arXivDaily arXiv每日学术速递 周一至周五更新
全部学科分类 1684
2603.18675 2026-03-20 math-ph math.MP

The Lee-Yang property of isotropic vector ferromagnets and lattice fields

Yuri Kozitsky

详情
英文摘要

The Lee-Yang property of a given spin model means that its partition function has purely imaginary zeros as a function of an external magnetic field. A similar property is also used in the theory of quantum anharmonic crystals and quantum lattice fields. A number of powerful analytic methods of the mathematical theory of such models employ this property. Its suitable generalization is used in the theory of models of isotropic $D$-dimensional spins (rotors) or $D$-component quantum lattice fields. So far, the (generalized) Lee-Yang property has been established only for two-dimensional isotropic models. In this work, we prove that isotropic spin and field models living on $\mathds{Z}$ have this property for all even $D$.

2603.18674 2026-03-20 math.CO

$t$-tone colorings of outerplanar and Halin graphs

Hadeel Al Bazzal, Olivier Togni

详情
英文摘要

A $t$-tone $k$-coloring of a graph $G$ assigns a set of $t$ distinct colors from $\{1, \dots, k\}$ to each vertex so that vertices at distance $d$ share fewer than $d$ common colors. The $t$-tone chromatic number of $G$ is the minimum $k$ such that $G$ has a $t$-tone $k$-coloring. This paper investigates the $t$-tone coloring of two specific subclasses of planar graphs: subcubic outerplanar graphs and Halin graphs. We provide a complete characterization of the $2$-tone chromatic number for subcubic outerplanar graphs and establish a sharp upper bound for their $3$-tone chromatic number. We then turn to Halin graphs and prove that every cubic Halin graph of order $n \ge 6$ is $2$-tone $7$-colorable. Moreover, we derive an upper bound on the $2$-tone chromatic number for Halin graphs with arbitrary maximum degree.

2603.18673 2026-03-20 cond-mat.mtrl-sci

Spectroscopic properties of Cr,Yb:YAG nanocrystals under intense NIR radiation

M. Chaika, R. Tomala, O. Bezkrovnyi, W. Strek

Journal ref Chaika, M., Tomala, R., Bezkrovnyi, O., & Strek, W. (2023). Spectroscopic properties of Cr, Yb: YAG nanocrystals under intense NIR radiation. Materials Research Bulletin, 163, 112201

详情
英文摘要

Laser induced white emission (LIWE) was thoroughly studied in recent decades. However, despite the progress in understanding of this phenomenon, the mechanism behind LIWE remains unclear. The present paper focuses on the influence of Yb content on the LIWE properties of Cr,Yb:YAG nanocrystals. Microstructure and optical properties of the samples were characterized and the influence of the concentration of Yb3+ ions on the spectroscopic properties of Cr,Yb:YAG and energy transfer processes between Cr3+ and Yb3+ ions was revealed. Multiphoton ionization theory was used to explain the findings of the paper.

2603.18672 2026-03-20 cond-mat.str-el

Fermi surface of Kagome metal CsCr$_3$Sb$_5$ observed by laser photoemission microscopy

Hayate Kunitsu, Iori Ishiguro, Natsuki Mitsuishi, Shunsuke Tsuda, Koichiro Yaji, Zehao Wang, Pengcheng Dai, Yoichi Yamakawa, Hiroshi Kontani, Takahiro Shimojima

Comments 11 pages, 3 figures

详情
英文摘要

We investigated the Fermi surface (FS) in the paramagnetic state of Kagome metal CsCr$_3$Sb$_5$ by employing a laser photoemission microscopy. We found a circular FS and two hexagonal FSs around the Brillouin zone (BZ) center. Polarization-dependent measurements further enable us to detect small FS pockets at the BZ boundary. According to the density functional theory calculations, the orbital characters of the FSs were determined from their shape and orientations. We found that the size of the FS is strongly modified for the d$_{xz}$ orbital, suggesting the orbital-dependent correlation effect. These results provide an electronic basis for exploring the interplay of antiferromagnetic/charge density wave order and possible unconventional superconductivity in this compound.

