arXiv subjects

Search papers

Search indexed arXiv papers on artificial intelligence, large language models, computer vision and robotics. Read source abstracts and follow links to arXiv.

At least 1,297 records · Page 72Linked to original sources

arXiv2026

Trion-1: Unifying Language, Protein Sequence, and Structure with Diffusion Language Models

We envision a general-purpose protein foundation model as a unified, interactive model of sequence, structure, and function, capable of understanding, generation, and cross-modal translation while retaining the instruction-following and reasoning capabilities of modern LLMs. Toward this vision, we introduce Trion-1, the first native, unified, multimodal diffusion language model (dLLM) for proteins. Trion-1 is built on two key design choices: (1) a unified discrete token space that jointly represents sequence, structure, and natural language; (2) a dLLM backbone that replaces strict left-to-right factorization with bidirectional or semi-bidirectional token interactions, enabling global residue communication and long-range contact modeling that are naturally suited to structure modeling. This formulation unifies six core capabilities: folding, inverse folding, sequence understanding, structure understanding, sequence design, and structure design, while retaining the native language capabilities of general-purpose LLMs. On established benchmarks, Trion-1 achieves broadly competitive performance. In folding, Trion-1 achieves a TM-score above 0.8 with a single sample under strict homology control, matching or exceeding the existing tri-modal model using 200 samples. For sequence understanding, Trion-1 performs on par with top-tier LLMs such as Claude Opus 4.7 (62.37%). These results support well-aligned sequence-structure-language representations and strong cross-modal generative capabilities.

cs.AI↗

arXiv2026

Local Discrimination of Binary Classifiers via Localized AUC Functional

Risk prediction models are frequently evaluated with AUC, which means that during evaluation we are blind to performance heterogeneity, which could lead to bad decision-making in clinics. In this work, we aim to change that by identifying patient cohorts for whom the risk prediction model might not be an accurate predictor. To separate these cohorts, we use a version of the weighted AUC, which we call Localized AUC or LAUC. Using this metric, we build a method that we coin LOCATOR. This method is able to identify cohorts of patients for whom the risk prediction model is inaccurate. We test this method both in real-world data and in simulations. We also build a statistical background for the use of Localized AUC for our purposes.

cs.LG↗

arXiv2026

Can An Array of Magnetometers Replace a DVL - A Cramér-Rao Bound Analysis

Underwater vehicles rely on noisy dead-reckoning systems, such as Doppler velocity log (DVL)-aided inertial navigation systems, for positioning. However, DVLs rely on active acoustic measurements and are thus unsuitable for covert operations. Magnetic velocity estimation using a magnetic sensor array is a potential silent alternative. In outdoor environments, spatial variations in magnetic field magnitude are small, whereas temporal variations are large, making the achievable velocity-estimation accuracy uncertain. In this paper, Cramér-Rao lower bounds (CRLBs) are derived for magnetic velocity estimation using different sensor configurations and measurement models in one dimension, ignoring platform disturbances, to quantify the potential accuracy of magnetic sensor arrays. The analysis suggests that, when spatial variations are sufficient and temporal variations can be corrected using correction data, the resulting CRLB is comparable to that of an export-controlled DVL. If, instead, temporal variations are not corrected, the sensor noise must be reduced by around two orders of magnitude for the CRLB to reach the accuracy of an export-controlled DVL. Therefore, the results indicate that current magnetic sensor arrays may complement, rather than replace, DVLs in inertial navigation systems.

eess.SP↗

arXiv2026

QICOM: Open-Source Software for Reproducible Image Quality Evaluation, Blinded Assessment, and Radiomic Comparison

QICOM (Quality Image COMparator) is open-source software for quantitative image comparison, paired radiomics, and blinded assessment. It saves processing settings, image identities, measurements, and response mappings so a comparison can be reopened and recalculated. We evaluate reference agreement, responses to controlled perturbations, and recovery of saved analyses. Synthetic experiments cover 37 quantitative descriptors using independentnumerical references and separate upstream integration comparisons. The QICOM/MIRP backend meets the reference tolerances for all 482 numeric IBSI 1 digital-phantom entries and all 1,622 entries across configurations A-E of the public CT reference case; these comprise 1,804 feature/aggregation comparisons and 300 preprocessing diagnostics. Restricting masked SSIM and HFEN to complete kernel support removes the observed dependence on excluded pixels. In a synthetic filtering example, stronger smoothing increases SSIM while worsening MSE and HFEN relative to milder smoothing and changing GLCM contrast more strongly. Reopened radiomics projects reproduce all 43 feature pairs per comparison, and two blinded deliveries return four correctly mapped scripted responses. These experiments document the calculations and data transfers linking the three workflows.

