arXivDaily arXiv每日学术速递 周一至周五更新
重置
全部学科分类 1260
2604.02793 2026-04-06 quant-ph cs.CC

Parity $\notin$ QAC0 $\iff$ QAC0 is Fourier-Concentrated

Lucas Gretta, Meghal Gupta, Malvika Raj Joshi

详情
英文摘要

A major open problem in understanding shallow quantum circuits (QAC$^0$) is whether they can compute Parity. We show that this question is solely about the Fourier spectrum of QAC$^0$: any QAC$^0$ circuit with non-negligible high-level Fourier mass suffices to exactly compute PARITY in QAC$^0$. Thus, proving a quantum analog of the seminal LMN theorem for AC$^0$ is necessary to bound the quantum circuit complexity of PARITY. In the other direction, LMN does not fully capture the limitations of AC$^0$. For example, despite MAJORITY having $99\%$ of its weight on low-degree Fourier coefficients, no AC$^0$ circuit can non-trivially correlate with it. In contrast, we provide a QAC$^0$ circuit that achieves $(1-o(1))$ correlation with MAJORITY, establishing the first average-case decision separation between AC$^0$ and QAC$^0$. This suggests a uniquely quantum phenomenon: unlike in the classical setting, Fourier concentration may largely characterize the power of QAC$^0$. PARITY is also known to be equivalent in QAC$^0$ to inherently quantum tasks such as preparing GHZ states to high fidelity. We extend this equivalence to a broad class of state-synthesis tasks. We demonstrate that existing metrics such as trace distance, fidelity, and mutual information are insufficient to capture these states and introduce a new measure, felinity. We prove that preparing any state with non-negligible felinity, or derived states such as poly(n)-weight Dicke states, implies PARITY $\in$ QAC$^0$.

2604.02792 2026-04-06 cs.CY cs.HC

Generative AI Use in Professional Graduate Thesis Writing: Adoption, Perceived Outcomes, and the Role of a Research-Specialized Agent

Kenji Saito, Rei Tajika, Satoru Shibuya, Hiroshi Kanno

Comments 11 pages, 5 figures

详情
英文摘要

This paper reports a survey of generative AI use among 83 MBA thesis students in Japan (target population 230; 36.1% response rate), conducted after thesis examiner evaluation. AI use was nearly universal: 95.2% reported at least some use and 77.1% heavy use. Students engaged AI across the full research-writing workflow - literature review, drafting, and consultation when stuck - reporting benefits centered on clearer argument and structure (82.3%), better revision quality (73.4%), and faster writing (70.9%), with a mean perceived quality improvement of 6.27 out of 7. Concerns about output accuracy (75.9%) and citation handling persisted alongside these gains. Among respondents who rated GAMER PAT, a research-specialized agent, against other AI, preferences significantly favored it for inquiry deepening and structural organization (both p < 0.05, exact binomial). A preliminary qualitative analysis of follow-up interviews further reveals active epistemic vigilance strategies and differentiated tool use across thesis phases. The central implication is not adoption itself but a shift in the educational challenge toward verification, source governance, and AI tool design - with GAMER PAT offering preliminary evidence that research-specialized scaffolding matters.

2604.02791 2026-04-06 cs.MA cs.SY eess.SY

Fully Byzantine-Resilient Distributed Multi-Agent Q-Learning

Haejoon Lee, Dimitra Panagou

Comments 8 pages, 3 figures, submitted to 2026 IEEE Conference on Decision and Control (CDC)

详情
英文摘要

We study Byzantine-resilient distributed multi-agent reinforcement learning (MARL), where agents must collaboratively learn optimal value functions over a compromised communication network. Existing resilient MARL approaches typically guarantee almost sure convergence only to near-optimal value functions, or require restrictive assumptions to ensure convergence to optimal solution. As a result, agents may fail to learn the optimal policies under these methods. To address this, we propose a novel distributed Q-learning algorithm, under which all agents' value functions converge almost surely to the optimal value functions despite Byzantine edge attacks. The key idea is a redundancy-based filtering mechanism that leverages two-hop neighbor information to validate incoming messages, while preserving bidirectional information flow. We then introduce a new topological condition for the convergence of our algorithm, present a systematic method to construct such networks, and prove that this condition can be verified in polynomial time. We validate our results through simulations, showing that our method converges to the optimal solutions, whereas prior methods fail under Byzantine edge attacks.