2603.18668 2026-03-20 cs.GT cs.CC cs.DS

Complexity of Auctions with Interdependence

Patrick Loiseau, Simon Mauras, Minrui Xu

详情
英文摘要

We study auction design in the celebrated interdependence model introduced by Milgrom and Weber [1982], where a mechanism designer allocates a good, maximizing the value of the agent who receives it, while inducing truthfulness using payments. In the lesser-studied procurement auctions, one allocates a chore, minimizing the cost incurred by the agent selected to perform it. Most of the past literature in theoretical computer science considers designing truthful mechanisms with constant approximation for the value setting, with restricted domains and monotone valuation functions. In this work, we study the general computational problems of optimizing the approximation ratio of truthful mechanism, for both value and cost, in the deterministic and randomized settings. Unlike most previous works, we remove the domain restriction and the monotonicity assumption imposed on value functions. We provide theoretical explanations for why some previously considered special cases are tractable, reducing them to classical combinatorial problems, and providing efficient algorithms and characterizations. We complement our positive results with hardness results for the general case, providing query complexity lower bounds, and proving the NP-Hardness of the general case.

2603.18667 2026-03-20 hep-lat hep-ex hep-ph

Doubly Bottom and Bottom-Strange Tetraquarks in the Isoscalar Channel

Bhabani Sankar Tripathy, Nilmani Mathur, M. Padmanath

Comments 10 pages, 4 figures, Proceedings of the 42nd International Symposium on Lattice Field Theory (Lattice 2025)

详情
英文摘要

We present our recent investigation on doubly bottom and bottom-strange tetraquarks in the isoscalar channel in search of a possible tetraquark bound state. The calculations are performed on four ensembles with dynamical quark fields up to the charm quark generated by the MILC Collaboration with various lattice spacings. Two volumes have been used to account for finite volume effects. Overlap action has been employed to calculate light and strange quark propagators and NRQCD formulation is utilized for heavy bottom quarks. Finite volume energy has been calculated using the variational method followed by rigorous scattering amplitude analysis à la Lüscher. We find strong evidence for a deeply bound state in the doubly bottom tetraquark channel, but no conclusive evidence for the existence of a bottom-strange tetraquark.

2603.18666 2026-03-20 quant-ph

On-chip Parametric Amplification in a Double Quantum Dots Circuit

Yong-Qiang Xu, Rui Wu, Si-Si Gu, Shun-Li Jiang, Shu-Kun Ye, Bao-Chuan Wang, Hai-Ou Li, Guang-Can Guo, Chang-Ling Zou, Gang Cao, Guo-Ping Guo

Comments 7 pages, 4 figures

Journal ref Yong-Qiang Xu, Rui Wu, Si-Si Gu, et al. On-chip parametric amplification in a double quantum dots circuit [J]. SCIENCE CHINA Physics, Mechanics & Astronomy, 2026, 69 (5): 2026-03-18. 2026-03-19

详情
英文摘要

In microwave-based quantum circuits, including double quantum dots (DQDs), superconducting qubits and spin qubits, parametric amplifiers are indispensable in achieving high-fidelity qubit readouts. Despite its importance, the application of parametric amplifiers is hampered by several challenges, such as high insertion losses, constrained tunability, and a pronounced vulnerability to magnetic fields. Here, we demonstrate an on-site single-atom parametric amplifier (SAPA) within a reconfigurable quantum circuit, which consists of a superconducting microwave cavity and two GaAs gate-defined DQDs. Leveraging the inherent nonlinearity of the DQD, a parametric gain exceeding 11 dB is achieved. This gain contributes to enhance the qubit readout, as evidenced by exceeding two times improvement in the signal-to-noise ratio (SNR) when employing the DQD-based amplifier for reading out another DQD. Our work not only presents a versatile experimental platform with enhanced readout capabilities in quantum computing, but also introduces alternative choices of parametric amplifiers for a variety of microwave-based quantum circuits.

2603.18665 2026-03-20 quant-ph cond-mat.stat-mech math-ph math.MP

Schrödinger Bridges via the Hacking of Bayesian Priors in Classical and Quantum Regimes

Clive Cenxin Aw, Peter Sidajaya

Comments 12 pages (main text, 23 pages total with appendix), 8 Figures,

详情
英文摘要

Bayes' rule is widely regarded as the canonical prescription for belief updating. We show, however, that one can arbitrarily preserve pre-specified beliefs while appearing to perform Bayesian updates via "prior hacking": engineering a reference prior distribution such that, for a fixed channel and evidence, the update matches a chosen target distribution. We prove that this is generically possible in both classical and quantum settings whenever Bayesian inversions are well-defined (with the Petz recovery map as the quantum analogue to Bayes' rule), and provide constructive algorithms for doing so. We further establish a duality between prior hacking and Schrödinger bridge problems (a key object in statistical physics with applications in generative modelling), yielding in the quantum setting a unique, inference-consistent selection among candidate bridges. This formally establishes the Bayes-like updating that Schrödinger bridges are performing with respect to the process as opposed to the reference prior, both in classical and quantum settings.

