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2605.14586 2026-05-15 quant-ph cond-mat.mes-hall

Fraxonium: Fractional fluxon states for qudit encoding

Luca Chirolli, Valentina Brosco, Uri Vool, Gianluigi Catelani, Luigi Amico

AI总结 本文提出了一种基于超导电路的量子比特编码方案,利用分数量子磁通态(fraxons)实现具有多个低能态的量子系统(qudit),有效避免了漏错误。该系统通过傅里叶工程方法设计的约瑟夫森势阱,实现了对分数量子磁通态的局域化控制,并展示了四维和五维量子系统的能谱。研究还提出了一种适用于该系统的非阿贝尔单量子门操控协议,为超越传统量子比特范式的量子计算提供了新的平台。

Comments 9 pages + appendices, 9 figures

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英文摘要

We propose a superconducting circuit hosting $d$ low-lying states, well separated from the rest of the spectrum, that naturally realizes a qudit system protected from leakage errors. The system represents a generalization of the fluxonium and the low-energy states are constituted by fractional fluxon states, that we call {\it fraxons}, localized in the minima of a suitably designed Josephson potential. The latter is tailored through a Fourier engineering approach, that employs multi-harmonic Josephson building block elements composed by a Josephson junction and an inductance connected in series. We present the spectrum of a $d=4$ and a $d=5$ qudit system and study in detail the qutrit case. We analyze the dipole matrix elements for coupling to radiation and propose a non-Abelian, stimulated Raman adiabatic passage (STIRAP) protocol for single-qutrit gates, that is particularly suited for the present system. The proposed platform opens novel perspectives in circuit engineering and quantum computing beyond the qubit paradigm.

2605.14585 2026-05-15 physics.optics

Sagnac-Loop-Reflector Fabry-Perot Lattices for Modular 1D Topological Photonics

Siwoo Kim, Yung Kim, Semin Choi, Taeyeon Kim, Seungmin Lee, Kyoungsik Yu, Sangyoon Han, Bumki Min

AI总结 该研究提出了一种基于级联可调萨格纳克环反射器的模块化硅光子法布里-珀罗共振腔阵列,通过单个定向耦合器的耦合系数实现对有效晶格跃迁的模块化调控。研究以交替排列两种SLR为例,将其映射到弱耦合极限下的苏-施瑞弗-海格模型,并通过传输矩阵法推导了布洛赫色散关系和有效紧束缚哈密顿量。仿真结果表明,该结构在拓扑相中表现出局域于边缘的中带共振,并对保持对称性的跃迁扰动具有鲁棒性,为片上拓扑光子学提供了新的实现平台。

Comments 7 pages, 3 figures

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英文摘要

We introduce a modular silicon-photonic Fabry-Perot resonator lattice based on cascaded tunable Sagnac loop reflectors. Each SLR is controlled by a single directional-coupler cross-coupling coefficient, enabling modular control of the effective lattice hoppings. As a representative example, alternating two SLR types maps the lattice onto the Su-Schrieffer-Heeger model in the weak-coupling limit. We derive the Bloch dispersion via a transfer-matrix formulation and obtain an effective tight-binding Hamiltonian in the weak-coupling limit. S-parameter simulations of a 20-site lattice show an isolated midgap resonance with edge-localized power profiles in the topological phase, and disorder tests show robustness against symmetry-preserving hopping perturbations. Our results establish SLR-based FP lattices as a complementary platform for on-chip topological photonics.

2605.14583 2026-05-15 math.AG

Weierstrass semigroups at totally ramified places of degree one on Kummer extensions

Huachao Zhang, Chang-An Zhao

AI总结 本文研究了Kummer扩张 $y^m = f(x)$ 上一度完全分歧点处的Weierstrass半群,给出了该半群的间隙集的显式描述,并统一适用于不同的一度完全分歧点。文章还给出了该半群对称性的充要条件,探讨了多个一度完全分歧点处Weierstrass半群的极小生成集,并构造了相应函数。最后,将结果应用于GGS曲线和BM曲线的函数域等具体例子中。

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英文摘要

We explicitly describe the set of gaps and the Weierstrass semigroup at a totally ramified place of degree one on a Kummer extension defined by the affine equation $y^m = f(x)$ over $K$, an algebraic extension of $\mathbb{F}_q$, where $f(x)\in K(x)$. Our description takes a unified form for distinct totally ramified places of degree one. We then provide a necessary and sufficient condition for the Weierstrass semigroup at a totally ramified place of degree one to be symmetric. Furthermore, we investigate the minimal generating set of the Weierstrass semigroups at many totally ramified places of degree one. We not only explicitly describe the minimal generating set, but also construct functions whose pole divisors have coefficients lying in the set. Finally, we apply our results to specific Kummer extensions, including function fields of GGS curves and subcovers of the BM curve.

2605.14582 2026-05-15 quant-ph

Quantum battery optimized by parametric amplification

Fang-Mei Yang, Jun-Hong An, Fu-Quan Dou

AI总结 本文研究了基于参量放大技术优化量子电池(QB)的实现方案,提出了一种利用超导电路系统构建高效量子电池的新方法。该方案通过双光子驱动的LC谐振腔作为充电器,结合一组传输子量子比特作为电池,显著增强了腔-比特耦合,实现了快速能量转移和高稳定性能量存储。研究还表明,该方案对实验中的参数波动和环境噪声具有较强的鲁棒性,为实现高功率、高稳定性的量子电池提供了可行的平台。

Comments 11 pages, 4 figures

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英文摘要

The parametric amplification enabled by two-photon driving constitutes a versatile platform for advanced quantum technologies. We present an optimized scheme for implementing quantum batteries (QBs) based on a superconducting circuit system, where a two-photon-driven LC resonator serves as the charger and an array of transmon qubits functions as the battery. Our results show that two-photon parametric driving exponentially enhances the effective cavity-qubit coupling, which in turn gives rise to near-degenerate energy-level structures and highly entangled quantum states. This significantly enhances the charging power and enables rapid energy transfer from the charger to the battery. Moreover, the engineered squeezed cavity mode and the associated quantum correlations effectively suppress environmentally induced decoherence, thereby delaying energy leakage and facilitating stable energy storage. The proposed scheme remains robust against practical experimental imperfections, such as parameter disorder and environmental noise, preserving its performance advantages. The work provides a feasible platform for realizing high-power, high-stability QBs and highlights the potential of parametric control in quantum energy technologies.

