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2511.07571 2026-05-11 q-fin.CP q-fin.MF

Forecasting implied volatility surface with generative diffusion models

Chen Jin, Ankush Agarwal

AI总结 本文研究如何利用生成扩散模型对未来隐含波动率曲面进行无套利预测。为捕捉波动率动态的路径依赖特性,模型以历史波动率曲面的指数加权移动平均、标的资产收益率及其平方收益率以及风险指标等市场变量作为条件输入。针对历史数据中可能存在的套利机会与生成无套利曲面目标之间的冲突,作者提出了一种基于信噪比的无参数加权方案,动态调整扩散过程中的套利惩罚强度,从而提升模型预测性能。实验表明,该方法在波动率预测方面优于现有方法。

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英文摘要

Diffusion Probabilistic Model (DDPM) for generating one-day-ahead arbitrage-free implied volatility surfaces. To capture the path-dependent nature of volatility dynamics, we condition our model on a set of market variables, including exponentially weighted moving averages (EWMAs) of historical vol-surfaces, returns and squared returns of the underlying asset, and scalar risk indicators associated with the underlying asset. A key challenge is that historical data often contains arbitrage opportunities in the earlier dataset for training, which conflicts with the goal of generating arbitrage-free surfaces. We address this by using a parameter-free weighting scheme based on the signal-to-noise ratio (SNR) to incorporate the arbitrage penalty into the loss function. The scheme dynamically adjusts the penalty strength across the diffusion process. Through numerical experiments using market data, we demonstrate the superior performance of our proposed model in volatility forecasting compared to existing approaches.

2511.03373 2026-05-11 nlin.SI hep-th math-ph math.AP math.MP

A superintegrable quantum field theory

Marine De Clerck, Oleg Evnin

AI总结 本文研究了一种具有四次哈密顿量的量子场论模型,该模型源自Gérard和Grellier提出的立方Szegő方程。该理论在经典层面表现出Lax可积性,并具有复杂的非线性动力学行为;在量子层面,其哈密顿量及相关守恒量展现出纯整数谱的特性,显示出超越普通量子可积性的结构。文章系统地分析了该量子系统的本征值、守恒律、阶梯算符等性质,揭示了其独特的数学和物理特征。

Comments Published version

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Journal ref
Commun. Math. Phys. 407, 131 (2026)
英文摘要

Gérard and Grellier proposed, under the name of the cubic Szegő equation, a remarkable classical field theory on a circle with a quartic Hamiltonian. The Lax integrability structure that emerges from their definition is so constraining that it allows for writing down an explicit general solution for prescribed initial data, and at the same time, the dynamics is highly nontrivial and involves turbulent energy transfer to arbitrarily short wavelengths. The quantum version of the same Hamiltonian is even more striking: not only the Hamiltonian itself, but also its associated conserved hierarchies display purely integer spectra, indicating a structure beyond ordinary quantum integrability. Here, we initiate a systematic study of this quantum system by presenting a mixture of analytic results and empirical observations on the structure of its eigenvalues and eigenvectors, conservation laws, ladder operators, etc.

2511.03296 2026-05-11 math.OC

Technical results on the convergence of quasi-Newton methods for nonsmooth optimization

Bennet Gebken

AI总结 本文研究拟牛顿方法在非光滑优化问题中的收敛性。针对BFGS方法在非光滑函数优化中缺乏理论收敛性保证的问题,作者分析了拟牛顿矩阵特征值的行为,提出了确保收敛性的充分条件,并基于数值实验推导出相关假设,证明了在这些假设下极限点的临界性。此外,文章还探讨了拟牛顿方法如何利用目标函数的分段可微结构,为非光滑优化的收敛性分析提供了新的见解。

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英文摘要

It is well-known by now that the BFGS method is an effective method for minimizing nonsmooth functions. However, despite its popularity, theoretical convergence results are almost non-existent. One of the difficulties when analyzing the nonsmooth case is the fact that the secant equation forces certain eigenvalues of the quasi-Newton matrix to vanish, which is a behavior that has not yet been fully analyzed. In this article, we show what kind of behavior of the eigenvalues would be sufficient to be able to prove the convergence for piecewise differentiable functions. More precisely, we derive assumptions on the behavior from numerical experiments and then prove criticality of the limit under these assumptions. Furthermore, we show how quasi-Newton methods are able to explore the piecewise structure. While we do not prove that the observed behavior of the eigenvalues actually occurs, we believe that these results still give insight, and a certain intuition, for the convergence for nonsmooth functions.

2511.01978 2026-05-11 hep-th math-ph math.MP

Single-Sided Black Holes in Double-Scaled SYK Model and No Man's Island

Xuchen Cao, Ping Gao

AI总结 本文研究了双标度SYK模型中带有终点世界膜(EoW膜)的单侧黑洞,引入了一个包含指数虫洞长度算符的新哈密顿量,从而提出了新的弦图规则。通过该算符,边界代数被定义为由新哈密顿量和边界物质生成,并发现其具有非平凡的交换子和类型II₁冯·诺依曼因子结构,表明从边界无法完全重构全空间,从而在半经典JT极限下存在“无人之境”。研究还表明,该结构与霍金辐射后的页时间后行为以及EoW膜在Kourkoulou-Maldacena框架中的角色密切相关。

Comments 54 Pages + Appendices, 17 Figures

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英文摘要

We study a single-sided black hole with an end-of-the-world (EoW) brane behind the horizon in the double-scaled SYK (DSSYK). The new Hamiltonian is a deformation of the original DSSYK Hamiltonian with an extra exponential wormhole length operator, which leads to a new chord diagram rule. The boundary algebra is defined as generated by the new Hamiltonian and boundary matter. There is an alternative but equivalent definition with a $q$-coherent state due to a nontrivial isomorphism of the vN algebra of DSSYK. This isomorphism induces a unitary equivalence, which yields a surprising result that the boundary algebra of a single-sided black hole in DSSYK has a non-trivial commutant and is a type II$_1$ vN factor. It follows that the full bulk reconstruction from the boundary is impossible, and there is a ``no man's island" behind the horizon in the semiclassical JT limit. Inspired by the EoW brane, we construct a family of matter-brane states with an arbitrary number of matter chords and behaving like an EoW brane. They exactly solve the full spectrum of DSSYK. We take different ways to understand the nontrivial commutant. We show that the commutant is complex on chord number basis and thus non-geometric. In the semiclassical JT limit, the commutant becomes the canonical purification of the boundary algebra and claims the no man's island. In the context of Hawking radiation after Page time, the unitary equivalence is interpreted as encoding the canonical purification into the old Hawking radiation, and the no man's island has the same essence as the island. Including the exponential wormhole length operator independently, the boundary algebra is extended to all bounded operators and reconstructs the no man's island. This can be regarded as a different choice for the definition of boundary algebra. This type I$_\infty$ algebra is closely related to the EoW brane in Kourkoulou-Maldacena.