2603.18664 2026-03-20 cond-mat.mtrl-sci

The influence of nonradiative relaxation on laser induced white emission properties in Cr:YAG nanopowders

M. Chaika, R. Tomala, O. Bezkrovnyi, W. Strek

Journal ref Chaika, M., Tomala, R., Bezkrovnyi, O., & Strek, W. (2023). The influence of nonradiative relaxation on laser induced white emission properties in Cr: YAG nanopowders. Journal of Luminescence, 257, 119734

详情
英文摘要

Laser Induced White Emission (LIWE) is the subject of research worldwide. Since its discovery, the understanding of this phenomenon has progressed successfully enough to reach industrial applications. However, a lack of understanding of the nature of this phenomenon limits its potential. This article is devoted to the study of the influence of nonradiative relaxation processes on the properties of laser induced white emission in Cr:YAG nanopowders. The concentration series of Cr:YAG nanopowders was synthetized by Pechini method. The microstructure, optical and LIWE properties were studied. The influence of chromium concentration on the number of photons involved in LIWE process (N parameter) is shown. The increase of N parameter is associated with an increase in the probability of non-radiative recombination processes with an increase of chromium concentration. A multiphoton ionization model is proposed to describe LIWE phenomenon.

2603.18663 2026-03-20 math.DS

A Julia-Fatou Theory via Random Systems with Complete Connections

Yoshiyuki Endo

Comments 29 pages

详情
英文摘要

We develop a Julia-Fatou theory for random dynamical systems of continuous self-maps on a compact metric space, driven by random systems with complete connections (RSCCs). This framework allows the selection rule to depend on the evolving state and, in general, on the entire past, going beyond the Markovian graph directed Markov system setting. For each state we define Julia, Fatou, and kernel Julia sets via equicontinuity of admissible composition families, and we introduce a pathwise and skew product viewpoint. Under natural compactness and continuity assumptions on the RSCC, we study the associated averaged dynamics on the product space and prove Cooperation Principle I: if the kernel Julia set is empty at every state and the admissible maps are open, then the iterates of the adjoint transition operator are equicontinuous on the whole space of probability measures, and along almost every admissible path the fiberwise Julia set has zero mass for any given finite measure. We further identify a new phenomenon specific to RSCCs, namely emptiness jumps of kernel Julia sets along admissible state trajectories, and provide criteria excluding such jumps, including discreteness of the state space and a propagation mechanism under phi-irreducibility. Several examples, motivated by reinforcement and feedback mechanisms, illustrate both the jump phenomenon and the applicability of the Cooperation Principle I in non-Markovian settings.

2603.18659 2026-03-20 cond-mat.mtrl-sci

Surface-related white light emission phenomenon in transparent solids

M. Chaika, R. Tomala, M. Oleszko, W. Strek

Journal ref Chaika, M., Tomala, R., Oleszko, M., & Strek, W. (2022). Surface-related white light emission phenomenon in transparent solids: M. Chaika et al. MRS Advances, 7(34), 1095-1098

详情
英文摘要

Laser induced white emission (LIWE) caused by infrared laser excitation in Cr:YAG transparent ceramics was investigated. It was found that ceramics generates bright LIWE for excitation powers above a critical threshold. The LIWE was observed on the surface but not in the bulk on both sides of the sample. The vacuum conditions are required to observe LIWE. This phenomenon was discussed within the frame of Inter-Valence Charge Transfer (IVCT) mechanism in the Cr3+/Cr4+ ion pair.

2603.18658 2026-03-20 eess.SY cs.SY

Mean-field control barrier functions for stochastic multi-agent systems

Cinzia Tomaselli, Gian Carlo Maffettone, Samy Wu Fung, Levon Nurbekyan, Mario di Bernardo

详情
英文摘要

Many applications involving multi-agent systems require fulfilling safety constraints. Control barrier functions offer a systematic framework to enforce forward invariance of safety sets. Recent work extended this paradigm to mean-field scenarios, where the number of agents is large enough to make density-space descriptions a reasonable workaround for the curse of dimensionality. However, an open gap in the recent literature concerns the development of mean-field control barrier functions for Fokker-Planck (advection-diffusion) equations. In this work, we address this gap, enabling safe mean-field control of agents with stochastic microscopic dynamics. We provide bounded stability guarantees under safety corrections and corroborate our results through numerical simulations in two representative scenarios, coverage and shepherding control of multi-agent systems.

