arXivDaily arXiv每日学术速递 周一至周五更新
重置
全部学科分类 1107
2605.01511 2026-05-05 astro-ph.SR physics.space-ph

On the Radial Evolution of the Solar Wind : The Source Alignment Method Applied to Parker Solar Probe and Solar Orbiter Observations

Jean-Baptiste Dakeyo, Tamar Ervin, Stuart Bale, Pascal Démoulin, Nikos Sioulas, Victor Réville, Mingzhe Liu, Alexis Rouillard, Milan Maksimovic, Davin Larson, Orlando Romeo, Philippe Louarn, Roberto Livi

Comments 17 pages, 6 figures, 1 table

详情
英文摘要

The properties of the solar wind, as measured in situ throughout the heliosphere, depend both on the characteristics of its coronal source and on the intrinsic processes governing its interplanetary evolution. Recently, radial and Parker spiral alignment techniques have been applied to Parker Solar Probe (PSP) and Solar Orbiter (SO) observations to investigate the radial evolution of the same solar wind parcel. These studies have shown that the solar wind can undergo significant acceleration even beyond its primary acceleration region (i.e., above 15 solar radii). However, such radial and Parker spiral alignments are rare in practice, which limits the statistical significance and general applicability of the results. We introduce a new source alignment technique designed to overcome these limitations. Using magnetic backmapping, we associate similar solar wind streams observed by the two spacecraft based on the proximity of their photospheric footpoints, combined with additional in-situ stream similarity criteria. Applying the source alignment method to PSP and SO observations, we identify a total of 548 alignment intervals, each lasting 30 minutes. By constructing statistics over all alignments, we find that the solar wind speed increases by an average of 45% per radial decade (approximately 147 km/s) between the two probes. This result demonstrates that solar wind acceleration in the inner heliosphere remains significant compared to that occurring below 15 solar radii. Among the different studied plasma parameters, the radial evolution of the electron temperature and plasma density, show the strongest anti-correlation with the increase in bulk velocity.

2605.01509 2026-05-05 math.GN

Perfect maps between submetrizable spaces

Vlad Smolin

详情
英文摘要

We investigate a question posed by Huaipeng Chen: if $X$ and $Y$ are paracompact submetrizable spaces and $f:X\to Y$ is a perfect map, can $X$ and $Y$ be submetrized by metrics $ρ$ and $d$ respectively such that $f$ remains perfect with respect to the induced topologies?

2605.01508 2026-05-05 math.CO

Multiplicative error set system sparsification: A simpler proof via chain length contraction

Joshua Brakensiek, Venkatesan Guruswami, Aaron Putterman

详情
英文摘要

The chain length of a set family $\mathcal{S} \subseteq 2^{[m]}$ is the largest ascending sequence of sets in containment order in the union-closure of $\mathcal S$. In this work, we provide a significantly simpler and more optimal characterization of the sparsifiability of set systems in terms of their chain length, improving on the work of Brakensiek and Guruswami [STOC 2025]. Our proof relies on a generalization of Karger's [SODA 1993] famous contraction algorithm and its recent linear algebraic extensions [Khanna-Putterman-Sudan SODA 2024], and our resulting bounds show that, just as VC dimension characterizes the \emph{additive sparsifiability} of a set system, chain length governs the \emph{multiplicative sparsifiability}. As a corollary, we obtain improved bounds for weighted CSP sparsification.

2605.01505 2026-05-05 astro-ph.GA

Non-Equilibrium Ionisation in Photoionised Haloes: Implications for Shock Stability and Absorption-Line Signatures

Itai Bromberg, Kartick C. Sarkar, Orly Gnat, Yuval Birnboim

Comments 14 pages, 6 figures

详情
英文摘要

We investigate the impact of nonequilibrium ionisation (NEI) and the metagalactic radiation-field on the thermal evolution, virial shock stability, and absorption signatures of gas surrounding galaxies. Using 1D, spherically symmetric hydrodynamical simulations with an extended version of the hydra code, we follow dark-matter growth, gas dynamics, time-dependent ionisation and cooling in the presence of the UV background. We explicitly track all ions of H, He, C, N, O, Ne, Mg, Si, S, and Fe in haloes of mass 1e11-1e13Msun from z=100 to z=0. Without a UV background, NEI enhances post-shock cooling due to underionised gas, reducing pressure support and raising the minimum mass for stable shock formation. Including the UV background pre-ionises the IGM, suppressing NEI, and restoring the CIE threshold. The IGM temperatures deviate from thermal equilibrium due to adiabatic expansion and collapse, while ionisation remains close to equilibrium in the presence of a UV background, except in transient rapidly cooling regions where NEI occurs. We compute absorption columns of OVI, CIV, and HI, showing that a photoionised IGM may produce substantial warm-ion columns extending beyond Rvir, including OVI column densities comparable to observed values. Our models indicate weak halo-mass dependence and extended distributions. We also find that z>~3 haloes can produce CIV (NCIV~1e13-15cm^-2) and HI (NHI~1e15-17cm^-2) columns out to ~10Rvir. Our results highlight the role of the UV background in regulating the thermal state and observable signatures of the gas surrounding galaxies, and emphasize the importance of accounting for IGM contributions when interpreting CGM absorption-line observations.

