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2603.18733 2026-03-20 physics.ins-det

Spatial resolution improvement of PICOSEC Micromegas precise timing detectors

F. M. Brunbauer, R. Aleksan, Y. Angelis, S. Aune, J. Bortfeldt, M. Brunoldi, J. Datta, D. Desforge, G. Fanourakis, D. Fiorina, K. J. Floethner, M. Gallinaro, F. Garcia, I. Giomataris, K. Gnanvo, Q. Huang, F. J. Iguaz, D. Janssens, A. Kallitsopoulou, I. Karakoulias, M. Kovacic, P. Legou, M. Lisowska, J. Liu, M. Lupberger, I. Maniatis, M. Micetic, H. Muller, E. Oliveri, T. Papaevangelou, M. Pomorski, L. Ropelewski, K. Salamon, D. Sampsonidis, L. Scharenberg, T. Schneider, E. Scorsone, L. Sohl, N. Shankman, M. van Stenis, Y. Tsipolitis, S. E. Tzamarias, A. Utrobicic, I. Vai, R. Veenhof, P. Vitulo, X. Wang, S. White, Z. Zhang, Y. Zhou

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英文摘要

The combination of a Cherenkov radiator with a semi-transparent photocathode and a Micromegas based amplification stage allows PICOSEC Micromegas detectors to achieve a time resolution of better than 15ps. While tileable prototypes with 10x10 channels feature 1x1 cm^2 readout pads, finer readout granularity can be used to improve the spatial resolution. We report on the study of high readout granularity PICOSEC Micromegas prototypes which achieve around 0.5mm spatial resolution with 3.5mm large pads. No significant improvement was found when readout pad size was further reduced to 2.2mm. The timing resolution of the leading pad was found to be slightly degraded but remained better than 20ps for a medium granularity prototype. The achieved spatial resolution can enable PICOSEC Micromegas to be used as precise timing and moderate resolution tracking detector simultaneously.

2603.18730 2026-03-20 math.OC

Scheduling Ground-Based Telescope Observations with Uncertain Nights

Thomas Rahab Lacroix, Pierre Lemaire, Anne-Marie Lagrange, Julien Milli, Nadia Brauner

Comments International Workshop on Planning & Scheduling for Space (IWPSS 2025), 2025, Toulouse, France

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英文摘要

The observation of celestial objects is a fundamental activity in astronomy. Ground-based and space telescopes are used to gather electromagnetic radiation from space, allowing astronomers to study a wide range of celestial objects and phenomena, such as stars, planets, galaxies, and black holes. The European Southern Observatory (ESO) charges each night 83 kEUR (Milli et al. 2019), so the schedules of the telescopes are really important in order to optimize every second. Ground-based telescopes are affected by meteorological conditions, such as clouds, wind, and atmospheric turbulence. Accurate scheduling of observations in the presence of such uncertainties can significantly improve the efficiency of telescopes use and support from automated tools is highly desirable. In this paper, we study a mathematical approach for scheduling ground-based telescope observations under an uncertain number of clear nights due to uncertain weather and atmospheric conditions. The model considers multiple targets, uncertain number of nights, and various observing constraints. We demonstrate the viability and effectiveness of an approach based on stochastic optimization and reactive strategy comparing it against other methods.

2603.18728 2026-03-20 math.NA cs.NA

Reconstructions of Single Pixel X-Ray Transforms with Applications in Nuclear-Disarmament Verification

Christopher Fichtlscherer, R. Scott Kemp, Christina Brandt

Comments 13 pages, 5 figures

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英文摘要

In nuclear arms control and disarmament processes, it is crucial to determine whether an object is a nuclear weapon or not without revealing sensitive information about it. At the MIT: Laboratory for Nuclear Security and Policy, such a nuclear verification method was developed, showcasing a transmission-based approach [1]. This method's essential part rests on a mathematical operation, the Single-Pixel X-Ray Transform: a cone of X-rays transmits an object and the remaining intensity is measured with a single-pixel detector. This transformation and the recovery of objects from dimensionless single-pixel measurements more generally has only been analyzed to a limited extent. In this work, we investigate some of the Single Pixel X-Ray Transform's mathematical properties. More specifically, we show that the Single Pixel X-ray transform is non-linear, continuous, Fréchet-differentiable and convex. We also introduce a method of reconstructing an object based only on a finite number of dimensionless, noisy Single Pixel X-Ray Transform measurement values. This method is based on Douglas-Rachford splitting and uses total variation denoising. We present an implementation for this method, focusing on rotational symmetric objects, as they allow the use of a one-dimensional direct total variation denoising algorithm [2].