2604.02789 2026-04-06 cond-mat.dis-nn

Dense Associative Memory with biased patterns: a Replica Symmetric analysis

Linda Albanese, Andrea Alessandrelli, Federico Carella

详情
英文摘要

We investigate dense higher-order associative memories in the high storage regime when the stored patterns are biased, namely when the entries of the patterns are not symmetrically distributed around zero. In this setting, the standard Hebbian prescription must be modified by recentering and rescaling the pattern entries, and an additional term must be introduced in the Hamiltonian to enforce consistency between the average activity of the network and that of the stored patterns. As a first step, we perform a signal-to-noise analysis in the zero-temperature limit and show that the bias reduces the effective storage capacity through a multiplicative correction factor (1-b^2)^P, while preserving the superlinear scaling with the system size. We then derive the quenched statistical pressure within the Replica Symmetric framework by means of Guerra's interpolation method and obtain the corresponding self consistency equations for the relevant order parameters. The analytical treatment confirms the heuristic prediction of the signal-to-noise argument, showing that the same bias dependent renormalization naturally emerges in the variance of the cross-talk noise. Finally, we discuss the resulting phase behavior of the model and its implications for retrieval performance in the model.

2604.02782 2026-04-06 astro-ph.HE nucl-th

Spin effects in superfluidity, neutron matter and neutron stars

Armen Sedrakian, Peter B. Rau

Comments Invited review article for Science Advances, 24 pages, 7 figures

详情
英文摘要

We review selected aspects of the interior physics of compact stars, focusing on the microscopic and macroscopic manifestations of spin, magnetic fields, and nucleonic superfluidity and superconductivity. Spin statistics of fermions allows quantum degeneracy pressure to determine the stability and global properties of neutron stars, whose structure depends sensitively on the strong interactions among baryons in dense matter. Using a generic meta-modeling framework based on an expansion of the nuclear energy density around the isospin-symmetric and saturation-density limits, we highlight how various lesser-known terms in this expansion affect compact-star observables and review multimessenger constraints on mass, radius, and moment of inertia. The influence of magnetic fields on dense matter is examined, showing that substantial effects in their structure require extremely strong fields, whereas lower fields are sufficient to affect their superfluid phases. At the mesoscopic scale, the coexistence of superfluid and superconducting components features vortex and flux-tube lattices, with pinning and mutual friction processes playing central roles in neutron-star rotational dynamics. We discuss unresolved issues concerning vortex structure, flux-tube configurations, and the origin of pulsar glitches and post-glitch relaxation. We also briefly address the possible emergence of deconfined quark phases in compact-star cores, including their color-superconducting properties, as well as the associated vortex structures and magnetic-field responses in such phases.

2604.02777 2026-04-06 hep-th gr-qc hep-lat nucl-th quant-ph

Quantum Information Dynamics of QED$_2$ in Expanding de Sitter Universe

Kazuki Ikeda, Yaron Oz

Comments 23 pages, 3 figures

详情
英文摘要

We study QED$_2$ in de Sitter space as a minimal interacting gauge theory in which cosmological expansion directly competes with quantum dynamics. In cosmic time, the hopping redshifts as $1/a(t)$ while the electric term grows as $g^2 a(t)$, sweeping the spectrum through a moving narrow-gap region in the $(τ,m)$ plane. Exact diagonalization shows that this defines a pseudo-critical line governing the loss of adiabaticity, excitation growth, and redshifted response. Using matrix-product states at a fixed mass, we separate the fixed-cutoff thermodynamic limit from the continuum extrapolation. The late-time dip survives in the infinite physical box size limit, and shifts to later $τ$ as the lattice spacing goes to zero, with current data favoring $τ_* \approx 3.1$, while the dip depth remains less controlled. For Gibbs initial states, the same mechanism produces an irreversibility front in the relative entropy that tracks the pseudo-critical line and is detectable via LOCC-accessible observables. These results identify de Sitter QED$_2$ as a controlled setting for linking curved-space gauge dynamics, near-critical spectral structure, and operational irreversibility.

2604.02776 2026-04-06 cs.SE

Evaluating the Environmental Impact of using SLMs and Prompt Engineering for Code Generation

Md Afif Al Mamun, Sayan Nath, Gias Uddin, Novarun Deb

Comments 12 pages

详情
英文摘要

The shift from cloud-hosted Large Language Models (LLMs) to locally deployed open-source Small Language Models (SLMs) has democratized AI-assisted coding; however, it has also decentralized the environmental footprint of AI. While prompting strategies - such as Chain-of-Thought and ReAct - serve as external mechanisms for optimizing code generation without modifying model parameters, their impact on energy consumption and carbon emissions remains largely invisible to developers. This paper presents the first systematic empirical study investigating how different prompt engineering strategies in SLM-based code generation impact code generation accuracy alongside sustainability factors. We evaluate six prominent prompting strategies across 11 open-source models (ranging from 1B to 34B parameters) using the HumanEval+ and MBPP+ benchmarks. By measuring Pass@1 accuracy alongside energy (kWh), carbon emissions (kgCO2eq), and inference latency, we reveal that sustainability often decouples from accuracy, allowing significant environmental optimizations without sacrificing performance. Our findings indicate that Chain-of-Thought, being a simpler prompting technique, can provide a near-optimal balance between reasoning capability and energy efficiency. Conversely, multi-sampling strategies often incur disproportionate costs for marginal gains. Finally, we identify grid carbon intensity as the dominant factor in deployment-time emissions, highlighting the need for practitioners to consider regional energy profiles. This work provides a quantitative foundation for "green" prompt engineering, enabling developers to align high-performance code generation with ecological responsibility.