2510.23688 2026-05-11 physics.soc-ph nlin.AO

Non-Markovian Collective Motion from Self-Regulated Perceptual Dynamics

Jyotiranjan Beuria

AI总结 该研究探讨了具有内部调节机制的主动物质系统中的非马尔可夫集体运动问题,提出了一种包含快慢两个时间尺度的模型,其中每个智能体拥有一个快速感知寄存器和一个慢速调节变量。通过引入基于GKSL导出的布洛赫表示的内部动力学,模型能够有效描述智能体对过去对齐状态的记忆与反馈机制,从而在快反馈条件下重现维谢克模型的行为,而在慢反馈条件下展现出非单调协调性、滞后效应等非马尔可夫特性,揭示了局部内部反馈如何引发集体运动的非马尔可夫行为。

Comments 15 pages, 5 figures

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英文摘要

Collective motion in active matter is usually modelled through instantaneous local alignment, where each agent updates its heading from the current configuration of its neighbours. Many biological and engineered agents, however, possess internal regulatory variables that evolve more slowly than alignment itself and can store information about past alignment states. We introduce a minimal two-timescale model in which each agent carries a fast perceptual register and a slow regulatory variable. The fast register encodes the instantaneous tendency to align with neighbouring headings, while the slow variable integrates recent alignment and feeds back into subsequent alignment decisions. The internal dynamics are formulated using a GKSL-derived Bloch representation, used only as a positivity-preserving effective description of bounded two-state variables; no microscopic quantum dynamics is assumed. The model reduces to Vicsek-type alignment in the fast-relaxation, weak-feedback limit, but shows distinct behaviour when slow feedback is active. Simulations reveal slow-fast relaxation, feedback-induced hysteresis, finite memory-dependent loop area, and non-monotonic coordination between collective order and regulatory tone. These results show how effective non-Markovian collective motion can emerge from local internal feedback.

2510.18242 2026-05-11 math.ST stat.ME stat.ML stat.TH

Fast and Efficient Parallel Sampling Using Higher Order Langevin Dynamics

Jaideep Mahajan, Kaihong Zhang, Feng Liang, Jingbo Liu

AI总结 本文研究了从高维强对数凹分布中进行快速并行采样的方法。传统基于朗之万动力学的采样方法在连续时间下收敛迅速,但其离散化版本通常需要多项式时间步数,限制了并行效率。本文提出了一种结合高阶朗之万动力学与分块拉格朗日插值的方法,显著减少了并行采样所需的处理器数量,同时保持对数多项式的时间复杂度,适用于包括贝叶斯逻辑回归和两层神经网络在内的多种模型,提升了现有并行采样方法的空间效率。

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英文摘要

We study parallel sampling from high-dimensional strongly log-concave distributions. Langevin-based samplers converge rapidly in continuous time, but their discretizations are typically sequential and often require polynomially many steps in the dimension $d$, the target accuracy $\varepsilon^{-1}$, or both. Picard-based parallel sampling methods reduce this sequential depth to polylogarithmic scale by solving for many time-discretization points in parallel; however, existing guarantees often require a polynomial number of processors, leading to substantial memory and gradient-evaluation costs in high dimensions. We show that higher-order Langevin structure can reduce this parallel resource burden while preserving polylogarithmic sequential depth. Our method combines arbitrary-order Langevin dynamics with blockwise Lagrange polynomial interpolation. This sharper discretization reduces the number of parallel points required to achieve a target accuracy. Our results cover both higher-order smooth potentials and ridge-separable potentials, including models such as Bayesian logistic regression and two-layer neural networks, and improve upon the space complexity of the current literature on parallel log-concave sampling.

2510.17239 2026-05-11 math.CO math.AG

Bounded core partitions and Borel-Weil-Bott

Fern Gossow, Andrew Huchala

AI总结 本文研究复Grassmannian流形上全纯形式层的上同调分解问题,利用Borel-Weil-Bott定理将其分解为一般线性群的不可约表示,并据此提出两种计算相关Hodge数的有效公式。其中一种涉及有界分拆的新型钩积统计量,另一种基于半标准Young表。文章还改进了Hodge数正性的条件及其出现范围的已知界,并将计算推广到q-analogue情形。

Comments 30 pages

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英文摘要

The Borel-Weil-Bott theorem can be used to decompose the cohomology of twisted sheaves of holomorphic forms on the complex Grassmannian into irreducible representations of the general linear group. By analyzing this decomposition, we provide two effective formulae for computing the associated Hodge numbers, and give examples in special cases. One of these involves a novel integer-valued hook-product statistic on bounded partitions, and the other is based on semistandard tableaux. We reformulate Snow's observation that the positivity of the Hodge numbers is equivalent to the existence of a partition satisfying certain properties, and improve known bounds on when this occurs. This involves a combinatorial proof of the Nakano vanishing theorem for the Grassmannian utilizing a map from core partitions to plane partitions. Finally, we extend our computation of the Hodge numbers of twisted holomorphic forms on the Grassmannian to a q-analogue.

2510.13770 2026-05-11 hep-ph

Gauge-independent Gravitational Waves from Cogenesis in a $B-L$ Conserving Universe

Wan-Zhe Feng, Jinzheng Li, Pran Nath, Zong-Huan Ye

AI总结 本文研究了一个保持 $B-L$ 守恒的标准模型扩展中,重子生成与随机引力波产生的关联机制。通过引入带 $U(1)_x$ 规范电荷的暗物质粒子和携带勒pton数但不带 $U(1)_x$ 电荷的暗场,利用Yukawa耦合诱导的CP破坏,分别在可见和隐藏部门生成等量相反的勒pton不对称性,并通过 sphaleron 作用将部分勒pton不对称性转化为重子不对称性。文章还基于规范无关的气泡成核动力学,分析了一阶相变产生的随机引力波背景,并指出在低温超冷却条件下该方法依然适用,为统一解释重子不对称性与暗物质的协同生成以及相关引力波信号提供了理论框架。

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英文摘要

An analysis of baryogenesis and stochastic gravitational wave production is presented for an extension of the standard model where the dark sector consists of dark matter particles charged under a $U(1)_x$ gauge symmetry, while a subset of dark fields also carry lepton number but no $U(1)_x$ charge. We demonstrate that with CP violation induced by Yukawa couplings, equal and opposite lepton asymmetries are generated in the visible and hidden sectors. Subsequent evolution preserves lepton number separately in each sector, and sphaleron interactions partially convert the lepton asymmetry into baryon asymmetry near the temperature of the first-order phase transition. Further, we discuss stochastic gravitational wave background production for the first-order phase transition using a gauge-independent bubble nucleation dynamics which yields spectra also valid in the supercooled low-temperature regime with {$T_p/m_{A_x} \ll 1$} where $T_p$ is the percolation temperature and $m_{A_x}$ is the dark photon mass. A parameter-space scan identifies regions that simultaneously account for cogenesis of baryon asymmetry and dark matter and predict stochastic gravitational wave signals within reach of current (NANOGrav, EPTA, PPTA) and future detectors at higher frequencies, providing a unified framework for cogenesis and associated gravitational wave production.