2605.14580 2026-05-15 hep-th gr-qc

Scattering off Chamblin-Reall Branes

Dongsheng Ge, Christopher P. Herzog

AI总结 本文研究了在三维时空中,标量-引力波在薄膜上的线性散射行为,该薄膜对应于一系列强耦合理论中的界面,这些理论来源于高维 $AdS_{d+2}$ 引力的维数约化。不同于纯 $AdS_3$ 情况,当 $d>1$ 时,散射过程会产生反射、透射和消逝波等多种成分。研究发现,在 $d=2$ 背景下,界面表现出类似粗糙半透明窗口的行为,导致角向扩散散射和表面模吸收,从对偶视角看,这类似于红外方向的耗散流动。对于 $d=4$ 情况,分析表明散射过程对红外边界条件敏感,暗示需要对零温几何进行正则化以确保散射过程的定义性。

Comments 31 pages + 4 appendices, 3 figures

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英文摘要

We study the linearized scattering of dilaton-graviton waves from a thin brane in three-dimensional spacetime. Holographically, the setup models scattering from an interface in a family of strongly coupled theories related to dimensional reductions of higher-dimensional $AdS_{d+2}$ gravity. Unlike the pure $AdS_3$ case, for $d>1$ the physical bulk mode allows incident radiation to be redistributed into reflected, transmitted, and evanescent components. For the $d=2$ background, we obtain a controlled solution in which the interface acts like a rough translucent window, producing diffuse angular scattering and absorption into surface modes. From the dual perspective, the scattering process is suggestive of dissipative flow toward the infrared. For $d=4$, the same analysis reveals a sensitivity to the infrared boundary condition, suggesting that the singular zero-temperature geometry must be regulated in order to have a well-defined scattering process. The structure of the equations nevertheless suggests that a regulated $d=4$ problem may exhibit the same qualitative redistribution of incident flux.

2605.14577 2026-05-15 math.NA cs.NA

Dimension Calculation for Spline Spaces over Rectilinear Partitions via Smoothing Cofactor Method

Bingru Huang, Falai Chen

AI总结 本文提出了一种基于平滑共因子方法的通用框架,用于计算任意矩形划分上样条空间的维度。通过引入TE连通分量的概念,将问题转化为显式可构造的符合性矩阵的秩计算,从而扩展了T网格上多项式样条的维度理论。此外,文章引入了一类新的矩形划分——具有不相交截断l边的划分,并证明在特定条件下,对应的样条空间维度可达到Schumaker下界,表明在某些划分配置下,该下界对任意次数和光滑阶都是可实现的。数值例子验证了该框架在三角形和非三角形矩形划分上的有效性与通用性。

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英文摘要

This paper presents a general framework for calculating the dimension of spline spaces over arbitrary rectilinear partitions using the smoothing cofactor method. The approach extends existing dimension theory for polynomial splines over T-meshes by introducing the concept of TE-connected components, reducing the problem to the rank computation of explicitly constructible conformality matrices. Furthermore, a new class of rectilinear partitions, termed partitions with disjoint truncated l-edges, is introduced. It is proven that under specific conditions, the dimension of the corresponding spline space attains Schumaker's lower bound. This shows that the lower bound is attainable for arbitrary degree d and smoothness order mu in certain partition configurations. Numerical examples, including the Morgan-Scott and Yuan-Stillman partitions, validate the effectiveness and generality of the framework for both triangular and non-triangular rectilinear partitions.

2605.14576 2026-05-15 math.NA cs.NA physics.flu-dyn physics.geo-ph

Verification of reciprocity in anisotropic poroelastic wave simulation using symmetric Strang splitting

Morten Jakobsen, Jose Carcione

AI总结 该研究针对各向异性多孔弹性波模拟中互易性验证的问题,提出了一种基于对称Strang分裂的数值方法。通过将Biot方程分解为可逆的波传播部分和不可逆的达西流动部分,揭示了连续方程中互易性的物理根源,并设计了一种保持能量守恒和稳定耗散的离散格式。该方法在二维各向异性介质中实现了高精度的互易性验证,展示了离散方案对连续算子对称性的继承能力。

Comments SEG Expanded abstract, peer-reviewed and accepted

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Journal ref
SEG Annual Meeting 2026, Expanded Abstract
英文摘要

Poroelastic wave simulations are important for many applications relating fluid flow and wave characteristics in porous rock formations. Reciprocity is a key physical property of wave propagation in porous media that is important for such applications, even when viscous dissipation is present. However, numerical poroelastic simulations often fail to reproduce reciprocal responses because the discretization does not preserve the balance between reversible wave dynamics and irreversible fluid-solid drag. To address this, we formulate the Biot equations in terms of a continuous evolution operator split into a reversible (skew-adjoint) wave part and an irreversible (self-adjoint, non-positive) Darcy part, including the leading-order Johnson-Koplik-Dashen correction. This structure clarifies why reciprocity holds in the continuous equations and how it is easily broken in discrete form. Guided by this interpretation, we construct a symmetric second-order Strang-splitting scheme with half-step source injection. The method conserves energy in the reversible subsystem, treats Darcy dissipation unconditionally stably, and retains Courant limits similar to elastic solvers. Using a staggered pseudo-spectral discretization, we model multimode propagation in 2D VTI media and obtain cross-component reciprocity with a relative L2 misfit approaching machine precision, demonstrating that the discrete scheme inherits the symmetry properties of the continuous evolution operator.

2605.14575 2026-05-15 econ.GN q-fin.EC stat.ME

The Asset Price Channel of Monetary Policy: Evidence from Regional Stock-Market Developments in the Successor States of Former Yugoslavia

Stefan Tanevski

AI总结 本研究旨在实证分析前南斯拉夫六个共和国地区是否存在货币政策的部门资产价格传导渠道。通过构建区域部门股票指数,并运用面板向量自回归模型和混合均值组估计方法,研究发现金融和电信部门存在明显的资产价格传导效应,这可能归因于跨国企业网络促进了子市场区域化。相比之下,制造业和电力部门则未表现出类似效应,表明当地股票市场仍较为分散,亟需更高效的区域市场整合或加强交易所合作。

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英文摘要

The aim of this study is to empirically investigate the existence of a sectoral asset price channel of monetary policy in the region of the six republics of former Yugoslavia. The study constructs sectoral indices for the entire region, building on the idea that one regional stock exchange may provide more efficiency for the listed companies in the region, while monetary policy relevance for it may be sector-specific. We employ panel vector autoregressive model to observe impulse responses of sectoral indices to innovations in monetary policy, while then disentangle the long- from the short-run relationships per index through a Pooled Mean Group estimation. Overall, we document presence of the asset price channel in the finance and telecom sectors, likely driven by the established multinational corporate networks fostering sub-market regionalization. Yet, this is not the case for the manufacturing and electricity sectors, which may imply that local stock markets are yet too fragmented and space for a more efficient regional stock market, either in the true sense of the word or, more realistically, though enhanced regional cooperation of the stock exchanges certainly exists.

