 and L_{\infty} error norms across different grid resolutions while retaining approximately second-order grid convergence. The no-slip and isothermal boundary-condition errors are reduced by 77% and 85%, respectively. Simulations involving various two- and three-dimensional geometries further show improved predictions relative to both the conventional DIBM and the original FODIBM. The results agree well with body-fitted reference solutions and experimental data, demonstrating accurate and computationally efficient simulations of compressible flows around complex geometries.
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All authors Qian Mao, Song Zhao, Pierre Boivin, Julien Favier
Materials Science
Growth of (111)-textured SrTiO3 thin films on Pt(111)/Al2O3(1-102) substrates by rf magnetron sputter deposition
Ekaterina Taylor, Ethan R. Cronk, Kalani Perera et al. (+2 more)
SrTiO3 thin films, 20-30nm, with high quality
crystal structure and low roughness can be used as growth templates for complex
oxides or as the dielectric materials for capacitor structures. In this work, stoichiometric STO thin films were grown by
radio frequency magnetron sputtering on Pt (111) templates grown on rAl2O3 substrates, and the effects of growth parameters as well as the underlying Pt templates structural properties on the quality of STO films were studied. A comparison between room temp grown Pt and Pt grown at elevated temps showed that the latter lead to highly ordered Pt and STO films with quasi 2D surface roughness. Xray diffraction showed that the STO thin films had (111) and (222)
crystal orientation. A rocking curve full width at half maximum value of 0.2{\deg} was achieved, indicating that the STO films are high-quality. The STO films have a roughness less than 1 nm, as measured using atomic force microscopy, comparable to the underlying Pt templates roughness.
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All authors Ekaterina Taylor, Ethan R. Cronk, Kalani Perera, Nuri W. Emanetoglu, Nicholas S. Bingham
Adaptation and Self-Organizing Systems
Chimera state in a neuronal network under the action of a magnetic field
Gael R Simo, Carmel T lambu, Adamou Dang Koko et al. (+3 more)
The Hindmarsh-Rose (HR) neuronal network has recently been the subject of studies highlighting the influence of the electric field on the chimera states within it. In this study, we demonstrate the influence of the
magnetic field on three categories of chimera states previously discovered in the same network: the traveling chimera state, the traveling multicluster chimera state, and the traveling multicluster chimera breather. The study is entirely numerical and proceeds in each case with three different applications of the
magnetic field: first, the entire network is subjected to the field; then, half of the network is subjected to it; and finally, two symmetrical but distinct regions are also subjected to the field. Several phenomena emerge, the most notable of which are the multitraveling chimera state and the multialternating chimera state. This thus illustrates the ability of the
magnetic field to transform areas of incoherence into areas of coherence, thus enriching the synchronization field and throwing more light on the field's influence on
brain cells.
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All authors Gael R Simo, Carmel T lambu, Adamou Dang Koko, Patrick Louodop, Robert Tchitnga, Hilda A. Cerdeira
General Relativity and Quantum Cosmology
Neural-Spectral Discovery of Rotating Black Holes Beyond General Relativity
Felipe Agurto-Sepúlveda, Marcelo Oyarzo, Anxo Biasi et al. (+6 more)
Finding rotating black hole solutions in higher-
curvature theories of
gravity is a problem of fundamental importance. Virtually every approach to reconcile
gravity with
quantum mechanics predicts corrections to the Einstein-
Hilbert action, yet no systematic solution-generating method exists for the stationary sector. We close this gap with Akribeia, a novel hybrid framework that pairs physics-informed neural networks with a pseudo-spectral refinement step, yielding certified neural-field rotating black hole solutions – continuous, globally defined functions, parametric in the coupling constants – whose residuals against the field equations are verified to extreme precision. We apply the method to theories quadratic and cubic in the
curvature and construct, for the first time, families of rotating black holes featuring multiple non-vanishing angular momenta, parametric in the new coupling constants. After validating against previously known five-dimensional spacetimes, we present new solutions in scenarios leading to a highly non-linear/non-perturbative coupled system of ordinary differential equations. Our method can be systematically adapted to other setups involving partial differential equations as well.
