arXivDaily arXiv每日学术速递 周一至周五更新
重置
全部学科分类 1296
2604.22603 2026-04-27 cs.NI cs.OS

Chamelio: A Fast Shared Cloud Network Stack for Isolated Tenant-Defined Protocols

Matheus Stolet, Simon Peter, Antoine Kaufmann

详情
英文摘要

Conventional cloud network virtualization sends packets through multiple guest and host layers, inflating CPU cost and tail latency. Shared host datapaths collapse this layering into one optimized path across tenants, but existing shared stacks are fixed-function: tenants cannot specialize their protocols. eBPF is the natural vehicle for restoring programmability to a shared datapath, but today's extensions are hook-sized, and its verifier provides safety -- not performance isolation: one tenant's per-packet work can inflate every other tenant's tail latency. Chamelio is a programmable shared network stack that lets tenants implement full protocols through a bounded eBPF fast path and a tenant slow path, while approaching the performance and preserving the strong isolation of fixed shared stacks. It combines three ideas: a shared-stack architecture for tenant-defined protocols; joint optimisation of tenant handlers with provider infrastructure and co-resident tenants in the shared fast path; and a bounded fast path contract with runtime cycle accounting that keeps tenant programmability compatible with strong performance isolation. A tenant programmable TCP on Chamelio reaches 9.2 Mreq/s, matching the hand-tuned TAS stack; joint compilation shrinks the programmability tax from 23.9% to 3.8%; and under a scaling TCP adversary that drives uninstrumented stacks to 154 microseconds, Chamelio bounds victim tail latency at 46 microseconds.

2604.22602 2026-04-27 cs.CR

PASS: A Provenanced Access Subaccount System for Blockchain Wallets

Jay Yu, Shunfan Zhou, Hang Yin, Brian Seong

详情
英文摘要

Blockchain wallets conventionally follow an ownership model where possession of a private key grants unilateral control. However, this assumption is brittle for emerging settings such as AI agent wallets, organizational custody, and enterprise payroll, where multiple actors must coordinate without exposing secrets or leaking internal activity. We present PASS, a Provenanced Access Subaccount System that replaces role-based or identity-based control with provenance-based control: assets can only be used by subaccounts that can trace custody back to a valid deposit. A simple Inbox-Outbox mechanism ensures all external actions have verifiable lineage, while internal transfers remain private and indistinguishable from ordinary EOAs. We formalize PASS in Lean 4 and prove core invariants, including privacy of internal transfers, asset accessibility, and provenance integrity. We implement a prototype with enclave backends on AWS Nitro Enclaves and dstack Intel TDX, integrate with WalletConnect, and benchmark throughput across wallet operations. These results show that provenance-based wallets are both implementable and efficient. PASS bridges today's gap between strict self-custody and flexible shared access, advancing the design space for practical, privacy-preserving custody.

2604.22600 2026-04-27 cond-mat.soft quant-ph

Anomalous Mean-Squared Displacement in Quantum Active Matter from a Wigner Phase-Space Framework

Sangyun Lee, Yehor Tuchkov, Alexander P. Antonov, Benno Liebchen, Hartmut Löwen, Giovanna Morigi, Michael te Vrugt

Comments 24 pages, 9 figures

详情
英文摘要

Active matter is driven out of equilibrium by a local influx of energy. While classical active matter has been extensively studied, the extension of active matter concepts to quantum systems has been explored far less. In this work we develop a full quantum description based on the Wigner function. By introducing a hybrid Wigner master equation that incorporates classical active motion and quantum degrees of freedom, we compute the quantum mean-squared displacement (MSD) using established techniques from classical active matter. We analytically derive the time dependence of the MSD and clarify the conditions under which the characteristic scaling with time $\mathrm{MSD}\sim t^{6}$ emerges. We further show that, for certain parameter and initial conditions, the MSD can exhibit an even steeper scaling regime $\mathrm{MSD}\sim t^{7}$, and we examine the robustness of these behaviors against quantum fluctuations of the initial state.

2604.22599 2026-04-27 nucl-th

The 0+-spectrum in rare earth nuclei within the pseudo-SU(3) shell model

Peter O. Hess, Sahila Chopra

Comments 27 pages, 10 figures, 27 Tables

详情
英文摘要

The study of the structure of the 0+ spectrum in heavy nuclei has drawn much attention in the last two decades. In this contribution we study their properties from a microscopic point of view. The pseudo-SU(3) model (\tilde{SU}(3)) is applied to some rare earth nuclei, namely to Sm, Gd, Dy, Er, Yb and Hf isotopes. It is shown that the 0+ spectrum, and the accumulation of states at certain energies, can be well understood using this microscopic model, which takes into account the Pauli Exclusion Principle (PES). Intentionally, a very simple model Hamiltonian is applied and only the valence shell is taken into account, in order to high-lighten certain cross features. It is demonstrated that the microscopic Hilbert space is essential in understanding the accumulation of 0+-states. A discussion to other models is provided. Also the dominance of B(E2)-transitions from the γ-band over those from the \b{eta}-band turns out to be trivial, in contrast to within some collective models.