2510.11954 2026-05-11 cs.HC

VizCopilot: Fostering Appropriate Reliance on Enterprise Chatbots with Context Visualization

Sam Yu-Te Lee, Jingya Chen, Albert Calzaretto, Richard Lee, Samir Passi, Alice Ferng, Mihaela Vorvoreanu

AI总结 本文提出了一种名为 VizCopilot 的原型系统,旨在通过上下文可视化技术提升企业聊天机器人在信息合成任务中的可靠性。该系统结合主题建模与文档可视化,使用户能够主动参与上下文对齐过程,从而修正机器人检索到的不相关或不准确的信息。研究发现,可视化不仅帮助用户识别和修正上下文偏差,还促使他们优化提示策略,提高系统检索相关性的能力,同时揭示了当前在验证支持和对AI摘要的信任方面仍存在的局限。

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英文摘要

Enterprise chatbots show promise in supporting knowledge workers in information synthesis tasks by retrieving context from large, heterogeneous databases before generating answers. However, when the retrieved context misaligns with user intentions, the chatbot often produces "irrelevantly right" responses that provide little value. In this work, we introduce VizCopilot, a prototype that incorporates visualization techniques to actively involve end-users in context alignment. By combining topic modeling with document visualization, VizCopilot enables human oversight and modification of retrieved context while keeping cognitive overhead manageable. We used VizCopilot as a design probe in a Research-through-Design study to evaluate the role of visualization in context alignment and to surface future design opportunities. Our findings show that visualization not only helps users detect and correct misaligned context but also encourages them to adapt their prompting strategies, enabling the system to retrieve more relevant context from the outset. At the same time, the study reveals limitations in verification support regarding close-reading and trust in AI summaries. We outline future directions for visualization-enhanced chatbots, focusing on personalization, proactivity, and sustainable human-AI collaboration.

2510.10673 2026-05-11 math.GR math.LO

The isomorphism problem for finitely generated bi-orderable groups

Filippo Calderoni, Adam Clay

AI总结 本文从描述集合论的角度研究有限生成有序群的分类问题,重点分析了有限生成左有序群和双有序群的标准波莱尔空间,并利用相对锥空间对其进行刻画。研究证明,有限生成双有序群的同构关系是弱普遍的,这一结果揭示了该分类问题的复杂性。

Comments 17 pages. We reworked Section 2, where we fixed a mistake from the previous version. We revised the rest of the paper accordingly. The main result is not affected by the revision

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英文摘要

We analyze the classification problem for finitely generated orderable groups from the viewpoint of descriptive set theory. We analyze the standard Borel space of finitely generated left-orderable groups, and the subspace of finitely generated bi-orderable groups using spaces of relative cones. We use this setup to show that the isomorphism relation on finitely generated bi-orderable groups is weakly universal.

2510.09406 2026-05-11 cond-mat.mtrl-sci

Are diffusion models ready for materials discovery in unexplored chemical space?

Sanghyun Kim, Gihyeon Jeon, Seungwoo Hwang, Jiho Lee, Jisu Jung, Seungwu Han, Sungwoo Kang

AI总结 本文评估了两种扩散模型MatterGen和DiffCSP在未探索化学空间中生成低能量材料结构的能力,发现它们在已充分采样的化学空间(如氧化物和氮化物)中表现稳定,但在包含稀土元素和非常规化学计量比的GNoME数据库中效果较差。研究还指出,当原子数超出模型训练范围时,性能显著下降,这归因于周期性边界条件的限制,即“周期性诅咒”。该研究揭示了扩散模型在材料设计中的优势与局限,为未来研究提供了重要参考。

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英文摘要

While diffusion models are attracting increasing attention for the design of novel materials, their ability to generate low-energy structures in unexplored chemical spaces has not been systematically assessed. Here, we evaluate the performance of two diffusion models, MatterGen and DiffCSP, against three databases: a ternary oxide set (constructed by a genetic algorithm), a ternary nitride set (constructed by template informatics), and the GNoME database (constructed by a combination of both). We find that diffusion models generally perform stably in well-sampled chemical spaces (oxides and nitrides), but are less effective in uncommon ones (GNoME), which contains many compositions involving rare-earth elements and unconventional stoichiometry. Finally, we assess their size-extrapolation capability and observe a significant drop in performance when the number of atoms exceeds the trained range. This is attributed to the limitations imposed by periodic boundary conditions, which we refer to as the curse of periodicity. This study paves the way for future developments in materials design by highlighting both the strength and the limitations of diffusion models.

2510.08171 2026-05-11 cond-mat.supr-con cond-mat.mes-hall

Odd-frequency Pairing in Josephson Junctions Coupled by Magnetic Textures

Ignacio Sardinero, Jorge Cayao, Rubén Seoane Souto, Pablo Burset

AI总结 该研究探讨了通过磁性纹理耦合的约瑟夫森结中的奇频配对现象,分析了在不同磁性和几何条件下诱导的配对关联与谱特性。研究发现,在拓扑平凡区域以偶频单态配对为主,而在拓扑非平凡区域则出现马约拉纳束缚态与奇频等自旋三重态配对共存的现象。奇频三重态在马约拉纳态解耦时表现出 $1/ω$ 发散行为,并在杂化后演化为共振峰和线性低频响应,突显了奇频配对在探测磁性调控约瑟夫森结中拓扑超导性中的重要作用。

Comments 14 pages, 9 figures

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Journal ref
Phys. Status Solidi RRL 20, (2026)
英文摘要

Josephson junctions coupled through magnetic textures provide a controllable platform for odd-frequency superconductivity and Majorana physics. Within a tight-binding Green function framework, induced pair correlations and spectral properties are analyzed under various magnetic and geometric conditions. When the junction is in the topologically trivial regime, even-frequency singlet pairing is dominant, whereas the topological phase is characterized by the coexistence of Majorana bound states and robust odd-frequency equal-spin triplet pairing at the interface edges. The odd-frequency polarized triplets reveal a divergent $1/ω$ behavior when the Majorana states are decoupled, which is intrinsically connected to their self-conjugation property. The zero-frequency divergence evolves into shifted resonances and linear low-frequency behavior once hybridization occurs. A nonmagnetic interruption in the texture separates the topological superconductor into two topological segments and generates additional inner Majorana modes. When the nonmagnetic barrier is comparable to the inner Majorana states localization length, they hybridize and modify their associated odd-frequency triplet pairing, while the outer edge modes preserve their self-conjugated nature. Tuning the superconducting phase difference further controls the onset of the topological regime and the stability of localized Majorana states. The results highlight the central role of odd-frequency triplet correlations as a probe of topological superconductivity in magnetically engineered Josephson junctions.