2605.14574 2026-05-15 math.GT math.MG math.NT

McShane-Rivin norm balls and simple-length multiplicities

Nhat Minh Doan, Xiaobin Li, Van Nguyen

AI总结 本文研究了带有一个穿孔的完整有限面积双曲环面的简单闭测地线长度分布问题,利用McShane-Rivin范数球的正常转向估计,证明了长度不小于2的简单闭测地线数量具有对数平方的上界。该结果在模曲线情形下进一步改进了关于Markoff数的纤维数量的先前估计,并揭示了McShane-Rivin范数球在某些无理方向上的局部几何性质。

Comments 25 pages, 4 figures. Comments welcome!

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英文摘要

We use normal-turn estimates for McShane--Rivin norm balls to prove that, for every complete finite-area hyperbolic once-punctured torus $X$, the number of simple closed geodesics of length exactly $L\geq 2$ is at most $C_X(\log L)^2$. For the modular torus, this gives $$ \#λ_M^{-1}(m)\leq C(\log\log(3m))^2 $$ for every Markoff number $m$, improving the previous logarithmic Markoff-fiber bounds. These estimates also give new quantitative information on the local geometry of McShane--Rivin norm balls, including obstructions to infinite-order flatness at certain irrational directions.

2605.14573 2026-05-15 hep-th

Black-hole formation and thermalization in open JT gravity

Ryo Adachi, Rumi Hasegawa, Takanori Ishii, Daichi Takeda

AI总结 本文研究了开放杰克逊-特纳(JT)重力中黑洞形成与热化的关系,通过全息原理将黑洞形成与边界理论中的热化过程对应起来。作者将全息林德布拉德方法推广到非马尔可夫情形,并应用于耦合标量场的JT重力模型中,通过半经典和高温条件下的数值模拟,展示了黑洞的动态形成过程,为理解开放量子系统中的热化与黑洞物理提供了新的视角。

Comments 25 (14 + 11) pages, 7 figures

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英文摘要

Black-hole formation is expected, via holography, to correspond to thermalization in the boundary theory. For open quantum systems, an initial pure state generically evolves into a mixed state irreversibly, suggesting that horizon formation in the bulk should arise. In this paper, we extend the holographic Lindblad prescription to a non-Markovian setting and apply it to JT gravity coupled to a scalar field. Using numerical simulations in the semiclassical and high-temperature regime, we demonstrate the dynamical formation of black holes.

2605.14564 2026-05-15 cond-mat.soft cond-mat.mtrl-sci

Kinetic effects on the phase behavior and microstructural transitions of a thermoresponsive polymer solution

Pritha Acharya, Riya Karmakar, Khushboo Suman

AI总结 本研究探讨了温度刺激对热响应型Pluronic F127溶液相变动力学及微观结构转变的影响。通过差示扫描量热法和流变学表征,揭示了加热和冷却过程中胶束化温度、相变峰强度及软固转变行为的变化规律,并发现冷却过程中存在多步转变现象,表明其结构重排路径比传统认知更为复杂。研究还构建了描述粘弹性参数动力学的数学模型,并通过小角X射线散射实验揭示了温度升高时从无序胶束态向有序晶格态的演变过程,为热响应聚合物溶液的自组装与结构演化提供了重要的实验与理论依据。

Comments 39 pages

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英文摘要

The thermoresponsive behavior of Pluronic F127 solutions is governed by temperature-dependent micellization and complex self-assembly of these micelles. This study investigates the effect of thermal stimuli on the kinetics of phase transition of Pluronic systems during heating and cooling cycles. We employ Differential Scanning Calorimetry measurements to investigate the dependence of the micellization temperature on thermal stimuli, revealing that both the micellization temperature and the peak intensity vary systematically with the applied thermal ramp rate. Furthermore, we employ rheological characterization which reveals a sharp sol to soft-solid transition upon heating. Interestingly, we observe a novel multi-step transition during the cooling phase, indicating a more complex reorganization pathway with intermediate metastable states than typically assumed for reversible micellization. Our findings indicate that the characteristic multi-step cooling transition is transient, gradually weakening with successive thermal cycles. We also present a comprehensive mathematical model which accurately captures the kinetics and multiple step transition in viscoelastic parameters. Significantly, the distinct peaks in Small-Angle X-ray Scattering (SAXS) measurements clearly reveal the evolution from a disordered unimers/micelles state at low temperatures to a highly ordered lattice with long-range spatial correlation at elevated temperatures. We also present a comprehensive phase diagram highlighting the critical role of thermal stimuli and pathways in defining the phase behavior of Pluronic system. This work, therefore, offers essential experimental and theoretical insights into the thermally driven self-assembly, transition kinetics, and microstructural evolution of thermoreversible Pluronic solution.

2605.14562 2026-05-15 q-bio.MN cond-mat.soft

Autonomous Reshaping of Expression Landscapes by DNA Methylation

Kaifeng Wang, Ming Han

AI总结 该研究探讨了DNA甲基化在基因表达调控中的动态作用,指出其不仅是细胞身份的稳定标记,还可以作为调控动态的内部变量。通过构建最小化启动子模型和命运切换模型,研究揭示了甲基化与转录因子之间的反馈机制能够自主重塑表达景观,使细胞状态的选择更加灵活和可预测。这一发现重新定义了DNA甲基化在细胞命运决定中的角色,表明其在调控网络中具有主动塑造表达动态的重要功能。

Comments 9 pages, 4 figures

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英文摘要

DNA methylation is usually treated as an epigenetic memory mark: transcriptional history is written into regulatory DNA and later stabilizes a chosen cell identity. This picture explains persistence, but it makes memory passive. Here we show that the same promoter-level coupling required for methylation memory can instead turn methylation into an internal control variable for regulatory dynamics. Transcription-factor occupancy protects regulatory DNA from methylation, while methylation shifts later transcription-factor binding thresholds. Under time-scale separation, this reciprocal loop separates into fast expression dynamics conditioned on methylation and a slow methylation flow written by expression. Minimal promoter, self-activation, and fate-toggle models show that this feedback does more than preserve a past state: it autonomously reshapes the expression landscape. In a methylation-coupled toggle, the preferred expression state can move continuously through single-well drift, allowing commitment without first entering a multiwell regime. Stochastic simulations further show that evolving methylation reduces fate reversals relative to a frozen landscape, making weak early expression bias more predictive of later fate. These results recast DNA methylation from a downstream stabilizer of cell identity into a slow dynamical coordinate that can help determine how regulatory states are chosen.