2605.01504 2026-05-05 math.AG

Equivariant sheaves on toric prevarieties

Jyoti Dasgupta, Kartik Roy

Comments 17 pages. Comments are welcome

详情
英文摘要

Toric prevarieties are non-separated analogues of toric varieties. Perling \cite{Perling_equivariant_sheaves_tor_var} provided a combinatorial description of equivariant quasicoherent sheaves on toric varieties, extending earlier ideas of Klyachko, who outlined a general framework for equivariant torsion free sheaves in an unpublished work \cite{kly_sheaf}. In this article, we present a combinatorial description of equivariant quasicoherent sheaves on toric prevarieties.

2605.01503 2026-05-05 eess.SY cs.SY

Recommender Systems as Control Systems

Giulia De Pasquale, Sarah Dean, Paolo Frasca

详情
英文摘要

We propose a control-theoretic interpretation of recommender systems and use this perspective to analyze how fairness interventions shape long-term system behavior. Fairness concerns arise for both users and creators, ranging from opinion polarization and representation bias on the user side to popularity bias on the creator side. A central insight of our analysis is that fairness should not be viewed as a simple trade-off against utility. When optimized over time, it can in fact be beneficial for overall system performance. Realizing these gains, however, requires a clear understanding of the underlying dynamics.

2605.01500 2026-05-05 hep-ph

Effects of the magnetic field on $π^0$ production in ultraperipheral Pb-Pb collisions

C. N. Azevedo, R. Fariello, F. C. Sobrinho, F. S. Navarra

Comments 7 pages, 3 figures; talk presented at the Workshop of Advances in QCD at the LHC and the EIC, CBPF, Rio de Janeiro, Brazil, November 9-15 2025

详情
英文摘要

In this work, we study the effect of the magnetic field on the production of neutral pions in photon-photon interactions in ultraperipheral Pb-Pb collisions at the LHC. The calculation is performed within the equivalent photon approximation, including a magnetic-field dependence in the decay width $Γ(π^0\toγγ)$, from which the corresponding production cross section is computed. We find that the reduction of the two-photon decay width in the presence of a strong magnetic field leads to a substantial reduction (by a factor of about 2-3) of the $π^0$ production cross section at LHC energies.

2605.01499 2026-05-05 eess.SP

Doppler Tomography Using Rydberg Sensors

Peter Vouras, Bariscan Yonel, Alexandra Artusio-Glimpse

Comments 2026 IEEE Conference on Computational Imaging Using Synthetic Apertures (CISA)

详情
英文摘要

Novel sensors that leverage the quantum properties of atoms for measuring propagating electromagnetic fields are becoming increasingly practical for a variety of applications. These sensors rely on the phenomenon of electromagnetically induced transparency (EIT), which is induced in a confined vapor of alkali atoms when the atoms are excited to a high-energy quantum state, known as a Rydberg state, with multiple resonant optical fields. In this state, the atoms are highly sensitive to electromagnetic radiation and yield a measurement output proportional to the magnitude of an impinging electric field when resonant with a Rydberg-Rydberg transition. In this paper, we consider the use of Rydberg sensors for a tomographic imaging application through a set of modeled system dynamics. Our contribution includes a novel method for placing nulls in the image by modulating the radiated local oscillator (LO) that is used to recover phase information from the received signal. We also present an algorithm for deblurring the image.

2605.01497 2026-05-05 cs.DS

Randomized $k$-server in polynomial time

Christian Coester, Romain Cosson

详情
英文摘要

We study the design of computationally efficient randomized algorithms for the $k$-server problem. Existing randomized algorithms with the best known competitive ratios are, on the one hand, inherently implicit and, on the other hand, employ a rounding scheme that maintains a distribution over exponentially many configurations. In this work, we introduce a derandomization framework that transforms any randomized $k$-server algorithm on a hierarchically separated tree into one that uses only $O(\log k)$ random bits for request sequences of arbitrary length; hence maintaining a distribution over only polynomially many server configurations. Leveraging this black-box derandomization, we obtain the first polynomial-time randomized $k$-server algorithm on arbitrary $n$-point metrics with a polylogarithmic competitive ratio. Our results also have implications for the advice complexity of the $k$-server problem.

