Rediscussion of eclipsing binaries. Paper XXIX. The F-type twin system BS Draconis
Comments Accepted for publication in The Observatory. 16 pages, 5 tables, 6 colour figures
John Southworth
Comments Accepted for publication in The Observatory. 16 pages, 5 tables, 6 colour figures
We present an analysis of BS Dra, a detached eclipsing binary containing two almost-identical F3 V stars in a 3.36-d circular orbit, based on 40 sectors of observations from the Transiting Exoplanet Survey Satellite (TESS) and published spectroscopic results. We measure masses of 1.305 +/- 0.015 Msun and 1.284 +/- 0.017 Msun, and radii of 1.409 +/- 0.006 Rsun and 1.400 +/- 0.006 Rsun, for the two components. The high quality of the TESS data allow -- for the first time -- a definitive identification of the primary eclipse, which is 0.007 mag deeper than the secondary. The primary star is the hotter, larger and more massive of the two: the ratios of the radii and surface brightnesses are both slightly but significantly below unity. We find a distance concordant with the Gaia DR3 parallax and, by comparison to theoretical models, an age of 1600 +/- 300 Myr and a slightly sub-solar chemical composition. Our mean times of primary eclipse, each representing all eclipses in one sector, have a scatter of only 0.37 s around a linear ephemeris: BS Dra may be useful as a celestial clock.
Christopher A. Browne, Paul G. Severino, Yvonne Zagzag, Jacob Z. Cloutier, Aaron C. Boyd, Yihao Chen, Arjun G. Yodh, Chinedum O. Osuji
Liquid-liquid crystal phase separation (LLCPS) occurs in many industrial and biological settings. To date the states of the separated condensed liquid crystals have been found to be nematic, columnar, or smectic phases. Interestingly, when smectic phases condense out of the liquid, they can form filamentous condensates that spontaneously assemble into sparse networks with rich life-like dynamics. Here, we study the underlying process of filament linking and conformational changes that mediates formation of these unique networks. Microscopy reveals that new linkages between filaments are initiated by an adhesive interaction between straight filaments; the filaments snap into contact and then rapidly wind into helical coils, despite the absence of molecular chirality or transitions between mesophases. Using polarized optical microscopy, theoretical modeling, and simulation, we show that filament linking into ribbon structures is driven by arrested coalescence that depends on both interfacial energy minimization and the constraints of smectic order. The linked filaments spontaneously coil into double helices to reduce interfacial area and smectic distortion, thus driving compaction into networks. We propose a microstructure consistent with this interpretation, which quantitatively predicts the extent of arrested coalescence. In total, these findings suggest a generic pathway for network formation in liquid crystals that provides insight about the formation of condensate networks in other engineered or biological materials.
Yirui Zheng, Juntai Shen, Bin-Hui Chen
Comments 14 pages, 7 figures. will be submitted to ApJ. Comments are welcome!
We run a suite of $N$-body simulations to investigate how classical bulges affect bar formation and properties under the internal formation mechanism. We incorporate bulges of varying mass and compactness into disk galaxy models and evolve them in isolation to examine the resulting bar pattern speeds and growth timescales. A more massive/compact bulge increases the Toomre $Q$ stability parameter and the circular velocity in the central region, while decreasing the disk mass fraction. It therefore delays the onset of bar formation and increases the bar growth timescale; sufficiently strong bulges can suppress bar formation entirely. During the formation stage, bars exhibit higher initial pattern speeds and faster deceleration rates when the bulges become more massive or compact. This faster deceleration persists after the bar buckling phase, leading to slower-rotating bars in the secular growth stage. However, when the bulge's "diluting" effect on the measured bar strength is removed or reduced, all bars within the same disk share similar distributions in the pattern speed-bar strength ($Ω_p$-$A_2$) space during the secular growth stage. They also show comparable ratios of the co-rotation radius to the bar length ($\mathcal{R}=R_{\mathrm{CR}}/R_{\mathrm {bar}}$) in this stage. These results suggest that the bulge's influence on the pattern speed is more significant during the bar formation stage, while in the secular growth stage, the bulge's effect may be less important, and the disk component dominates the pattern speed evolution.