2603.18654 2026-03-20 cs.DB

QuaQue: Design and SQL Implementation of Condensed Algebra for Concurrent Versioning of Knowledge Graphs

Jey Puget Gil, Emmanuel Coquery, John Samuel, Gilles Gesquière

Comments 11 pages, 6 figures, DBKDA conference

Journal ref DBKDA 2026, The Eighteenth International Conference on Advances in Databases, Knowledge, and Data Applications

详情
英文摘要

The management of versioned knowledge graphs presents significant challenges, particularly in querying data across multiple versions efficiently. This paper introduces QuaQue, a key component of the ConVer-G system, which addresses this challenge by translating SPARQL (SPARQL Protocol and RDF Query Language) queries into SQL (Structured Query Language). QuaQue leverages a novel condensed algebra to operate on a relational model where versioning information is compactly stored using bitstrings. This approach allows for efficient querying of concurrent versions of knowledge graphs within a standard relational database system. We present the key concepts of our condensed algebra, detail the translation process from SPARQL algebra to SQL, and provide a comparative benchmark against a native RDF (Resource Description Framework) triple store, demonstrating the viability and performance benefits of our approach.

2603.18653 2026-03-20 math.OC

Robust Discrete Pricing Optimization via Multiple-Choice Knapsack Reductions

Zi Yuan Eric Shao

Comments 28 pages, 10 figures. Code available at https://github.com/eric939/robust_mckp

详情
英文摘要

We study a discrete portfolio pricing problem that selects one price per product from a finite menu under margin and fairness constraints. To account for demand uncertainty, we incorporate a budgeted robust formulation that controls conservatism while remaining computationally tractable. By reducing the problem to a Multiple-Choice Knapsack Problem (MCKP), we identify structural properties of the LP relaxation, in particular upper-hull filtering and greedy filling over hull segments, that yield an exact solution method for the LP relaxation of the fixed-parameter subproblems. For the resulting fixed-parameter subproblems, we show that the integrality gap is bounded additively by a single-item hull jump, and that the corresponding relative gap decays as O(1/n) under standard boundedness and linear-growth assumptions. Numerical experiments on synthetic portfolios and a stylized retail case study with economically calibrated parameters are consistent with these bounds and indicate that robust margin protection can be achieved with less than 1 percent nominal revenue loss on the instances tested.

2603.18651 2026-03-20 math.MG

Proof of the Generalization of the Sawayama-Thébault Theorem

Miłosz Płatek

详情
英文摘要

We prove two conjectures posed in 2016 concerning a generalization of the Sawayama-Thébault Theorem and the Sawayama Lemma. We show that this generalized statement can be viewed in Laguerre geometry, which provides a natural framework for resolving the problem.

2603.18650 2026-03-20 cond-mat.mtrl-sci cs.DB

DeePAW: A universal machine learning model for orbital-free ab initio calculations

Tianhao Su, Shunbo Hu, Yue Wu, Runhai Oyang, Xitao Wang, Musen Li, Jeffrey Reimers, Tong-Yi Zhang

详情
英文摘要

Developing universal machine learning models for ab initio calculations is the frontier of materials cutting edge research in the new era of artificial intelligence. Here, we present the Deep Augment Way model (DeePAW) that is a universal machine learning (ML) model for orbital-free (OF) ab initio calculations, based on the density functional theory (DFT). DeePAW is currently the best OFDFT ML model according to the three criterions, 1) covering the largest number of elements, 2) having the widest application capability to diverse crystal structures, and 3) achieving the highest prediction accuracy without further fine-tuning. These scientific merits and innovations of DeePAW are stemmed from the novel SE(3)-equivariant double massage passing neuron networks. Besides predicting electron density distributions, DeePAW predicts formation energies of crystals as well and therefore paves an efficient avenue for multiscale materials modeling beyond conventional electronic structure calculation methods.