2605.01494 2026-05-05 math.NA cs.NA quant-ph

Completely Positive and Trace Preserving Schemes with Tensor Train Compression for the Lindblad Equation

Peter DelMastro, Daniel Appelö, Yingda Cheng

Comments 33 pages, 9 figures

详情
英文摘要

We propose a family of low-rank, completely positive and trace preserving schemes for the Lindblad equation, a common model for open quantum systems. Low-rank representation is employed at two levels: the density matrix is factorized into the product of tall-skinny matrices, and the columns of these matrices are further represented using the tensor train (TT) format, also know as matrix product states (MPS). This two-level low-rank format fits naturally into our existing Kraus is King scheme (arXiv:2409.08898v2 [math.NA]) for the Lindblad equation, whose underlying operations are arithmetic on the columns of the tall-skinny matrices. We show how these operations can be performed efficiently in the TT/MPS format, with particular emphasis on density matrix rank-truncation. We conclude with extensive numerical experiments demonstrating the convergence of this scheme and its efficiency in simulating systems with up to $10^{19}$ degrees of freedom using only modest compute resources.

2605.01493 2026-05-05 math.OC

On the convex hull of the graph of a simple monomial

Jon Lee, Daphne Skipper, Emily Speakman

详情
英文摘要

Motivated by previous efforts toward mathematically analyzing the treatment of monomials in spatial branch-and-bound, we study the convex hull of the graph of a simple monomial on a nonnegative box domain in arbitrary dimension, where at most one of the variable lower bounds is positive. We give: (i) a description via linear inequalities, and (ii) a formula for the volume.

2605.01491 2026-05-05 math.AP

On the stability of Lamb-Chaplygin dipole for the 2D Euler equation

Zexing Li, Peicong Song, Tao Zhou

Comments 37 pages, 1 figure

详情
英文摘要

The Lamb-Chaplygin dipole is a traveling wave solution to the 2D incompressible Euler equation, whose orbital stability was established in [Abe-Choi, 2022] and [Abe-Choi-Jeong, 2025] assuming the odd symmetry in $x_2$ (O) and non-negativity in upper half-plane (N). This paper is devoted to further study of its stability in the following two aspects. Firstly, we prove the spectral stability of the linearized operator around the Lamb-Chaplygin dipole without conditions (O) or (N), based on the index theory established in [Lin-Zeng, 2022]. This excludes an instability mechanism by unstable eigenmodes, and provides rigorous evidence towards nonlinear stability in this general setting. Secondly, assuming (O) and (N), we refine the orbital stability results in [Abe-Choi, 2022] and [Abe-Choi-Jeong, 2025] quantitatively by proving a linear bound of the fluctuation and a uniform control of the moving velocity. Instead of using a variational approach, our proof relies on the construction of a new coercive Lyapunov functional with a delicate mixed structure: it is quadratic in the interior region, but linear in the exterior region.

2605.01488 2026-05-05 hep-ph

Multi-Lepton Probes of the Drell-Yan Production of Triplet Higgses

Siddharth P. Maharathy, Srimoy Bhattacharya, Andreas Crivellin, Mukesh Kumar, Rachid Mazini, Bruce Mellado

Comments 13 pages, 6 Figures, 11 Tables

详情
英文摘要

Excesses in di-photon, $Zγ$, and $WW$ spectra indicate the existence of a new Higgs boson with mass $152 \pm 1$ GeV. However, no excess is observed in the $ZZ$ channel. This pattern aligns with a Real Higgs Triplet model with hypercharge $Y = 0$ ($Δ$SM). A prediction of this model is the Drell--Yan production of scalars at the LHC, which dominantly decay to electroweak bosons, thus enhancing the cross sections of triboson channels such as $WWZ$, $WZZ$, and $WWW$. Interestingly, both ATLAS and CMS have reported higher-than-expected significances for such processes: $6.4σ$ (observed) vs $4.7σ$ (expected) in the $VVZ$ (where $V = W$ or $Z$) channel and $4.4σ$ vs $3.6σ$ in $WWZ$, suggesting the possibility that these signals may be manifestations of an extended Higgs sector. We investigate whether the $Δ$SM can account for these triboson excesses through electroweak production and decay of triplet scalars. We find that while current data prefers a non-zero new physics signal ($2.6σ$), the $Δ$SM predicts more events than observed, such that it is consistent with data but not preferred over the SM. However, this tension could be clarified with Run~3 and HL-LHC data.