2510.07622 2026-05-11 quant-ph cs.CC cs.DS

Conjugate queries can help

Ewin Tang, John Wright, Mark Zhandry

AI总结 本文研究了量子算法中使用共轭和转置查询(如 $U^*$ 和 $U^{\mathrm{T}}$)相较于仅使用正向和逆向查询(如 $U$ 和 $U^\dagger$)所具有的额外计算能力。通过构造具体问题和量子承诺方案,作者展示了这些查询形式能显著增强算法性能,并对密码学安全性的分析具有重要意义。核心贡献包括一个关键引理,表明使用正向和逆向状态制备查询的电路可以用一定数量的状态拷贝模拟,从而揭示了这类查询在决策任务中的二次优势,并提出了“橡果技巧”这一通用方法,用于绕过确定性算法的限制以增强量子资源。

Comments 28 pages; v2 expanding and clarifying discussion of the acorn trick and random purification

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英文摘要

We give a natural problem over input quantum oracles $U$ which cannot be solved with exponentially many black-box queries to $U$ and $U^\dagger$, but which can be solved with constant many queries to $U$ and $U^*$, or $U$ and $U^{\mathrm{T}}$. We also demonstrate a quantum commitment scheme that is secure against adversaries that query only $U$ and $U^\dagger$, but is insecure if the adversary can query $U^*$. These results show that conjugate and transpose queries do give more power to quantum algorithms, lending credence to the idea put forth by Zhandry that cryptographic primitives should prove security against these forms of queries. Our key lemma is that any circuit using $q$ forward and inverse queries to a state preparation unitary for a state $σ$ can be simulated to $\varepsilon$ error with $n = \mathcal{O}(q^2/\varepsilon)$ copies of $σ$. Consequently, for decision tasks, algorithms using (forward and inverse) state preparation queries only ever perform quadratically better than sample access. We also identify a motif, which we call the "acorn trick", where generically strengthening a quantum resource can be possible if the output is allowed to be random, bypassing no-go theorems for deterministic algorithms. We demonstrate this idea for several settings, including controlization and purification.

2510.05293 2026-05-11 eess.SY cs.SY

Pricing Short-Circuit Current via a Primal-Dual Formulation for Preserving Integrality Constraints

Peng Wang, Luis Badesa

AI总结 本文研究了在同步发电机逐步被电力电子发电机替代的背景下,如何优化采购短路电流(SCC)服务并合理定价的问题。为解决单元组合(UC)中的整性约束带来的挑战,作者提出了一种基于对偶规划的定价方法,能够有效计算SCC服务的影子价格。该方法在改进的IEEE 30节点系统中进行了验证,结果显示其能够在无需额外补偿支付的情况下,实现收入充足且明确的SCC定价,优于现有方法。

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英文摘要

Synchronous Generators (SGs) currently provide important levels of Short-Circuit Current (SCC), a critical ancillary service that ensures line protections trip during short-circuit faults. Given the ongoing replacement of SGs by power-electronics-based generation, which has a hard limit on current injection, it has become relevant to optimize the procurement of SCC services provided by remaining SGs. Pricing this service is, however, challenging due to the integrality constraints in Unit Commitment (UC). Existing methods, e.g., dispatchable pricing and restricted pricing, attempt to address this issue but exhibit limitations in handling non-convexities, resulting in SCC prices that either fail to cover the operating costs of units or lack interpretability. To overcome these pitfalls, we adopt a primal-dual formulation of the SCC-constrained dispatch that preserves the binary UC for effectively computing shadow prices of SCC services. Using a modified IEEE 30-bus system, the proposed method is compared with the previously developed pricing schemes. It is demonstrated that, under the proposed pricing method, revenue-adequate and explicit service prices can be assigned without the need for uplift payments, an advantage that cannot be achieved by other pricing approaches.

2510.00378 2026-05-11 hep-ph hep-ex

$\bar{B}_{s,d}^{0} \to J/ψμ^{+}μ^{-}$ Decays in QCD Factorization

Xin-Qiang Li, Yan Shi, Ya-Dong Yang, Xing-Bo Yuan, Chun-Yang Zhao

AI总结 本文基于LHCb首次对罕见衰变 $\bar{B}_{s,d}^{0} \to J/ψμ^{+}μ^{-}$ 的搜索,采用QCD因子化方法对其进行了详细研究。通过引入领先阶和次领先阶的QCD修正,并结合光锥分布振幅,计算了这些衰变的分支比,发现其最大值分别可达 $2.21\times10^{-9}$ 和 $7.69\times10^{-11}$(在QCD耦合常数的领先阶近似下)。考虑非因子化的顶点修正后,分支比进一步降低约一个数量级。此外,文章还给出了双缪子不变质量分布和 $J/ψ$ 介子纵向极化分量,为未来实验提供了重要的理论参考。

Comments 40 pages, 10 figures, and 7 tables; more discussions and references added, final version published in the journal