2604.02774 2026-04-06 cs.CR cs.NI

Open Challenges for Secure and Scalable Wi-Fi Connectivity in Rural Areas

Philip Virgil Berrer Astillo, Jayasree Sengupta, Mathy Vanhoef

Comments 7 pages, 2 figures and 2 tables; Accepted for publication at SPAIC, AsiaCCS Workshops 2026

详情
英文摘要

Providing reliable, affordable, and secure Internet connectivity in rural areas remains a major challenge. Pay-for-use Wi-Fi hotspots are emerging as a scalable solution to provide affordable Internet access in underserved and rural regions. Despite their growing adoption, their security properties remain largely unexplored. In this paper, we present a security analysis of these hotspot ecosystems based on Wi-Fi surveys and practical attack validation. We first perform a Wi-Fi survey conducted in two countries, namely the Philippines and India, to understand the deployment and adoption of such systems in practice. Our results suggest that Piso-WiFi pay-to-use hotspots are particularly widespread in rural regions of the Philippines, and that India's PM-WANI initiative is slowly gaining traction. We then perform a security assessment of these deployments and demonstrate two practical attacks: hijacking another user's paid connection; and rogue hotspots. We analyze the root causes of these vulnerabilities, introduce threat models tailored to pay-for-use hotspot deployments, and outline practical security improvements, including a secure caching architecture. Our findings highlight security challenges in emerging rural connectivity infrastructure and provide directions toward more secure and scalable deployments.

2604.02771 2026-04-06 cs.CR

ContractShield: Bridging Semantic-Structural Gaps via Hierarchical Cross-Modal Fusion for Multi-Label Vulnerability Detection in Obfuscated Smart Contracts

Minh-Dai Tran-Duong, Nguyen Hai Phong, Nguyen Chi Thanh, Doan Minh Trung, Tram Truong-Huu, Van-Hau Pham, Phan The Duy

Comments 9 figures, 8 tables, 16 pages

详情
英文摘要

Smart contracts are increasingly targeted by adversaries employing obfuscation techniques such as bogus code injection and control flow manipulation to evade vulnerability detection. Existing multimodal methods often process semantic, temporal, and structural features in isolation and fuse them using simple strategies such as concatenation, which neglects cross-modal interactions and weakens robustness, as obfuscation of a single modality can sharply degrade detection accuracy. To address these challenges, we propose ContractShield, a robust multimodal framework with a novel fusion mechanism that effectively correlates multiple complementary features through a three-level fusion. Self-attention first identifies patterns that indicate vulnerability within each feature space. Cross-modal attention then establishes meaningful connections between complementary signals across modalities. Then, adaptive weighting dynamically calibrates feature contributions based on their reliability under obfuscation. For feature extraction, ContractShield integrates (1) CodeBERT with a sliding window mechanism to capture semantic dependencies in source code, (2) Extended long short-term memory (xLSTM) to model temporal dynamics in opcode sequences, and (3) GATv2 to identify structural invariants in control flow graphs (CFGs) that remain stable across obfuscation. Empirical evaluation demonstrates resilience of ContractShield, achieving a 89 percentage Hamming Score with only a 1-3 percentage drop compared to non-obfuscated data. The framework simultaneously detects five major vulnerability types with 91 percentage F1-score, outperforming state-of-the-art approaches by 6-15 percentage under adversarial conditions.

2604.02769 2026-04-06 cond-mat.str-el

Semiclassical representation of the Hubbard model

Yuki Yamasaki, Hidemaro Suwa, Cristian D. Batista, Shintaro Hoshino

Comments 21 pages, 5 figures

详情
英文摘要

By revisiting the path-integral formulation of the Hubbard model, we propose a theoretical approach based on a semiclassical approximation employing an unconventional coherent-state representation. Within this framework, a subset of the dynamical variables is treated as static, yielding a nonperturbative scheme that is applicable at finite temperature, incorporates intersite correlations, and can be naturally extended to multiorbital systems. We assess the validity of the approximation by comparing its results with exact solutions for one- and two-site systems, focusing in particular on the particle number, double occupancy, hopping amplitude, and spin correlations, and find that the present approach qualitatively reproduces the exact behavior. Quantitatively, deviations arise, which is associated with the continuum (non-discretized) character of the underlying density of states. Furthermore, we derive the exact transformation associated with the coherent-state construction, thereby providing additional insight into the representation of the Hubbard model.