2605.01487 2026-05-05 astro-ph.SR

Speckle Interferometry at SOAR in 2024 and 2025

Andrei Tokovinin, Brian D. Mason, Rene A. Mendez, Edgardo Costa

Comments Accepted by The Astronomical Journal. 18 pages, 10 figures, 9 tables. The MRT tables can be obtained from the first author

详情
英文摘要

Results of speckle interferometry observations at the 4.1 m SOuthern Astrophysical Research (SOAR) telescope obtained during 2024-2025 are presented. We present 5316 measurements of relative positions and magnitude differences in 3532 pairs (including 524 unpublished measures made before 2024) with median and minimum separations of 0.19" and 12 mas, respectively; non-resolutions of 1723 stars are documented as well. More than 400 pairs have been resolved here for the first time and not resolved by Gaia; among those are 222 TESS objects of interest, 46 inner subsystems in known wider binaries within 100 pc, and 43 subdwarfs. Positional measurements are used to compute or improve binary orbits; elements of 202 orbits with meaningful errors are given here, while preliminary and tentative orbits are published elsewhere. Of special note are orbits with large and accurately measured eccentricties (e.g. e=0.9866+/-0.0014 for J13038-2035) and orbits of pre-main sequence binaries. Appendix contains parameters of 86 binaries used for calibration of pixel scale and orientation.

2605.01481 2026-05-05 math.OC cs.DM

On the redundancy of transitivity constraints in the clique partitioning problem

Noriyoshi Sukegawa

详情
英文摘要

In this study, we identify a class of redundant transitivity constraints in a 0-1 integer linear programming formulation of the clique partitioning problem. The transitivity constraints in this class can be removed from the formulation without changing the optimal solution set, although each transitivity constraint defines a facet of the associated polytope. This leads to a smaller formulation that is particularly effective for instances arising from correlation clustering, where edge weights are drawn from $\{-1,1\}$. Our computational experiments show that the resulting formulation outperforms existing formulations on such instances.

2605.01476 2026-05-05 math.MG math.CA math.DS

How Thick Is the Sierpiński Triangle?

Scott Duke Kominers

Comments 10 pages, 5 figures

详情
英文摘要

Although the Sierpiński triangle has planar area $0$, it is uniformly non-flat: at every point and every scale, its nearby points span a two-dimensional region of comparable size. We prove a sharp version of this statement, showing that the Feng--Wu thickness of $E$ is exactly $\sqrt{3}/6$, the inradius of a unit equilateral triangle. More precisely, if $E$ is the standard Sierpiński triangle of side length $1$ and $B(x,r)$ denotes the closed disk of radius $r$ centered at $x$, then for every $x\in E$ and every $0<r\le 1$, the convex hull of $E\cap B(x,r)$ contains an equilateral triangle of side length $r$. Consequently, $\operatorname{conv}(E\cap B(x,r))$ contains a closed disk of radius $(\sqrt{3}/6)r$; this constant is best possible. The proof is elementary -- boundary edges of all construction triangles survive in the limit set, and self-similarity reduces the problem to the normalized range $1/2\le r\le 1$.

2605.01475 2026-05-05 cs.NI

An Intelligent eUPF for Time-Sensitive Path Selection in B5G Edge Networks

Rodrigo Moreira, Larissa Ferreira Rodrigues Moreira, Tereza Cristina Carvalho, Flávio de Oliveira Silva

Comments 26th International Conference on Computational Science and Its Applications (ICCSA 2026), June 30 - July 3, 2026, Braga, Portugal

详情
英文摘要

In Beyond 5G (B5G) networks, intelligent, flexible traffic management is essential to meet the stringent speed and reliability requirements of new applications. This paper presents an improved User Plane Function (eUPF) design that uses a Deep Q-Network (DQN) agent for real-time path selection between Multi-access Edge Computing (MEC) and cloud endpoints. The path selection problem is formulated as a Partially Observable Markov Decision Process (POMDP). We propose a novel passive delay measurement method that uses eBPF programs to link TEID-based timestamps in GTP-U traffic, allowing for low-cost delay estimation without active testing. Experiments show that the DQN agent substantially outperforms a random baseline, with lower average latency, more stable rewards, and more reliable low-delay path choices. These results demonstrate the effectiveness of AI-driven control in B5G core networks and the promise of reinforcement learning for modern network management.