2605.14557 2026-05-15 cond-mat.mtrl-sci

Tunable Dual-Type Weyl Points in Dirac-Weyl Semimetal CaAgBi

Shenghao Huang, Heng Gao, Hongfei Wang, Wei Ren

AI总结 本研究通过第一性原理计算,提出了一种具有可调类型I和类型II韦尔点的狄拉克-韦尔半金属材料CaAgBi。除了先前报道的沿旋转轴的三对狄拉克点外,研究还发现了分布在三个不同平面内的18对双类型韦尔点,并通过韦尔点的手性及表面费米弧验证了其拓扑特性。研究进一步表明,通过合金工程和外部应变可以调控狄拉克点和韦尔点的位置及其湮灭行为,为拓扑电子学提供了可调控的平台。

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Journal ref
Physical Review B 112 (15), 155165 Physical Review B 112 (15), 155165(2025)
英文摘要

Dirac-Weyl semimetals host both Dirac and Weyl fermions and the exploration of material candidates with tunable topological properties is essential to realize topological spintronic devices. In this work, we propose CaAgBi as a Dirac-Weyl semimetal with tunable type-I and type-II Weyl points based on first-principle calculations. In addition to the three pairs of Dirac points located along the rotational axis as previously reported, our calculations reveal 18 additional pairs of dual-type Weyl points distributed across three distinct planes: type-I in the $k_z=0$ plane and type-II in the $k_z= \pm 0.0698\,\frac{2π}{c}$ planes. The topological features are further confirmed through chirality of the Weyl points as well as the existence of surface Fermi arcs. Moreover, we find that the position and annihilation of Dirac and Weyl points are tunable by the alloy engineering and external strains. The alloy engineering is employed to modulate the positions of Weyl points, revealing different annihilation concentrations for type-I and type-II Weyl points, potentially offering novel experimental strategies for Weyl point manipulation. Under tensile biaxial strain, the Weyl points in the $k_{z}=0$ plane annihilate along the $Γ$--$\mathrm{M}$ path at $2.1\%$ strain, whereas the Weyl points in the $k_{z}\neq 0$ planes remain robust within $6\%$ strain. This work provides a versatile platform for manipulating Dirac/Weyl interactions, with spin-orbit coupling (SOC) driven alloy control and strain-selective engineering opening avenues for topological electronics.

2605.14554 2026-05-15 hep-lat hep-ph

Glue Condensate, Quark Condensate and Dirac Spectral Density

Ivan Horváth

AI总结 本文推导了胶子标量密度(胶子凝聚)在狄拉克谱密度下的正则化表达式,并探讨了其意义与应用。研究重点在于揭示胶子与夸克标量密度之间的关系,阐明其与红外相的联系,以及对对称性破缺机制和紫外与红外行为在QCD中关系的澄清。这一公式为理解强相互作用的非微扰特性提供了新的视角。

Comments 8 pages, 3 figures. Talk at 42nd International Symposium on Lattice Field Theory, TIFR, Mumbai, Nov 2-8 2025

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Journal ref
PoS LATTICE2025 (2025) 165
英文摘要

I derive the regularized formula for glue scalar density (gluon condensate) in terms of Dirac spectral density [arXiv:2509.03509], and elaborate on its uses and meaning. Particular attention is given to understanding of what this new formula reveals about the relation between glue and quark scalar densities, how it relates to IR phase, how it clarifies the distinction between anomalous and spontaneous ways of breaking symmetries, and what it says about the relation between UV and IR in QCD.

2605.14549 2026-05-15 cs.LO

CSLibPremiseBench: Structure-Guided Premise Retrieval and Label Robustness for Lean 4 Computer-Science Theorems

Junye Ji

AI总结 CSLibPremiseBench 是一个针对 Lean 4 计算机科学定理的可复现前提检索基准,旨在评估在源代码可见前提下的检索性能。该基准基于 CSLib v4.29.0 构建,包含 801 个可标记任务和 1875 个候选声明,并通过多种方法(如 BM25、符号重叠、模块优先级等)进行对比实验。研究发现,结构引导的 CSG-Rerank 方法在严格策略下略有提升,但整体表现仍有限,表明 CSLib 的前提检索高度依赖于库结构和候选策略设计。

Comments 12 pages, 10 tables; artifact available at https://doi.org/10.5281/zenodo.20176641

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英文摘要

CSLib is an emerging Lean 4 library for computer-science formalization, but its premise-retrieval behavior is not well represented by broad mathematical theorem-proving benchmarks. We introduce CSLibPremiseBench, a reproducible CSLib-specific benchmark and empirical study for source-visible premise retrieval over Lean 4 theorem and lemma declarations. The benchmark pins CSLib v4.29.0 at commit 0d37cc7fcc985cfc53b155e7eef2453f846c6da2, builds with Lean 4.29.0, and evaluates a strict import/source-order task set with 801 proxy-labelable tasks and 1875 CSLib candidate declarations. The labels are source-visible CSLib proof-reference proxies, not elaborated Lean dependency traces. We audit label robustness using stricter source-visible matching and a 300-task Lean environment expression probe, then compare BM25, symbol/name overlap, namespace/module and import-graph heuristics, PageRank-style module priors, fixed hybrids, and CSG-Rerank, a structure-guided graph-lexical reranker. CSG-Rerank gives a modest early-rank MRR gain over lexical BM25 under the strict policy, but does not reliably outperform BM25+symbol and does not improve Recall@10. A context-packet audit similarly finds stronger module/family concentration without reliable top-k proxy-gold coverage or token-utility gains. We position CSLibPremiseBench as a benchmark and audit paper: repository structure and candidate-policy design materially shape CSLib premise retrieval, proxy labels require explicit caveats, and proof-generation or proof-repair performance is not claimed.