2604.02768 2026-04-06 eess.SY cs.SY

Rollout-Based Charging Scheduling for Electric Truck Fleets in Large Transportation Networks

Ting Bai, Xinfeng Ru, Shaoyuan Li, Andreas A. Malikopoulos

详情
英文摘要

In this paper, we investigate the charging scheduling optimization problem for large electric truck fleets operating with dedicated charging infrastructure. A central coordinator jointly determines the charging sequence and power allocation of each truck to minimize the total operational cost of the fleet. The problem is inherently combinatorial and nonlinear due to the coupling between discrete sequencing decisions and continuous charging control, rendering exact optimization intractable for real-time implementation. To address this challenge, we propose a rollout-based dynamic programming framework built upon an inner-outer two-layer structure, which decouples ordering decisions from the schedule optimization, thus enabling efficient policy evaluation and approximation. The proposed method achieves near-optimal solutions with polynomial-time complexity and adapts to dynamic arrivals and time-varying electricity prices. Simulation studies show that the rollout-based approach significantly outperforms conventional heuristics with high computational efficiency, demonstrating its effectiveness and practical applicability for real-time charging management in large-scale transportation networks.

2604.02762 2026-04-06 math.OC cs.SY eess.SY

A Canonical Structure for Constructing Projected First-Order Algorithms With Delayed Feedback

Mengmou Li, Yu Zhou, Xun Shen, Masaaki Nagahara

Comments submitted to CDC2026

详情
英文摘要

This work introduces a canonical structure for a broad class of unconstrained first-order algorithms that admit a Lur'e representation, including systems with relative degree greater than one, e.g., systems with delayed gradient feedback. The proposed canonical structure is obtained through a simple linear transformation. It enables a direct extension from unconstrained optimization algorithms to set-constrained ones through projection in a Lyapunov-induced norm. The resulting projected algorithms attain the optimal solution while preserving the convergence rates of their unconstrained counterparts.

2604.02761 2026-04-06 cs.SE

Sustainability Analysis of Prompt Strategies for SLM-based Automated Test Generation

Pragati Kumari, Novarun Deb

Comments 11 pages

详情
英文摘要

The growing adoption of prompt-based automation in software testing raises important issues regarding its computational and environmental sustainability. Existing sustainability studies in AI-driven testing primarily focus on large language models, leaving the impact of prompt engineering strategies largely unexplored - particularly in the context of Small Language Models (SLMs). This gap is critical, as prompt design directly influences inference behavior, execution cost, and resource utilization, even when model size is fixed. To the best of our knowledge, this paper presents the first systematic sustainability evaluation of prompt engineering strategies for automated test generation using SLMs. We analyze seven prompt strategies across three open-source SLMs under a controlled experimental setup. Our evaluation jointly considers execution time, token usage, energy consumption, carbon emissions, and coverage test quality, the latter assessed through coverage analysis of the generated test scripts. The results show that prompt strategies have a substantial and independent impact on sustainability outcomes, often outweighing the effect of model choice. Reasoning intensive strategies such as Chain of Thought and Self-Consistency achieve higher coverage but incur significantly higher execution time, energy consumption, and carbon emissions. In contrast, simpler strategies such as Zero-Shot and ReAct deliver competitive coverage test quality with markedly lower environmental cost, while Least-to-Most and Program of Thought offer balanced trade-offs.

2604.02760 2026-04-06 cs.HC

AI Disclosure with DAISY

Yoana Ahmetoglu, Marios Constantinides, Anna Cox

Comments accepted at CHIWORK'26

详情
英文摘要

The use of AI tools in research is becoming routine, alongside growing consensus that such use should be transparently disclosed. However, AI disclosure statements remain rare and inconsistent, with policies offering limited guidance and authors facing social, cognitive, and emotional barriers when reporting AI use. To explore how structured disclosure shapes what authors report and how they experience disclosure, we present DAISY (Disclosure of AI-uSe in Your Research), a form-based tool for generating AI disclosure statements. DAISY was developed from literature-derived requirements and co-design (N =11), and deployed in a user study with authors (N=31). DAISY-supported disclosures met more completeness criteria, offering clearer breakdowns of AI use across research and writing than unsupported disclosures. Surprisingly, despite concerns about how transparently disclosed AI use might be perceived, the use of DAISY did not reduce author comfort with the disclosure statements. We discuss design implications and a research agenda for AI disclosure as a sociotechnical practice.