2605.01473 2026-05-05 cs.DS cs.DM

A Unified Approach to Minimizing Symmetric Submodular Functions

Satoru Iwata, Haruto Konno

详情
英文摘要

Symmetric submodular function minimization admits purely combinatorial algorithms using special orderings of the ground set. Extending the minimum-cut algorithm of Nagamochi and Ibaraki (1992), Queyranne (1998) showed that the maximum adjacency ordering yields a pendent pair, which can be used to find a nontrivial minimizer. Nagamochi (2010) later introduced the minimum degree ordering, which yields a flat pair and leads to the identification of extreme sets. Despite the apparent similarity between these two algorithms, their connection remained unclear. In this paper, we introduce yet another ordering called minimum capacity ordering, and extend it to a one-parameter family of orderings, called $α$-orderings, that unifies these two previously known orderings. We prove a general inequality for $α$-orderings, and our framework recovers the known pendent-pair and flat-pair results as special cases, corresponding to $α= -1$ and $α= 1$, respectively. For each $α\in [-1, 1]$, the last two elements of an $α$-ordering form a contractible pair, i.e., a pair whose contraction preserves the existence of a nontrivial minimizer, which leads to a contraction algorithm that finds a nontrivial minimizer of a symmetric submodular function in $O(n^3)$ oracle calls, where $n$ is the cardinality of the ground set. In addition, we discuss the ranges of $α$ that ensure $α$-ordering to obtain these special pairs.

2605.01472 2026-05-05 physics.optics q-bio.QM

Label-Free Microrefractometry of Interfacial Processes Using Fluorescent Smart Coverslips

Hodaya Klimovsky, Amitay Ginsberg, Dmytro Ohorodniichuk, Maria Shehadeh, Ilya Olevsko, Gerardo Byk, Martin Oheim, Adi Salomon

Comments 38 pages, 4 figures (main text) and 9 supporting figures

详情
英文摘要

Molecular dipoles near interfaces emit highly directional radiation due to near-field interactions, making surface-bound fluorophores sensitive probes of local physicochemical changes. We introduce smart coverslips, stably coated with uniform, brightly fluorescent nanobead films, that exploit refractive-index-dependent emission shifts for sensitive micro-refractometry in small volumes. Supercritical-angle fluorescence refractometry uses single back-focal-plane images to allow us real-time RI sensing and nanometric thin-film height measurements without the need for multi-angle or multi-wavelength acquisition. Our fast, label-free, and non-invasive approach allows measurements of thin-film properties and monitoring of interfacial dynamics on a standard inverted microscope and is broadly applicable to nanobiophotonics, chemical sensing, and in-situ materials analysis.

2605.01470 2026-05-05 cond-mat.soft cond-mat.stat-mech physics.comp-ph

Colloidal layer deposition with a controllable number of layers and compositional order

Akshaya Kumar Jena, Aashima Aashima, Pritam Kumar Jana, Bortolo Matteo Mognetti

Comments These last two authors contributed equally to this work

详情
英文摘要

We design a system with a binary suspension of colloids and a surface that triggers the self-assembly of crystallites with a finite thickness. The proposed design allows controlling the number of layers forming the aggregate and constrains the two types of particles to lie on different planes. These functionalities are achieved by decorating the colloids and the surface with multiple DNA oligomers featuring specific interactions. The surface triggers a chain of reactions between DNA oligomers, leading to localized self-assembly. Equilibrium principles control the thickness of the aggregates. Instead, compositional order is achieved by engineering the reaction kinetics between DNA oligomers in a way that limits interactions between colloids of the same type. We validate our design using theory and reaction-diffusion simulation algorithms, which capture the multibody nature of the interactions. This work demonstrates how engineering the kinetics provides a new avenue for controlling the morphology of aggregates assembled by DNA.

2605.01465 2026-05-05 cond-mat.mtrl-sci

Deterministic Realization of Complex Local Strain Fields and Bandgap Profiles in Two-Dimensional Materials

Lottie L. Murray, Eric Herrmann, Igor Evangelista, Sai Rahul Sitaram, Ke Ma, Anderson Janotti, Xi Wang, Matthew F. Doty

Comments arXiv admin note: substantial text overlap with arXiv:2601.08984

详情
英文摘要

Emerging classical and quantum device concepts demand precise spatial control over the optoelectronic properties of two-dimensional (2D) materials, but deterministic engineering via local multiaxial strain distributions remains challenging. Using Ga$_2$Se$_2$, we demonstrate a material-agnostic platform in which nanostructure geometry deterministically prescribes in-plane strain profiles in suspended van der Waals membranes. We first use hyperspectral photoluminescence mapping and experimentally-constrained finite element analysis to quantify the experimental biaxial and uniaxial strain gauge factors that relate strain to the change in bandgap. We next show that a two-component analytical model can predict, with less than 12% error, spatially-resolved bandgap shifts arising from multiaxial strain distributions in complex geometries, including the interactions between adjacent nanostructures. Finally, we demonstrate that this approach can be extended to other materials. The results demonstrate that nanostructure design provides a quantitative, deterministic framework for the realization of designed strain and bandgap distributions in 2D materials.