2603.18727 2026-03-20 math.OC

Non-linear in-band interference cancellation on base of conjugate gradients method

Alexander Degtyarev, Sergei Bakhurin, Nikita Yudin

Comments 7 pages, 4 figures, 1 table

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英文摘要

This paper investigates one possible solution to the problem of self-interference cancellation (SIC) arising in the design of in-band full-duplex (IBFD) communication systems. Self-interference cancellation is performed in the digital domain using multilayer nonlinear models adapted via gradient-based optimization. The presence of local minima and saddle points during the adaptation of multilayer models limits the direct use of second-order methods due to the indefiniteness of the hessian matrix. The mixed Newton method can address the saddle-point issue; however, it requires significant computational resources. In this work, a conjugate gradient (CG) method constructed on the base of the mixed Newton method (MNM) is proposed. The method exploits information from mixed second-order derivatives of the loss function without explicit computation the full hessian matrix. As a result, the proposed approach achieves a higher convergence rate than first-order methods while requiring significantly lower computational resources than conventional second-order methods when adapting multilayer nonlinear self-interference cancellers in full-duplex communication systems.

2603.18726 2026-03-20 cond-mat.mes-hall

Geometric blockade in a quantum dot coupled to two-dimensional and three dimensional electron gases

K. Yamada, M. Stopa, T. Hatano, T. Yamaguchi, T. Ota, Y. Tokura, S. Tarucha

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Journal ref
Phys. Rev. B 84 (2011) 201303(R)
英文摘要

We fabricated a quantum dot coupled laterally to a two-dimensional electron gas and vertically to a three-dimensional electron gas in order to investigate the eigenstate dependence of tunneling rate to these gases. We observed a bias-dependent ``geometric" current blockade. By tunneling via the asymmetric couplings, population inversion is induced and a dark metastable triplet state is revealed. The metastable state stops the current transport process, suppresses the current and asymmetrically widens the Coulomb diamond. By analyzing the current as a function of source-drain and gate voltage and the magnetic field, we concluded that this effect is due to the geometric shape of the electronic states in the dot and the current is limited by the tunneling rate due to the eigenstates, that is, artificial $σ$-coupling and $π$-coupling.

2603.18725 2026-03-20 cond-mat.mtrl-sci quant-ph

A first-principles linear response theory for open quantum systems and its application to Orbach and direct magnetic relaxation in Ln-based coordination polymers

Mikolaj Żychowicz, Jakub J. Zakrzewski, Szymon Chorazy, Alessandro Lunghi

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Single-Molecule Magnets (SMMs) exhibit slow magnetic relaxation as a result of axial magnetic anisotropy inhibiting spin-phonon transitions. In order to establish a direct link between physical observables and the microscopic theory of magnetic relaxation, we here develop and numerically implement a first-principles linear-response theory for open quantum systems that provides access to the complex a.c. magnetic susceptibility in the presence of an oscillating a.c. magnetic field. Once combined with density functional theory and multiconfigurational electronic structure simulations, this formalism is applied in a fully first-principles fashion to three cyanido-bridged Ln/Y-based coordination polymers with general formula {Ln$^{III}_x$ Y$^{III}_{1-x}$ [Co(CN)$_6$]}, where Ln = Yb (1), Tb (2), and Dy (3). The method is able to reproduce the low-temperature direct relaxation process and its field dependence, as well as the high-temperature Orbach relaxation regime for all the investigated compounds. These results demonstrate the feasibility of ab initio simulations of magnetic a.c.susceptibility in lanthanide-based SMMs and support the potential of further development of ab initio open quantum systems methods towards the completion of a magnetization dynamics theory.

2603.18724 2026-03-20 math.AC math.AG

Bass numbers of local cohomology modules at the first and last non-vanishing levels

M. Jahangiri, R. Ahangari Maleki

Comments 9 pages, comments are well come!

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英文摘要

Let $R $ be a commutative Noetherian ring, $\mathfrak{a}$ be an ideal of $R$ and $M$ be a finitely generated $R$-module. In this paper, we study the Bass numbers $\{μ^i(\mathfrak{p}, H^j_{\mathfrak{a}}(M))\} $ of local cohomology modules with respect to an ideal $\mathfrak{p}\in Spec(R)$ in each of the following cases: $i\in \{ 0, 1, 2\}$ and $j= grade_{\mathfrak{a}}(M),$ $R$ is regular and $i\in\{ ht(\mathfrak{p}), ht(\mathfrak{p})- 1\}$ and $j= cd_{\mathfrak{a}}(M)$, the cohomological dimension of $M$ with respect to $\mathfrak{a}$.