2604.02758 2026-04-06 cs.GT cs.DS

Optimal Pricing with Unreliable Signals

Zhihao Gavin Tang, Yixin Tao, Shixin Wang

详情
英文摘要

We study a single-buyer pricing problem with unreliable side information, motivated by the increasing use of AI-assisted decision-making and LLM-based predictions. The seller observes a private sample that may be either accurate (coinciding with the buyer's valuation), or hallucinatory (an independent draw from the prior), without knowing which case has realized. The buyer does not observe the realized signal, yet knows whether it is accurate or hallucinatory. This creates a higher-order informational asymmetry: the seller is uncertain about the reliability of his own side information, while the buyer has private information about that reliability. Adopting a consistency-robustness framework, we characterize the exact Pareto frontier of tradeoffs between consistency (performance under an accurate signal) and robustness (performance under a hallucinatory signal). We show that keeping the unreliable signal private generates substantial value, yielding tradeoffs that strictly dominate any public-signal benchmark. We further show that perfect consistency does not preclude meaningful protection against hallucination: for every prior, there exists a mechanism achieving perfect consistency together with a nontrivial robustness guarantee of $\frac{1}{2}$. Moreover, if the prior has an infinite mean or a mean of at most its monopoly price, we provide a mechanism that is simultaneously 1-consistent and 1-robust. Our results illustrate a new mechanism design paradigm: rather than relying only on information directly possessed by the designer, mechanisms can be built to leverage the other side's knowledge about the reliability of the designer's information.

2604.02755 2026-04-06 cs.DC

Accelerating Nonlinear Time-History Analysis with Complex Constitutive Laws via Heterogeneous Memory Management: From 3D Seismic Simulation to Neural Network Training

Tsuyoshi Ichimura, Kohei Fujita, Hideaki Ito, Muneo Hori, Lalith Maddegedara

Comments 16 pages, 5 figures, accepted for IHPCES/ICCS 2026 (16th International Workshop on Advances in High-Performance Computational Earth Sciences: Numerical Methods, Frameworks & Applications / 26th International Conference on Computational Science)

详情
英文摘要

Nonlinear time-history evolution problems employing high-fidelity physical models are essential in numerous scientific domains. However, these problems face a critical dual bottleneck: the immense computational cost of time-stepping and the massive memory requirements for maintaining a vast array of state variables. To address these challenges, we propose a novel framework based on heterogeneous memory management for massive ensemble simulations of general nonlinear time-history problems with complex constitutive laws. Taking advantage of recent advancements in CPU-GPU interconnect bandwidth, our approach actively leverages the large capacity of host CPU memory while simultaneously maximizing the throughput of the GPU. This strategy effectively overcomes the GPU memory wall, enabling memory-intensive simulations. We evaluate the performance of the proposed method through comparisons with conventional implementations, demonstrating significant improvements in time-to-solution and energy-to-solution. Furthermore, we demonstrate the practical utility of this framework by developing a Neural Network-based surrogate model using the generated massive datasets. The results highlight the effectiveness of our approach in enabling high-fidelity 3D evaluations and its potential for broader applications in data-driven scientific discovery.

2604.02754 2026-04-06 cs.SE

An Empirical Study of Sustainability in Prompt-driven Test Script Generation Using Small Language Models

Pragati Kumari, Novarun Deb

Comments 6 pages. arXiv admin note: substantial text overlap with arXiv:2602.18012

详情
英文摘要

The increasing use of language models in automated test script generation raises concerns about their environmental impact, yet existing sustainability analyses focus predominantly on large language models. As a result, the energy and carbon characteristics of small language models (SLMs) during prompt-driven unit-test script generation remain largely unexplored. To address this gap, this study empirically examines the environmental and performance tradeoffs of SLMs (in the 2B-8B parameter range) using the HumanEval benchmark and adaptive prompt variants (based on the Anthropic template). The analysis uses CodeCarbon to characterize energy consumption carbon emissions and duration under controlled conditions, with unit-test script coverage serving as an initial proxy for generated test quality. Our results show that different SLMs exhibit distinct sustainability profiles - some favor lower energy use and faster execution, while others maintain higher stability or coverage under comparable conditions. Overall, this work provides focused empirical evidence on sustainable SLM-based test script generation, clarifying how prompt structure and model selection jointly shape environmental and performance outcomes.

2604.02750 2026-04-06 math.DS

Linear response asymmetry between SRB and physical measures for families of intermittent maps with a transition point

Yuya Arima

Comments 22 pages

详情
英文摘要

We study linear response for families of intermittent maps whose SRB measure undergoes a transition from finite to infinite total mass at a critical parameter value. Our results reveal the following fundamental asymmetry arising from this transition. Smooth parameter dependence of the SRB measure implies continuity of the physical measure at the transition point, while simultaneously precluding its differentiability there. In particular, although the physical measure varies continuously with respect to the parameter at the transition, it fails to admit a linear response for a large class of potentials in the usual sense. We derive an explicit one-sided derivative formula describing this singular behavior and thereby give a quantitative characterization of how statistical properties degenerate as the total mass of the SRB measure diverges. The key ingredient in the proof of our main theorem is a new method that relates the parameter dependence of physical measures near the transition point to the behavior of the Riemann zeta function near its pole at 1.