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英文摘要

Motivated by the first LHCb searches for the rare $\bar{B}_{s,d}^{0} \to J/ψμ^{+}μ^{-}$ decays, we perform a detailed study of these processes within the QCD factorization formalism. Since the transverse size of the $J/ψ$ meson is small in the heavy quark mass limit, this formalism is generally expected to hold for these decays. We include both the leading- and next-to-leading-order QCD corrections to the hard-scattering kernels, which are convoluted with the light-cone distribution amplitudes (LCDAs) of the initial- and final-state hadrons. It is numerically found that, depending on the model parameters for the leading-twist $B$-meson LCDA, the maximum branching ratios of $\bar{B}_{s}^{0}\to J/ψμ^{+}μ^{-}$ and $\bar{B}_{d}^{0} \to J/ψμ^{+}μ^{-}$, integrated over the dimuon invariant mass squared $q^2$ from $1\,\mathrm{GeV}^2$ to $(m_{B_{s,d}}-m_{J/ψ})^2$, can reach up to $2.21\times10^{-9}$ and $7.69\times10^{-11}$ at the leading order in $α_s$, respectively. After incorporating the non-factorizable one-loop vertex corrections, these branching ratios are further reduced by about one order of magnitude, with $\mathcal{B}(\bar{B}_{s}^{0} \to J/ψμ^{+}μ^{-})|_{q^2 \geq 1\,\mathrm{GeV}^2}=2.88\times10^{-10}$ and $\mathcal{B}(\bar{B}_{d}^{0} \to J/ψμ^{+}μ^{-})|_{q^2 \geq 1\,\mathrm{GeV}^2}=1.07\times10^{-11}$. In addition, we have presented the dimuon invariant mass distributions of the individual and total helicity amplitudes squared, as well as the differential and integrated longitudinal polarization fractions of the $J/ψ$ meson, which could be probed by the future LHCb and Belle II experiments with more accumulated data.

2509.22180 2026-05-11 astro-ph.CO

Detection of HI filament: Pair Stacking vs. Filament Stacking

Yuxi Meng, Jie Wang, Yingjie Jing, Hongxiang Chen, Zerui Liu

AI总结 本文研究了如何检测宇宙网中中性氢(HI)丝状结构的微弱21厘米信号,比较了两种堆叠方法——配对堆叠和丝状堆叠的效果。通过EAGLE和IllustrisTNG模拟分析发现,尽管配对堆叠方法操作简便,但易受大质量结构的干扰;而丝状堆叠方法在去除大质量结构干扰后,仍能获得较高的中性氢柱密度,达到$10^{16}$–$10^{17}~\mathrm{cm}^{-2}$,表现出更大的检测潜力。研究认为,随着观测数据密度和空间分辨率的提升,丝状堆叠方法在未来的中性氢丝状结构探测中具有更广阔的应用前景。

Comments 12 pages, 7 figures; accepted for publication in ApJ

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Journal ref
The Astrophysical Journal, 1002, 210 (2026)
英文摘要

The faint 21 cm signal emitted by neutral hydrogen in cosmic filaments is expected to be detectable. However, due to its weakness, stacking techniques are required. We assessed two stacking methods--pair stacking and filament stacking--using the EAGLE and IllustrisTNG simulations. Pair stacking leverages the fact that cosmic filaments connect massive structures (i.e., knots) in the cosmic web, while filament stacking directly aggregates filaments identified from galaxy distributions. Our analysis indicates that, although pair stacking is convenient, it faces contamination from massive structures; after removing this contamination, the filament signal is significantly reduced. In contrast, HI detection via filament stacking appears more promising. The column density in filament stacking reaches $\sim 10^{16}$--$10^{17}~\mathrm{cm}^{-2}$ even when all haloes are masked, whereas pair stacking does not reach this level even without masking, and is further suppressed by several orders of magnitude once masking is applied. The effectiveness of filament stacking can be further improved with higher galaxy number density and better spatial resolution in radio intensity mapping observations. With the advent of upcoming optical and radio data, the detection of HI in cosmic filaments remains promising.

2509.21112 2026-05-11 cs.IT eess.SP math.IT

Adapt or Regress: Rate-Memory-Compatible Spatially-Coupled Codes

Bade Aksoy, Doğukan Özbayrak, Ahmed Hareedy

AI总结 本文提出了一类可重构的时空耦合码(RMC-SC码),旨在实现码率与内存的兼容性,以适应不同信道条件和数据速率的需求。通过增加时空耦合码的内存,该方法在保证码率兼容性的同时提升了性能。研究采用概率设计方法,结合梯度下降算法优化新增组件的分布,以减少短环数量并提升译码性能,实验结果表明RMC-SC码在性能上显著优于现有方案。

Comments 11 pages (double column), 4 figures, submitted to the IEEE Information Theory Workshop (ITW)

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英文摘要

Spatially-coupled (SC) codes are a class of low-density parity-check (LDPC) codes that have excellent performance thanks to the degrees of freedom they offer. An SC code is designed by partitioning a base matrix into components, the number of which implies the code memory, then coupling and lifting them. In the same system, various error-correction coding schemes are typically needed. For example, in wireless communication standards, several channel conditions and data rates should be supported. In storage and computing systems, stronger codes should be adopted as the device ages. Adaptive code design enables switching from one code to another when needed, ensuring reliability while reducing hardware cost. In this paper, we introduce a class of reconfigurable SC codes named rate-memory-compatible SC (RMC-SC) codes, which we design probabilistically. In particular, rate compatibility in RMC-SC codes is achieved via increasing the SC code memory, which also makes the codes memory-compatible and improves performance. We express the expected number of short cycles in the SC code protograph as a function of the fixed probability distribution characterizing the already-designed SC code as well as the unknown distribution characterizing the additional components. We use the gradient-descent algorithm to find a locally-optimal distribution, in terms of cycle count, for the new components. The method can be recursively used to design any number of SC codes needed, and we show how to extend it to other cases. Next, we perform the finite-length optimization using a Markov chain Monte Carlo (MC$^2$) approach that we update to design the proposed RMC-SC codes. Experimental results demonstrate significant reductions in cycle counts and remarkable performance gains achieved by RMC-SC codes compared with a literature-based straightforward scheme.

2509.17708 2026-05-11 math.OA math-ph math.FA math.MP

Real decomposable maps on operator systems

David P. Blecher, Christiaan H. Pretorius

AI总结 本文研究了实算子系统之间的“实可分解映射”理论,扩展了传统上仅限于复C*-代数的复杂可分解映射理论。作者探讨了该定义与现有理论及复化之间的关系,并发现实可分解映射的Jordan分解中出现了一个新的项,这一项构成了一类新的完全有界映射,可能在实非交换凸性研究中具有重要应用。文章还验证了多项与可分解性相关的已知结果在实数情况下的适用性。

Comments 28 pages, to appear IEOT

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英文摘要

We initiate and study the theory of ``real decomposable maps" between real operator systems. Formally, this is new even in the complex case, which hitherto has restricted itself to the case where the systems are complex C*-algebras. We investigate how our definition interacts with the existing theory (which it generalizes) and with the complexification. In particular, a surprising term appears in the `Jordan decomposition' of real decomposable maps. This term constitutes a new class of completely bounded maps, a class that also showed up in disguised form in our recent study of real noncommutative (nc) convexity, and whose theory is likely to have applications in that subject. We also check the real case of many important known results related to decomposability, for example results about the weak expectation property or injectivity of von Neumann algebras.