2603.18723 2026-03-20 eess.IV

A Hybrid Physical--Digital Framework for Annotated Fracture Reduction Data Evaluated using Clinically Relevant 3D metrics

Basile Longo, Paul-Emmanuel Edeline, Hoel Letissier, Marc-Olivier Gauci, Aziliz Guezou-Philippe, Valérie Burdin, Guillaume Dardenne

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A major bottleneck in Computer-Assisted Preoperative Planning (CAPP) for fracture reduction is the limited availability of annotated data. While annotated datasets are now available for evaluating bone fracture segmentation algorithms, there is a notable lack of annotated data for the evaluation of automatic fracture reduction methods. Obtaining precise annotations, which are essential for training and evaluating automatic CAPP algorithm, of the reduced bone therefore remains a critical and underexplored challenge. Existing approaches to assess reduction methods rely either on synthetic fracture simulation which often lacks realism, or on manual virtual reductions, which are complex, time-consuming, operator-dependant and error-prone. To address these limitations, we propose a hybrid physical-digital framework for generating annotated fracture reduction data. Based on fracture CTs, fragments are first 3D printed, physically reduced, fixed and CT scanned to accurately recover transformation matrix applied to each fragment. To quantitatively assess reduction quality, we introduce a reproducible formulation of clinically relevant 3D fracture metrics, including 3D gap, 3D step-off, and total gap area. The framework was evaluated on 11 clinical acetabular fracture cases reduced by two independent operators. Compared to preoperative measurements, the proposed approach achieved mean improvements of 168.85 mm 2 in total gap area, 1.82 mm in 3D gap, and 0.81 mm in 3D step-off. This hybrid physical--digital framework enables the efficient generation of realistic, clinically relevant annotated fracture reduction data that can be used for the development and evaluation of automatic fracture reduction algorithms.

2603.18722 2026-03-20 cond-mat.mes-hall

Reversible Steady Domain-Wall Motion Driven by a Direct Current

K. Y. Jing, X. R. Wang, H. Y. Yuan

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Understanding and manipulating nanoscale domain wall (DW) dynamics is a central topic in magnetism and spintronics for its promising applications in logic and memory devices. In most magnetic systems, inertia affects only transient DW dynamics, while the long-time DW motion is uniquely determined by the magnitude and direction of the applied current. Here we show that this paradigm breaks down in ferrimagnets near the angular momentum compensation point. We demonstrate that a DW can propagate steadily either forward or backward even under a direct current, with the direction controlled solely by the current strength. This anomalous phenomenon originates from the inertial dynamics of an internal DW collective coordinate, which behaves as a massive object evolving in a current-dependent double-well potential. Depending on the driving current, the system relaxes into distinct stable states associated with opposite directions of motion. Our findings reveal an unexpected role of inertia in nonlinear spin dynamics, and enable low-energy spintronic functionalities including sensitive magnetic-field detection and reconfigurable one-port devices.

2603.18720 2026-03-20 cs.DS math.OC

Resource-Constrained Joint Replenishment via Power-of-$m^{1/k}$ Policies

Danny Segev

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The continuous-time joint replenishment problem has long served as a foundational inventory management model. Even though its unconstrained setting has seen recent algorithmic advances, the incorporation of resource constraints into this domain precludes the application of newly discovered synchronization techniques. Such constraints arise in a broad spectrum of practical environments where resource consumption is bounded as an aggregate rate over time. However, for nearly four decades, the prevailing approximation guarantee for resource-constrained joint replenishment has remained $\frac{ 1 }{ \ln 2 } \approx 1.4427$, achieved via classical power-of-$2$ policies. In this paper, we circumvent these structural policy restrictions by devising generalized rounding frameworks, demonstrating that a well-known convex relaxation is much tighter than previously established. In particular, we expand our analytical scope to encompass fractional base expansion factors, randomized shifting, and staggered interleaved grids. Through this multifaceted methodology, we present a sequence of gradually improving performance guarantees. First, by proposing a best-of-two framework that exploits structural asymmetries between deterministic power-of-$m^{1/k}$ policies, we surpass the classical barrier to obtain a $1.3776$-approximation. Second, by injecting a random shift into the logarithmic grid domain and formulating a factor-revealing linear program to optimize a dual-policy approach, we attain a $1.2512$-approximation. Finally, by superimposing a secondary offset grid to subdivide rounding intervals and suppress holding cost inflation, we utilize interleaved policies to arrive at our ultimate approximation ratio of $\frac{5}{6\ln 2} \approx 1.2023$, which is proven to be best-possible for the class of interleaved power-of-$m^{1/k}$ policies.

2603.18716 2026-03-20 econ.GN q-fin.EC

Poverty traps are rare, but trappedness isn't

Isaak Mengesha, Debraj Roy

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英文摘要

The persistence of poverty is not well explained by who is poor. We argue the relevant object of measurement is trappedness--expected escape time from deprivation--which varies systematically across institutional environments and is invisible to standard poverty indices. Using Markov chains estimated on twenty years of longitudinal data from 27 European countries, we show that countries with identical deprivation rates differ in escape times by up to fourfold. These differences are not explained by household characteristics alone: exogenous shocks reshape welfare landscapes differently across countries, with divergence tracking welfare regime architecture rather than household composition. The mechanism is behavioural: health constrains a household's capacity to convert income gains into durable welfare improvement. Income transfers without health improvement fail to reduce poverty-return risk; combined interventions are super-additive across 28 countries, and the gap widens with transfer size. These findings dissolve the long-running poverty trap debate--studies that rejected traps measured the wrong dimension; studies that found them captured one projection of a multidimensional dynamic process. Trappedness is continuous, multidimensional, and institutionally shaped.