2604.02749 2026-04-06 eess.SY cs.SY

Residual-Aware Distributionally Robust EKF: Absorbing Linearization Mismatch via Wasserstein Ambiguity

Minhyuk Jang, Jungjin Lee, Astghik Hakobyan, Naira Hovakimyan, Insoon Yang

Comments Submitted to the 2026 65th IEEE Conference on Decision and Control (CDC)

详情
英文摘要

The extended Kalman filter (EKF) is a cornerstone of nonlinear state estimation, yet its performance is fundamentally limited by noise-model mismatch and linearization errors. We develop a residual-aware distributionally robust EKF that addresses both challenges within a unified Wasserstein distributionally robust state estimation framework. The key idea is to treat linearization residuals as uncertainty and absorb them into an effective uncertainty model captured by a stage-wise ambiguity set, enabling noise-model mismatch and approximation errors to be handled within a single formulation. This approach yields a computable effective radius along with deterministic upper bounds on the prior and posterior mean-squared errors of the true nonlinear estimation error. The resulting filter admits a tractable semidefinite programming reformulation while preserving the recursive structure of the classical EKF. Simulations on coordinated-turn target tracking and uncertainty-aware robot navigation demonstrate improved estimation accuracy and safety compared to standard EKF baselines under model mismatch and nonlinear effects.

2604.02747 2026-04-06 math.OC

A Sequential Cubic Programming Method with Second-Order Complexity Guarantees for Equality Constrained Optimization

Nikos Dimou, Michael J. O'Neill

详情
英文摘要

We develop a new method for equality constrained optimization problems based on a sequential cubic programming framework. Each iteration utilizes a step decomposition based on the Jacobian of the constraints into a normal and a tangential component, the latter of which is found by solving a subproblem involving cubic regularization. The method incorporates second-order correction steps as necessary to ensure global convergence to second-order stationary points as well as local quadratic convergence. In addition, we show that the algorithm is the first to obtain worst case complexity guarantees on the order of $\mathcal{O}(ε_g^{-3/2})$ for the gradient of the Lagrangian, $\mathcal{O}(ε_H^{-3})$ in terms of second-order stationarity, and $\mathcal{O}(ε_c^{-1})$ in terms of the constraint violation. These are the best known complexity guarantees of any method for this class of problems.

2604.02746 2026-04-06 cond-mat.stat-mech cs.DS math-ph math.MP math.PR

Zero-Freeness of the Hard-Core Model with Bounded Connective Constant

Yuan Chen, Shuai Shao, Ke Shi

详情
英文摘要

We study the zero-free regions of the partition function of the hard-core model on finite graphs and their implications for the analyticity of the free energy on infinite lattices. Classically, zero-freeness results have been established up to the tree uniqueness threshold $λ_c(Δ-1)$ determined by the maximum degree $Δ$. However, for many graph classes, such as regular lattices, the connective constant $σ$ provides a more precise measure of structural complexity than the maximum degree. While recent approximation algorithms based on correlation decay and Markov chain Monte Carlo have successfully exploited the connective constant to improve the threshold to $λ_c(σ)$, analogous results for complex zero-freeness have been lacking. In this paper, we bridge this gap by introducing a proper definition of the connective constant for finite graphs based on a lower bound on the number of $k$-depth self-avoiding walks. We prove that for any graph family with a lower connective constant $μ$, the partition function is zero-free in a complex neighborhood of the interval $[0, λ]$ for all $λ< λ_c(μ)$. As a direct consequence, we establish the uniqueness and analyticity of the free energy density for infinite lattices up to the connective constant threshold, extending the known regions derived from maximum degree bounds. Our proof utilizes a block contraction technique that lifts the correlation decay property from a real interval to a strip-like complex neighborhood.

2604.02741 2026-04-06 quant-ph

Computational framework for non-Markovian multi-emitter dynamics beyond the single-excitation limit