2605.14547 2026-05-15 math.CO

A non-hereditary Pollyanna class that is not strongly Pollyanna

Hongzhang Chen, Kaiyang Lan

AI总结 本文研究了图类的Pollyanna性质及其强Pollyanna性质之间的区别。作者构造了一个非遗传的Pollyanna图类,该类对于任意的$k \ge 1$都不是$k$-强Pollyanna,从而证明了存在非强Pollyanna的Pollyanna图类。这一结果回答了Chudnovsky等人提出的开放问题,揭示了两类性质之间的本质差异。

Comments 7 pages. Any comments and suggestions are welcome

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英文摘要

Chudnovsky, Cook, Davies, and Oum introduced the notion of Pollyanna graph classes: a class $\mathcal{C}$ is Pollyanna if for every $χ$-bounded class $\mathcal{F}$, the intersection $\mathcal{C} \cap \mathcal{F}$ is polynomially $χ$-bounded. They further defined $\mathcal{C}$ to be strongly Pollyanna if it is $k$-strongly Pollyanna for some integer $k$, meaning that $\mathcal{C} \cap \mathcal{F}$ is polynomially $χ$-bounded for every $k$-good class $\mathcal{F}$. They asked whether there are Pollyanna graph classes that are not strongly Pollyanna. In this note we answer this question affirmatively, under the literal interpretation that graph classes are not required to be hereditary. We construct a class $\mathcal{C}$ that is Pollyanna but, for every $k \ge 1$, is not $k$-strongly Pollyanna; in particular $\mathcal{C}$ is not strongly Pollyanna.

2605.14545 2026-05-15 cond-mat.mtrl-sci

Biquadratic exchange coupling effect on the magnetic properties of (Fe/Ti) multilayers

Melissa Yactayo, H. S. Tarazona, O. Copie, J. -C. Rojas-Sánchez, J. Quispe-Marcatoma, C. V. Landauro

AI总结 本研究探讨了弱反铁磁耦合的Fe/Ti超晶格的静态和动态磁性能,重点分析了磁性行为与结构特征之间的关系。通过高分辨透射电镜和X射线衍射分析确认了Fe和Ti层交替排列且界面粗糙,尤其在上层更为明显。研究引入包含二阶和四阶耦合项的宏观自旋模型,成功再现了实验数据,并揭示了结构缺陷对磁耦合行为的影响,突出了四阶交换耦合在Fe/Ti/Fe多层结构中的重要作用。

Comments 6 pages, 7 figures and 2 tables

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Journal ref
2025 IEEE Latin American Conference on Nanotechnology (LANANO), 2025, pp. 1-4
英文摘要

This work explores the static and dynamic magnetic properties of weakly antiferromagnetically coupled Fe/Ti superlattices, emphasizing the link between magnetic behavior and structural characteristics. HRTEM and XRD analyses confirm alternating Fe and Ti layers with rough interfaces, especially in upper layers. Magnetic measurements reveal two-step hysteresis loops and a temperature and thickness-dependent interlayer exchange coupling (IEC). A macrospin model incorporating bilinear and biquadratic coupling reproduces the experimental data and supports a phase diagram analysis identifying non-collinear configurations. The results underscore the impact of structural imperfections and highlight the crucial role of biquadratic exchange in Fe/Ti/Fe multilayers.

2605.14541 2026-05-15 gr-qc

Particle Creation and Variable Generalized Chaplygin Gas in $\mathcal{F}(\mathcal{R},Σ,\mathcal{T})$ Gravity

N. Myrzakulov, S. H. Shekh, Anirudh Pradhan, M. Zeyauddin

AI总结 本文研究了在广义 $\mathcal{F}(\mathcal{R},Σ,\mathcal{T})$ 引力框架下,包含引力诱导粒子产生和可变广义 Chaplygin 气体的平坦弗里德曼-勒梅特-罗伯逊-沃克宇宙的宇宙学动力学。通过引入开放热力学描述和可变暗能量模型,修正了标准宇宙演化过程,并利用超新星和哈勃数据对模型参数进行了限制。研究结果表明,该模型在热力学性质和宇宙学行为上均表现出良好的一致性,为晚期加速宇宙提供了可行的几何描述。

Comments 17 pages, 6 figures

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英文摘要

In this work, we investigate the cosmological dynamics of a spatially flat Friedmann--Lemaître--Robertson--Walker Universe in the framework of generalized \( \mathcal{F}(\mathcal{R},Σ,\mathcal{T}) \) gravity by incorporating gravitationally induced particle creation together with the variable generalized Chaplygin gas scenario. The modified gravitational action depends explicitly on the Ricci scalar \( \mathcal{R} \), the matter-coupling scalar \( Σ\), and the trace of the energy--momentum tensor \( \mathcal{T} \), which collectively generate significant corrections to the standard cosmological evolution. The particle creation mechanism is introduced through an open thermodynamic description of the Universe. In addition, the dark sector is modeled using the variable generalized Chaplygin gas formalism. To examine the observational consistency of the model, the free parameters are constrained using the Pantheon\(^+\) Type Ia Supernova compilation together with the combined observational Hubble and Pantheon\(^+\) datasets through a statistical \(χ^2\)-analysis. The cosmological behavior of the model is further explored through the evolution of the cosmological parameters. Furthermore, the thermodynamic properties of the model are investigated using the apparent horizon formalism. The obtained results demonstrate that the entropy evolution remains physically consistent throughout the cosmic evolution. Hence, the present \( \mathcal{F}(\mathcal{R},Σ,\mathcal{T}) \) gravity framework with particle creation provides a viable geometrical description of the late-time accelerated Universe and remains compatible with recent cosmological observations.

2605.14540 2026-05-15 cs.DC

Analysis of wireless network access logs for a hierarchical characterization of user mobility

Francisco Talavera, Isaac Lera, Carlos Guerrero

AI总结 本文提出了一种基于Wi-Fi连接数据生成用户移动性分层模型的方法,通过分析用户经过的接入点序列,结合地理空间特征将接入点递归分组,构建多层级的区域划分。该方法利用聚类算法进行用户分型,并为每类用户定义区域间的转移矩阵和停留时间向量,旨在降低大规模场景下的模型复杂度并提升对不同地理特征场景的适应性。实验应用于巴利阿里群岛大学校园,结果显示分层模型在复杂度和转移矩阵准确性方面优于非分层模型,但时间向量的定义仍有改进空间。

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Journal ref
Journal of King Saud University - Computer and Information Sciences, Volume 34, Issue 6, Part A, 2022, Pages 2471-2487, ISSN 1319-1578
英文摘要

This paper presents a method that generates a hierarchical user mobility model from the analysis of the data available from Wi-Fi connections. The data obtained from the Wi-Fi infrastructure is defined in terms of the coverage areas of the access points that the users move through. These access points are recursively grouped into different levels of granularity based on their geospatial features. The track of a user is defined as a sequence of Wi-Fi access points, which is enough to simulate user mobility in, for example, fog scenarios. The hierarchical definition of the region under study is proposed to reduce the complexity of the model in high-scale scenarios and to increase the adaptability between scenarios with different geospatial features. The model creation is based on a user profiling method that uses a clustering algorithm and each user type is defined with a transition matrix between coverage areas and a time length vector for the areas. The method is applied to the case of the campus of the University of the Balearic Islands. From the analysis of the mean square error of the results, we determined that the proposed method obtains good results for the transition matrices, but that the time vector definition should be improved. The results also show lower complexity in the case of the hierarchical model, with one area for each building and three levels, in regard to a non-hierarchical model, with only one area and one level for the whole campus.