2604.22598 2026-04-27 astro-ph.HE

Synchrotron polarization of anisotropic electron distribution in GRB prompt emission

Kang-Fa Cheng, Kai-Xian Luo, Xiao-Hong Zhao, Jirong Mao, Hong-Bang Liu, Yu-Hang Mo, Jin-Rong Huang, Rong-Li Weng, Wen-Jie Xie, Gao-Jin Yu

Comments 13 pages, 6 figures, 1 table. Accepted for publication in ApJ

详情
英文摘要

In gamma-ray bursts (GRBs), the electron pitch angle ($α$) is usually assumed to be isotropically distributed. However, recent numerical simulations indicate that only the high-energy electrons (with Lorentz factors $γ>γ_{iso}$) are distributed isotropically, whereas the low-energy electrons (with $γ<γ_{iso}$) follow an energy-dependent anisotropic distribution during magnetic reconnection. The mean value of $\sin^2 α$ approximately follows the relation $\langle \sin^2 α\rangle \propto γ^{m}$ for $γ<γ_{iso}$. In principle, polarization measurements may help us constrain the pitch-angle distribution of electrons in GRBs, since different pitch-angle distributions produce distinct synchrotron polarization signatures. The polarization of GRBs produced by isotropically distributed electrons has been extensively studied. In this paper, we investigate synchrotron polarization produced by anisotropically distributed electrons within a globally toroidal magnetic field in GRB prompt emission. Our results show that the synchrotron PDs in the $γ$-ray and X-ray bands produced by anisotropically distributed electrons are systematically lower than those produced by isotropically distributed electrons, while the PD in the optical band could be either lower or higher than that of isotropically distributed electrons, depending primarily on the value of the energy slope $m$. In addition, we compared our numerical results with observational data, and the comparison suggests that an anisotropic distribution of electrons may offer a potential explanation for the PD and spectral data of some GRBs.

2604.22596 2026-04-27 cond-mat.supr-con physics.acc-ph

Resonance Frequency Shift Measurements of SRF Cavities at DESY

Rezvan Ghanbari, Thorsten Buettner, Wolfgang Hillert, Karol Kasprzak, Tom Krokotsch, Ricardo Monroy-Villa, Detlef Reschke, Lea Steder, Alexey Sulimov, Hans Weise, Marc Wenskat, Mateusz Wiencek, Jonas Wolff

详情
英文摘要

The variation of the resonance frequency and intrinsic quality factor of superconducting radio-frequency cavities during the transition from the superconducting to the normal-conducting state provides essential insight into the fundamental superconducting properties of the cavity material. Investigating these transition dynamics is crucial for the continued advancement of niobium cavities whose near-surface regions are intentionally modified through the controlled introduction of interstitial atoms, such as oxygen and nitrogen, leading to the emergence of several novel behaviors whose underlying mechanisms are not yet fully understood. This work reports on the development and commissioning of a dedicated frequency-shift measurement setup. In its initial implementation, the system establishes a precise framework for determining the electron mean free path within both the superconducting penetration depth and the normal-conducting skin depth. It further enables investigation of an anomalous dip in the temperature dependence of the frequency shift near the critical temperature in cavities containing interstitial atoms in the near-surface lattice, a novel phenomenon previously reported in the literature. A recent upgrade, currently in the final stage of validation, significantly improves measurement accuracy and reproducibility. The improved setup enables comprehensive studies of the frequency shift and quality factor over the full temperature range above 7 K, contributing to a deeper understanding of the superconducting properties.

2604.22593 2026-04-27 quant-ph cond-mat.mes-hall

Stability Thresholds for Gravitationally Induced Entanglement in Shielded Setups

Jan Bulling, Marit O. E. Steiner, Julen S. Pedernales, Martin B. Plenio

Comments 33 pages, 16 figures

详情
英文摘要

Proposed experiments for gravitationally induced entanglement (GIE) typically suppress direct electromagnetic interactions between two massive particles by inserting a conducting Faraday shield. For superconducting particles, their large diamagnetism requires additional magnetic shielding to screen magnetic dipolar interactions. Here, we analyze the effect of residual particle-shield interactions and show that both Casimir and magnetic-dipole interactions can severely limit GIE tests by imprinting large phases. We quantify how run-to-run positional and orientational fluctuations of the setup elements, including the shield, trapping potentials, and detectors, convert these phases into effective decoherence, strongly reducing the detectable bipartite entanglement. In particular, we show that magnetic interactions between the particles and a superconducting shield constitute a major noise source, especially relevant for levitated superconducting particles. Treating the vibrational modes of the shield quantum mechanically, we further find that thermal vibrations generate persistent particle-shield correlations and can even mediate particle-particle entanglement that can mimic a gravitational signal. Finally, we derive quantitative thresholds on the maximum tolerable positional and orientational fluctuations of the setup elements required to observe entanglement, and propose mitigation strategies including geometry optimization and shield cooling to preserve a genuine GIE signature.