Wojciech Kotlarski, Alexander Voigt
Comments 26 pages, 5 figures, 2 tables
FlexibleSUSY is a framework for an automated calculation of observables in user-defined models of a Beyond the Standard Model (BSM) physics, starting from the model's field content and its Lagrangian. Among a plethora of observables it is capable of calculating are the high precision predictions for Higgs bosons decay widths. Building on these previous developments we present here an interface between FlexibleSUSY and HiggsTools/Lilith. Combined with other FlexibleSUSY capabilities this extension provides a fully automatized tool chain leading directly from a user-defined BSM model to the state-of-the-art validation of the global agreement of a BSM Higgs sector with experimental measurements. We demonstrate this extension on a handful of phenomenologically relevant examples: a CP-conserving version of the Type-II Two Higgs Doublet Model, the CP-violating Next-to-Minimal Supersymmetric Standard Model and the Minimal R-symmetric Supersymmetric Standard Model. These examples show the power of FlexibleSUSY when applied to supersymmetric and non-supersymmetric models, both with and without CP-violation, and illustrate the handling of invisible and undetected decay widths.
Kristian Uldall Kristiansen
In this paper, we present a geometric approach to exponentially small splitting in zero-Hopf bifurcations of arbitrary co-dimension. In further details, we consider a family of problems that generalizes the third order Michelsen/Kuramoto-Sivashinsky-type equations $ε^{2(κ-1)} f'''+f'={Q}(f)$, where ${Q}$ is an arbitrary real polynomial with $κ=\operatorname{degree}Q\ge 2$ simple real roots. For $ε=0$, the system has $(κ-1)$-many heteroclinic connections and we describe the exponentially small splitting for each connection for all $0<ε\ll 1$ under a separate nondegeneracy condition. In particular, we find that the $j$th-splitting is of the form $ε^{-\frac{3κ}{2}}\exp\left({-ε^{1-κ}T^j}\right)(C^j+\mathcal O(ε))$, where $T^j>0$ can be calculated explicitly and be interpreted as the blowup time of special unbounded solutions of the $ε=0$-limiting system in imaginary time $f'=iQ(f)$. Our approach extends a similar geometric method developed by the present author for the generic zero-Hopf bifurcation of co-dimension two, which does not rely on explicit time-parametrizations of the unperturbed heteroclinic connections and their singularities in the complex plane. Instead, we work exclusively in the complexified phase space and relate the exponentially small splitting to the lack of analyticity of center-like invariant manifolds of associated generalized saddle-nodes.
Nicholas Zobrist, John Mark Kreikebaum, Mostafa Khezri, Sergei V. Isakov, Brian J. Lester, Yaxing Zhang, Agustin Di Paolo, Daniel Sank, W. Clarke Smith
Fast and high-fidelity qubit measurement plays a key role in quantum error correction. In superconducting qubits, measurement is typically performed using a resonant microwave drive on a readout resonator dispersively coupled to the qubit. Shorter measurement times require larger numbers of photons populating the readout resonator, which ultimately leads to undesired measurementinduced state transitions (MIST) of the qubit. MIST can be particularly problematic because these transitions often leave the qubit in a high energy state, and the MIST locations in readout parameter space drift as a function of qubit offset charge. In transmon qubits, these drifts have been avoided using very large qubit-resonator detunings or dedicated offset charge biases. In this work, we take an alternative approach and add an inductive shunt to the transmon to eliminate the offset charge dependence and stabilize the MIST. We experimentally characterize MIST in several different inductively-shunted transmons, in agreement with quantum and semiclassical models for MIST. These results extend to other inductively-shunted qubits.
Luigi Alfonsi, Leron Borsten, Mehran Jalali Farahani, Hyungrok Kim, Martin Wolf, Charles Alastair Stephen Young
Comments v1: 25 pages
Homotopy algebraic methods have become increasingly influential in studying field theories. We consider semi-holomorphic Chern-Simons theory and its relation with the principal chiral model. In particular, we establish an explicit quasi-isomorphism between the cyclic $L_\infty$-algebras governing both theories which directly gives the Lax connection. This provides a concrete example for studying integrability of a two-dimensional system through the homotopy algebraic lens.
Andreas Kalavas, Ioannis Psarros
Comments 22 pages
We study the following range searching problem in high-dimensional Euclidean spaces: given a finite set $P\subset \mathbb{R}^d$, where each $p\in P$ is assigned a weight $w_p$, and radius $r>0$, we need to preprocess $P$ into a data structure such that when a new query point $q\in \mathbb{R}^d$ arrives, the data structure reports the cumulative weight of points of $P$ within Euclidean distance $r$ from $q$. Solving the problem exactly seems to require space usage that is exponential to the dimension, a phenomenon known as the curse of dimensionality. Thus, we focus on approximate solutions where points up to $(1+\varepsilon)r$ away from $q$ may be taken into account, where $\varepsilon>0$ is an input parameter known during preprocessing. We build a data structure with near-linear space usage, and query time in $n^{1-Θ(\varepsilon^4/\log(1/\varepsilon))}+t_q^{\varrho}\cdot n^{1-\varrho}$, for some $\varrho=Θ(\varepsilon^2)$, where $t_q$ is the number of points of $P$ in the ambiguity zone, i.e., at distance between $r$ and $(1+\varepsilon)r$ from the query $q$. To the best of our knowledge, this is the first data structure with efficient space usage (subquadratic or near-linear for any $\varepsilon>0$) and query time that remains sublinear for any sublinear $t_q$. We supplement our worst-case bounds with a query-driven preprocessing algorithm to build data structures that are well-adapted to the query distribution.