2603.18715 2026-03-20 physics.plasm-ph quant-ph

Quantum Kinetics of Fast-Electron Inelastic Collisions in Partially-Ionized Plasmas

Yeongsun Lee, Pavel Aleynikov, Jong-Kyu Park

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Fast electrons in partially ionized plasmas lose energy through inelastic collisions with bound electrons. While the mean energy loss is well described by stopping-power theory, fluctuations associated with discrete excitation and ionization events produce energy straggling and an additional longitudinal diffusion in momentum space. We incorporate this effect into fast-electron kinetics through a derived Fokker-Planck operator whose coefficients are obtained from ab initio quantum many-body simulations. We demonstrate that neglecting inelastic energy diffusion in partially ionized D-Ar plasmas can underestimate primary runaway-electron generation by several orders of magnitude.

2603.18713 2026-03-20 quant-ph

Comment on "Association between quantum paradoxes based on weak values and a realistic interpretation of quantum measurements"

Juan José Seoane, Xabier Oianguren-Asua, Albert Solé, Xavier Oriols

Comments 5 pages, 0 figures. Comment on arXiv:2402.0987

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Journal ref
Phys. Rev. A 111 (2025) 066201
英文摘要

In their paper (arXiv:2402.09879), Aredes and Saldanha analyze several paradoxes related to weak values and present a "general argument" that aims to show that "realistic interpretations ...of weak values lead to inconsistencies". Although we agree with the identified inconsistencies for the specific weak values analyzed there, in this Comment we demonstrate that the origin of these inconsistencies is not their general argument, which is formally incorrect. We use Bohmian mechanics as a counterexample to confirm that their conclusions are not valid for all weak values and quantum theories. In particular, we show that weak values postselected in position can in fact be interpreted within Bohmian mechanics as properties of quantum systems, detached from any measuring devices, in a consistent and meaningful way.

2603.18710 2026-03-20 cond-mat.mtrl-sci

Origin of Reduced Coercive Field in ScAlN: Synergy of Structural Softening and Dynamic Atomic Correlations

Ryotaro Sahashi, Po-Yen Chen, Teruyasu Mizoguchi

Comments Main manuscript: 13 pages, 4 figures. Supporting Information: 6 pages with 5 fiugres

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Among wurtzite-type ferroelectrics, scandium-doped aluminum nitride (ScAlN) has emerged as a leading candidate for CMOS-compatible low-voltage memory, combining strong spontaneous polarization with process compatibility. A remarkable feature of this system is the pronounced reduction of the coercive field (Ec) with increasing Sc concentration; however, its microscopic origin remains poorly understood at the atomic scale, particularly under finite temperature and applied electric fields. Here, we integrate a density-functional-theory-accurate machine-learning force field with an equivariant neural-network-based Born effective charge model to perform large-scale electric-field-driven molecular dynamics simulations at near-first-principles accuracy. The framework correctly reproduces the experimentally observed qualitative trends in key experimental trends, including the decrease in the c/a ratio and the monotonic reduction of Ec with increasing Sc content. Beyond static structural softening, we uncover a dynamic mechanism underlying Ec reduction. Sc atoms exhibit larger thermal vibrations and undergo preceding displacements during switching, acting as dynamic triggers for polarization reversal. Moreover, the displacement correlation between Sc and Al atoms evolves systematically with composition, enhancing cooperative atomic rearrangements and lowering the effective switching barrier. These results demonstrate that Ec reduction in ScAlN arises from the synergy of structural softening and dynamic correlation evolution, providing a new perspective for designing hexagonal ferroelectrics.

2603.18709 2026-03-20 cs.DB

Let's Play Tag: Linear Time Evaluation of Conjunctive Queries under TGD Constraints

Nofar Carmeli, Carsten Lutz, Marcin Przybyłko

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We study the limits of linear time evaluation of conjunctive queries under constraints expressed as tuple-generating dependencies (TGDs), across several modes of query evaluation: single-testing, all-testing, counting, lexicographic direct access, and enumeration. While full classifications seem far beyond reach, we propose an approach that, for some evaluation modes and classes of TGDs, makes it possible to lift known dichotomies from the unconstrained setting. In particular, our approach applies to all mentioned evaluation modes except enumeration, when the constraints fall into one of two classes: non-recursive sets of TGDs in which every TGD uses at most binary relation symbols in the head or has at most two frontier variables; and frontier-guarded full TGDs. We further provide a collection of examples showcasing the challenges that arise for enumeration and for less restrictive classes of TGDs.