2604.22592 2026-04-27 physics.plasm-ph

Scaling laws of multi-shock implosions toward the quasi-isentropic limit

M. Murakami

详情
Journal ref
Phys. Plasmas 33, 042703 (2026)
英文摘要

We present a unified theoretical and numerical framework for self-similar multi-shock implosions achieving ultrahigh compression in a uniform solid spherical target. Extending the classical Guderley model to N stacked, spherically converging shocks, we derive selfsimilar solutions and the scaling law for the final density. One dimensional Lagrangian hydrodynamic simulations confirm this relation over a broad range of parameters, from the weakly to the strongly nonlinear regime. The results show that cumulative compression increases systematically with the number of stacked shocks while entropy generation is strongly suppressed, asymptotically approaching a quasi isentropic limit as N increases infinity. This volumetric scheme strongly suppresses the Rayleigh Taylor instability that plagues shell based implosions and thus provides a robust, largely instability-resistant compression pathway applicable to inertial confinement fusion and other high energy density systems. The framework bridges similarity theory with realistic multi-shock dynamics, guiding the design of advanced laser-driven compression schemes.

2604.22590 2026-04-27 math.AP

Strong solutions and stability for a thin-film equation of shear-thinning fluids with contact line in partial wetting

Manuel V. Gnann, Christina Lienstromberg, Katerina Nik

详情
英文摘要

We consider a power-law thin-film equation for strongly shear-thinning fluids. Weak solutions to this equation have been constructed more than twenty years ago by Ansini and Giacomelli. Here, we pass over to analyzing strong solutions with nonzero contact angle (partial-wetting regime), and place emphasis on studying the behavior of solutions near points where the film height vanishes (the contact-line region) by considering perturbations of a linear profile. The leading-order equation in von-Mises coordinates shows similarities with the evolution equation for the $p$-Laplace, though being of fourth order. Using a time discretization, we reduce the leading-order problem to finding a variational solution, and pass to the limit in the discretization scheme on suitably estimating higher-order nonlinear terms in conjunction with compactness arguments. This proves existence and asymptotic stability of strong solutions that are perturbations of the linear profile, and yields control on the contact-line velocity on carefully tracking singular terms in our estimates. While we believe that the transformed equation shows mathematical features the analysis of which stands on its own merit, it also physically corroborates shear thinning behavior as an alternative in resolving the no-slip paradox, as opposed to more standard approaches like introducing slip at the liquid-solid interface.

2604.22589 2026-04-27 math.NA cs.NA

Nonconforming virtual element method for the Monge-Ampère equation

Scott Congreve, Alice Hodson, Anwesh Pradhan

详情
英文摘要

In this article, we develop the $C^1$-nonconforming $C^0$-conforming virtual element method (VEM) for the vanishing moment approximation of the second-order fully nonlinear Monge-Ampère equation in two dimensions. In the vanishing moment equation an artificial biharmonic term is introduced which produces a quasilinear fourth order problem. We derive optimal a priori error estimates in the $H^2$-, $H^1$- and $L^2$-norms for the virtual element method, and show the existence and uniqueness of the virtual element solution. We perform several numerical experiments to validate the convergence rate of the error with respect to the mesh size.

2604.22588 2026-04-27 quant-ph

Analytical and Compressed Simulation of Noisy Stabilizer Circuits

Paul Aigner, Jasmin Matti, Maria Flors Mor-Ruiz, Julius Wallnöfer, Wolfgang Dür

Comments 17 pages, 7 figures

详情
英文摘要

We develop analytical and algorithmic techniques that enable efficient simulation of a broad class of noisy stabilizer circuits. We derive closed-form expressions of expectation values for tensor product of Paulis in circuits with non-deterministic Pauli measurements, yielding an efficient strong simulation method that avoids explicit density matrix construction and enables direct noise parameter sweeps. We introduce a circuit compression framework that reduces the per-sample cost of weak simulation in general noisy stabilizer circuits, including deterministic measurements, by separating parameter-independent preprocessing from sampling. Finally, we extend the analytical framework beyond its standard domain to include a small number of deterministic measurements, general rotations, and non-diagonal noise channels. Our results provide a unified framework for both strong and weak simulation of noisy stabilizer circuits and corresponds to an extension of the noisy stabilizer formalism introduced in \cite{PhysRevA.107.032424}. They offer applications ranging from calculation of the expectation values of entanglement witnesses, determination of reduced states, to energy evaluation.

2604.22587 2026-04-27 cs.IT math.IT

On the Optimum Secrecy Outage Probability and Ergodic Secrecy Rate over Wireless Channels

Clement Leroy, Tarak Arbi, Benoit Geller, Olivier Rioul

详情
英文摘要

We study the secrecy of wireless channels in the presence of an eavesdropper, where the channels are random and the transmitter only has knowledge of the channel statistics. We investigate the optimal input distribution with respect to several secrecy metrics: the Secrecy Outage Probability (SOP), defined as the probability that the coding rate $r$ exceeds the instantaneous secrecy rate; the Ergodic Secrecy Rate (ESR), defined as the expected secrecy rate over channel realizations; and the Ergodic Positive Secrecy Rate (EPSR), defined as the expected value of the positive part of the secrecy rate. We introduce two partial orderings for random channels: the uniformly less noisy order and the less noisy on average order. We show that when the main channel is uniformly less noisy than the eavesdropper channel, the optimal input distribution is a non-precoded Gaussian input for both the SOP and the EPSR. Furthermore, we show that the same input distribution is optimal for the ESR when the less noisy on average order holds. In addition, similar optimality results for the SOP and the EPSR are obtained for single-transmit-antenna channels without requiring any channel ordering assumptions. Closed-form expressions of the secrecy metrics are derived for special cases of Rayleigh fading channels.