Maïté Dupuis, Florian Girelli, Oleksandra Hrytseniak, Wolfgang Wieland
Comments 60 pages
Four-dimensional gravity admits many equivalent formulations - metric, Einstein-Cartan, teleparallel, McDowell-Mansouri, among others - each offering distinct advantages, particularly, in view of quantization. We propose a new formulation based on Weyl spinor-valued 1-forms, ultimately encoding the frame-field data. Starting from a topological field theory with a global $\mathrm{SL}(2,\mathbb{C})$ symmetry, we show that promoting this symmetry to a local gauge symmetry leads to the emergence of gravity. We analyze the covariant phase space of this theory, its symmetries and charge structure and explore the role of admissible corner terms together with their impact on boundary charges and their algebra. We study several extensions of this framework, including the incorporation of a cosmological constant and a novel $ G \rightarrow 0 $ scaling limit obtained from this model. The presence of the frame field already at the topological level allows point particles to be coupled uniformly in both the topological and gravitational theories. We perform a detailed Hamiltonian analysis of the theory and clarify the implementation of the reality conditions. We argue that this formulation provides structural features that make it particularly well suited for both discretization and quantization.
Anqi Dong, Anzhi Sheng, Xin Mao, Can Chen
Random walks are fundamental tools for analyzing complex networked systems, including social networks, biological systems, and communication infrastructures. While classical random walks focus on pairwise interactions, many real-world systems exhibit higher-order interactions naturally modeled by hypergraphs. Existing random walk models on hypergraphs often focus on undirected structures or do not incorporate entropy-based inference, limiting their ability to capture directional flows, uncertainty, or information diffusion in complex systems. In this article, we develop a maximum-entropy random walk framework on directed hypergraphs with two interaction mechanisms: broadcasting where a pivot node activates multiple receiver nodes and merging where multiple pivot nodes jointly influence a receiver node. We infer a transition kernel via a Kullback--Leibler divergence projection onto constraints enforcing stochasticity and stationarity. The resulting optimality conditions yield a multiplicative scaling form, implemented using Sinkhorn--Schrödinger-type iterations with tensor contractions. We further analyze ergodicity, including projected linear kernels for broadcasting and tensor spectral criteria for polynomial dynamics in merging. The effectiveness of our framework is demonstrated with both synthetic and real-world examples.
Nileema Sharma, Fangjun Cheng, Hyeok Jun Yang, Matthew Toole, James McKenzie, Mitchell M. Bordelon, Sean M. Thomas, Priscila F. S. Rosa, Yi-Ting Hsu, Xiaolong Liu
Comments 40 pages, 15 figures
UTe2 is a rare example of a correlated quantum material in which unconventional density wave orders, Kondo physics, spin-triplet pairing, and reentrant superconductivity coexist within the same electronic system. Its superconducting state develops out of a strongly correlated normal phase. The identification and control of competing or intertwined normal-state orders are thus central to elucidating the electronic landscape from which its superconductivity arises. Here, using scanning tunnelling microscopy (STM) in a vector magnetic field, we uncover a previously unreported staggered charge-density-wave (CDW) in high-quality UTe2 crystals and demonstrate its strong directional response to an external magnetic field: the staggered CDW is completely quenched by a modest 1.7 T field aligned with the quasi-one-dimensional uranium chain direction (a-axis), while remaining robust against fields along other crystallographic directions. This pronounced anisotropy is consistent with an orbital-driven mechanism that leads to a field-tuned quantum phase transition. Strikingly and counterintuitively, the same field orientation and strength concomitantly alter the hybridization gap and suppress the 5f Kondo resonance. Modelling indicates that this correlated evolution arises from a switch of the dominant hybridization channel from Te 5p- U 5f to U 6d- U 5f coupling, suggesting an intimate interplay between CDW and the Kondo effect. Our work establishes an effective tuning knob for the intertwined orders in UTe2 and provides evidence for orbital-selective Kondo hybridization, shedding light on its correlated normal state.