eess.IV↗

arXiv2026

A Chern-Weil theory for Lie groupoids with Cartan connections

We extend Chern-Weil theory to Lie groupoids carrying a Cartan connection. For a principal $(Σ, ω)$-bundle $(P, θ)$ over $X$ we construct a map of differential graded algebras from an $ω$-basic subcomplex of the Weil algebra of the Lie algebroid of $Σ$ to $Ω^\bullet(X)$, whose map in cohomology does not depend on $θ$. It recovers the classical Chern-Weil map for Lie groups, the Cartan model for action groupoids, and the characteristic classes of Cartan geometries for gauge groupoids.

math.DG↗

arXiv2026

Quartz Crystal Microbalance impedance of discrete adsorbates with lubricated contact

We present a thorough theoretical investigation of the shear force exerted on a horizontal plate undergoing fast (MHz range) longitudinal oscillations in presence of a spherical particle suspended in the liquid at close proximity to the plate. This hydrodynamic problem is relevant toward the analysis of frequency response (i.e., complex impedance) of Quartz Crystal Microbalance (QCM) to discrete (particulate) adsorbates. For low areal density of adsorbates, the contributions of individual particles remain additive, rendering the theory applicable towards quantitative interpretation of the experimental measurements. For adsorbates much smaller than the viscous penetration depth, the closed-form analytical expressions for the complex impedance were derived for particles of arbitrary density, assuming a lubricated contact (i.e., non-localized adsorption). The theoretical predictions were shown to be in an excellent agreement with accurate Finite Element numerical computations. The validity of the theoretical approach was confirmed by QCM measurements conducted for polystyrene nanoparticles in a broad range of sizes, from 32 nm to 510 nm, adsorbing onto gold/silica sensor upon varying the oscillation frequency.

physics.flu-dyn↗

arXiv2026

Consistent Distributed Invariant EKF SLAM with Point and Object Features

Multi-robot SLAM allows robots to improve their estimates by exchanging map information, but repeated exchanges create unknown correlations between local estimators. Covariance intersection (CI) can fuse estimates without tracking these correlations. In right-invariant extended Kalman filter (RI-EKF) SLAM, however, point features obtain their invariant errors through the robot rotation, so a neighbor's map estimate is expressed in its own error coordinates and is correlated with its pose, and cannot be fused by CI directly. This paper presents Joint-CI, a unified fusion method for distributed RI-EKF SLAM with point, object, and mixed point--object maps. Using a neighboring robot's local posterior and an inter-robot observation, a joint estimate of the receiving robot's pose and the common features is constructed in the receiving robot's error coordinates, retaining the robot--feature and feature--feature correlations. Partial-state CI then fuses this estimate with the receiving robot's local posterior. We show that the unified formulation and the fusion preserve the six unobservable directions associated with global rotation and translation, and that communication and fusion preserve first-order covariance consistency given consistent local posteriors. Monte Carlo simulations and a real-world dataset-derived experiment show that Joint-CI improves estimation accuracy while maintaining consistent, mildly conservative uncertainty.

cs.RO↗

arXiv2026

GLOW-FM: Efficient Generative Low-Light Image Enhancement with One-Step Latent Flow Matching

Low-light image enhancement (LLIE) aims to recover well-exposed and perceptually faithful images from severely degraded observations. Recent diffusion-based generative methods achieve strong perceptual quality by leveraging powerful image priors, but their iterative sampling incurs substantial computational cost, limiting practical deployment. Despite recent efficiency gains in generative LLIE, high-quality enhancement with a single function evaluation and low overall computation remains challenging, particularly under diverse real-world low-light conditions. We introduce GLOW-FM, a one-step latent flow-matching framework for efficient generative LLIE. GLOW-FM performs conditional transport in the latent space of a frozen Tiny-VAE and leverages Terminal Velocity Matching (TVM) to enable enhancement with a single function evaluation. Matched comparisons with alternative one-step objectives support TVM as an effective design choice, and, to the best of our knowledge, this is its first adaptation to image restoration and specifically to LLIE. Extensive experiments on challenging real-world benchmarks demonstrate that GLOW-FM achieves competitive image quality and state-of-the-art cross-dataset generalization while requiring only a single function evaluation and 34 GFLOPs for the small variant. These findings highlight the potential of GLOW-FM to bring generative LLIE closer to practical deployment through single-step inference and compact latent modeling. Code will be made publicly available upon publication.