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All authors Felipe Agurto-Sepúlveda, Marcelo Oyarzo, Anxo Biasi, Devansh Agarwal, Ethan Tregidga, James F. Steiner, Jose D. Edelstein, Gaston Giribet, Cecilia Garraffo
Physics and Society
Hyperlocal monitoring of urban activity reveals responses to heat exposure
Dominique Geissler, Felix Creutzig, Ramit Debnath et al. (+1 more)
Rising temperatures create new challenges for local heat adaptation. Yet, it remains unclear how urban activity changes during hot periods and which urban environments people concentrate in as temperatures rise. Here, we perform a hyperlocal spatiotemporal analysis of urban activity across 10 German cities over a two-month period in 2024 with different levels of heat exposure. To monitor urban activity, we use fine-grained telecommunication data to map locations of people with high spatio-temporal resolution (i.e., hourly at 100m x 155m grid
cells), yielding more than 100 million data points. We then link activity counts with hourly weather records and point-of-interest data. We find that sustained periods of hot weather, defined as at least three consecutive days with daily maximum temperatures $\geq 25${\deg}C, are characterized by below-expected city-wide presence, with activity counts that are 1.5 percentage points below regular urban activity. During hot periods, urban activity concentrates more strongly around leisure- and culture-oriented amenities (e.g., cafés or swimming pools), with an increase of up to around 10 percentage points relative to cooler days, while public-service environments (e.g., educational and health facilities) show weaker or negative shifts. Our study provides policy-makers with fine-grained monitoring of which urban areas attract citizens during heat exposure, which can enable evidence-based, spatially-targeted urban heat adaptation plans.
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All authors Dominique Geissler, Felix Creutzig, Ramit Debnath, Stefan Feuerriegel
Instrumentation and Methods for Astrophysics
SETI's blind spot: Technological Acceleration and fleeting technosignatures
Michael A. Garrett
The search for extraterrestrial intelligence (SETI) has traditionally framed the detection challenge with a focus on the parameter $L$ in the Drake equation - the communicative lifetime of a civilisation. I argue that the more pertinent quantity is $\tau_d$, the duration during which a civilisation produces technosignatures that are actually detectable by us, now. Modelling technological progress as an exponential process, we show that $\tau_d = \alpha^{-1}\ln(K_{\rm max}/K_{\rm min})$, where $\alpha$ is the rate of technological acceleration and $[K_{\rm min},K_{\rm max}]$ brackets the technology levels accessible to our instruments. As $\alpha$ increases, $\tau_d$ can shrink to mere decades, dramatically narrowing the window in which civilisations overlap technically. This “technology mismatch” has implications for future search strategies, emphasising broadband and technology-agnostic approaches, as well as anomaly detection across multi-wavelength/messenger survey data.
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Soft Condensed Matter
Hyperuniform systems are maximally irreversible
Mathias Casiulis, Satyam Anand and Stefano Martiniani
Hyperuniform systems, defined by the anomalous suppression of large-scale density fluctuations, are a paradigm of non-
equilibrium self-assembly. While mechanisms underlying the self-assembly of hyperuniform states have been widely studied, the energetics of this process remain unexplored. This raises a fundamental question: what is the energetic cost of self-assembling a hyperuniform system? Here, we address this question across several noisy particle systems drawn from soft matter and machine learning, in which hyperuniformity can be induced by tuning noise correlations. Despite their distinct microscopic dynamics, we uncover a universal behavior across all systems: hyperuniform states are maximally irreversible, as quantified by the
entropy production rate. Further, we develop a path integral formulation of the
entropy production rate directly from the microscopic dynamics, which explains our observations. Our work establishes a direct link between emergent long-range structure and time irreversibility and opens a new avenue of probing the energetic cost of hyperuniform self-assembly, ubiquitous across physics, biology, and materials science.
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High Energy Physics (Phenomenology)
Dark Neutrons as Dark Matter: Collisions in Halos and Direct Detection from Dark CP Violation
Pablo Figueroa, Camilo García-Cely and Giacomo Landini
We consider confining gauge theories with a non-vanishing topological angle $\theta$, which induces CP-violating interactions among dark pions and dark
baryons, with dark matter consisting of dark
neutrons. The $\theta$ term generates scalar pion–
baryon couplings analogous to the CP-violating pion–nucleon interactions of QCD. These interactions give rise to an attractive long-range Yukawa potential mediated by the dark pions, whose strength is proportional to $\theta$. Since the dark pions are naturally light pseudo-Goldstone
bosons, the resulting force can lead to sizable dark matter self-interactions, providing a simple and theoretically motivated realization of the self-interacting dark matter paradigm. We also investigate the implications for direct detection in scenarios where the dark sector communicates with the Standard Model through a dark
photon portal. The $\theta$ term induces dark electric dipole moments proportional to $\theta$, which couple directly to the electric fields of
nuclei and can substantially enhance direct detection rates. We show how the underlying interactions shape the
recoil spectra and discuss the possibility of identifying the CP-violating origin of the signal through its time dependence. Finally, we analyze the interplay between dark matter self-interactions and direct detection signals, showing that both are controlled by the same CP-violating parameter. Our results demonstrate that the topological angle $\theta$ can play a central role in determining the phenomenology of composite dark matter.