2604.22585 2026-04-27 math.DG math.AP

Static Vacuum Spacetimes with $Λ<0$ as Attractors of the Ricci-Harmonic Flow

Rasmus Jouttijärvi, Klaus Kroencke, Louis Yudowitz

Comments 73 pages, comments welcome!

详情
英文摘要

We prove dynamical stability and instability theorems for asymptotically hyperbolic static solutions of Einstein's equation with $Λ<0$, viewed as self-similar solutions of the Ricci-harmonic flow. More precisely, we show that static metrics are dynamically stable if and only if a positive mass type theorem holds for nearby metrics. Our key tool is a new variant of the expander entropy for the Ricci-harmonic flow.

2604.22584 2026-04-27 math.CO cs.DM

Increasing arc-connectivity by bounded- and fixed-size inversions

Florian Hörsch, Lucas Picasarri-Arrieta

详情
英文摘要

For a digraph $D$ and some $X \subseteq V(D)$, the inversion of $X$ is the operation of flipping all arcs both of whose endvertices are in $X$. We initiate the study of establishing arc-connectivity properties by applying inversions of bounded or fixed size. For fixed-size inversions, the feasibility problem is interesting. For all integers $p \geq 2$ and $k \geq 1$, we give a characterization of the digraphs that can be made $k$-arc-strong by applying inversions of size exactly $p$, provided they are sufficiently large. For bounded-size inversions, the feasibility problem is easy, so we focus on minimising the number of inversions. We prove that for all integers $p\geq 3$ and $k \geq 1$ and any $ε>0$, there exists a polynomial-time $(4k-2+ε)$-approximation algorithm for computing the minimum number of inversions of size at most $p$ that make a given digraph $k$-arc-strong. This is in stark contrast to other results on inversion optimization problems. On the other hand, we show that for any $p\geq 3$ and $k \geq 1$ the problem is NP-hard, and, moreover, APX-hard. As a result on parameterized complexity, we show that for any $k \geq 2$, it is $W[1]$-hard with respect to $p$ to decide whether a given digraph can be made $k$-arc-strong by applying a single inversion of size at most $p$. We also prove that for a given multidigraph, it is $W[1]$-hard with respect to $\ell$ to decide whether it can be made 2-arc-strong by applying $\ell$ inversions of size 2.

2604.22582 2026-04-27 hep-th

Carrollian ABJM: Fermions and Supersymmetry

Arjun Bagchi, Arthur Lipstein, Saikat Mondal, Alex Jiayi Zhang

Comments 35 pages, 1 figure

详情
英文摘要

A natural approach for constructing a concrete example of flat space holography is to take the flat space limit of a well-understood example of AdS/CFT, such as the one relating M-theory in AdS$_4$ times an orbifolded 7-sphere to a certain three dimensional superconformal Chern-Simons-matter theory known as the ABJM theory living in the boundary of AdS$_4$. In particular, taking the flat space limit of the bulk corresponds to taking the speed of light $c$ to zero in the boundary, giving rise to a Carrollian superconformal theory. This limit is subtle to implement for fermions, however, since the Dirac algebra is sensitive to the spacetime metric and therefore takes a different form in Carrollian spacetimes than it does in Minkowski space. In fact, we show that there are four possible ways of realising Carrollian fermions, one of which arises at leading order in the $c\rightarrow0$ limit of relativistic fermions. In three dimensions, there is an additional complication that the minimal realisation of the Carrollian Dirac algebra requires $4\times4$ matrices rather than $2\times 2$ matrices familiar from the relativistic case. Nevertheless, we show that the $c\rightarrow0$ limit of the ABJM theory can be recast in terms of Carrollian Dirac matrices and enjoys and infinite-dimensional Carrollian superconformal symmetry whose bosonic subsector is the extended BMS$_4$ algebra encoding the asymptotic symmetries of four dimensional Minkowski space. This provides a concrete starting point for constructing a Carrollian gauge theory dual to M-theory in flat space.

2604.22578 2026-04-27 math.CT math.GR

Weak action representability of 2-nilpotent groups

Alessandro Dioguardi Burgio, Manuel Mancini, Tim Van der Linden

详情
英文摘要

In this article, we investigate the representability of actions of the category $\mathsf{Nil}_2(\mathsf{Grp})$ of $2$-nilpotent groups. We first provide an algebraic characterisation of derived actions in $\mathsf{Nil}_2(\mathsf{Grp})$ by determining a universal strict general actor of an object $X$, which turns out to be the group $\operatorname{Aut}_c(X)$ of central automorphisms of $X$. We also characterise the morphisms $B \to \operatorname{Aut}_c(X)$ that define an action of $B$ on $X$ in $\mathsf{Nil}_2(\mathsf{Grp})$. We then show that $\mathsf{Nil}_2(\mathsf{Grp})$ is not action representable, and that the existence of a weak representation is related to the amalgamation property. Using the construction of an amalgam of a suitable family of abelian subgroups of $\operatorname{Aut}_c(X)$, we prove that the category $\mathsf{Nil}_2(\mathsf{Grp})$ is weakly action representable, and that a weak representing object can be chosen to be an abelian group. Finally, we show that $\mathsf{Nil}_2(\mathsf{Grp})$ is not locally algebraically cartesian closed.