cs.CV↗

arXiv2026

Sharp quantitative stability of the Ashbaugh--Benguria inequality

We establish sharp quantitative stability of the Ashbaugh--Benguria inequality on bounded convex domains in $\mathbb R^n$. After volume and centroid normalization, the eigenvalue-ratio deficit controls the squared $H^{-1/2}(\mathbb S^{n-1})$ norm of the radial displacement from the unit sphere. This yields the optimal exponent $5/2$ for the Fraenkel asymmetry and, for small deficits, the optimal exponent $(n+4)/2$ for the normalized Hausdorff distance. All three exponents are sharp even among smooth strictly convex domains whose principal curvatures lie in $[1/2,2]$. In particular, the quadratic Fraenkel-asymmetry estimate proposed by Brasco and De Philippis (2017, Open Problem 7.65) fails. We also determine the optimal stability exponents under higher-order radial regularity bounds.

math.AP↗

arXiv2026

Particle-level parton densities and uncertainties for the resolved photon at NLO

We present a new set of parton distribution functions (PDFs), PL$γ$26, for the resolved photon at next-to-leading order (NLO), the first to be fitted to a wide range of jet measurements from several experiments. Jet production in photoproduction at HERA and in $γγ$ collisions at LEP is sensitive to both the quark and the gluon content of the photon, but the measurements lie at low scales, where non-perturbative corrections are large. We therefore choose a novel approach and fit the PDFs to these measurements at particle level, using NLO predictions from the general-purpose event generator SHERPA, matched to the parton shower and including hadronisation and multi-parton interactions (MPI). As part of the procedure, we tune the MPI model separately for photon--proton and photon--photon collisions. Modelling these non-factorisable effects in the fit, rather than through external correction factors, lets us include many more measurements and data points. We estimate the experimental uncertainties with replicas and compare the fitted PDFs with previous sets.

hep-ph↗

arXiv2026

Exact controllability and rapid stabilization of linear difference delay equations and one-dimensional hyperbolic systems

This paper addresses exact controllability and rapid stabilization issues for linear difference delay systems with finitely many pointwise delays. We first establish a criterion for exact controllability in $L^r$, $r \in [1, +\infty)$, characterized by a necessary and sufficient Hautus-type frequency-domain condition. The sufficiency of this condition in $L^r$ was already known [https://hal.science/hal-04830757/], whereas its necessity had previously been established only in $L^1$ [arXiv:2210.13590]. We answer [arXiv:2210.13590, Conjecture 3.8] by proving that this condition is also necessary for $r \in (1, +\infty)$. The analysis is based on rewriting the system as an evolution equation in a suitable Banach space, which allows one to apply duality arguments in the spirit of [https://doi.org/10.1137/S036301299119795X]. Building on this controllability analysis and the abstract stabilization framework developed in [https://doi.org/10.1137/S0363012996301609, arXiv:1301.5744], we prove that our exact controllability criterion in $L^r$ is also a sufficient condition for rapid stabilization in $L^2$, i.e., that the system of interest can be stabilized by a family of state feedback control laws ensuring that the closed-loop system is exponentially stable in $L^2$ with an arbitrarily large decay rate. As an application, we extend our results to linear one-dimensional hyperbolic partial differential equations, which can be reduced to linear difference delay systems via the method of characteristics, obtaining also a necessary and sufficient frequency-domain criterion for exact controllability in $L^r$, $r\in [1, +\infty)$, which, as before, is a sufficient condition for rapid stabilization in $L^2$.

math.OC↗

arXiv2026

Clarifications on black/white hole metastable relics as dark matter

The idea that the evaporation of black holes could end around the Planck mass and lead to relics possibly accounting for dark matter is quite old. In this article we focus on new models where the relics are metastable, typically with a lifetime of order $M^5$, where $M$ is the initial mass of the black hole. We show that those relics would actually be quite luminous, radiating -- possibly as much as the stars -- in the optical or UV band. We explicitly construct a proposal for their direct detection.