2603.18708 2026-03-20 math.CO

More Shattering News

Attila Sali, Jun Yan

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An ordered variant of the well-known set theory concept of shattering was introduced by Anstee, Rónyai, and Sali. In this paper, we prove several new results related to order shattering. Given a family $\mathcal F$ of subsets of $[n]$, we show that $\mathrm{osh}(\mathcal F)$, the family of all sets order shattered by $\mathcal F$, coincides with $T(\mathcal F)$, the family obtained from $\mathcal F$ by the down-shift operation. We then give a full characterization of all sets that can be order shattered by some $\ell$-Sperner family. Finally, we completely determine $\mathrm{osh}\left(\binom{[n]}{a}\cup\binom{[n]}{b}\right)$.

2603.18706 2026-03-20 math.OC stat.ML

A mathematical framework for time-delay reservoir computing analysis

Anh-Tuan Clabaut, Jean Auriol, Islam Boussaada, Guilherme Mazanti

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Reservoir computing is a well-established approach for processing data with a much lower complexity compared to traditional neural networks. Despite two decades of experimental progress, the core properties of reservoir computing (namely separation, robustness, and fading memory) still lack rigorous mathematical foundations. This paper addresses this gap by providing a control-theoretic framework for the analysis of time-delay-based reservoir computers. We introduce formal definitions of the separation property and fading memory in terms of functional norms, and establish their connection to well-known stability notions for time-delay systems as incremental input-to-state stability. For a class of linear reservoirs, we derive an explicit lower bound for the separation distance via Fourier analysis, offering a computable criterion for reservoir design. Numerical results on the NARMA10 benchmark and continuous-time system prediction validate the approach with a minimal digital implementation.

2603.18705 2026-03-20 physics.app-ph

Fueling Dynamics towards Tunable Liquid Metal Machine

Jingyi Li, Minghui Guo, Ju Wang, Xi Zhao, Jing Liu

Comments 24 pages, 6 figures. This article was submitted to Exploration in August 2025 and has been under review twice since then

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英文摘要

Self-propelled liquid metal-aluminum hybrid machines represent a promising class of autonomous motion systems capable of sustained movement without external power sources. While interactions between machines and their environment inevitably occur, the fundamental question of how spatial confinement affects the motion dynamics and the controllability of speed, direction, and lifetime of such liquid metal machines (LMMs) remains underexplored. Understanding these confined dynamics is essential for practical applications. Here, we present a comprehensive investigation of the non-symmetrical fueling principle governing the direction-tuning effect in LMMs. By confining LMMs within one-dimensional semi-open channels, we thoroughly disclose their impact and turning dynamics with different end obstacles throughout their lifecycle, with particular focus on fuel region morphological evolution, overall motion, and local flow characteristics after reaction times exceeding one hour. Utilizing ultra-high-speed imaging techniques, we systematically clarify how fuel region evolution and end-obstacle interactions influence symmetry-breaking mechanisms and reciprocating dynamics. Our findings reveal complex interactions between material properties, charge transfer processes, and fluid dynamics during end-turning processes, establishing a theoretical foundation for LMM driving dynamics. Beyond the theoretical mechanisms, we further demonstrate that LMM exhibits efficient heat and mass transfer capabilities, paving the way for applications in controlled transport systems and autonomous robotics.

2603.18704 2026-03-20 math.AT

Cohomology of dilute Temperley--Lieb algebras

Andrew Fisher, Daniel Graves

Comments 12 pages. Accepted for publication in Canadian Mathematical Bulletin

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英文摘要

Dilute Temperley--Lieb algebras are variants of Temperley--Lieb algebras arising in statistical mechanics in the study of solvable lattice models. In this paper we prove that the (co)homology of dilute Temperley--Lieb algebras vanishes in all positive degrees.

2603.18701 2026-03-20 eess.SY cs.SY math.DS physics.soc-ph

Assessing performance tradeoffs in hierarchical organizations using a diffusive coupling model

Lorenzo Zino, Mengbin Ye, Brian D. O. Anderson

Comments Paper submitted to IFAC for publication

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英文摘要

We study a continuous-time dynamical system of nodes diffusively coupled over a hierarchical network to examine the efficiency and performance tradeoffs that organizations, teams, and command and control units face while achieving coordination and sharing information across layers. Specifically, after defining a network structure that captures real-world features of hierarchical organizations, we use linear systems theory and perturbation theory to characterize the rate of convergence to a consensus state, and how effectively information can propagate through the network, depending on the breadth of the organization and the strength of inter-layer communication. Interestingly, our analytical insights highlight a fundamental performance tradeoff. Namely, networks that favor fast coordination will have decreased ability to share information that is generated in the lower layers of the organization and is to be passed up the hierarchy. Numerical results validate and extend our theoretical results.