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Optics
Coexistence and manipulation of multiple singularities in a reconfigurable non-Hermitian metasurface
Xintong Shi, Yanjie Wu, Rui Zhou et al. (+6 more)
Non-Hermitian frameworks extend conventional Hermitian physics, offering a powerful paradigm for describing open systems. Central to this field are various singularities within the complex parameter space, such as exceptional points (EPs) and scattering zeros, which dictate exotic physical behaviors. As research shifts from isolated singularities toward multi-singularity interactions, conventional planar metasurfaces remain constrained by limited tuning dimensions. Here, we propose a mirror-coupled design that maps a metasurface into a quasi-high-dimensional parameter space. By employing a metallic plane to generate image resonators, this scheme multiplies the system degrees of freedom without increasing the number of physical resonators. Its implementation on a reconfigurable platform integrated with PIN diodes yields the coexistence and manipulation of an EP and multiple reflection zeros. Through simulations and microwave experiments, we characterize the dynamic
evolution of these singularities and exploit their synergistic effects for two distinct applications. First, for tunable absorption, multiple reflection zeros are spectrally coordinated to achieve a near-perfect absorption band exceeding $99.9\%$ across the X-band, thereby dynamically suppressing target scattering. Second, for enhanced sensing, a reflection zero couples with the EP to form a hybrid singularity. This hybrid state inherits the power-law sensitivity of the EP while substantially boosting robustness against fluctuations, resolving the conventional trade-off between sensitivity and stability and simplifying detection to direct peak tracking rather than complex multimode
eigenvalue fitting. Our work provides a general methodology to circumvent parameter competition among non-Hermitian singularities, opening new avenues for multifunctional metadevices across the electromagnetic spectrum.
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All authors Xintong Shi, Yanjie Wu, Rui Zhou, Zuxing Lu, Tengyu Li, Tingting Liu, Hai Lin, Qiegen Liu, Shuyuan Xiao
Physics and Society
Allocation Condensation in Redistributive Networks
T. Ashwin Bhattathiripad and Vipin P. Veetil
We study a fixed network on which new mass is allocated in proportion to a power of each node's stock and then redistributed. Transport retains a fraction of both old and new mass at each node and divides the rest according to fixed background shares. We show that a small amount of retention can sustain concentration on networks where complete redistribution would leave every node's share of new mass vanishing as the network grows. A node receiving most new mass may retain little relative to the network total, yet much more than redistribution alone would supply. For a power above one, the allocation rule amplifies this relative stock advantage at the next step. We identify retention rates tending to zero with network size that allow widely spread and concentrated stationary allocations to coexist on the same network. One of them stays close to the allocation under complete redistribution. Each node can also dominate a separate concentrated allocation, receiving a share of new mass tending to one. The stocks supporting these allocations attract nearby trajectories, although every stationary stock approaches the same background, with even its largest share tending to zero. These allocations continue to coexist under specified changes in transport that preserve the background. Redistribution can therefore spread the stock widely without spreading new allocations in the same way.
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General Relativity and Quantum Cosmology
Impact of $H_0$ on gravitational wave propagation: prospects for the LISA mission
Nil Blanco and Domenec Espriu
It was previously shown that $H_0$ influences gravitational wave propagation beyond simple
redshift, by modifying the effective wavenumber. While earlier studies focused on
Pulsar Timing Arrays, we analyze the observability of this effect with LISA. Modeling the LISA arm geometry, we derive the timing residual and identify a clear angular enhancement at frequencies above 100 mHz. Using the stationary phase approximation and numerical methods, we show that the optimal incidence angle depends on $Z_A H_0$, providing a direct,
redshift-independent measurement of the Hubble parameter. We estimate that LISA could determine $H_0$ to within a few percent using this method, independent of standard siren approaches.
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Astrophysics of Galaxies
Divergent Evolution of Radial Metallicity Gradients in the Thin and Thick Disks of the Milky Way
Weixiang Sun, Gaohuan Long, Hui Li et al. (+6 more)
Using 200,388 red clump
stars from LAMOST and APOGEE, we investigate the radial
metallicity gradients of the
Galactic disk as a function of vertical height and
stellar age. The thin disk displays a pronounced negative radial
metallicity gradient near the
Galactic mid-plane that progressively flattens with increasing $|Z|$, following $\Delta \mathrm{[Fe/H]}/\Delta R$ = $-$0.0784 $+$ 0.0776 (1 $-$ exp ($-$ $|Z|$/1.42)). The thin disk also exhibits a clear age dependence in radial
metallicity gradients, evolving smoothly from a strong gradient regime for young
stars to a weak gradient regime for old
stars, following $\Delta \mathrm{[Fe/H]}/\Delta R$ = $-$0.0438 $+$ 0.0233 tanh (($\tau$ $-$ 11.29)/4.21). The thick disk shows weakly positive radial
metallicity gradients that remain statistically invariant with respect to both vertical height and
stellar age, following respectively, $\Delta \mathrm{[Fe/H]}/\Delta R$ = 0.0038 $+$ 0.0009 $|Z|$ and $\Delta \mathrm{[Fe/H]}/\Delta R$ = 0.0146 $-$ 0.0007 $\tau$. These results indicate that the thin disk retains radial
metallicity gradients shaped by relatively ordered inside-out growth and long-term secular
evolution processes. The thick disk exhibits spatially and temporally homogeneous radial
metallicity gradients, which are consistent with a formation environment characterized by mergers of gas-rich systems and/or the turbulent ISM.