2604.22576 2026-04-27 cs.SE

A Comparison of ROS 2 and AUTOSAR Adaptive Platform Against Industry-Elicited Automotive Middleware Requirements

Lucas Hegerath, David Philipp Klüner, Philipp Pelcz, Viswanatha Reddy Batchu, Marius Molz, Julius Kahle, Thomas Schulik, Stefan Kowalewski, Alexandru Kampmann

详情
英文摘要

In software-defined vehicles, automotive middleware plays a fundamental role in enabling efficient communication, integration, and coordination among software components. This paper examines how well two of the currently most popular middleware frameworks, ROS 2 Jazzy and AUTOSAR Adaptive Platform R24-11, meet practical requirements elicited from automotive software engineers at one of the major automotive supplier companies, ZF Group. Our objective is to provide insight into an otherwise difficult-to-obtain industrial perspective and support a clearer understanding of priorities in the development and evaluation of middleware for automotive applications.

2604.22573 2026-04-27 astro-ph.GA astro-ph.IM astro-ph.SR

A homogeneous three-dimensional view of Molecular Cloud kinematics out to 2.5 kpc. Using Young Stellar Objects and Open Clusters as complementary tracers

Xabier Pérez-Couto, Santiago Torres, Nuria Miret-Roig, Friedrich Anders, Alexander J. Mustill, Eva Villaver, Minia Manteiga

Comments 16 pages, 5 figures. Submitted to A&A; revised version after first referee report

详情
英文摘要

Understanding the large-scale dynamics of molecular clouds (MCs) is crucial for constraining the processes that govern star formation and the structure and evolution of the Galaxy. While gas tracers have traditionally been used to map MC kinematics, stellar tracers such as young stellar objects (YSOs) and open clusters (OCs) provide a complementary approach that enables direct comparisons between the stellar and gaseous components. We aim to validate OCs as complementary tracers by testing whether they retain the same bulk kinematic imprint as YSOs, and to reconstruct the three-dimensional (3D) motions of the main MC complexes within 2.5 kpc of the Sun using YSOs and young OCs as tracers. Using Gaia DR3 astrometry together with complementary spectroscopic surveys for radial velocities, we compiled a unified sample of 24,732 stellar tracers. We applied robust clustering in proper motion space to identify co-moving YSOs and derived cloud-averaged motions via Monte Carlo sampling. These were compared with the kinematics of OCs younger than 30 Myr. Finally, we performed orbital integrations in a realistic Galactic potential to trace the past evolution of the clouds and quantify their expansion and rotation. We derive homogeneous 3D kinematics for 15 MC complexes within 2.5 kpc. YSOs and OCs exhibit strongly consistent kinematics, with a median spatial velocity offset of $\simeq 2$ km s$^{-1}$, confirming that both populations trace the bulk motion of their parent clouds. The resulting cloud kinematics show a median peculiar velocity of $\simeq 8.7$ km s$^{-1}$ with respect to Galactic rotation. We trace back the Solar System's voyage through the Orion cloud and the common origin of Lupus, Ophiuchus, and Corona Australis in Sco-Cen. Internally, we detect significant expansion in Orion and Ophiuchus ($5σ$) and coherent rotation in at least seven complexes.

2604.22572 2026-04-27 hep-ex

Searches for light exotic scalar decays at the e$^+$e$^-$ Higgs factory

Bartłomiej Brudnowski, Kamil Zembaczyński, Aleksander Filip Żarnecki

Comments 8 pages, 7 figures. Contribution to the International Workshop on Future Linear Colliders (LCWS 2025), 20-24 October 2025. Valencia, Spain (C25-10-20.1). This preprint has not undergone peer review or any post-submission improvements or corrections

详情
Journal ref
Eur. Phys. J. Plus 141, 392 (2026)
英文摘要

The physics program of the Higgs factory will focus on measurements of the 125 GeV Higgs boson, with the Higgs-strahlung process being the dominant production channel at 250 GeV. However, similar production of exotic light scalars, in a scalar-strahlug process, is still not excluded by the existing experimental data, provided their coupling to the SM gauge bosons is sufficiently suppressed. This was selected as one of the focus topics of the ECFA Higgs/Top/EW factory study. Presented are the expected cross section limits from the search in the $b\,\bar{b}$ decay channel, based on a full simulation of the International Large Detector (ILD), as well as the expected sensitivity in $τ^+τ^-$ and invisible decay channels, based on the fast simulation in the Delphes framework, assuming 250 GeV ILC running scenario.