2605.14538 2026-05-15 quant-ph

Are free choices absolute, when internalized in Wigner's friend?

Laurens Walleghem

AI总结 本文探讨了在量子力学框架下,当将自由选择内化到“维格纳的朋友”思想实验中时,自由选择的绝对性是否依然成立。作者基于扩展的维格纳朋友场景和普赛-巴雷特-鲁道夫定理,提出了一个挑战自由选择绝对性的论证。研究在局域性假设下,揭示了不同观察者之间在量子系统中进行一致推理时可能存在的矛盾,为理解量子观测与自由意志的关系提供了新的视角。

Comments 6+2 pages, all comments welcome!

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英文摘要

Wigner's thought experiment illustrates quantum theory's measurement problem by considering an observer who measures a quantum system inside a sealed lab, modeled unitarily by an outsider. Recent extensions of this thought experiment, referred to as extended Wigner's friend arguments, question how different observers can reason consistently about each other in quantum setups, and challenge the absoluteness of the outcome value obtained by the friend under a notion of locality. In this work, we present an argument against the absoluteness of free choices under the same notion of locality, using an extended Wigner's friend scenario based on the Pusey--Barrett--Rudolph theorem. Similar arguments based on other contextuality or nonlocality models are possible.

2605.14536 2026-05-15 math.AT math.AG math.CO

Non-vanishing of homotopy groups of Manin--Schechtman arrangements

Takuya Saito, So Yamagata

AI总结 本文研究了Manin-Schechtman超平面排列的拓扑性质,探讨其补空间是否为$K(π,1)$空间这一核心问题。通过证明这些排列的补空间具有非平凡的高阶同伦群,作者指出在多数情况下这类排列并非$K(π,1)$空间,从而揭示了其拓扑结构的复杂性。这一结果丰富了对高维排列拓扑性质的理解。

Comments 30 pages, 5 figures. Comments are welcome

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英文摘要

One of the central problems in the topology of hyperplane arrangements is determining whether the complement is a $K(π,1)$-space. In this paper, we study Manin--Schechtman arrangements, introduced as higher-dimensional analogs of the braid arrangement, and prove that their complements have non-vanishing higher homotopy groups. Consequently, these arrangements fail to be $K(π,1)$ in a broad range of cases.

2605.14533 2026-05-15 cond-mat.mtrl-sci

Methane hydrate nucleation frustration and dimensional reduction of structural order under nanoconfinement

Jose Torres-Arenas, Ángel M. Fernández-Fernández, Martín Pérez-Rodríguez, Manuel M. Piñeiro

AI总结 本研究探讨了甲烷水合物在纳米限制条件下的成核行为,揭示了几何约束与分子有序化之间的复杂相互作用。通过分析不同孔径和温度下的水-甲烷体系,发现强限制条件下(孔径小于2纳米)水合物类结构有序性受到显著抑制,表明成核受阻;而二维投影相关性则显示出明显的平面结构有序性,说明纳米限制导致分子有序维度降低。这一发现为理解受限空间中水合物形成机制提供了新的视角。

Comments 4 pages , 3 figures

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英文摘要

Methane hydrate nucleation under nanoconfinement remains poorly understood due to the complex interplay between geometric restriction and molecular ordering. Here, we investigate the structural organization of water-methane systems confined between silica planar slit pores with widths ranging from 1 to 5 nm and temperatures between 250 and 295 K. Three-dimensional radial distribution functions reveal a clear suppression of hydrate-like ordering at strong confinement (below 2 nm), indicating frustrated nucleation. In contrast, projected two-dimensional correlations exhibit pronounced in-plane structural organization, evidencing a confinement-induced reduction in the dimensionality of molecular order.

2605.14532 2026-05-15 gr-qc hep-th

Consistency in the Quantum-Improved Charged Black Holes

Chiang-Mei Chen, Akihiro Ishibashi, Nobuyoshi Ohta

AI总结 本文研究了具有尺度依赖耦合的量子改进带电黑洞在热力学和场方程层面的一致性问题。通过分析量子改进的赖斯纳-诺德斯特伦黑洞,发现热力学一致性允许牛顿和电磁耦合随径向坐标任意变化,并指出在尺度依赖电磁耦合下化学势存在细微问题。研究还表明,爱因斯坦方程在场方程和作用量层面与比安奇恒等式兼容需要引入额外的量子能量-动量张量,并要求牛顿耦合满足特定性质。最后将分析扩展到宇宙学解,表明量子诱导修正可能驱动早期宇宙的各向同性化。

Comments 15 pages, no figures

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英文摘要

We investigate the consistency in the thermodynamics and the approaches at the equation and action levels for the quantum-improved charged black holes with scale-dependent couplings. For the quantum-improved Reissner-Nordström black holes, we find that the thermodynamic consistency allows both the Newton and electromagnetic couplings to have arbitrary dependence on the radial coordinate. We point out a subtlety in the chemical potential with the scale-dependent electromagnetic coupling in the study of thermodynamics. We also examine the compatibility of the Einstein equations at the equation and action levels with the Bianchi identity, identifying the need for an additional quantum energy-momentum tensor. We then find that the consistency between the approaches at the equation and action levels requires that the Newton coupling satisfy certain property. Finally, we extend the analysis to cosmological solutions, suggesting that quantum-induced modifications can drive the isotropization of the early universe.