2605.01464 2026-05-05 math.NA cs.NA

A Family of Iterative Methods for Computing Generalized Inverses of Quaternion Matrices and its Applications

Biswarup Karmakar, Neha Bhadala, Ratikanta Behera

Comments 28 pages

详情
英文摘要

The computation of generalized inverses of quaternion matrices is a fundamental problem in quaternion linear algebra, with wide-ranging applications in signal processing, image restoration, and multidimensional data analysis. This paper presents three efficient quaternion iterative algorithms for computing the Moore-Penrose pseudoinverse: (i) the quaternion rapid iterative method (QRAPID), (ii) the quaternion strong approximate inverse (QSAI), and (iii) the quaternion hyperpower iterative method of order nineteen (QHPI19). Convergence theorems and perturbation bounds are established to ensure numerical stability and robustness. The QSAI method is further employed as a preconditioner for quaternion Krylov subspace solvers, resulting in substantial reductions in the iteration count and runtime for large-scale linear systems. Comprehensive numerical experiments demonstrate that the proposed algorithms achieve an accuracy comparable to or better than existing approaches, including quaternion SVD, quaternion Newton-Schulz, and classical hyperpower schemes, while offering significant computational savings. The practical utility of the framework is illustrated through two representative applications: image completion via CUR decomposition and signal filtering, which confirm its scalability and effectiveness in real-world multidimensional data applications.

2605.01463 2026-05-05 math.NA cs.NA

A Neural Latent Dynamics Approach for Solving Inverse Problems in Cardiac Electrophysiology

Edoardo Centofanti, Giovanni Ziarelli, Simone Scacchi, Luca Franco Pavarino

Comments 29 pages, 9 figures

详情
英文摘要

Solving inverse problems in cardiac electrophysiology consists in the recovery of physiological parameters from surface electrocardiogram (ECG) measurements, a task which is often computationally unfeasible due to the severe ill-posedness and the prohibitive computational complexity of PDE-constrained optimization. In this work, we introduce a data-driven framework leveraging Latent Dynamics Networks (LDNets) to construct efficient surrogate models of the forward operator. By mapping low-dimensional parameters, representing ectopic activation sites or ischemic region descriptors, to the ECG signals via latent dynamics governed by neural ordinary differential equations, our approach circumvents the computational burden of evaluating high-fidelity cardiac models during iterative parameter estimation. The surrogate is trained offline on high-fidelity data, enabling rapid and robust inversion. We validate the proposed framework through rigorous numerical experiments with synthetic data across both 2d and 3d geometries. Results show that the LDNet-based surrogate achieves precise reconstruction of cardiac parameters while drastically reducing computational overhead, thereby enabling near real-time clinical applications.

2605.01462 2026-05-05 cs.CR

LocalAlign: Enabling Generalizable Prompt Injection Defense via Generation of Near-Target Adversarial Examples for Alignment Training

Yuyang Gong, Zihao Wang, Jiawei Liu, XiaoFeng Wang

详情
英文摘要

Large language models are increasingly embedded into systems that interact with user data, retrieved web content, and external tools, creating a new attack surface: prompt injection, where malicious commands embedded in untrusted data override the trusted command and induce unintended behavior. Existing defenses mainly rely on fine-tuning the model to preserve an explicit boundary between trusted commands and the untrusted data portion, so that the model learns to prioritize the trusted field and ignore malicious commands in data. However, we observe that while these defenses can block obviously malicious responses caused by injected commands, they generalize poorly to real-world scenarios where the model's response to the injected command is much nearer to the correct response. This is because existing methods typically train against only a fixed set of hand-crafted attack targets, which yields a loose boundary around the correct response and leaves it easier to bypass. To address this challenge, we propose LocalAlign, a more generalizable prompt injection defense inspired by adversarial training. LocalAlign automatically and efficiently generates adversarial examples in which the command embedded in the data portion induces a response that stays near to the correct response while still being wrong. We generate such near-but-wrong adversarial examples using prompting and a single inference step. This design enforces a tighter robustness boundary around the correct response: even small response shifts induced by commands in untrusted data are explicitly penalized. Moreover, the resulting adversarial examples can vary substantially in quality across samples. To address this issue, we further introduce a margin-aware alignment algorithm that quantifies each sample's distance to the correct response and assigns larger training weight to nearer ones.