2604.22571 2026-04-27 physics.comp-ph

LARA: Validation-Driven Agentic Supercomputer Workflows for Atomistic Modeling

William Dawson, Louis Beal, Yoann Curé, Giuseppe Fisicaro, Dorian Rolland, Luigi Genovese

Comments 12 pages, 2 figures

详情
英文摘要

Large language models (LLMs) and agentic systems have recently demonstrated potential for automating scientific workflows, including atomistic simulations. However, their deployment in high-performance computing (HPC) environments remains limited by the lack of mechanisms ensuring correctness, reproducibility, and safe interaction with computational resources. Generated workflows suffer from inconsistencies, incorrect API usage, or invalid physical configurations - leading to failed or unreliable simulations. In this work, we introduce LARA-HPC, a validation-driven agentic framework to enable reliable workflow generation for atomistic modeling on HPC systems. Our approach is based on three key components: (i) a controlled execution layer that mediates all interactions with HPC resources; (ii) simulation-native validation through dry-run capabilities, enabling execution-level verification without incurring resource cost; and (iii) a multi-phase agentic pipeline combining retrieval-augmented generation and iterative refinement. We demonstrate the effectiveness of this approach performing an end-to-end atomistic simulation workflow on HPC by applying LARA-HPC to Density Functional Theory simulations. The results show that validation-driven generation significantly improves robustness and enables iterative correction of both syntactic and physical inconsistencies. More broadly, this work advocates for a shift from generation-first to validation-first paradigms in Artificial Intelligence (AI) assisted scientific computing. We argue that the future task of the computational physics community is to develop domain specific agentic systems based on structured tooling to realize an HPC enabled co-piloted research ecosystem.

2604.22570 2026-04-27 math.FA math.OC

Acyclic Monotone Operators Are Not Closed Under Addition

Henry Shugart

详情
英文摘要

Borwein and Wiersma [SIAM J. Optim. 18(3) (2007), 946-960] asked if the set of acyclic monotone operators is closed under addition. We answer this question in the negative.

2604.22568 2026-04-27 quant-ph math-ph math.MP

On truncations of hierarchical equations of motion for finite-dimensional systems

Vasilii Vadimov

Comments 21 page, 1 figure Submission to SciPost

详情
英文摘要

We study truncations of hierarchical equations of motion (HEOM) for finite-dimensional open quantum systems. We prove that for finite-dimensional approximations constructed with a Schur-complement type of terminator, the spectrum converges to that of the full HEOM as the truncation depth increases. We also prove that this approximation is free of spectral pollution: sufficiently deep truncations do not produce spurious unstable modes, provided the exact HEOM is stable. We illustrate the results for the spin-boson model.

2604.22564 2026-04-27 cs.CY

Relational Archetypes: A Comparative Analysis of AV-Human and Agent-Human Interactions

Antoni Lorente, Amin Oueslati, Robin Staes-Polet

Comments 4 pages, 1 table. Accepted and presented at FAST workshop, AAAI 2026

详情
英文摘要

Over the last couple of years, AI Agents have gained significant traction due to substantial progress in the capabilities of underlying General Purpose AI (GPAI) models, enhanced scaffolding techniques, and the promise to drive societal transformation. Companies, researchers, and policy makers have started to consider the different effects that AI agents may have across different dimensions of our lives. However, the literature exploring the broader effects of human-agent interactions is still underdeveloped. In this paper, we review the problem of traffic modulation by autonomous vehicles (AVs) in mixed traffic flows and extrapolate the learnings to the different modes of interaction between humans and AVs to the pair humans-AI agents. In doing so, we propose a preliminary taxonomy of relational archetypes based on literature on Human-Computer Interaction (HCI) and AV-human interaction and tentatively explore how the resulting framework may lead to new questions regarding human-agent interactions. Our effort is aimed at strengthening existing bridges between these two research communities, which share similar traits: autonomy, fast adoption, high impact, and great potential for economic transformation. Building on previous analogies between AI Agents and AVs (e.g., regarding autonomy levels), we anticipate this paper to spark scholarly debate on the different types of impact that agents may have on our societies, while inviting other researchers to expand the scope of their comparative analysis regarding AI Agents.

2604.22563 2026-04-27 econ.TH cs.GT

Preplay Losing Contracts: Inducing Strong Nash Equilibrium in the $n$-player Prisoner's Dilemma

Ian Fligler

Comments 34 pages, 19 tables

详情
英文摘要

In strategic games such as the prisoner's dilemma, allowing players to make binding offers of utility transfers before play has been shown to alter incentives and potentially support cooperative outcomes. These preplay exchange mechanisms reshape payoffs by transferring utility while being contingent on actions; however, they typically require side payments that can reduce individual benefits relative to joint cooperation. In this paper, we extend the analysis to a finite $n$-player prisoner's dilemma with ordered strategy sets, defined such that any restriction of strategies by any subset of players still yields a prisoner's dilemma. To achieve a robust cooperative outcome that resists group deviations, we introduce a novel class of mechanisms: $\textit{losing contracts}$. Unlike transfer-based preplay mechanisms, losing contracts require players to irrevocably reduce their own utility if they defect, thereby aligning individual incentives with cooperation without inter-player payments. With appropriately chosen loss amounts, losing contracts induce joint cooperation as the unique strong Nash equilibrium in the modified game and in every restricted game within it, ensuring that cooperative incentives persist even under possible external constraints on strategy sets. We show that our contracts can be constructively defined, reducing the preplay stage to a simple and binary decision for each player: whether to sign the contract or not. Furthermore, if the losing contract is only executed when all players sign, signing is a strictly dominant strategy for all. Finally, we extend these results to certain public goods games.