2605.14529 2026-05-15 quant-ph physics.atom-ph

Quantum-enabled complete RF-polarimetry with an optically-wired atomic sensor

Matthew Chilcott, Laurits N. Stokholm, Matthew Cloutman, J. Susanne Otto, Amita B. Deb, Niels Kjærgaard

AI总结 该研究利用里德伯原子传感器实现了无需校准的完整射频偏振测量,通过光学读取方式将射频场的极化状态映射到庞加莱球上。研究提出了一种基于原子能级分裂的普适性方法,能够连续追踪不同极化状态下原子本征能量谱的变化,无需依赖具体设备参数。该方法在铷原子中的实验验证表明其具有通用性和高灵敏度,适用于所有具有单价电子的体系。

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英文摘要

Rydberg atomic electrometry leverages the extreme sensitivity of highly excited atoms for calibration-free electric field measurements. The technique uses a non-metallic vapor cell to link properties of an RF field to a spectroscopic readout in the optical domain. Most demonstrations have so far focused on detecting linearly-polarized fields, for which the induced splitting of dressed atomic levels is rotationally invariant. Here we report on Rydberg atomic measurements of RF fields in a general state of polarization (SOP) which we map onto the Poincaré sphere through spectroscopic fingerprints. For a Stokes vector circumnavigating a Poincaré sphere meridian, we witness a continuous transformation of the atomic eigenenergy spectrum. Because the relative positions of eigenenergies are locked in place by quantization of angular momentum, the framework is universal and calibration free. We provide a specific demonstration in rubidium, which generalizes to all systems with a single valence electron.

2605.14523 2026-05-15 quant-ph

HQTN-SER: Speech Emotion Recognition with Hybrid Quantum Tensor Networks

Mahad Mohtashim, Nouhaila Innan, Muhammad Shafique

AI总结 该论文提出了一种名为HQTN-SER的混合量子经典框架,用于解决语音情感识别(SER)在真实环境下因情感线索细微、说话人依赖性强以及录音条件变化大而表现不稳定的问题。其核心方法是引入基于矩阵乘积态(MPS)的量子张量网络模块,以少量可训练参数建模语音表示中的相关性,并结合量子测量特征与经典潜在嵌入进行端到端情感分类。实验表明,该模型在三个公开数据集上取得了稳定的高识别准确率,验证了结构化量子模块在量子辅助情感计算中的有效性与可行性。

Comments 9 pages, 5 figures

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英文摘要

Speech emotion recognition (SER) remains fragile in real-world conditions because emotional cues are subtle, speaker-dependent, and easily confounded by recording variability, while high-performing deep models typically rely on large and carefully curated training sets. Quantum machine learning offers an alternative way to introduce nonlinear correlation modeling with compact modules, yet existing quantum SER studies remain limited and the impact of circuit structure is not well understood. This paper presents HQTN-SER, a hybrid quantum-classical framework that investigates how quantum tensor network connectivity can support SER under small-qubit settings. HQTN-SER introduces (i) an MPS-inspired quantum tensor network module that enforces structured interactions to model correlations in speech representations with a small number of trainable parameters, and (ii) a fusion strategy that combines quantum measurement features with a learned classical latent embedding for end-to-end emotion classification. We evaluate HQTN-SER on three public benchmarks (RAVDESS, SAVEE, and MDER) under a unified preprocessing and training protocol. The proposed model achieves consistent performance across datasets, RAVDESS = 80.12%, SAVEE = 78.26% and MDER = 73.51% accuracy, with stable convergence and low qubit counts, showing that tensor network structure can be an effective and hardware-aware design choice for quantum-assisted SER. The results provide a reproducible baseline and clarify when structured quantum modules can add value to affective computing today.

2605.14522 2026-05-15 cond-mat.stat-mech cond-mat.dis-nn

Matrix-Product Belief Propagation for continuous-state-space variables

Federico Florio, Alfredo Braunstein

AI总结 本文提出了一种适用于连续或混合连续/离散状态空间模型的矩阵乘积信念传播方法,通过在希尔伯特函数基上进行可调节的展开,实现了对大规模稀疏网络中可观测量的半解析估计。该方法计算成本与网络规模成线性关系,其效率通过傅里叶基在混合连续/离散的动能伊辛模型中的应用得到验证,并与蒙特卡洛模拟结果进行了对比,展示了其在时间自相关、能量和磁化演化以及磁化大偏差函数计算中的准确性。

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英文摘要

Computation of observables in discrete stochastic, possibly conditioned, dynamics over large sparse networks is at the basis of a myriad of applications. The Matrix-Product Belief Propagation method allows a semi-analytical estimation of such observables with a controlled error that depends on the size of the employed matrices, called bond size. Its computational cost is linear in the time horizon and the network size for a large family of models with discrete degrees of freedom. Here, a generalization of this method to models with continuous or mixed continuous/discrete degrees of freedom is presented, using a tunable expansion in a Hilbert function basis. The computational cost of the method is linear in the network size with a prefactor that depends on the basis size and the bond size. The method's efficacy is demonstrated by employing a Fourier basis for a mixed continuous/discrete representation of the Kinetic Ising dynamics with real-valued random couplings, where intermediate ``local fields'' are treated as continuous. The accuracy of the method is verified via comparison with Monte-Carlo simulations. For this model, we calculate time auto-correlations, time evolution of energy and magnetization, and finally we estimate the large deviation function of the magnetization at a given future time.

2605.14520 2026-05-15 math.AP

Runaway avalanches in plasmas with external electric fields: spatially inhomogeneous case in a perturbation framework

Ling-Bing He, Richard M. Höfer, Jie Ji, Raphael Winter

AI总结 本文研究了在外部电场作用下氢等离子体中逃逸电子的形成机制,这类电子虽持续加速却仅导致等离子体温度的微小增长,对核聚变反应堆构成严重威胁。通过严格的数学分析,论文证明了开系统Landau-Coulomb方程在扰动框架下的适定性,并揭示了平均速度随时间线性增长、温度呈对数增长的精确行为。研究还表明电子分布最终趋于散射型麦克斯韦分布,并通过微宏观分解方法分析了电子-电子与电子-离子相互作用的不同耗散结构。

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英文摘要

We consider the Landau-Coulomb equation for a (hydrogen) plasma heated by an external electric field. In this setting, theoretical and experimental results in plasma physics show the emergence of so-called \emph{runaway electrons} which are linearly accelerating but only lead to a minimal increase of the plasma temperature. Runaway electrons are a major obstacle in nuclear fusion since they can overcome the confinement and damage the structure of the reactor. We rigorously prove the well-posedness of the underlying nonlinear \emph{open} Landau-Coulomb system in a perturbative setting and the conjectured growth bounds for the mean velocity and plasma temperature. We show that the mean velocity is linearly increasing in time, and capture the sharp logarithmic growth of the temperature. Furthermore, we prove that the electron distribution can be asymptotically described by a scattering-type Maxwellian. Due to the different nature of the electron-electron and electron-ion interactions, we recast the equation as a novel coupled system that allows us to isolate the dissipation structures of the two operators. For the coupled system, we perform a micro-macro decomposition to show convergence to the scattering-type Maxwellian.