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All authors Weixiang Sun, Gaohuan Long, Hui Li, Han Shen, Shu Wang, Xiaodian Chen, Biwei Jiang, Xiaowei Liu, Di Li
Quantum Physics
Circuit Depth Reduction of One-Ancilla Quantum Differential Equation Solver via Extrapolation
Di Fang and Justin Park
Solving linear differential equations is a fundamental task in scientific computing and an important primitive for
quantum computing. A recent one-ancilla
quantum differential equation solver provides a hardware-friendly and locality-preserving approach with provable performance guarantees, making it highly suitable for the early fault-tolerant and near-term regimes. Its simple
circuit structure comes with a natural trade-off: the maximum single-run
circuit depth scales as $O (1/\epsilon)$ in the target accuracy $\epsilon$. In this work, we reduce this depth by combining the solver with classical step-size postprocessing. By running the one-ancilla solver at a logarithmic number of finite time step sizes and using classical post-processing to cancel leading discretization errors, we reduce the maximum single-run
circuit depth to $O(\mathrm{polylog}(1/\epsilon))$ without adding
quantum ancillae or sacrificing locality. Technically, extending extrapolation ideas beyond
Hamiltonian and Lindbladian dynamics requires regularity estimates for observable maps under nonunitary
evolution, which we obtain through a holomorphic extension of the adjoint
evolution. Numerical experiments on the Hatano-Nelson model (ODE) and the convection-
diffusion equation (PDE) demonstrate the effectiveness of the approach.
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Physics and Society · Cross-listed from cs.MA
A Large Language Model-Driven Agent-Based Modeling Framework with Multi-Round Communication for Simulating Vaccine Opinion Dynamics
Bo Zhang and Na Jiang
Recently, Large
Language Models (LLMs) have been utilized in various applications of computational social science and provide the possibility to integrate such models into
agent-based modeling to explore the cognitive processes. However, how specific cognitive modules drive individual decisions and macro-level opinion dynamics remains unclear. Therefore, this study introduces a framework that integrates an LLM (Qwen3-8B) into
agent-based modeling to investigate this problem, using vaccination opinion dynamics as a case study. We utilize this framework to simulate opinion dynamics among
agents with heterogeneous profiles and social networks, evaluating scenarios by enabling different cognitive modules: a
memory module and a
prompt diversity module. The simulation results reveal that different cognitive modules have opposite impacts on our emergent opinion. Furthermore, the framework reproduces the non-linear behavior patterns of social influence observed in existing research, demonstrating our framework's validity and potential to reach the level 3 validation of
agent-based models.
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Materials Science
Optimizing high-temperature electron mobility in single-crystal Bi$_2$O$_2$Se based on its unconventional dependence on concentration
Antonín Sojka, Petr Knotek, Jan Zich et al. (+10 more)
Quasi-2D Bi$_2$O$_2$Se is part of an intensive materials research effort aimed at finding new
semiconductors that outperform silicon-based electronics in terms of speed and power consumption. This material exhibits exceptionally high carrier mobility at low temperatures but mediocre mobility at 300 K. Its high mobility is generally associated with its high permittivity ($\varepsilon_r$~500), which is also associated with
metallicity persisting down to very low carrier concentrations. This material exhibits a counterintuitive increase in carrier mobility as the concentration increases. The connection between low both carrier concentration and mobility in Se-rich conditions, and both high carrier concentration and mobility in Se-poor conditions suggests that the increase is related to native defects. We demonstrate that these defects can alter the effective mass of charge carriers. Specifically, substitutional Se(Bi) defects, which appear under Se-rich conditions, destroy the Bi$_2$O$_2$ channel and compromise charge transport properties. These defects increase the effective mass of charge carriers transforming the original
semiconductor into a semimetal and introducing holes into charge transport. Additionally, we show that single
crystals are generally inhomogeneous, particularly those grown under Se-rich conditions. Unlike Se-poor conditions, Se-rich conditions induce a higher concentration of dislocations and extraneous phases. These findings suggest that the perfection of the Bi$_2$O$_2$ channel is crucial for mobility, particularly at room temperature.