Hyunwoo Choi, Weng Cho Chew, Dong-Yeop Na

详情
英文摘要

While non-Markovian dynamics have been extensively studied in the single-excitation limit to predict non-trivial phenomena, this regime remains an idealization. Moving beyond it is essential, as optical nonlinearities and phase-error accumulation in multi-photon processes render the Markovian approximation fragile. In this work, we present a Green's function-based framework for modeling non-Markovian multi-emitter quantum electrodynamics within the two-excitation manifold. The modified Langevin noise (M-LN) formalism is employed for first-principles treatment of dissipative environments, while the emitter-centered mode (ECM) framework ensures computational tractability. Unlike conventional approaches that integrate out the reservoir, we construct a non-Markovian hierarchy of coupled differential equations by explicitly retaining photonic amplitudes. Within the two-excitation hierarchy, the formulation preserves total probability and retains phase information necessary to capture multi-photon interference. As numerical demonstrations, we investigate non-Markovian atom-field interactions in structured semi-infinite waveguide environments. We first consider a homogeneous waveguide as a baseline, observing enhanced Bell-state fidelity in selected configurations. Next, we examine collective decay of symmetric Dicke states in a waveguide with an embedded lossy dielectric slab, revealing selective stabilization and delayed excitation transfer induced by the structured reservoir. Finally, we analyze entanglement dynamics in the same setting, highlighting entanglement sudden birth and oscillatory revivals. In principle, the framework applies to arbitrary electromagnetic environments for which the dyadic Green's function can be obtained numerically, providing a versatile tool for investigating complex non-Markovian multi-photon phenomena beyond the single-excitation limit.

2604.02739 2026-04-06 stat.ME stat.ML

Quotient-Based Posterior Analysis for Euclidean Latent Space Models

Kisung You, Mauro Giuffrè

详情
英文摘要

Latent space models are widely used in statistical network analysis and are often fit by Markov chain Monte Carlo. However, posterior summaries of latent coordinates are not canonical because the likelihood depends only on pairwise distances and is invariant under rigid motions of the latent space. Standard post hoc alignment can aid visualization, but the resulting summaries depend on an arbitrary reference configuration. We propose a quotient-based posterior analysis for Euclidean latent space models using the centered Gram map, which represents identifiable latent structure while removing nonidentifiability. This yields intrinsic posterior summaries of mean structure and uncertainty that can be computed directly from posterior samples, together with basic theoretical guarantees including canonicality, existence, and stability. Through simulations and analyses of the Florentine marriage network and a statisticians' coauthorship network, the proposed framework clarifies when alignment-based summaries are stable, when they become reference-sensitive, and which nodes or relationships are weakly identified. These results show how coherent posterior analysis can reveal latent relational structure beyond a single embedding.

2604.02735 2026-04-06 math.NA cs.NA math.OC

Error Estimates of the Gain Approximation by Hermite-Galerkin Method in Feedback Particle Filter

Ruoyu Wang, Peng Sun, Xue Luo

Comments 8 pages, 3 figures, 1 table

详情
英文摘要

The feedback particle filter (FPF) is a promising nonlinear filtering (NLF) method, but its practical implementation is hindered by the intractability of the gain function, which satisfies a boundary value problem (BVP). This paper proposes a novel two-step Hermite-Galerkin spectral method to address this challenge. First, the unknown density in the BVP is approximated by a kernel density estimator, whose error bounds are well-established in the literature. Second, rather than directly approximating the gain function, we approximate an auxiliary variable via the Galerkin spectral method using generalized Hermite functions. This auxiliary variable inherits the rapid decay property of the density at infinity, which aligns perfectly with the exponential decay characteristic of generalized Hermite functions, thereby obviating the need for artificial boundary conditions or domain truncation. Furthermore, we rigorously establish two fundamental error estimates: the kernel approximation error decays at the rate $O(N_p^{-\frac{s}{2s+1}})$, while the spectral approximation error converges at $O(M^{-s+1}\log M)$, providing complete theoretical guarantees for the method's accuracy. Comprehensive numerical experiments validate the theoretical results and demonstrate that the proposed method outperforms existing gain approximation schemes in both accuracy and computational efficiency.

2604.02732 2026-04-06 cond-mat.mtrl-sci

Noble-Gas Solubility in Solid and Fluid Metallic Hydrogen

Jakkapat Seeyangnok, Udomsilp Pinsook, Graeme J Ackland

Comments 8 pages, 4 Figures

详情
英文摘要

Metallic hydrogen dominates the deep interiors of giant planets, where trace elements interact with dense quantum matter under extreme pressure. We investigate the thermodynamic stability of noble-gas impurities (He, Ne, Ar, Kr, Xe) in metallic hydrogen at 500 GPa using ab initio molecular dynamics combined with first-principles free-energy calculations. In the solid metallic phase, all noble gases exhibit positive formation free energies, driven by unfavorable electronic enthalpy and zero-point vibrational contributions. By contrast, heavier noble gases (Ar, Kr, Xe) appear soluble in liquid hydrogen, while He and Ne phase separate. This crossover reflects a competition between electronic repulsion and disorder-driven stabilization intrinsic to the liquid phase. Our results reveal noble-gas retention in metallic hydrogen, providing a microscopic mechanism for noble-gas fractionation in giant-planet interiors.