2605.01460 2026-05-05 physics.optics physics.atom-ph quant-ph

FID Magnetometer Based on Paraffin-Coated Planar Reflective Multipass Cells

Xiangyu Li, Tingxuan Guo, Yang Li, Kaifeng Zhao

Comments 8 pages, 7 figures

详情
英文摘要

We demonstrate a paraffin-coated planar reflective multipass vapor cell for compact optical atomic magnetometry. The cell has an internal volume of $12 \times 12 \times 8~\mathrm{mm}^3$ and supports 20 optical passes with a total transmittance exceeding $65\%$, while maintaining a longitudinal spin-relaxation time of $^{87}\mathrm{Rb}$ longer than $1~\mathrm{s}$. The planar geometry provides spatially separated input and output beams, enabling compact optical integration. A single-cell free-induction-decay (FID) magnetometer reaches $10~\mathrm{pT}/\sqrt{\mathrm{Hz}}$ in the geomagnetic-field range, presently limited by current-source noise in the field coils. A two-cell differential configuration achieves a sensitivity of $\sim 28~\mathrm{fT}/\sqrt{\mathrm{Hz}}$ over the $1$--$15~\mathrm{Hz}$ band for bias fields of $0.3$--$0.7~\mathrm{G}$. These results establish that paraffin-coated planar multipass cells offer high optical depth, long coherence times, and an integration-friendly platform for ultrasensitive magnetometry.

2605.01458 2026-05-05 cond-mat.mtrl-sci cond-mat.mes-hall physics.app-ph

Revealing the kinetics of interfacial surfactant phase transitions through multiscale simulations and in-situ plasmonic sensing

Esmée Berger, Narjes Khosravian, Ferry Anggoro Ardy Nugroho, Joakim Löfgren, Christoph Langhammer, Paul Erhart

Comments 8 pages, 4 figures

详情
英文摘要

Surfactant self-assembly at solid-liquid interfaces governs interfacial stability, transport, and reactivity across many technologies, yet resolving interfacial surfactant phases and their transition kinetics in situ remains challenging. Here, we establish an atomistically grounded plasmonic framework that quantitatively maps interfacial surfactant phases and phase transitions onto optical signatures. Distinct morphologies differ in packing and hydration, modifying the effective permittivity within the optical near field and producing surfactant phase-specific plasmonic extinction peak shifts. Using cetyltrimethylammonium bromide on silica as a prototypical surfactant-surface system, we combine atomistic simulations, electronic-structure calculations, and continuum electrodynamics to translate molecular morphologies into predicted spectral shifts for literature-reported surface phases. We experimentally confirm the predicted ordering and magnitude of steady-state peak shifts during stepwise concentration changes, and extract transition kinetics from exponential relaxations of the time-resolved peak shift. A key mechanistic signature is reversal of the spectral shift direction upon transition from an impermeable bilayer to a water-accessible, channel-containing phase, consistent with hydration-driven reduction of the local effective permittivity. Because the approach relies on dielectric contrast in the plasmonic near field and works through a dielectric overlayer, it provides a broadly applicable route for real-time identification of interfacial surfactant phases and their kinetics in aqueous conditions.

2605.01456 2026-05-05 cs.GR

How Historians Use Visualization: A Corpus-Backed Taxonomy and Analysis for Cross-Disciplinary Practice

Xinyue Chen, Yu Zhang, Weili Zheng, Chiteng Ma, Xiaoru Yuan

详情
英文摘要

Visualization in historical research is shifting from isolated attempts to systematic practices. However, data-driven evidence about how historians actually use visualization remains scarce. We present a corpus-driven, mixed-methods study that combines analysis of images from 4,142 research articles across history and digital humanities journals with a collaboratively developed visualization taxonomy and a semi-automatic labeling pipeline. We construct a corpus of 14,021 images, classify 4,831 visualization instances using a hierarchical, domain-informed taxonomy, and analyze patterns of visualization adoption across venues, history subfields, and time. To interpret these patterns, we conduct interviews with 11 historians and use HiFigAtlas system as a boundary object to support joint inspection of the corpus. We identify distinct roles for visualizations in historical research: primary-source, evidence-synthesis, communicative, confirmative, and exploratory. We further find that while historians pursue diverse goals with figures, persistent epistemological and practical barriers, such as uncertainty, provenance, justification burden, and publication constraints, impede the adoption of visualization. This work contributes a grounded account of visualization use in historical scholarship and points to opportunities to better support domain-specific needs.

2605.01455 2026-05-05 math.AG hep-th math.CT

Defect Triangles and Intersection-Space Hodge Atom Shadows for Calabi--Yau Conifolds