2509.16642 2026-05-11 eess.SY cs.SY

A LiDAR-Driven Fallback Longitudinal Controller for Safer Following in Sudden Braking Scenarios

Mohamed Sabry, Enrico Del Re, Walter Morales-Alvarez, Cristina Olaverri-Monreal

AI总结 本文提出了一种基于激光雷达的后备纵向控制器,用于在突发刹车场景中实现更安全的跟车控制。该控制器仅依赖激光雷达测距和跟随车辆的速度信息,无需依赖车联网通信,从而提高了系统可靠性。研究证明,该方法能够在传感器延迟或同步问题存在的情况下实现从静止起步跟车,并有效避免紧急刹车时的碰撞。

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英文摘要

Adaptive Cruise Control has seen significant advancements, with Collaborative Adaptive Cruise Control leveraging Vehicle-to-Vehicle communication to enhance coordination and stability. However, the reliance on stable communication channels limits its reliability. Research on reducing information dependencies in Adaptive Cruise Control systems has remained limited, despite its critical role in mitigating collision risks during sudden braking scenarios. This study proposes a novel fallback longitudinal controller that relies solely on LiDAR-based distance measurements and the velocity of a follower vehicle. The controller is designed to be time-independent, ensuring operation in the presence of sensor delays or synchronization issues. Simulation results demonstrate that the proposed controller enables vehicle-following from standstill and prevents collisions during emergency braking, even under minimal onboard information.

2509.15887 2026-05-11 gr-qc hep-th

Charged rotating Casimir wormholes

Remo Garattini, Athanasios G. Tzikas

AI总结 本文研究了在外部电场存在的情况下,旋转可穿越虫洞如何由卡西米尔效应源支撑的条件。通过扩展静态卡西米尔虫洞和中性旋转虫洞的研究,作者构建了一个带电旋转卡西米尔虫洞的解,并确定了满足爱因斯坦场方程所需的热应力-能量张量。研究发现,当旋转速度恒定且与零角动量观测者测得的旋转一致时,该虫洞在红移和形状函数上与已知的静态带电卡西米尔虫洞一致,同时满足场方程的约束条件。此外,作者还探讨了角速度随径向坐标变化并随距离衰减的配置,该机制有效消除了远距离框架拖曳的不现实持续性,同时仍能由卡西米尔、电磁和热贡献支持一致解。

Comments 9 pages

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Journal ref
Phys. Lett. B 877 (2026) 140469
英文摘要

We investigate the conditions under which a rotating traversable wormhole can be supported by a Casimir source in the presence of an external electric field. Extending previous studies of static Casimir wormholes and neutral rotating configurations, we construct an electrically charged rotating Casimir wormhole solution and determine the thermal stress-energy tensor required to consistently satisfy the Einstein field equations. A particularly simple configuration arises when the rotation is constant and coincides with that measured by a zero-angular-momentum observer (ZAMO). In this case, the rotating wormhole preserves the same redshift and shape functions as the well-known static charged Casimir case, provided that the angular velocity and thermal components satisfy specific constraints imposed by the field equations. We also examine a configuration in which the angular velocity depends on the radial coordinate and decreases exponentially away from the throat. This damping mechanism removes the unrealistic persistence of frame dragging at large distances, while still allowing a consistent solution supported by Casimir, electromagnetic and thermal contributions.

2509.09390 2026-05-11 cond-mat.mtrl-sci

A review on scanning photocurrent microscopy and its application to one- and two-dimensional materials

Talip Serkan Kasırga

AI总结 本文综述了扫描光电流显微镜(SPCM)及其在一维和二维材料中的应用。SPCM通过聚焦激光束的扫描实现光电响应的空间成像,有助于深入理解光电器件中的物理机制。文章系统总结了SPCM的基本原理、测量结果及对光电响应机制的解读方法,特别强调了激光诱导热效应在光电响应中的作用,并指出了SPCM在确定光电响应机制方面存在的不足。

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英文摘要

The electrical response of a material when illuminated with light is a key to many optoelectronic device applications. This so-called photoresponse typically has a non-uniform spatial distribution through the active device area, and the ability to spatially resolve the photoresponse enables an in-depth understanding of the underlying physical mechanisms. Scanning photocurrent microscopy (SPCM) is a method that allows the spatial mapping of the photoresponse by raster scanning a focused laser beam over the sample. SPCM is becoming more popular due to its simplicity and power in unraveling fundamental optoelectronic processes. In this review, first, we provide the fundamentals of SPCM to lay the basics for the subsequent discussions. Then, we focus on the literature that employs SPCM to identify the photoresponse of one- and two-dimensional materials. We discuss SPCM measurement results of common materials in detail and introduce a systematic approach to interpreting the SPCM measurements. We have given particular emphasis on the photothermal mechanisms that are excited by the focused laser beam and critically reviewed studies in the literature from the perspective of laser-induced heating of the electronic and the lattice degrees of freedom. Finally, we discuss the shortcomings of SPCM in determining the mechanisms leading to the photoresponse.

2509.06812 2026-05-11 nucl-th astro-ph.HE nucl-ex

Ab initio calculations of beta-decay half-lives for $N=50$ neutron-rich nuclei

Zhen Li, Takayuki Miyagi, Achim Schwenk

AI总结 本文首次从理论上计算了中子丰富核素(特别是中子数 $N=50$ 的核)的β衰变半衰期,为$r$-过程核合成提供了关键输入。研究基于手征有效场论的核力和电流,结合中子介质相似性重整化群方法,自洽地推导出价空间哈密顿量和弱相互作用算符,无需经验调整即可计算核态和格拉夫-泰勒跃迁强度,并考虑了首次禁止跃迁的影响。结果表明,引入二体电流显著提高了半衰期的计算值,与现有实验数据吻合良好,验证了该方法的预测能力。

Comments 7 pages, 5 figures

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Journal ref
Phys. Rev. Lett. 136, 182501 (2026)
英文摘要

Beta-decay rates of extreme neutron-rich nuclei remain largely unknown experimentally, while they are critical inputs for $r$-process nucleosynthesis. We present first ab initio calculations of total beta-decay half-lives, with a focus on $N=50$ nuclei. Starting from nuclear forces and currents based on chiral effective field theory, we use the in-medium similarity renormalization group to consistently derive valence-space Hamiltonians and weak operators, from which we calculate the nuclear states involved and the Gamow-Teller transition strengths, without phenomenological adjustments. In addition, we explore effects of first-forbidden contributions. Our results show that the inclusion of two-body currents increases the total half-lives, which then show good agreement with the existing experimental data, thereby validating the predictive capability of our approach.