2603.18648 2026-03-20 math.SG math.DS

Birkhoff normal forms, Dirac brackets and symplectic reduction

Jose Lamas, Lei Zhao

详情
英文摘要

Dirac brackets are widely used to study constrained Hamiltonian dynamics. In this paper we develop a Dirac-bracket approach to normal forms on momentum levels and relate it to symplectic reduction in the cases where reduction yields a (stratified) symplectic quotient. We consider a proper Hamiltonian $G$-action on a symplectic manifold $(M,ω)$ with an equivariant momentum map $J$. We fix $μ\in \mathfrak g^*$and work on $J^{-1}(μ)$. For $G$-invariant Hamiltonians whose induced vector field on $J^{-1}(μ)$ is tangent to a local $G_μ$-slice, we show that the induced evolution on $J^{-1}(μ)$ coincides with that defined by the Dirac bracket on a local second-class slice, and descends to the corresponding symplectic stratum of $J^{-1}(μ)/G_μ$. As a main application we study Birkhoff normal forms near a relative equilibrium. When the quadratic part of a symmetric Hamiltonian is tangent to a local $G_μ$-slice, a Birkhoff normal form can be constructed entirely on the manifold $J^{-1}(μ)$, and it descends to a Birkhoff normal form for the reduced dynamics on the corresponding stratum, even when the reduced space is singular. We show that for a class of simple mechanical systems this condition holds automatically at a relative equilibrium. We illustrate the method on the double spherical pendulum. Finally, we relate our results to Moser's constrained dynamics by identifying Moser's constrained vector field with the Dirac Hamiltonian vector field. We show that, if the reduced Hamiltonian is near-integrable on a stratum, then its pullback to the symplectic slice is near-integrable with respect to the Dirac bracket, and vice versa. In particular, this provides a practical route to KAM-type results for the constrained dynamics.

2603.18646 2026-03-20 math.CO

Constructing orientable and negative orientable sequences with asymptotically optimal period

Chris J Mitchell, Peter R Wild

详情
英文摘要

Orientable sequences, periodic sequences in which any $n$-tuple appears at most once in either direction, were introduced in the early 1990s for use in certain position location applications; constructions and upper bounds on the period for the binary case were published by Dai et al. More recent work has focussed on $k$-ary sequences for arbitrary $k>2$; one method of construction involves negative orientable sequences, in which an $n$-tuple appears at most once in either the sequence or the negative of its reverse. In this paper we show how additional $n$-tuples can be added to one previously described approach for generating negative orientable sequences, resulting in new sequences with asymptotically optimal period. These sequences can in turn be used to generate orientable sequences, again with asymptotically optimal period.

2603.18644 2026-03-20 astro-ph.EP

Dust, gas activity and morphology of comet 12P/Pons-Brooks at heliocentric distances beyond 1.1 au

Marek Husárik, Gulchehra Kokhirova, Valerii Kleshchonok, K. Aravind, Firuza Rakhmatullaeva, Margarita Safonova, Oleksandra Ivanova, Olena Shubina, Arsenii Kasianchuk

Comments 19 pages

详情
英文摘要

Comet 12P/Pons-Brooks is a periodic comet with an orbital period of approximately 71 years. Because of the period duration, aphelion of 35.3 au, and highly inclined orbit (74.2 deg), it is classified as a Halley-type comet. In this work, we present the results of the analysis of photometric and spectral observations of comet 12P/Pons-Brooks while it was at a heliocentric distance beyond 1.1 au, before perihelion passage. Quasisynchronous observations were carried out from July 2023 to March 2024 using 0.61-m and 1.3-m telescopes at the Skalnaté Pleso Observatory, 1-m telescope Zeiss-1000 Sanglokh International Astronomical Observatory, and 0.7-m telescope AZT8 at the observation station of Taras Shevchenko National University of Kyiv. Photometric observations were conducted using B, V, and R filters of the Johnson-Cousins and Bessel photometric systems. We completed our data collection with broadband photometric and spectral observations on the 2-m HCT telescope at the Indian Astronomical Observatory. During this period, the dust coma morphology and photometric data measured in the R filter, such as the apparent, absolute magnitudes and dust activity level, indicate several repeated outbursts in brightness and dust activity occurred around July 22, September 25, October 17-23, and a significant outburst was recorded on November 1-7. We detected strong gas emission features in the cometary spectrum belonging to CN, C2, and C3 molecules. Furthermore, gas production rates of these molecules were estimated using Haser's model. A comparison of dust activity level and CN gas production rate shows that dust activity increased significantly as the comet approached the Sun, while gas activity exhibited more moderate changes.

2603.18643 2026-03-20 math.AG cs.NA math.NA

The Geometry of Polycons and a Counterexample to Wachspress' Conjecture

Clemens Brüser

Comments 17 pages, 5 figures

详情
英文摘要

Polycons, initially introduced by Wachspress in 1975 as a tool in finite element methods, are generalizations of polygons in that they allow conic boundary components. We are interested in the adjoint curve of a given polycon, i.e. the unique curve of minimal degree vanishing in the so-called residual arrangement. It was conjectured by Wachspress that under some regularity assumptions this curve does not vanish in the interior of its defining polycon. However, until recently the only class of polycons for which this was proven were convex polygons. We present a polycon bounded by three conics that constitutes a counterexample to Wachspress' conjecture. The origin of this counterexample reveals some beautiful geometry of polycons. Replacing one degree two boundary component of a polycon with a line produces a new polycon. We show that the adjoint of the latter is a contact curve to the adjoint of the former. This naturally leads to the consideration of symmetric linear determinantal representations of adjoints, which lets us explicitly describe the fibers of the adjoint map in the case of polycons bounded by three conics. As a corollary we prove that generically the adjoint of a polycon bounded by three conics is smooth.