2605.14516 2026-05-15 cond-mat.soft physics.bio-ph

A Brownian dynamics study of liquid-liquid phase separation in multi-scale chromatin networks

Léa Beaulès, Judith Miné-Hattab, Pierre Illien, Vincent Dahirel

AI总结 本研究通过布朗动力学模拟,探讨了多尺度染色质网络环境中液-液相分离(LLPS)凝聚体的形态与空间组织规律。研究结合伦纳德-琼斯粒子模型与固定纤维基底,分析了局部纤维几何结构与整体网络组织对凝聚体大小、形态及数量的影响,揭示了蛋白-纤维相互作用在凝聚体定位中的关键作用。结果表明,染色质环境的多尺度结构异质性在调控生物分子凝聚体的形成与空间分布中起着重要作用。

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英文摘要

In living cells, proteins involved in specialized biochemical functions are often spatially organized within biomolecular condensates. Increasing evidence suggests that some of these condensates, including DNA repair condensates, emerge through liquid-liquid phase separation (LLPS). In the nucleus, however, condensates form within a highly heterogeneous environment composed of chromatin fibers, RNA, and additional protein scaffolds such as PAR chains, all of which may interact with phase-separating proteins. Moreover, condensate formation is frequently associated with specific chromatin conformations; for instance, loop extrusion has been proposed as a mechanism promoting DNA repair condensates. Here, we investigate how the surrounding fibrous environment controls the morphology and spatial organization of phase-separated condensates. Using Brownian dynamics simulations of minimal models combining Lennard-Jones particles with fixed fibrous substrates, we examine the respective roles of local fiber geometry and large-scale network organization, reflecting the multiscale architecture of chromatin. We show that protein-fiber interactions strongly influence droplet positioning relative to the substrate, in a manner analogous to wetting transitions in soft condensed matter systems. Both local geometric constraints and global network organization markedly affect droplet size, morphology, and multiplicity. In addition, large-scale asymmetries in fiber organization can induce robust spatial localization of the dense phase. Our results thus highlight how multiscale structural heterogeneity of the nuclear environment can regulate the emergence and organization of biomolecular condensates.

2605.14515 2026-05-15 quant-ph

Spin chirality across quantum state copies detects hidden entanglement

Patrycja Tulewicz, Karol Bartkiewicz, Franco Nori

AI总结 该研究探讨了量子纠缠的两种隐藏方式,并提出了一种基于自旋手性关联的新型检测方法。通过分析多副本量子态之间的关联,研究发现手性-手性关联量能够精确分解多副本纠缠与纯度之间的差异,揭示了多副本纠缠检测所依赖的物理结构。基于此,研究构建了一个多通道光谱分类器,实现了对绑定纠缠态的高精度识别,并在实验中验证了其有效性,展示了在实际量子处理器上的优异性能。

Comments Main text: 16 pages, 3 figures. Supplementary Information: 46 pages, 12 figures, 18 tables

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英文摘要

Entanglement can hide in two fundamentally different ways. First, multi-copy correlations can carry information that no single-copy measurement on an unknown state is able to access. Second, bound entangled states possess a positive partial transpose, which makes them invisible to the Peres-Horodecki criterion and all moment inequalities that depend on it. Here we show that the moment difference between the partial transpose and purity decomposes exactly as a chirality-chirality correlator, where the relevant operator is the scalar spin chirality -- the same quantity that governs chiral spin liquids and the topological Hall effect. This decomposition identifies the specific physical structure that multi-copy entanglement detection probes. Using the same controlled-SWAP circuits, we develop a multi-channel spectral classifier for bound entanglement. The classifier combines realignment spectral features with chirality corrections and achieves 99.9% recall at zero false positives across all three known 3x3 bound entangled families, compared with ~40% for the CCNR criterion alone. We also introduce a marginal-noise construction that produces CCNR-invisible bound entangled states, which the classifier detects but which remain invisible to all single-parameter criteria. We validate our approach experimentally on three IBM Quantum processors and demonstrate negativity reconstruction with mean errors of 0.002-0.027, chirality detection for pure and mixed entangled states, and bound entanglement detection across two structurally distinct families (Horodecki and chessboard) on a single gate-based superconducting processor.

2605.14514 2026-05-15 cs.CR

Defenses at Odds: Measuring and Explaining Defense Conflicts in Large Language Models

Xiangtao Meng, Wenyu Chen, Chuanchao Zang, Xinyu Gao, Jianing Wang, Li Wang, Zheng Li, Shanqing Guo

AI总结 该研究探讨了在大型语言模型中,不同防御措施在连续部署时可能产生的冲突问题。作者系统评估了多种防御组合在不同顺序下的效果,发现部分防御顺序会导致原有防护能力下降,并通过机制分析揭示了防御冲突的成因。研究还提出了一种基于层冲突度的轻量级缓解方法,能够在不损害后续防御性能的前提下,保留先前的防护效果。

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英文摘要

Large Language Models (LLMs) deployed in high-stakes applications must simultaneously manage multiple risks, yet existing defenses are almost exclusively evaluated in isolation under a one-shot deployment assumption. In practice, providers patch models incrementally throughout their lifecycle-responding to newly exposed vulnerabilities or targeted data-removal requests without retraining from scratch. This raises a fundamental but underexplored question: does a later defense preserve the protections established by an earlier one? We present the first systematic study of cross-defense interactions under sequential deployment. Evaluating 144 ordered sequences across three risk dimensions and three model families, we find that 38.9% exhibit measurable risk exacerbation on the originally defended dimension. These interactions are highly asymmetric and order-dependent. To explain these phenomena, we conduct a mechanistic analysis on representative deployment sequences. Using layer-wise representational divergence and activation patching, we localize each defense to a compact set of critical layers. In conflicting sequences, the overlapping critical layers exhibit strongly anti-aligned parameter updates, whereas benign orderings maintain near-orthogonal updates. PCA trajectory analysis reveals that defense collapse stems from activation pattern reversals in these shared layers. We further introduce a layer-wise conflict score that quantifies the geometric tension between defense-induced activation subspaces, offering mechanistic insight into the observed reversals. Guided by this diagnosis, we propose conflict-guided layer freezing, a lightweight mitigation that selectively freezes high-conflict layers during sequential deployment, preserving prior protections without degrading secondary defense performance.