2509.03512 2026-05-11 stat.ME

Bayesian Multivariate Sparse Functional Principal Components Analysis

Joseph Sartini, Scott Zeger, Ciprian Crainiceanu

AI总结 本文提出了一种全贝叶斯推断框架MSFAST,用于处理多变量、稀疏观测的函数型数据,旨在更准确地建模并量化主成分的不确定性。该方法基于FAST方法进行扩展,通过标准化变量、改进正交基函数、优化计算稳定性等策略,提升了模型在稀疏数据下的表现。研究通过模拟实验验证了MSFAST在低信噪比情况下的优越性,并将其应用于儿童生长研究,展示了其在实际分析中的有效性。

Comments 23 pages, 6 figures for main text. Appendix contains supplemental material

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英文摘要

Functional Principal Components Analysis (FPCA) provides a parsimonious, semi-parametric model for multivariate, sparsely-observed functional data. Frequentist FPCA approaches estimate principal components (PCs) from the data, then condition on these estimates in subsequent analyses. As an alternative, we propose a fully-Bayesian inferential framework for multivariate, sparse functional data (MSFAST) which explicitly models the PCs and incorporates their uncertainty. MSFAST builds upon the FAST approach to FPCA for univariate, densely-observed functional data. Like FAST, MSFAST represents PCs using orthonormal splines and samples the orthonormal spline coefficients using parameter expansion. MSFAST extends FAST to multivariate, sparsely-observed data by (1) standardizing each functional covariate to mitigate poor posterior conditioning due to disparate scales; (2) using a better-suited orthogonal spline basis; (3) updating parameterizations for computational stability; (4) introducing routines that leverage multiple cores and threads to accelerate compute; (5) using a Procrustes-based posterior PC alignment procedure; and (6) providing efficient prediction routines. We evaluate MSFAST alongside existing implementations using simulations. MSFAST produces uniquely valid inferences and accurate estimates, particularly in smaller signal-to-noise regimes. MSFAST is motivated by and applied to a study of child growth, with an accompanying vignette illustrating the implementation step-by-step.

2509.02115 2026-05-11 hep-ph nucl-th

Probing nuclear structure with the Balitsky-Kovchegov equation in full impact-parameter dependence

J. Cepila, M. Matas, M. Vaculciak

AI总结 本文基于具有完整撞击参数依赖性的巴利茨基-科夫切夫方程(BK方程)的新解,将部分子演化研究从质子拓展到核子目标,旨在探究核物质结构。研究通过预测深部非弹性散射和矢量介子衍射产生等关键过程,揭示核子中胶子动力学及饱和现象,并引入线性化BK方程和四面体氧模型,以寻找胶子饱和的实验信号,为未来对撞机和当前LHC上的核子矢量介子产生研究提供理论支持。

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Journal ref
Phys. Rev. C 113, 055204 (2026)
英文摘要

Building on the newly available solution of the Balitsky-Kovchegov (BK) equation with the full impact-parameter dependence, we extend the study of parton evolution from proton to nuclear targets. Since a key part of the scientific programme for future experimental facilities such as the EIC is to study gluon dynamics and shed new light on the phenomenon of parton saturation, we present predictions for key processes, such as deep-inelastic scattering or the diffractive production of vector mesons, on a variety of nuclear targets. Besides the standard BK equation, we employ its linearised version to identify a promising channel to search for gluon saturation in the nuclear collisions. Furthermore, we implement a tetrahedral model of oxygen to search for deviations from the standard, isotropic, Woods-Saxon approach. In addition to the future colliders, the presented results are also of interest for the current studies of nuclear vector meson production at the LHC.

2508.21662 2026-05-11 math.QA

Rank-two parabolic-type VOAs and nilpotency of nil ideals

Jianqi Liu

AI总结 本文系统研究了二阶格顶点算子代数 $V_L$ 的抛物型子顶点算子代数 $V_P$,并对其类型进行了分类。通过分析对应的子单群 $P \subseteq L$,作者进一步分类了每类 $V_P$ 的不可约模。研究还发现某些Zhu代数 $A(V_P)$ 为具有非幂零零理想的新环类提供了例子。最后,作者证明了任何抛物型子顶点算子代数 $V_P$ 的单商 $V_H$ 是一个满足强单位性质的 $C_1$-有限非理性顶点算子代数。

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英文摘要

In this paper, we undertake a systematic study of the parabolic-type sub-vertex operator algebras (subVOAs) \(V_P\) of rank-two lattice VOAs \(V_L\), originally introduced by the first-named author. We first classify all possible types of such subVOAs by analyzing the corresponding submonoids \(P \subseteq L\). For each type of \(V_P\), we then classify its irreducible modules. Certain Zhu algebras \(A(V_P)\) provide new examples of rings with nil ideals that are not nilpotent. Finally, we show that the simple quotient \(V_H\) of any parabolic-type subVOA \(V_P\) is a \(C_1\)-cofinite irrational VOA satisfying the strongly unital property recently introduced by Damiolini--Gibney--Krashen.

2508.14824 2026-05-11 physics.med-ph

Calibration offset estimation in mobile hearing tests via categorical loudness scaling

Chen Xu, Birger Kollmeier

AI总结 该研究旨在通过开发基于分类响度标度(CLS)的方法,提高智能手机进行听力评估的可靠性,解决设备校准偏差的问题。研究采用贝叶斯回归和最近邻两种模型,利用来自奥尔登堡听力健康数据库的CLS数据进行训练,结果表明贝叶斯模型能将估计的校准偏差与真实值之间的相关性提升至0.81,并显著降低校准不确定性。该方法为在非实验室环境下进行便捷、可靠的听力检测提供了可行方案,有助于扩大听力健康服务的可及性。

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英文摘要

Objective: To enable reliable smartphone-based hearing assessments by developing methods to estimate device calibration offsets using categorical loudness scaling (CLS). Design: Calibration offsets were simulated from a Gaussian distribution. Two prediction models - a Bayesian regression model and a nearest neighbor model - were trained on CLS-derived parameters and data from the Oldenburg Hearing Health Repository (OHHR). CLS was chosen because it provides level-independent measures (e.g., dynamic range) that remain robust despite calibration errors. Study Sample: The dataset comprised CLS results from N = 847 participants with a mean age of 70.0 years (SD = 8.7), including 556 male and 291 female listeners with diverse hearing profiles. Results: The Bayesian regression model achieved correlations of up to 0.81 between estimated and true calibration offsets, enabling accurate individual-level correction. Compared to threshold-based approaches, calibration uncertainty was reduced by factors between 0.41 and 0.79, demonstrating greater robustness in uncontrolled environments. Conclusions: CLS-based models can effectively compensate for missing calibration in mobile hearing assessments. This approach provides a practical alternative to threshold-based methods, supporting the use of smartphone-based tests outside laboratory settings and expanding access to reliable hearing healthcare in everyday and resource-limited contexts.