gr-qc↗

arXiv2026

In Search of the Gravitational Wave of Fast X-Ray Transient in the Second Part of the LIGO-Virgo-KAGRA Fourth Observing Run

Fast X-ray Transients (FXTs) are brief, intense X-ray flashes unassociated with persistent X-ray sources or known stellar objects, typically lasting from seconds to hours. With the launch of the Einstein Probe in January 2024, the study of FXTs has entered a new phase. Its large field of view significantly increases the discovery rate, enabling more robust statistics. The leading discoveries have revealed a fraction of gamma-ray bursts, while the rest remain unexplained. We propose a methodology to search for possible relations between gravitational waves (GWs) and FXTs, as it may serve as a discrepancy among proposed theoretical models. To achieve this, we intend to utilize X-Pipeline, an unmodeled search algorithm, to identify excess coherent signals in LIGO-Virgo-KAGRA (LVK) O4b observations. Out of 64 FXTs events, we obtained 19 FXTs for constructing robust searches. Given the absence of any detectable GW signals, we subsequently calculated upper limits and estimated exclusion distances for each source. In order to enrich the sample base and statistical analysis, this methodology could henceforth be conducted through future GW searches, including KAGRA in the O4c and O5 observations.

astro-ph.HE↗

arXiv2026

Lightweight Frame Compensation for Real-Time Polyp Segmentation under Frame Skipping

Real-time polyp segmentation in computer-assisted colonoscopy is hampered by the difficulty of deploying high-accuracy models under strict latency budgets. Frame skipping, which performs inference every K frames and reuses or interpolates the rest, improves throughput but introduces motion blur and lesion misalignment that degrade temporal consistency. To close this gap, we propose the Lightweight Frame Compensator (LFC), a 77K-parameter plug-and-play module inserted before a frozen segmentation backbone. Operating on a three-frame window, LFC fuses consecutive frames via spatio-temporal attention into a single compensated frame, and is trained only on pseudo-labels generated by a differently seeded model, without any expert annotation. Experiments on three polyp video benchmarks show that LFC recovers most of the accuracy degraded by direct frame skipping and, in several settings, reaches the accuracy of frame-by-frame inference, while retaining a 2.05X--2.55X throughput gain. We further evaluate the temporal stability of three backbones spanning CNN, pyramid Transformer, and global-attention Transformer architectures, revealing a spectrum of sensitivity to frame skipping that arises from how locally or globally each architecture aggregates misaligned input. The compensation gain of LFC follows this spectrum: it is largest for high-capacity Transformer backbones, which achieve the best static accuracy but suffer the most under skip-frame inference. LFC thus offers a lightweight, pluggable, and deployment-friendly route to real-time polyp segmentation.

cs.CV↗

arXiv2026

Iterative Randomized Rounding for Better-Than-2 k-Median Approximation

We study the classic $k$-median problem and refine the iterative rounding framework recently introduced by Byrka, Guo, Hu, Li, Wan, and Wang [FOCS'26], which yields a $(2+\varepsilon)$-approximation. Our algorithm opens $k+O(1)$ facilities and achieves an expected connection cost of at most $1.9999$ times the value of the standard LP relaxation. Although the numerical improvement over $2$ is small, it establishes a conceptual result: the integrality gap of the standard relaxation is strictly below $2$ when a constant number of extra facilities is allowed. This partially answers an open question of Li and Svensson [STOC'13]. Combined with their reduction, our result yields a $1.9999$-approximation algorithm for $k$-median. Our approach builds on several technical ingredients. First, we develop a preprocessing routine that makes the LP solution $\mathrm{poly}(\varepsilon)$-integral, at the cost of a $(1+\varepsilon)$ factor in the connection cost and $O(1)$ extra facilities. Unlike the preprocessing of Byrka et al. [FOCS'26], our conversion is unconditional: it requires no special treatment of clients whose fractional facilities are concentrated. Next, we show that the main rounding algorithm can open facilities one at a time, eliminating the batch processing used by Byrka et al. [FOCS'26]. Finally, the improvement over 2 comes from a tighter analysis for clients whose distances from to its facilities are not all equal, and a complementary algorithm for the case in which these distances are nearly uniform.