2604.02728 2026-04-06 cs.MA

Multi-agent Reinforcement Learning-based Joint Design of Low-Carbon P2P Market and Bidding Strategy in Microgrids

Junhao Ren, Honglin Gao, Sijie Wang, Lan Zhao, Qiyu Kang, Aniq Ashan, Yajuan Sun, Gaoxi Xiao

Comments 10 pages, 6 figures

详情
英文摘要

The challenges of the uncertainties in renewable energy generation and the instability of the real-time market limit the effective utilization of clean energy in microgrid communities. Existing peer-to-peer (P2P) and microgrid coordination approaches typically rely on certain centralized optimization or restrictive coordination rules which are difficult to be implemented in real-life applications. To address the challenge, we propose an intraday P2P trading framework that allows self-interested microgrids to pursue their economic benefits, while allowing the market operator to maximize the social welfare, namely the low carbon emission objective, of the entire community. Specifically, the decision-making processes of the microgrids are formulated as a Decentralized Partially Observable Markov Decision Process (DEC-POMDP) and solved using a Multi-Agent Reinforcement Learning (MARL) framework. Such an approach grants each microgrid a high degree of decision-making autonomy, while a novel market clearing mechanism is introduced to provide macro-regulation, incentivizing microgrids to prioritize local renewable energy consumption and hence reduce carbon emissions. Simulation results demonstrate that the combination of the self-interested bidding strategy and the P2P market design helps significantly improve renewable energy utilization and reduce reliance on external electricity with high carbon-emissions. The framework achieves a balanced integration of local autonomy, self-interest pursuit, and improved community-level economic and environmental benefits.

2604.02727 2026-04-06 eess.SY cs.SY

Data-Driven Synthesis of Probabilistic Controlled Invariant Sets for Linear MDPs

Kazumune Hashimoto, Shunki Kimura, Kazunobu Serizawa, Junya Ikemoto, Yulong Gao, Kai Cai

详情
英文摘要

We study data-driven computation of probabilistic controlled invariant sets (PCIS) for safety-critical reinforcement learning under unknown dynamics. Assuming a linear MDP model, we use regularized least squares and self-normalized confidence bounds to construct a conservative estimate of the states from which the system can be kept inside a prescribed safe region over an \(N\)-step horizon, together with the corresponding set-valued safe action map. This construction is obtained through a backward recursion and can be interpreted as a conservative approximation of the \(N\)-step safety predecessor operator. When the associated conservative-inclusion event holds, a conservative fixed point of the approximate recursion can be certified as an \((N,ε)\)-PCIS with confidence at least \(η\). For continuous state spaces, we introduce a lattice abstraction and a Lipschitz-based discretization error bound to obtain a tractable approximation scheme. Finally, we use the resulting conservative fixed-point approximation as a runtime candidate PCIS in a practical shielding architecture with iterative updates, and illustrate the approach on a numerical experiment.

2604.02724 2026-04-06 math.OC

Sparse control for VCHE with abstract J

Giang Nguyen Hai Ha

详情
英文摘要

We investigate a distributed optimal control problem for the viscous Camassa--Holm equations with sparse controls and a general cost functional. Considering three different forms of sparsity-promoting terms, we prove the existence of optimal solutions, derive the corresponding optimality conditions and analyze the stability of optimal solutions with respect to the sparsity parameter.

2604.02723 2026-04-06 math.NT

Explicit hypergeometric modularity of certain weight two and four Hecke eigenforms

Sipra Maity, Rupam Barman

Comments 19 pages

详情
英文摘要

Recently, Allen et al. developed the Explicit Hypergeometric Modularity Method (EHMM) that establishes the modularity of a large class of hypergeometric Galois representations in dimensions two and three. Motivated by this framework, we construct two explicit families of eta-quotients, which we call the $\mathbb{K}_4$ and $\mathbb{K}_5$ functions, from the hypergeometric background. These $\mathbb{K}_4$ and $\mathbb{K}_5$ functions are constructed using the theory of weight $1/2$ Jacobi theta functions and their cubic analogues, respectively. Using these constructions, we then express the Fourier coefficients of certain Hecke eigenforms of weight two and four in terms of finite field period functions. As an application, we obtain new identities relating the Fourier coefficients of modular forms to special values of the finite field Appell series $F_1^p$ and $F_2^p$.

2604.02722 2026-04-06 math.ST stat.TH

Parameter Estimation of Incomplete Gamma Subordinators

Meena Sanjay Babulal, Sunil Kumar Gauttam, Aditya Maheshwari

详情
英文摘要

In this paper, we estimate the parameters of InG, InG-$ε$ and TInG subordinators which have been studied by Babulal \textit{et al} (see \cite{babulal}). We have modified the method of moments technique to use fractional moments of the InG and InG-$ε$ subordinator due to their infinite moments. For the TInG subordinator's parameter estimation, we have used the method of moments. We also compute the maximum likelihood estimator(MLE) for the parameter $α$ of the InG and InG-$ε$ subordinators using jump distribution of the process. We also discussed the asymptotic normality of MLE.