2603.18638 2026-03-20 math.CO math.AT

Holey Hyperbolic Polyforms

Summer Eldridge, Adithya Prabha, Aiden Roger, Cooper Roger, Érika Roldán, Rosemberg Toalá-Enríquez

Comments 5 figures, 7 tables

详情
英文摘要

A polyform is a planar figure formed by gluing congruent regular polygons along entire edges. We study polyforms in hyperbolic ${p,q}$-tessellations and the extremal problem of minimizing the number of tiles needed to realize exactly $h$ holes. Denoting this minimum by $g_{p,q}(h)$, we establish general lower and upper bounds, compute exact values in several small cases, and give a sufficient structural condition for a polyform to have $h$ holes and $g_{p,q}(h)$ tiles.

2603.18635 2026-03-20 eess.SP

Secure Cell-Free Massive MIMO ISAC Systems: Joint AP Selection and Power Allocation Against Eavesdropping

Ruiguang Wang, Takumi Takahashi, Hideki Ochiai

Comments Accepted by IEEE WCNC 2026

详情
英文摘要

This paper investigates a cell-free massive multiple-input-multiple-output (CF-mMIMO) integrated sensing and communication (ISAC) system that addresses the critical challenge of information leakage to potential eavesdroppers located within sensing zones. A novel access point (AP) selection strategy is proposed, which partitions the distributed APs into two functional groups: communication APs (C-APs), dedicated exclusively to data transmission, and sensing APs (S-APs), responsible for target detection and eavesdropper suppression. Closed-form expressions for the achievable communication rate, eavesdropping rate, and mainlobe-to-average-sidelobe ratio (MASR) are derived to evaluate system performance. Two complementary optimization problems are formulated using the successive convex approximation (SCA): (i) maximizing user rates under security constraints and (ii) minimizing eavesdropping rates while satisfying quality of service (QoS) requirements. The proposed joint optimization framework determines the optimal AP operational modes and power allocation across communication and sensing links. Extensive numerical results validate the theoretical analysis and demonstrate significant performance gains, revealing inherent trade-offs among communication efficiency, sensing accuracy, and security. These insights offer practical guidelines for designing secure CF-mMIMO ISAC systems.

2603.18632 2026-03-20 nucl-ex nucl-th

Single-particle strength toward N = 32: Spectroscopy of 51 Ca via the 50 Ca(d, p) reaction

C. Ferrera, K. Wimmer, D. Suzuki, N. Imai, A. Jungclaus, T. Miyagi, Y. Utsuno, D. Das, T. Chillery, S. Hanai, J. W. Hwang, N. Kitamura, R. Kojima, S. Michimasa, R. Yokoyama, Y. Anuar, M. Armstrong, S. Bae, Y. Cho, M. Dozono, F. Endo, S. Escrig, N. Fukuda, T. Haginouchi, S. Hayakawa, Y. Hijikata, G. Ikemizu, S. Ishio, A. Kasagi, K. Kawata, J. Li, S. Masuoka, B. Moon, K. Okawa, S. Ota, H. Qin, T. Saito, A. Sakaue, H. Sakurai, Y. Shimizu, S. Shimoura, Y. Son, T. Sumikama, H. Suzuki, H. Takeda, Y. Togano, J. Vesic, K. Yako, Y. Yamamoto, K. Yoshida, M. Yoshimoto

Comments PRC accepted

详情
英文摘要

States in the neutron-rich isotope 51 Ca were populated via the 50 Ca(d, p) transfer reaction in inverse kinematics at a beam energy of about 14 AMeV. The experiment was performed using a decelerated radioactive 50 Ca beam from the OEDO facility and the TiNA2 silicon array in combination with the SHARAQ magnetic spectrometer at RIBF/RIKEN. The energies of excited states in 51 Ca were reconstructed via missing mass spectroscopy, and angular distributions of protons were measured to extract differential cross sections. From a comparison with adiabatic distorted wave approximation (ADWA) calculations, spectroscopic factors were deduced for several states, including the ground state and excited states up to 4.2 MeV. These results are compared with shell-model calculations, as well as ab initio valence-space in-medium similarity renormalization group (VS-IMSRG) predictions. The data support the assignment of the 1/2- and 5/2- single-particle states and provide evidence for a candidate 9/2+ state with a structure consistent with neutron excitation into the 0g9/2 orbital. These findings contribute new constraints on the single-particle structure and shell evolution in neutron-rich calcium isotopes.