2604.22561 2026-04-27 cond-mat.mtrl-sci

Influence of Ni Doping on the Structural, Morphological, Optical, and Electrical Properties of Nanocrystalline Cd1-xMnxS Thin Films

Himanshu Sharma Pathok, Padma Pani Shahu, Himanshu Kalita, Prasanta Kumar Saikia

Comments 39 pages, 19 figures

详情
英文摘要

Ni-doped Cd1-xMnxS (x=0.4) thin films were prepared via a cost-effective chemical bath deposition (CBD) method to investigate their suitability for optoelectronic applications. Incorporation of a secondary transition metal such as Ni is expected to influence lattice strain, defect density, and electronic structure through ionic size effects and sp-d exchange interactions, thereby providing an additional degree of freedom for tuning the properties of Cd1-xMnxS-based ternary systems. X-ray diffraction (XRD) analysis confirmed the cubic zinc blende structure of the Cd1-xMnxS crystal, which was further corroborated by high-resolution transmission electron microscopy (HRTEM). Crystallinity increases where as microstrain and dislocation density found to be decreases as the doping concentration of Ni increases. Field emission scanning electron microscopy (FESEM) analysis revealed uniform, dense, and crack-free films with grain size increasing as a function of Ni content, and the FESEM cross-sectional images indicated a nearly constant thickness in the range of 181.2-189.1 nm. The films exhibited high optical transmittance (75-90%) in the visible and near-infrared (NIR) regions. The optical band gap decreases from 2.72 to 2.62 eV as the Ni concentration increases from 1% to 4%. Current-voltage (I-V) measurements revealed enhanced electrical conductivity, which further increased under illumination, confirming the photoconducting nature of the films. These results demonstrate that Ni doping effectively tunes the properties of Cd1-xMnxS thin films, highlighting their potential as efficient window layer materials for thin-film solar cells and related optoelectronic devices.

2604.22559 2026-04-27 astro-ph.GA

A Quasar--Companion System Without AGN Outflow at $z \sim 6$: The Case of PSO J083+11

Muhammad Akmal Husain, Irham Taufik Andika, Mochamad Ikbal Arifyanto

Comments 16 pages, 13 figures

详情
英文摘要

PSO J083.8371+11.8482, a quasar at $z = 6.34$ with a nearby companion galaxy, provides an opportunity to study the impact of active galactic nucleus (AGN) activity on the surrounding environment during the epoch of reionization. We analyze ALMA observations of the [C\,\textsc{ii}] 158~$μ$m emission line and the far-infrared (FIR) continuum, which trace cold interstellar gas and dust-reprocessed radiation from star formation and AGN heating. The quasar host shows star formation rates (SFRs) of $544$--$3764~\mathrm{M_{\odot}~yr^{-1}}$ from [C\,\textsc{ii}] and $1861$--$2932~\mathrm{M_{\odot}~yr^{-1}}$ from FIR emission, while the companion galaxy exhibits lower SFRs of $21$--$145$ and $76$--$211~\mathrm{M_{\odot}~yr^{-1}}$ from the same diagnostics. Both galaxies follow typical $L_{\mathrm{[C\,II]}}/L_{\mathrm{FIR}}$ ratios observed in star-forming galaxies and show no evidence for a [C\,\textsc{ii}] deficit, indicating that stellar heating dominates the interstellar medium energetics. The [C\,\textsc{ii}] moment maps reveal compact emission with centrally peaked intensity and ordered rotational kinematics in both systems. Velocity dispersions remain well below values associated with powerful AGN-driven outflows, and no significant morphological asymmetries or disturbed velocity fields indicative of AGN feedback or major mergers are detected, although marginal kinematic substructure in the quasar's high-velocity channels warrants further investigation. Although the companion lies at a projected distance of $18.248 \pm 0.277$~kpc within the quasar proximity zone, neither morphological nor kinematic signatures indicate AGN-driven outflows affecting the circumgalactic medium. We therefore interpret this system as being observed in a pre-outflow accretion phase, where rapid supermassive black hole growth precedes the development of large-scale AGN feedback.

2604.22556 2026-04-27 physics.ao-ph

Moisture Budgets and Circulation Analogs: Diagnosing Dynamic and Thermodynamic Precipitation Change

Robert Doane-Solomon, Isla R. Simpson, Tim Woollings

详情
英文摘要

Precipitation trends can arise from both dynamic factors (changes in atmospheric circulation) and thermodynamic factors (changes in atmospheric moisture content). Disentangling these contributions can aid in understanding regional climate change and improving projections. We compare two approaches which separate dynamic and thermodynamic contributions to precipitation trends over Central Chile: a moisture budget analysis and constructed circulation analogs. Both methods are applied to fields from the CESM2 Large Ensemble as well as two reanalyses. We analyze the methodological differences that lead to distinct results in each approach and evaluate their respective capabilities in capturing dynamic, thermodynamic and coupled trends. We find that the estimated dynamic trends from both methods often differ substantially for individual ensemble members, although the ensemble mean generally agrees in sign but not in magnitude. Finally, we apply circulation analogs to moisture budget terms to refine estimates of historical and future precipitation change in Central Chile. This combined framework reduces dynamic contamination of thermodynamic trends and yields projections of thermodynamic precipitation change that are weaker than that suggested by either method alone.