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All authors Antonín Sojka, Petr Knotek, Jan Zich, Martin Míšek, Roman Tesař, Kyo-Hoon Ahn, Petr Levinský, Jiří Navrátil, Pavlína Ruleová, Jiří Hejtmánek, Karel Knížek, Václav Holý, Čestmír Drašar
High Energy Astrophysical Phenomena · Cross-listed from cs.LG
Generalist Vision-Language Models for Fast Radio Burst detection: a zero-shot benchmark against a specialized detector
Raiff H. Santos, Amilcar R. Queiroz, Tharcisyo S. S. Duarte et al. (+2 more)
Fast
Radio Burst (FRB) detection increasingly relies on specialized deep learning models that require large task-specific training sets and cannot be redefined without retraining. We evaluate whether small, open-weight, locally run generalist
Vision-
Language Models (VLMs) can detect FRBs in dynamic spectra under a zero-shot,
prompt-only regime. On a balanced binary
benchmark of 2000 simulated L-band spectra, Gemma 4 E2B reaches an accuracy of 94.05%, statistically indistinguishable from the specialized detector SwinYNet (92.85%), with a far lower false-positive rate on structured RFI (4.8% vs. 24.6%) and none on pure noise, though SwinYNet ranks perfectly (ROC-AUC 1.0000 vs. 0.9520). Rewriting the
prompt alone reconfigures the same models for three-class FRB/RFI/noise classification, reaching up to 86.0% accuracy without a single false FRB while classifying each 2 s spectrum in 1.0–1.5 s, faster than the observation itself. Applied unchanged to the 1600 real FAST observations of FAST-FREX, they reject real interference almost perfectly (2 and 5 false positives in 1000 negatives) but recover only 28.5% and 27.0% of the 600 catalogued bursts, against 95.7% reported for SwinYNet on the same files. Stratifying those bursts by the dispersed signal in the image shows the limit to be the input representation rather than the classifier, recall rising to 84–85% where the sweep is unambiguous and collapsing to 1% on the 13% of positives carrying no detectable signal in a 2 s undedispersed full-band view. The simulated bursts are nearly 30 times brighter in median, and at matched brightness the recalls agree to within a few points.
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All authors Raiff H. Santos, Amilcar R. Queiroz, Tharcisyo S. S. Duarte, K. E. L. de Farias, Rafael A. Batista
Strongly Correlated Electrons
Quantitative DFT+DMFT description of spectra and transport in the moderately correlated metal SrVO$_3$
Gurshidali P. and N. S. Vidhyadhiraja
A quantitative, material-specific account of spectral and transport properties remains a central challenge in the theory of strongly correlated materials. Combining density functional theory with dynamical mean-field theory (DFT+DMFT) has proven to be a powerful approach for treating electron correlation effects and material specificity on an equal footing. Here, we examine the single-particle spectra and the dc and optical conductivity of SrVO$_3$, a prototypical, moderately correlated metal, within this framework. The degenerate $t_{2g}$ active space of SrVO$_3$, together with its well-established
Fermi-
liquid behavior, admits an effective-mass description governed by a single quasiparticle weight, yielding a nearly universal picture of the low-frequency, low-temperature regime. Employing a computationally efficient, real-frequency multi-orbital iterative perturbation theory (MO-IPT)
impurity solver, we find reasonable agreement with experimental measurements of dc resistivity and optical conductivity across the entire experimentally relevant $(\omega, T)$ range within a single, unified scheme. The agreement is shown to not depend on specific interaction parameters provided the quasiparticle weight is kept constant. These results indicate that, in SrVO$_3$, the $\mathbf{k}$-dependence of the self-energy may be weak, and vertex corrections may not dominate the dc and optical transport in this material.
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Biological Physics
Stiffness by design in biological fibers: the influence of microstructure and temperature
Eli Yovel and Noy Cohen
Biological fibers exhibit exceptional mechanical properties such as high stiffness, toughness, and elasticity. The stiffness of bio-fibers is governed by a hierarchical microstructure that is highly sensitive to the extraction method, post-processing, and environmental factors such as temperature. Commonly, the microstructure features an amorphous
matrix comprising polypeptide chains that interact through weak intermolecular bonds and interconnect via crystalline domains. In this work, we develop a microscopically motivated energy-based model that sheds light on the underlying mechanisms governing the stiffness of bio-fibers. The initial deformation is driven by (1) the entropic extension of polypeptide chains, (2) the elastic stretching and rotation of rigid crystalline domains, and (3) the distortion of weak intermolecular interactions, leading to the relative sliding of polypeptide chains. The model captures the influence of key physical microstructural quantities such as chain
alignment, chain stretch, intermolecular bond strength, and crystallite size on the overall stiffness. The merit of the model is demonstrated through a comparison to spider silk and cocoon silk fibers. We also employ the model to show that the reeling speed during the extraction of spider silk fibers governs the microstructure and, therefore, leads to different stiffnesses. We follow with a parametric analysis that sheds light on how different microstructural quantities affect the stiffness. Lastly, the framework is extended to account for thermally-induced microstructural changes and the model predictions are compared to experimental data on the stiffness of cocoon silk fibers as a function of temperature. The findings from this work delineate the role of microstructure on the overall stiffness and offer a pathway for the efficient design of tunable and optimized biomimetic fibers for target applications.