Abdul Rahman

Comments Initial draft

详情
英文摘要

We prove a projection-triangle statement for projective Calabi--Yau threefold conifold degenerations and use it to organize an intersection-space Hodge atom shadow package. For a nodal central fiber $X_0$, assume the relevant Banagl--Budur--Maxim, multi-node gluing, mixed-Hodge-module, and specialization-splitting hypotheses, so that $ψ_π(F)\simeq \mathcal{IS}^{H}_{X_0}\oplus\mathcal C^H_Σ$. Projection of the variation morphism to the intersection-space summand defines $\operatorname{var}_I:ϕ_π(F)\to\mathcal{IS}^{H}_{X_0}$, and the octahedral axiom gives $P^H\to P^H_I\to\mathcal C^H_Σ\xrightarrow{+1}$, where $P^H=\operatorname{Cone}(\operatorname{var})[-1]$ and $P^H_I=\operatorname{Cone}(\operatorname{var}_I)[-1]$. This realizes the intersection-space atom shadow package $\mathsf{HA}^{I}(X_0)$ and compares it with the intersection-homology package $\mathsf{HA}^{IH}(X_0)$. Under the self-dual specialization-splitting hypothesis, the projected variation object satisfies $\mathbb D P^H_I\simeq Q^H_I(3)$, where $Q^H_I=\operatorname{Cone}(\operatorname{can}_I)[-1]$. Under the mixed-Hodge realization of Banagl's middle exact sequence, we isolate a rigid--vanishing filtration and identify the IIB vanishing atom with the realized kernel. For the classical $125$-node quintic, the middle-degree IC--intersection-space defect has rank $202$. The construction remains at Hodge-realization level and identifies $\mathcal C^H_Σ$ and $Δ_{I/IC}(X_0)$ as geometry-side handoff objects for future DT/BPS comparisons.

2605.01454 2026-05-05 cs.CR

PQC Validator: Validating Post-Quantum Readiness in Cloud-Native 5G Core Networks

Lakshya Chopra, Vipin Kumar Rathi

Comments 31 pages, 10 figures

详情
英文摘要

5G Core networks are entering a decisive phase of post-quantum (PQ) migration: operators and vendors are beginning to advertise PQ-TLS 1.3, PQ-IPsec, and hybrid KEM support across the Service-Based Interface (SBI) and N2, N3, N4 reference points, in line with 3GPP TS 33.501, emerging IETF drafts, and NIST FIPS 203, 204, 205. Yet deploying PQ primitives does not guarantee PQ security. A Network Function may advertise ML-KEM-768 and silently fall back to X25519; negotiate a hybrid KEM but authenticate with ECDSA-P256; present an ML-DSA leaf on a classical chain; or skip mutual TLS altogether. These failures are silent on the wire, and today scanners (testssl.sh, sslyze, Qualys) together with 5G-specific fuzzers are PQ-unaware and telecom-blind. We present PQC Validator, a layered PQC assurance framework purpose-built for the cloud-native 5G Core, comprising a PQ Crypto Engine (L1), a PQ Conformance Prober (L2), a PQ Robustness Tester (L3), a PQ Overhead Meter (L4), and an eBPF Attestation Plane for wire-level ground truth. Its scope spans the full control-plane cryptographic surface: an independent PQ-TLS 1.3 client and server, a strongSwan-driven PQ-IPsec harness for N2/N3/N4, an eBPF/XDP/TC monitoring plane that extracts wire-level ground truth on negotiated groups and signatures, and a Kubernetes-native UI that auto-discovers NFs and emits structured PQ evidence classifying every endpoint as classical, hybrid-pq, or full-pq. A compliance suite spans TLS, PQC, 3GPP SBI, NRF OpenAPI, and security hardening, while a protocol fuzzer exercises CVE-class regressions and downgrade paths.

2605.01445 2026-05-05 astro-ph.HE physics.plasm-ph

Powerful parametric instability of Alfven waves in astrophysical pair plasma

Maxim Lyutikov

详情
英文摘要

We demonstrate that in highly magnetized pair plasmas, nonlinear Alfven waves with wave-number $k \leq k_0 = ω_p^2 /(δω_B)$ ($δ=( δB)/B_0$ are relative fluctuations of the magnetic field) experience powerful modulational instability. In the two-fluid approximation, we develop an analytic set-up for circularly polarized (CP) Alfven mode in its frame (where the initial configuration is stationary; it is moving with relativistic, amplitude-dependent Alfven velocity $v_A (σ, δ) $, while both charges experience different, amplitude-dependent, synchrotron gyration). PIC simulations using EPOCH code demonstrate that for Alfven waves with $k$ near $k_0$, large, parametrically-driven density fluctuations develop, and lead to fast modulational instability. Charge separation effects, for a CP wave in magnetized pair plasma, might be temporarily important; on longer time-scales the density fluctuations are charge neutral and in symmetric pair plasma quickly grow to large amplitudes. In highly magnetized plasma, $σ\gg 1$, high frequency modes $k / k_0 \sim (2-3 ) \times σ\gg 1 $ are quickly generated; for smaller plasma magnetization, the dominant mode is at the Bragg's condition $k = 2 k_0$. Long term behavior of CP and LP modes is similar. We discuss application of the results to the physics of Fast Radio Bursts generated/propagating in the magnetospheres of magnetars.