cs.DS↗

arXiv2026

Local Dephasing Sustains Continuous Time Crystals in a Spin-1/2 Ensemble

Local pure dephasing suppresses single-spin coherence, yet we show that it sustains continuous time-crystalline order in a fully connected ferromagnetic spin-$1/2$ ensemble with local decay. An exact operator identity reveals the mechanism: dephasing raises the interaction energy, while energy relaxation on a finite timescale converts this charging into delayed feedback. Within homogeneous mean-field theory, we prove that dephasing is necessary for periodic motion in this model and that feedback exactly balances transverse damping over each cycle. Beyond mean field, the identity fixes the relative amplitude and phase of energy and longitudinal magnetization in oscillatory Liouvillian modes. Liouvillian spectra and stationary two-time correlations characterize temporal order through decay rates that decrease algebraically with system size, frequencies approaching nonzero mean-field values, and comparable per-spin oscillatory weights. Semiclassical trajectories further reveal recurrent switching between a limit-cycle region and two symmetry-related stationary regions: fluctuations interrupt and reactivate collective oscillations, and oscillatory episodes provide an intermediate channel between stationary regions. These results establish local dephasing as a resource for autonomous collective motion and show how the resulting temporal order can participate in metastable dynamics.

quant-ph↗

arXiv2026

Fock-space relativistic coupled-cluster study of systematic shifts and fine-structure constant sensitivity in {\rm Cf$^{17+}$}, {\rm Cm$^{15+}$} and {\rm Bk$^{16+}$} highly charged ions

Highly charged ions (HCIs) are among the most promising candidates proposed for the development of next-generation optical clocks and the precision tests of fundamental physics. In this work, we investigate the clock-relevant properties of $\rm Cf^{17+}$, $\rm Cm^{15+}$ and $\rm Bk^{16+}$ HCIs using Fock-space relativistic coupled-cluster (FSRCC) theory. The corrections from Breit interaction, QED effects and perturbative triples are incorporated to improve the accuracy of results further. We compute excitation energies, transition amplitudes, lifetimes, hyperfine structure constants, electric quadrupole moments, and electric dipole polarizabilities for low-lying states of these ions. These properties are further used to characterize important clock transitions and estimate key systematic frequency shifts. Our calculations reveal that the proposed clock transitions exhibit strongly suppressed systematic frequency shifts. We also compute the sensitivity coefficients, $q$, and enhancement factors, $K_α$, for the proposed clock transition as a probe to variation in the fine-structure constant, $α$. Our calculations predict exceptionally large $K_α$ of $-55.3$ and $57.5$ for $5f_{5/2} \rightarrow 6p_{1/2}$ transition in $\rm Cf^{17+}$ and $6p_{1/2} \rightarrow 5f_{5/2}$ transition in $\rm Bk^{16+}$, respectively. These giant $K_α$s place the proposed transitions among the most sensitive optical probes for the laboratory searches for $α$ variation. Further, a comparative analysis of proposed transitions in $\rm Cm^{15+}$ and $\rm Bk^{16+}$ shows that, $5f_{5/2} \rightarrow 5f_{7/2}$ transition possess smaller systematic shifts and is therefore attractive for precision frequency metrology, whereas $6p_{1/2} \rightarrow 5f_{5/2}$ transition exhibit significantly enhanced sensitivity to $α$ variation.

physics.atom-ph↗

arXiv2026

Precise Determination of Electric Dipole Polarizabilities of Sr Clock States Using Linear-Response and Equation-of-Motion Relativistic Coupled-Cluster Methods

We present accurate values of the electric dipole polarizabilities ($α$) of the ground and excited states of Sr using four-component relativistic coupled-cluster (RCC) theory within the linear-response (LR) and equation-of-motion (EOM) frameworks. We first investigated accuracy of the ground-state polarizability using the LR-RCC method in both spherical and Cartesian coordinate representations. Upon obtaining consistent results for the ground state, we determine the polarizabilities of the excited states using the EOM-RCC method within the finite-field approach. The uncertainties in our results are assessed by examining the completeness of the basis set, higher-order relativistic corrections, and contributions from higher-level excitation configurations beyond the truncation in our RCC method. We also discuss various procedures for extrapolating contributions to the complete basis set limit and examine their respective limitations. Our calculated ground-state polarizability is found to be inconsistent with the latest atomic calculation, but agrees with other calculations and experimental value. Using the differential $α$ value from the EOM-RCC method, we estimate the fractional black-body-radiation-induced frequency shift of the Sr $^{1}$S$_{0}$$\rightarrow$$^{3}$P$_{0}$ clock transition to be $-5.40\times10^{-15}$.

physics.chem-ph↗