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Instrumentation and Detectors
Ultra-trace analysis of 40K in organic liquid scintillators
A. Barresi, D. Chiesa, D. Merli et al. (+64 more)
Rare-event searches require exceptionally low background levels, motivating the development of increasingly sophisticated screening methods to push sensitivity limits.
Liquid scintillators are particularly attractive detector media due to their intrinsic radiopurity and the ability to scale to large target masses. In this work, we present a screening strategy capable of measuring ultra-trace concentrations of $^{40}\text{K}$ with sensitivities below $10^{-15}$g/g. The method combines
neutron activation analysis with a dedicated radiochemical treatment, followed by low-background HPGe gamma spectroscopy. Using this approach, we achieved a minimum detectable concentration of $2.9\cdot10^{-16}$g/g for $^{40}\text{K}$, placing this technique among the most sensitive currently available.
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All authors A. Barresi, D. Chiesa, D. Merli, M. Nastasi, S. Nisi, E. Previtali, M. Sisti, M. Borghesi, A. Cammi, C. Coletta, G. Ferrante, L. Loi, G. Andronico, V. Antonelli, D. Basilico, M. Beretta, A. Bergnoli, A. Brigatti, R. Brugnera, R. Bruno, A. Budano, B. Caccianiga, A. Caslini, V. Cerrone, R. Caruso, C. Clementi, L.V. D'Auria, S. Dusini, A. Fabbri, G. Felici, A. Garfagnini, M.G. Giammarchi, N. Giudice, A. Gavrikov, M. Grassi, N. Guardone, F. Houria, A. Islam, C. Landini, L. Lastrucci, I. Lippi, P. Lombardi, F. Mantovani, S.M. Mari, A. Martini, L. Miramonti, M. Montuschi, D. Orestano, F. Ortica, A. Paoloni, L. Pelicci, E. Percalli, F. Petrucci, G. Ranucci, A.C. Re, B. Ricci, A. Romani, A. Serafini, C. Sirignano, L. Stanco, E. Stanescu Farilla, V. Strati, M.D.C Torri, C. Tuvé, C. Venettacci, G. Verde, L. Votano
Quantum Physics · Cross-listed from cs.AR
Vectorizing Quantum Control: A RISC-V Vector Extension Architecture for Scalable Qubit Systems
Xiaorang Guo, Kun Qin, Yanbin Chen et al. (+2 more)
The
Quantum Control Processor (QCP) bridges the gap between compiler toolchains and control electronics, and is responsible for translating compiled
quantum circuits into executable instructions that directly manipulate
qubits and handle measurement feedback. However, existing designs rely primarily on customized instruction sets, limiting design reuse and requiring significant effort to build supporting toolchains. Furthermore, efficiently addressing
qubits and scheduling operations in highly scalable scenarios remains a critical challenge. In this work, we present a vectorized
quantum control approach built upon the RISC-V Vector (RVV) engine with a
quantum-oriented extension. Leveraging the high parallelism of RVV, our approach can address up to 128
qubits in a single instruction. We also embed parameterized rotation information into the instruction set, enabling dynamic tuning of gate rotations in hybrid
quantum-classical programs. To support mid-
circuit measurements, we design a hardware-based halt-resume protocol that resumes pipeline execution within 80 $ns$ of receiving the measurement result. Comprehensive evaluation using both RISC-V toolchains and FPGA prototypes demonstrates that our design achieves up to 2.52$\times$ speedup over the baseline in program execution time, with excellent scalability.
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All authors Xiaorang Guo, Kun Qin, Yanbin Chen, Carsten Trinitis, Martin Schulz
High Energy Physics (Theory)
Projections and topological classification of black hole thermodynamics
Di Wu
Black hole thermodynamic
topology has evolved from classifications based on global topological numbers to more refined schemes including boundary behavior. This development motivates a deeper question: how are different topological manifestations connected within the complete thermodynamic structure? In this paper, we propose the thermodynamic projection
conjecture, which seeks to address this question by examining different topological manifestations in the context of the complete thermodynamic structure and exploring their underlying physical connections and formation mechanisms. As a representative application of this idea, we investigate temperature-dependent thermodynamic topological phase transitions, in which the topological number varies with temperature while the physical parameters are held fixed. We examine how the complete thermodynamic structure gives rise to different topological outcomes on different temperature slices. Our results demonstrate that temperature-dependent thermodynamic topological phase transitions arise from boundary effects, whereas the pairwise generation or annihilation of
equilibrium states in the interior leaves the total topological number unchanged. These results establish that, at fixed physical parameters, the topological differences observed on different temperature slices originate from the same complete thermodynamic structure and can be understood within a unified framework of thermodynamic projections. Furthermore, this study offers a new approach to understanding black hole thermodynamic structures and their rich physical behavior through the interplay between global structures and their local manifestations.