2603.18700 2026-03-20 hep-lat

Hadronic screening masses in thermal QCD up to the electroweak scale

Marco Cè, Leonardo Giusti, Michele Pepe, Pietro Rescigno

Comments 9 pages, 3 figures, talk presented at the 42nd International Symposium on Lattice Field Theory (LATTICE2025), 2-8 November 2025, Tata Institute of Fundamental Research, Mumbai, India

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英文摘要

Novel theoretical and computational strategies have opened the possibility of exploring thermal QCD at the non-perturbative level at unprecedented temperatures, reaching from the GeV scale up to the electroweak scale. A number of observable quantities are now being investigated in this regime. Key ones are the hadronic screening masses, which encode the correlation length of the medium and thus the extent to which strong interactions are screened in a thermal environment. In these proceedings we present recent lattice results for hadronic screening masses, including baryonic modes and preliminary non-static mesonic modes. These results can be compared with predictions from the perturbative expansion in the three-dimensional effective theory valid at asymptotically large temperatures. The comparison reveals persistent higher-order effects including those of non-perturbative origin, up to the electroweak scale, shedding new light on the microscopic structure of QCD at extreme temperatures.

2603.18699 2026-03-20 cs.DS cs.SC

A more accurate rational non-commutative algorithm for multiplying 4x4 matrices using 48 multiplications

Jean-Guillaume Dumas, Clément Pernet, Alexandre Sedoglavic

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英文摘要

We propose a more accurate variant of an algorithm for multiplying 4x4 matrices using 48 multiplications over any ring containing an inverse of 2. This algorithm has an error bound exponent of only log 4 $γ$$\infty$,2 $\approx$ 2.386. It also reaches a better accuracy w.r.t. max-norm in practice, when compared to previously known such fast algorithms. Furthermore, we propose a straight line program of this algorithm, giving a leading constant in its complexity bound of 387 32 n 2+log 4 3 + o n 2+log 4 3 operations over any ring containing an inverse of 2. Introduction: An algorithm to multiply two 4x4 complex-valued matrices requiring only 48 non-commutative multiplications was introduced in [16] 1 using a pipeline of large language models orchestrated by an evolutionary coding agent. A matrix multiplication algorithm with that many non-commutative multiplications is denoted by ___4x4x4:48___ in the sequel. An equivalent variant of the associated tensor decomposition defining this algorithm, but over the rationals (more precisely over any ring containing an inverse of 2), was then given in [8]. Most error analysis of sub-cubic time matrix multiplication algorithms [3, 4, 2, 1, 17] are given in the max-norm setting: bounding the largest output error as a function of the max-norm product of the vectors of input matrix coefficients. In this setting, Strassen's algorithm has shown the best accuracy bound, (proven minimal under some assumptions in [2]). In [6, 8], the authors relaxed this setting by shifting the focus to the 2-norm for input and/or output; that allowed them to propose a ___2x2x2:7___ variant with an improved accuracy bound. Experiments show that this variant performs best even when measuring the max-norm of the error bound. We present in this note a variant of the recent ___4x4x4:48___ algorithm over the rationals (again in the same orbit under De Groot isotropies [10]) that is more numerically accurate w.r.t. max-norm in practice. In particular, our new variant improves on the error bound exponent, from log 2 $γ$ $\infty$,2 $\approx$ 2.577 Consider the product of an M x K matrix A by a K x N matrix B. It is computed by a ___m, k, n___ algorithm represented by the matrices L, R, P applied recursively on ${\ell}$ recursive levels and the resulting m 0 x k 0 by k 0 x n 0 products are performed using an algorithm $β$. Here M = m 0 m ${\ell}$ , K = k 0 k ${\ell}$ and n = n 0 n ${\ell}$ . The accuracy bound below uses any (possibly different) p-norms and q-norms for its left-handside, ___$\bullet$___ p and right-hand side, ___$\bullet$___ q . The associated dual norms, are denoted by ___$\bullet$___ p $\star$ and ___$\bullet$___ q $\star$ respectively. Note that, these are vector norms, hence ___A___ p for matrix A in R mxn denotes ___Vect(A)___ p and is the p-norm of the mn dimensional vector of its coefficients, and not a matrix norm.

2603.18698 2026-03-20 math.PR

Pareto points in growing dimensions

Andrii Ilienko, Bochen Jin

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We consider $n$ independent random points uniformly distributed in the $d_n$-dimensional unit cube and study Pareto points, that is, points that do not coordinatewise dominate any other point. We identify the critical growth rate of $d_n$ at which a phase transition occurs: below this threshold, the number of non-Pareto points diverges in probability, whereas above it there are asymptotically no such points. At criticality, the number of non-Pareto points converges in distribution to a Poisson random variable. We further describe their asymptotic spatial distribution in terms of convergence of random point measures. We also investigate points that dominate exactly $r$ other points and establish analogous phase transitions. For $r=1$, the critical dimension is the same as for non-Pareto points, whereas for every fixed $r\geq 2$ it is different, but, surprisingly, common to all such $r$.