2603.18630 2026-03-20 hep-ex

Combined effective field theory interpretation of measurements sensitive to quartic gauge boson couplings in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

ATLAS Collaboration

Comments 35 pages in total, author list starting page 18, 5 figures, 3 tables, submitted to PLB. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2023-21/

详情
英文摘要

A combination of measurements sensitive to anomalous quartic electroweak gauge boson couplings is presented using proton-proton collision data collected by the ATLAS detector at $\sqrt{s} = 13$ TeV at the LHC. Contributing analyses include measurements of vector-boson scattering in numerous final states as well as a tri-boson measurement. The combined measurement is used to constrain anomalous electroweak boson quartic self-couplings that result from dimension-8 operators in the Éboli model using an effective field theory. Results are presented as 68% and 95% confidence level intervals parameterised by one or two Wilson coefficients, both with and without unitarity constraints applied. Theoretical bounds from unitarity and positivity are overlaid where relevant. Confidence intervals obtained from simultaneous profiled fits to all Wilson coefficients are also presented.

2603.18629 2026-03-20 eess.SP

Enabling 6G Wireless Communications: UWB Characterization of Corridors within the H-Band

Juan E. Galeote-Cazorla, Alejandro Ramírez-Arroyo, Mauricio Rodríguez, Reinaldo Valenzuela, Juan F. Valenzuela-Valdés

详情
英文摘要

Future sixth-generation of wireless system is expected to provide data-rates in the order of 1 Tbps and latencies below 1 ms. Among others, one of the most promising strategies to meet these requirements is to operate at higher frequencies than millimeter wave bands: the THz bands. Nevertheless, because of the higher losses and the detriment of classical propagation mechanisms, deploying systems operating at these frequencies becomes a real challenge. Consequently, short-range scenarios are of special interest since these effects of THz bands can be managed. This work conducts an extensive campaign within corridors at frequencies within the H-band in the range from 250 GHz to 330 GHz. For the first time in literature, an ultra wideband of 80 GHz is studied simultaneously. Large scale effects are assessed by estimating and modeling path gain. The path gain exponent varies between -2.1 and -1.6, which is explained by a guiding effect also observed at millimeter wave bands. Small scale effects are also evaluated in terms of parameters such as rice $K$-factor, root mean squared delay spread and coherence bandwidth. Additionally, an analytical approximation based on the classical N-rays model is proposed obtaining an accurate representation of the wireless channel which is coherent with the empirical analysis. The full analysis reveals the suitability of these THz bands for deploying point-to-point links due to the predominance of the line-of-sight contribution respect to the reflected components.

2603.18622 2026-03-20 physics.flu-dyn

Reduced-order turbulent flow solver to simulate streamwise periodic fins with iso-thermal walls

Nitish Anand, Praharsh Pai Raikar, Carlo De Servi

详情
英文摘要

Assessment of the thermo-hydraulic performance of heat exchangers using computational fluid dynamics is a challenging task. The intricate geometries of a heat exchanger require a fine discretization of the flow passage, which consequently leads to high computational costs. A streamwise periodic flow model can significantly reduce this cost, particularly for heat exchangers featuring repeating structures. This manuscript presents the streamwise-periodic turbulent source terms for flows in channels with isothermal walls, along with the implementation of the corresponding periodic flow solver in the open-source CFD-Suite, SU2. The accuracy of the implemented solver was verified by comparing its predictions against those of a full fin array simulation for the test case of offset circular fins. The results show that the streamwise periodic flow solver accurately reproduces the solutions of the full array simulation under both laminar and turbulent flow conditions.