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Mesoscale and Nanoscale Physics
Force-Isosurface Simulations Probe the Limits of High-Resolution AFM on Three-Dimensional Molecules
Edward J Dunn, Robert J Young and Samuel P Jarvis
High-resolution atomic force microscopy has transformed molecular imaging by revealing intramolecular structure directly in real space. A major remaining challenge is to extend this capability from largely planar molecules to non-planar molecular systems, where the most important structural information may be distributed across different heights above the surface. Here we use probe-particle-model simulations to predict the constant-force contours expected above molecules with increasing structural complexity. By extracting force isosurfaces from simulated three-dimensional force fields, we compare the molecular information retained in constant-height and constant-force images. For tilted benzene and pyrrole, constant-force images preserve the molecular framework across a range of adsorption angles and allow the molecular orientation to be recovered quantitatively. For larger non-planar and three-dimensional systems, simulations identify characteristic force-isosurface contrast associated with adsorption geometry, lower-lying molecular structure and curved molecular surfaces. These results provide target contrasts for force isosurfaces that could be extracted from three-dimensional force-mapping experiments, evaluating the molecular information retained by ideal force-isosurface imaging across progressively non-planar systems.
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High Energy Astrophysical Phenomena
Multiband ALMA polarimetry of the jet base and kiloparsec-scale jet of 3C 273: A multicomponent Faraday structure in the nucleus
T. Hovatta, S. P. O'Sullivan, I. Marti-Vidal et al. (+1 more)
Polarization observations at millimeter wavelengths can be used to study magnetized
plasma in jets launched by supermassive black holes. We used multiband Atacama Large Millimeter Array (ALMA) data to study the polarization structure of both the
nucleus and the kiloparsec-scale jet of the archetypal
quasar 3C 273. We modeled the wavelength-dependent polarization of the
nucleus using multiband observations (2, 1.3, and 0.85 mm) and applied QU-fitting to constrain Faraday rotation models with one or more polarized components. We also produced total intensity and polarization maps of the kiloparsec-scale jet to study the
evolution of the
magnetic field structure along and across the jet. The data of the
nucleus were best fit by two Faraday components: a high rotation measure (RM) component with RM = +(2.6 +/- 0.1) x 10^5 rad/m^2 and comparable RM dispersion, and a second component with RM = +(1.5 +/- 0.2) x 10^4 rad/m^2 and lower dispersion. The high RM is comparable to previous ALMA observations at 1.3 mm, although we found clear evidence of variability when compared to previous single-band ALMA studies, highlighting the importance of broad wavelength coverage. On kiloparsec scales, the millimeter polarization structure closely resembled that observed at centimeter wavelengths, revealing a complex
magnetic field configuration around the jet head and brightest hotspot region. Our results indicate a multicomponent, time-variable Faraday screen in the
nuclear region of 3C 273 that is likely associated with a dense, magnetized environment close to the jet base. Future spatially resolved millimeter polarimetry with the Event Horizon
Telescope will be crucial to disentangling these components and directly localizing the high-RM emission region.
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All authors T. Hovatta, S. P. O'Sullivan, I. Marti-Vidal, T. Savolainen
High Energy Physics (Theory) · Cross-listed from math.DG
On the generalised Lie derivative of (s)pinor fields
Frederik Ďalak and Fridrich Valach
Although the action of diffeomorphisms on pinor (or spinor) fields is geometrically unambiguous, the definition of a natural Lie derivative is more subtle and requires some understanding of the geometry of the space of metrics at a point. In this work we revisit the classical construction of Kosmann and Bourguignon-Gauduchon and develop the corresponding theory in generalised geometry.
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Plasma Physics
Observation of Self-Similarity in the Magnetic Fields Generated by the Ablative Nonlinear Rayleigh-Taylor Instability
L. Gao, P. M. Nilson, I. V. Igumenschev et al. (+10 more)
Magnetic fields generated by the nonlinear Rayleigh-Taylor growth of
laser-seeded three-dimensional broadband perturbations were measured in
laser-accelerated planar targets using ultrafast
proton radiography. The experimental data show self-similar behavior in the growing cellular
magnetic field structures. These observations are consistent with a bubble competition and merger model that predicts the time
evolution of the number and size of the bubbles, linking the cellular
magnetic field structures with the Rayleigh-Taylor bubble and spike growth.