2508.12676 2026-05-11 math.CA math.CO

On the Carlitz-Mehler formula for Hermite polynomials

Manish Chaurasia

AI总结 本文研究了Hermite多项式相关的Carlitz-Mehler公式的一般化形式。作者给出了该公式的进一步推广,并提供了直接的证明方法。该工作为理解此类特殊函数的组合性质提供了新的视角和工具。

Comments Comments are welcome

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英文摘要

Carlitz proved a few generalizations of Mehler's formula. Later, Srivastava et al. gave a new proof for some extensions of Carlitz's formula. Here, a direct proof of the further generalization is given.

2508.11742 2026-05-11 cs.CR cs.NI

Cross-Flow Correlations Survive Synthesis: Measuring Source-Level Privacy Leakage in Synthetic Network Traces

Minhao Jin, Hongyu Hè, Maria Apostolaki

AI总结 本文揭示了合成网络数据生成器(SynNetGens)中一个根本性的隐私漏洞:尽管这些工具旨在保护原始数据隐私,但它们保留了跨流的行为关联,可能暴露特定用户或服务是否参与了训练数据。为此,作者提出了一种名为TraceBleed的源级成员推理攻击方法,验证了该漏洞在实际中的可利用性。研究还发现,现有基于流或数据包的差分隐私方法在不显著降低数据保真度的情况下无法有效保护源级隐私,并展示了合成数据量增加会显著加剧隐私泄露问题。

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英文摘要

Synthetic network data generators (SynNetGens) are increasingly used to share realistic traffic traces without exposing sensitive raw data. While substantial effort has gone into improving fidelity, privacy is either assumed to be a built-in property of synthesis or addressed through differential privacy at the packet or flow level. This paper uncovers a fundamental privacy vulnerability: SynNetGens preserve cross-flow behavioral correlations that expose source-level membership, allowing an attacker to determine whether traffic of specific user, or service was included in the training data. This leakage arises from a mismatch in abstraction: existing SynNetGens operate and are protected at the packet or flow level, while sensitive information is encoded in correlations across flows from the same source. To demonstrate that this vulnerability is exploitable in practice, we develop TraceBleed, the first source-level membership inference attack against black-box SynNetGens. Our evaluation spans five datasets and six SynNetGens, revealing that: (i) every generator leaks source-level information on at least some datasets; (ii) flow- or packet-level differential privacy fails to protect source privacy unless fidelity is degraded to unusable levels; and (iii) releasing 10X more synthetic data amplifies leakage by 130% on average. To support ongoing research in this area, we will maintain a public privacy-fidelity leaderboard so practitioners can choose generators that fit their needs and researchers can benchmark new designs faithfully.

2508.11563 2026-05-11 cs.CR

How Query Distribution Knowledge Breaks Multidimensional Encrypted Range Queries, With Guarantees

Daniel Blackley, Nathaniel Moyer, Charalampos Papamanthou, Evgenios M. Kornaropoulos

AI总结 本文研究了在已知查询分布的情况下,如何利用访问模式泄露信息破解多维加密范围查询,并给出了可证明的安全性保证。作者提出了LAMa方法,通过匹配频率的方式,在无需事后转换或数据注入的前提下,成功重建任意维度的明文坐标。该方法提供了多维频率匹配分析的首个严格理论保证,并在真实数据上的实验表明其性能优于现有技术。

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英文摘要

In this work, we show how knowledge of the query distribution, combined with access-pattern leakage, is sufficient to break multi-dimensional encrypted range queries, with provable guarantees. Prior attacks either recover only data topology without concrete coordinates for plaintexts (and as a result require post-hoc transformations), or assume adversarial control over database content; a strong and unrealistic threat model. Given knowledge of the query distribution, we revisit frequency matching, one of the earliest cryptanalytic ideas in this area, and push it to its limits in the multi-dimensional regime through LAMa ($\underline{L}$eakage-$\underline{A}$buse via $\underline{Ma}$tching). LAMa is a three-component framework that reconstructs plaintext coordinates in arbitrary dimensions without post-hoc transformations or data injection/poisoning. We complement LAMa with the first rigorous guarantees for multi-dimensional frequency-matching cryptanalysis, covering its query complexity, optimal parameterization, and worst-case reconstruction quality. Experiments on real-world data show that LAMa consistently outperforms the state of the art.

2508.08691 2026-05-11 math.CO

On packing total coloring

Jasmina Ferme, Daša Mesarič Štesl

AI总结 本文引入了一种新的图着色概念——打包总着色(packing total coloring),将打包着色的思想同时应用于图的顶点和边。打包总着色要求相同颜色的顶点或边之间必须满足一定的距离条件,具体距离的定义根据元素类型有所不同。研究给出了打包总色数的上下界,并从图的最大度数角度分析了该色数的性质,同时刻画了打包总色数为1到5的所有图类。

详情
英文摘要

In this paper, we introduce a new concept in graph coloring, namely the \textit{packing total coloring}, which extends the idea of packing coloring to both the vertices and the edges of a given graph. More precisely, for a graph $G$, a packing total coloring is a mapping $c: V(G) \cup E(G) \rightarrow \{1, 2, \ldots\}$ with the property that for any integer $i$, any two distinct elements $A, B \in V(G) \cup E(G)$ with $c(A) = c(B) = i$ must be at distance at least $i+1$ from each other. Note that the distance between $A$ and $B$ means: a) the usual shortest-path distance between $A$ and $B$ if $A, B \in V(G)$; b) the $\min \{d(a,d), d(a,c),d(b,c), d(b,d)\}+1$ if $\{A, B\} =\{ab, cd\} \subseteq E(G)$; c) the $ \min \{d(a,X), d(b,X)\}+1$ if $\{A, B\}=\{ab, X\}$, where $ab \in E(G)$ and $X \in V(G)$. The smallest integer $k$ such that $G$ admits a packing total coloring using $k$ colors is called the \textit{packing total chromatic number}, denoted by $χ_ρ^{''}(G)$. In addition to introducing this new concept, we provide lower and upper bounds for the packing total chromatic numbers of graphs. Furthermore, we consider packing total chromatic numbers of graphs from the perspective of their maximum degrees and characterize all graphs $G$ with $χ_ρ^{''}(G) \in \{1, 2, 3, 4, 5\}$.