2603.18695 2026-03-20 cs.DC cs.PF

High-Performance Portable GPU Primitives for Arbitrary Types and Operators in Julia

Emmanuel Pilliat

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英文摘要

Portable GPU frameworks such as Kokkos and RAJA reduce the burden of cross-architecture development but typically incur measurable overhead on fundamental parallel primitives relative to vendor-optimized libraries. We present KernelForge.jl, a Julia library that implements scan, mapreduce, and matrix-vector primitives through a two-layer portable architecture: KernelIntrinsics.jl provides backend-agnostic abstractions for warp-level shuffles, memory fences, and vectorized memory access, while KernelForge.jl builds high-performance algorithms exclusively on top of these interfaces. Evaluated on an NVIDIA A40 and an AMD MI300X, KernelForge.jl matches or exceeds CUB kernel execution time on scan and mapreduce on the A40, and matches cuBLAS throughput on matrix-vector operations across most tested configurations-demonstrating, as a proof of concept, that portable JIT-compiled abstractions can achieve vendor-level throughput without sacrificing generality.

2603.18694 2026-03-20 cond-mat.soft

Tuning polymer architecture for quasicrystal self-assembly

D. J. Ratliff, A. Scacchi, P. Subramanian, A. J. Archer, A. M. Rucklidge

Comments 6 pages plus 4 pages of Supplementary Information, 4 figures

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英文摘要

Using computer simulations and theory, we investigate the ultrasoft interactions between dendrimers formed of a central polymer connected by stiff linkers to a corona of flexible polymers, forming `pompoms' at the ends of the linkers. We show that the resulting coarse-grained interaction potential between pairs of dendrimers exhibits tunable lengthscale competition based on properties of the core and corona polymers. We present a simple model for this pair potential, which we confirm using accelerated Monte Carlo methods. We then demonstrate the connection between dendrimer structure and mesoscopic phases by presenting parameter choices that result in stable dodecagonal quasicrystals, and show that the size of the region in the phase diagram where quasicrystals are stable can be controlled by tuning details of the polymer architecture alone. These results pave the way for experimental realization of soft matter quasicrystals by identifying what overall molecular architecture leads to their stability.

2603.18691 2026-03-20 hep-ph hep-ex hep-th

A Systematic Approach to Finite Multiloop Feynman Integrals

Prasanna K. Dhani, Konstantinos Pyretzidis, Selomit Ramírez-Uribe, José Ríos-Sánchez, German F. R. Sborlini, Surabhi Tiwari, Germán Rodrigo

Comments 8 pages, 3 figures

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英文摘要

Finite Feynman integrals have been advocated as the optimal components for constructing a basis of master integrals in multiloop calculations, due to their improved analytic and numerical properties. In this paper, we show how the Loop-Tree Duality (LTD) is particularly well suited for systematically identifying finite integrals, as it makes the origin of infrared and threshold singularities fully transparent at the integrand level. This clear separation of singular and non-singular contributions enables a more efficient strategy for isolating and promoting finite integrals, thereby streamlining both reduction and numerical evaluation. We present a new strategy based on numerator and raised propagator Ansätze that provides results similar to other methods, although in a clearer and compact way. While this construction and other approaches establish a robust foundation, they often produce integrands that exhibit a rapid growth in the ultraviolet (UV) regime. To mitigate this bad UV behaviour, we introduce a generalized set of integrands fully defined within LTD. This new set is inherently infrared-finite and frequently free of threshold singularities, offering a more versatile framework for high-order calculations.

2603.18689 2026-03-20 astro-ph.GA astro-ph.IM

ATT12: The Antarctic 12-m Terahertz Telescope for Studies of Dusty Galaxies. I. Instrument Sensitivity and Science Forecasts

Koki Wakasugi, Takuya Hashimoto, Nario Kuno, Yu Nagai, Naomasa Nakai, Ken Mawatari, Masumichi Seta, Shun Ishii, Shunsuke Honda, Mana Ito, Hiroshi Matsuo, Makoto Nagai, Yuri Nishimura, Dragan Salak, Kazuo Sorai, Hidenobu Yajima

Comments 17 pages, 10 figures, 9 tables. Accepted for publication in PASJ

详情
英文摘要

We present a feasibility study of the Antarctic 12m Terahertz Telescope (ATT12), a next-generation facility to be constructed at New Dome Fuji in Antarctica, designed to open up the FIR and THz windows for extragalactic astronomy. While ATT12 will enable a wide range of Galactic and extragalactic science, this paper focuses on its potential for studies of dusty star-forming galaxies (DSFGs) across cosmic time. Using realistic atmospheric transmission models and the planned instrumental specifications of heterodyne spectrometers and wide-field multi-color continuum cameras, we assess the expected sensitivity and scientific capabilities. We show that spectroscopic observations will enable detections of [CII]158um from galaxies with log(LIR/Lsun)>12 out to z~7, while [OIII]88um will remain observable for HyLIRG-class systems up to z~10. Line ratios including [OIII]52/88um, [NII]122/205um, and [OIII]/[NIII] will provide unique diagnostics of electron density and O/N abundance at z~4-8. Wide-field continuum surveys with the continuum cameras (KIDS-1/2; 300-850 GHz) will reach confusion-limited depths of ~1-2 mJy over ~10,000 deg$^2$, detecting of order $10^{6}$-$10^{7}$ DSFGs with log(LIR/Lsun)>12 at z<5 and $\lesssim10^{3}$--$10^{4}$ HyLIRGs up to z~7 or higher. Higher-frequency cameras (KIDS-3/4; >850 GHz) are designed for targeted follow-up observations and to extend coverage toward the THz regime. Taken together, ATT12 will provide the first statistically representative samples of DSFGs across cosmic time and, through synergy with ALMA, JWST, and the proposed FIR Probe PRIMA, will establish a multi-wavelength framework in which ATT12 discovers large samples through wide-area surveys, ALMA provides high-resolution follow-up of gas and ISM structure, JWST probes stellar populations and metallicity in the rest-frame optical/NIR, and PRIMA delivers ultra-sensitive FIR spectroscopy.