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All authors L. Gao, P. M. Nilson, I. V. Igumenschev, G. Fiksel, R. Yan, J. R. Davies, D. Martinez, V. Smalyuk, M. G. Haines, E. G. Blackman, D. H. Froula, R. Betti, D. D. Meyerhofer
Mathematical Physics · Cross-listed from math.AG
Involution-equivariant topological recursion and mirror symmetry for the affine binary dihedral Calabi–Yau threefold
Bohan Fang, Zhuoming Lan and Jingxiang Ma
We prove a closed-string remodeling statement for the affine binary dihedral Calabi–Yau orbifold threefold $\mathcal X=[\mathbb C^2/\Gamma]\times\mathbb C$, where $\Gamma$ is a binary dihedral subgroup of $SU(2)$. This target lies outside the toric setting of the Bouchard–Klemm–Mariño–Pasquetti remodeling
conjecture: the toric mirror curve is replaced by the type-$D_l$ relativistic Toda curve of Brini–Ma–Strachan, and the Chekhov–Eynard–Orantin topological recursion is replaced by the $\mathbb Z_2$-equivariant topological recursion of Giacchetto–Kramer–Lewański, run in the sign sector of the Toda-curve involution with the Prym kernel as its two-point input. We identify the equivariant orbifold
quantum cohomology Frobenius
manifold of $\mathcal X$ with the invariant Jacobian Frobenius structure of the Toda curve, and we prove that the B-model $R$-
matrix, defined by regularized stationary phase, equals the A-side normalized canonical Givental–Teleman $R$-
matrix on a chosen simply connected domain; this equality is anchored at the orbifold point through a semistable degeneration of the Toda curve. Comparing the resulting Givental–Teleman and Dunin-Barkowski–Orantin–Shadrin–Spitz graph sums then identifies, after a parity-twisted leaf substitution, the sign-sector recursion with the descendant Gromov–Witten generating functions of $\mathcal X$ in the stable range ($2g-2+n>0$ with $n>0$), and identifies the recursion free energies with the equivariant Gromov–Witten free energies of $\mathcal X$ for $g\geq2$. We also match the genus-one potential defined by the reduced calibrated tau function with the Gromov–Witten potential up to an additive constant.
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High Energy Physics (Phenomenology)
Fierz-complete four-quark interactions and the QCD phase diagram
Zi-ning Wang, Li-jun Zhou, Chuang Huang et al. (+3 more)
The dynamics of Fierz-complete four-
quark interactions and its influence on the QCD phase diagram have been investigated within the functional renormalization group approach to QCD at finite temperature and densities. It is found that in the
vacuum the pion and sigma channels play the overwhelmingly dominant role, and all the other channels are negligible. However, when it is near the critical end point (CEP), the magnitude of four-
quark couplings in other channels increases sizably and they become more and more important. In comparison to the single scalar-pseudoscalar channel of four-
quark interactions, the dynamics of Fierz-complete four-
quark interactions increases a bit the
curvature of the phase boundary, and moves the CEP to location of larger
baryon chemical potential and smaller temperature.
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All authors Zi-ning Wang, Li-jun Zhou, Chuang Huang, Rui Wen, Shi Yin, Wei-jie Fu
Statistical Mechanics · Cross-listed from q-bio.BM
Bayesian Learning of Distance Metrics Beyond RMSD for Biomolecule Alignment, Clustering, and Domain Identification
Saumyak Mukherjee and Gerhard Hummer
Root-mean-square deviation (RMSD) is the standard metric of structural comparison in molecular dynamics (MD) simulations. In its conventional form, RMSD assigns equal weight to all atoms regardless of mobility. Hence, flexible loops and disordered regions can dominate a global RMSD, while the rigid functional core contributes negligibly to the overall metric. To address this issue, we introduce the Bayes-optimal RMSD (BRMSD), which optimizes per-atom weights jointly with structural averages by maximizing a
Bayesian posterior. In a trade-off between low RMSD and weight uniformity, a position-fluctuation parameter $\sigma$ controls the transition from classical RMSD ($\sigma \to \infty$) to a progressive focus on a rigid core ($\sigma \to 0$). The BRMSD framework supports analysis modules for structural
alignment, focused
alignment onto a user-specified domain, trajectory smoothing, soft $K$-means conformational clustering, and rigid-domain identification. These modules are implemented in the open-source Python package BRMSD (https://github.com/bio-phys/BRMSD) and benchmarked on two MD systems, the endoplasmic reticulum translocon-associated
protein SND3 and the phosphotransferase adenylate kinase.
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Optics
Transmissibility, boundary-guided waves, and representative unit cell choice in finite-sized metamaterials
Plastiras Demetriou and Gianluca Rizzi
The implications of selecting different unit
cells are often overlooked in both direct studies of microstructured materials and their homogenized equivalents. Investigating the effects of unit
cell selection is crucial not only for understanding boundary phenomena but also for identifying which finite-sized metamaterial performs best for a given purpose (e.g., achieving zero or minimal transmissibility in the band-gap range). This study examines how the choice of a representative unit
cell in periodic metamaterials influences boundary effects and, consequently, the transmissibility of finite-size samples, while providing a strategy based on eigenfrequency calculations that enables a priori optimization.
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