2604.22553 2026-04-27 cond-mat.mes-hall cond-mat.supr-con quant-ph

Corner Majorana states in semi-Dirac

M. García Olmos, Y. Baba, R. A. Molina, M. Amado

Comments 16 pages, 8 figures

详情
英文摘要

Proximity-induced superconductivity in low-dimensional systems offers a powerful pathway to engineer topological superconducting phases in, otherwise, non-superconducting systems. These exotic phases are of fundamental and technological interest due to the presence of robust zero-energy modes, the Majorana bound states. In this work, we propose a theoretical framework to realize Majorana bound states from the edge states of a two-dimensional semi-Dirac system. This anisotropic system, under specific conditions, can host non-chiral edge states that propagate only along particular edges, effectively forming separated one-dimensional channels. We show that the interplay between Rashba spin-orbit coupling and a Zeeman field on this setup provides the right conditions to get an effective p-wave pairing between the edge states by proximity with a s-wave superconductor. In finite geometries, each edge can independently undergo a topological phase transition into a one-dimensional topological superconductor and give rise to four zero-energy modes localized at the strip corners. At low energies, the edge states subspace admits a description in terms of coupled Kitaev chains, providing a clear picture of the origin, robustness, and tunability of the corner Majorana modes. Our results establish semi-Dirac materials as a natural platform for realizing Majorana modes in two dimensions without relying on engineered nanostructures, vortices, or crystalline higher-order topology.

2604.22549 2026-04-27 cs.IR

ASPIRE: Make Spectral Graph Collaborative Filtering Great Again via Adaptive Filter Learning

Yunhang He, Cong Xu, Zhangchi Zhu, Hongzhi Yin, Wei Zhang

详情
英文摘要

Graph filter design is central to spectral collaborative filtering, yet most existing methods rely on manually tuned hyperparameters rather than fully learnable filters. We show that this challenge stems from a bias in traditional recommendation objectives, which induces a spectral phenomenon termed low-frequency explosion, thereby fundamentally hindering the effective learning of graph filters. To overcome this limitation, we propose a novel adaptive spectral graph collaborative filtering framework (ASPIRE) based on a bi-level optimization objective. Guided by our theoretical analysis, we disentangle the filter learning objective, which in turn leads to excellent recommendation performance, spectral adaptivity, and training stability in practice. Extensive experiments show our learned filters match the performance of carefully engineered task-specific designs. Furthermore, ASPIRE is equally effective in LLM-powered collaborative filtering. Our findings demonstrate that graph filter learning is viable and generalizable, paving the way for more expressive graph neural networks in collaborative filtering.

2604.22547 2026-04-27 cond-mat.mes-hall

Valley enhanced Rabi frequency in n-type planar Silicon-MOS quantum dot

Xunyao Luo, Xander Peetroons, Tsung-Yeh Yang, Ruben M. Otxoa, Normann Mertig, Sofie Beyne, Julien Jussot, Yosuke Shimura, Clement Godfrin, Bart Raes, Roy Li, Roger Loo, Sylvain Baudot, Stefan Kubicek, Shuchi Kaushik, Danny Wan, Kristiaan De Greve, Takuma Kuno, Takeru Utsugi, Noriyuki Lee, Itaru Yanagi, Toshiyuki Mine, Satoshi Muraoka, Hideo Arimoto, Shinichi Saito, Digh Hisamoto, Ryuta Tsuchiya, Hiroyuki Mizuno, Charles Smith, Andrew Ramsay

Comments 15 pages, 6 figures

详情
英文摘要

Electron spin resonance spectroscopy (ESR) of a single electron in planar Si-MOS quantum dot is reported in the vicinity of a valley level anti-crossing. A number of one and two-photon resonances are observed due to mixing of magnetic spin-flip and electric valley-flip transitions. This allows the reconstruction of the energy-level diagram of a four state system with two valley and two spin states. Near the anti-crossing, an enhancement of the Rabi frequency is observed. This is attributed to an electric-dipole transition activated by admixing of the upper energy level due to inter-valley spin coupling. The electric-dipole transition may be driven via capacitive coupling between the ESR antenna, and the confinement gate. To characterize spin-valley coupling responsible for the enhancement, we measure the anisotropy of the g-factor difference between the two valley states, the mean g-factor and the inter-valley spin coupling for both in and out-of-plane magnetic fields. The inter-valley spin coupling is strongly modulated by the direction of the B-field, and is strongest for out-of-plane B-field, consistent with an in-plane spin-valley field. In principle, this strong Electric dipole spin resonance (EDSR) effect could be utilized for fast all-electrical spin control in small-scale devices.