2603.18684 2026-03-20 cond-mat.supr-con

Weak Localization and Magnetoconductance in Percolative Superconducting Aluminum Films

Kazumasa Yamada, Bunjyu Shinozaki, Takashi Kawaguti

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英文摘要

In order to investigate the crossover from the homogeneous behavior to inhomogeneous (percolative) one, the temperature $T$ and magnetic field H dependence of the sheet resistance $R_\square$ have been measured for two-dimensional granular aluminum films. Fitting the theory to data of magnetoconductance near $T_C$ with use of the diffusion constant $D(T)$ as a fitting parameter, we have obtained the anomalous $T$-dependent diffusion constant $D$. From the analysis of $D(T)$, the electron diffusion index $θ$, a certain critical exponent in percolation theory, has been obtained. In the relation $R_\square-θ$, the value of $θ$ varies abruptly near $1.5kω$. This behavior suggesting the above mentioned crossover is similar to our previous results determined from the temperature dependence of the upper critical field. For percolative films in $H = 5\mathrm{T}$, we have found the strong $R_\square$ dependence of the prefactor $α_T$ in the expression$σ=[α_T e^2/(2π^2\hbar)]\ln T+σ_0$. The relation $α_T\propto1/R_\square$ can be explained qualitatively by a model of scaling law for percolation.

2603.18682 2026-03-20 cond-mat.mes-hall

Extended saddle points govern long-lived antiskyrmions

Megha Arya, Moritz A. Goerzen, Lionel Calmels, Shiwei Zhu, Bhanu Jai Singh, Stefan Heinze, Dongzhe Li

Comments 20 pages, 14 figures

详情
英文摘要

Achieving long-lived nanoscale magnetic solitons remains a central challenge, as their lifetimes typically decrease rapidly with temperature. Here, we demonstrate that anisotropic Dzyaloshinskii-Moriya interaction (aDMI) enables spatially extended saddle points (SPs) that fundamentally alter thermally activated decay. In contrast to conventional localized SPs, these extended configurations completely suppress the entropic contribution to the activation rate, rendering the lifetimes effectively temperature independent. To establish this mechanism, we develop a first-principles method based on spin spirals to compute DMI beyond the isotropic approximation, resolving its full directional dependence for arbitrary nearest neighbors. We apply this method to oxidized Fe$_3$GeTe$_2$ (FGT-O), an experimentally accessible van der Waals magnet. Oxygen adsorption simultaneously breaks inversion symmetry and lowers the in-plane crystalline symmetry, thereby generating a sizable aDMI. We demonstrate that aDMI stabilizes nanoscale antiskyrmions with energy barriers exceeding 120 meV at low external magnetic fields. Crucially, extended SPs enhance the lifetime in FGT-O by more than five orders of magnitude at room temperature compared to conventional ultrathin-film skyrmion systems. We further show that aDMI is not the only route to such extended SPs and identify the general conditions under which they emerge, establishing a general route to soliton decay pathways with temperature-independent prefactors. Our results uncover a new paradigm for enhancing soliton stability through transition-state geometry rather than energy-barrier height.

2603.18679 2026-03-20 quant-ph

Teleporting an unknown qutrit state via a 2-qudit entangled channel

Xiao-Xu Li, Feng-Li Yan, Ting Gao

Comments 11 pages, 1 figure

详情
英文摘要

We propose a quantum teleportation scheme for transmitting a single qutrit state by adopting a 2-qudit entangled state as the quantum channel. The measurement basis for Alice has been carefully and systematically constructed, which is essential for the successful implementation of the teleportation protocol. Based on Alice's measurement outcomes, we design the corresponding collective unitary transformations to be performed by Bob on an auxiliary qubit and information particle. After implementing the collective unitary transformation, Bob performs a von Neumann measurement on the auxiliary qubit. The single qutrit state is then teleported to the distant receiver Bob with a finite success probability. We obtain the achievable success probabilities of the proposed teleportation scheme for different quantum channels. The obtained results not only enrich the theory of quantum teleportation over high-dimensional entangled channels but also provide a novel and feasible approach to implementing qutrit teleportation.