2603.18621 2026-03-20 cond-mat.mes-hall cond-mat.supr-con

Topological superconductivity of a two-dimensional electron gas at the (001) LaAlO\textsubscript{3}/SrTiO\textsubscript{3} interface

Piotr Żeberek, Paweł Wójcik

Comments 17 pages, 12 figures

详情
英文摘要

We investigate the emergence of topological superconductivity and Majorana zero modes in the two-dimensional electron gas formed at the LaAlO$_3$/SrTiO$_3$ (001) interface. Using a realistic multiband tight binding model that incorporates the $t_{2g}$ orbital structure together with atomic and Rashba spin-orbit couplings, we determine the topological phase diagrams for both fully two-dimensional and quasi-one-dimensional geometries. In the two-dimensional limit, we show that a finite out-of-plane magnetic-field component is required to drive a topological phase transition. In this case, the critical field is strongly band dependent, and for higher-lying bands, it is controlled by the interplay of spin and orbital Zeeman effects, as well as atomic spin-orbit coupling. Although a purely in-plane field is insufficient to induce the topological transition in a full 2D system, we demonstrate that a lateral confinement relaxes this constraint. In this case, the character of the edge modes depends sensitively on the field orientation, with out-of-plane fields producing conventional counterpropagating chiral modes and transverse in-plane fields giving rise to co-propagating antichiral modes. Finally, Majorana zero modes in LAO/STO nanowires with varying widths are analyzed. We demonstrate that subbands predominantly composed of $d_{yz/xz}$ orbitals exhibit exceptionally long localization lengths, which may preclude the observation of Majorana bound states in nanowires of typical experimental dimensions.

2603.18619 2026-03-20 math.GT

Local Knots, $ν^+$-Sharp Knots, and Rational Slice Genus

Junghwan Park, Zhongtao Wu, Jingling Yang

Comments 16 pages, 1 figure

详情
英文摘要

Hom and Wu introduced the knot concordance invariant $ν^{+}$ for knots in $S^{3}$ and proved that it gives a lower bound for the slice genus. Wu and Yang extended $ν^{+}$ to knots in rational homology $3$-spheres, where it gives a lower bound for the rational slice genus, an analogue of the slice genus for knots in rational homology $3$-spheres. We call a knot $ν^{+}$-sharp if this bound is realized as an equality. An open question asks whether a local knot in a $3$-manifold $Y$, that is, a knot contained in a $3$-ball, can bound a surface of smaller genus in $Y\times I$ than in $S^{3}\times I$. Using the Heegaard Floer invariant $ν^+$, we show that this does not occur for local knots arising from $ν^+$-sharp knots: if $K\subset S^3$ is $ν^+$-sharp and $Y$ is a rational homology $3$-sphere, then the induced local knot in $Y$ has rational slice genus equal to the slice genus of $K$. The proof proceeds by establishing an additivity result for the rational slice genus.

2603.18618 2026-03-20 cond-mat.soft cond-mat.stat-mech

Non-equilibrium (thermo)dynamics of colloids under mobile piston compression

Arturo Moncho-Jordá, José López-Molina, Joachim Dzubiella

Comments 17 pages, 10 figures

详情
英文摘要

We investigate the non-equilibrium compression of a confined hard-sphere colloidal fluid driven by a mobile boundary within dynamical density functional theory. The system consists of a fluid confined between two parallel walls, one acting as an overdamped piston subjected to a sudden increase in external pressure. The piston motion is controlled by a mobility parameter $K$, which sets the relative timescale between mechanical driving and diffusive relaxation. By varying $K$ over several orders of magnitude, we identify a crossover from quasi-static compression to a diffusion-limited strongly driven regime. For small $K$, the system evolves close to equilibrium and the total injected work approaches the equilibrium free-energy difference. For large $K$, the piston rapidly adjusts and the dynamics becomes governed by diffusive relaxation, leading to saturation in the piston trajectory, pressure--position relation, particle currents, and center-of-mass velocity. In this regime, the injected work and entropy production are bounded, reflecting constraints imposed by diffusive transport. The maximum injected power scales linearly with $K$, while the entropy-production peak exhibits a crossover from quadratic growth to saturation, with peak times displaying $1/K$ scaling. The entropy change of the thermal bath interpolates between a reversible limit and a strongly driven dissipative regime. Finally, the evolution of configurational entropy and external potential energy reveals a dynamical decoupling between confinement and structural relaxation, including transient non-monotonic behavior. These results provide a quantitative thermodynamic characterization of boundary-driven compression.

2603.18617 2026-03-20 math.DS

Periodicity and Rotation Number for Random Circle Homeomorphisms

Zixu Li, Simon Lloyd

Comments 14 pages,3 figures

详情
英文摘要

We study discrete-time random dynamical systems where each fibre map is an orientation-preserving homeomorphism of the circle. We prove that the existence of a random periodic cycle with period at least two implies that the random rotation number is rational almost surely. Moreover, in clear contrast with the deterministic setting, we demonstrate that a common fixed point for the fibre maps does not imply that the random rotation number is an integer. Conversely, we show that if the mean random rotation number is an integer, then the fibre maps have a fixed point with positive probability.