Francesco Fournier-Facio
Comments 21 pages
We construct Grothendieck pairs witnessing that the following are not profinite invariants: stable commutator length, quasimorphisms (answering a question of Echtler and Kammeyer), property NL (which obstructs actions on hyperbolic spaces), and property FW$_\infty$ (which obstructs actions on finite-dimensional CAT(0) cube complexes). We also recover that property FA and non-abelian free subgroups are not profinite invariants. The method combines Rips constructions with iterated group-theoretic Dehn filling on hyperbolic virtually special groups.
Allan McRobie
Comments 16 pages, 11 figures
This paper extends graphic statics by describing the forces and moments in any 3D rigid-jointed frame structure in terms of cell complexes using homology theory of algebraic topology. Graphic statics provides a highly geometric way to represent the equilibrium in bar structures. Unlike traditional matrix-based linear structural analysis which represents a structure as a set of nodes connected by bars, graphic statics imagines that the bar network defines a variety of higher-dimensional objects (polygonal faces, polyhedral cells, polytopes). These objects are related to piecewise-linear stress functions, the liftings of Maxwell, Rankine or Cremona. The requirement for such stress-functions to be plane-faced places a major limitation on the set of structures that can be analysed, as in many structures the spaces between bars do not correspond to flat polygonal regions. The CW-complexes of cellular homology provide a far-reaching generalisation of geometric notions such as polygons, polyhedra and polytopes, and their use here removes the requirement that spaces between bars must be flat. Here we demonstrate how any frame structure with bar-like members can be decomposed into a union of closed loops, each consisting of a closed circuit of bars. For general structures these loops are general closed space curves which cannot be spanned by flat polygons. Using chains of CW-complexes makes the new theory applicable to a much richer set of structural geometries. Unlike most descriptions of graphic statics, this approach is not restricted to purely axial forces. Shear forces, bending moments and torsional moments are included naturally, as described in Part 1 of this sequence of papers. Later papers will extend the approach to displacements, rotations and Virtual Work, and will give greater detail on how the loop formalism may be lifted toinvolve higher dimensional CW-complexes.
Amit Basu, Samrat Ash, Ritajit Kundu, Neha Bhatia, Sakshi Nema, Tejaswini Gawade, Khushabu Agrawal, Abhishek Das, Joydip Sarkar, Amit Shah, Ruta Kulkarni, Digambar A. Jangade, Arijit Kundu, A. Thamizhavel, Mandar M. Deshmukh
Comments 28 pages, 5 main figures, 2 extended figures
Engineering artificial systems by twisting and stacking van der Waals materials has proven to be an excellent platform for exploring emergent quantum phenomena that can be significantly different from the constituents. Recent advances in the fabrication of high-quality twisted interfaces provide a unique opportunity to study the little-explored interfacial superconducting order in twisted cuprate superconductors. In our work, we fabricate superconducting quantum interference devices (SQUID) that utilize the twisted interface of $\mathrm{Bi_2Sr_2CaCu_2O_{8+δ}}$, a high-Tc cuprate superconductor. By measuring the magnetic field modulation of switching current and differential resistance, we find a $\mathrmπ$ phase difference between the two Josephson junction arms of the SQUID reflecting chiral superconducting order -- a crucial aspect inaccessible to single Josephson junction devices of the past. Our observations also indicate co-tunneling of the Cooper pairs and a time-reversal symmetry-broken emergent superconducting order. Additionally, these SQUIDs are well suited for use as state-of-the-art flux sensors close to 77 K, achieving a flux noise sensitivity of $\sim$1.5 $\mathrm{μΦ_0/\sqrt{Hz}}$. Stabilizing new superconducting orders using twisted interfaces and probing them using quantum interference opens new avenues to understanding the microscopic origin of unconventional superconductors. Our SQUID architecture is suitable for investigating the charge transport mechanisms and the symmetry of superconducting order at the interfaces of other systems, reflecting the broad applicability beyond cuprate superconductors.
Haodong Zhao, Jinming Hu, Yijie Bai, Tian Dong, Wei Du, Zhuosheng Zhang, Yanjiao Chen, Haojin Zhu, Gongshen Liu
Comments Work in progress
Federated Language Model (FedLM) allows a collaborative learning without sharing raw data, yet it introduces a critical vulnerability, as every untrustworthy client may leak the received functional model instance. Current watermarking schemes for FedLM often require white-box access and client-side cooperation, providing only group-level proof of ownership rather than individual traceability. We propose EmbTracker, a server-side, traceable black-box watermarking framework specifically designed for FedLMs. EmbTracker achieves black-box verifiability by embedding a backdoor-based watermark detectable through simple API queries. Client-level traceability is realized by injecting unique identity-specific watermarks into the model distributed to each client. In this way, a leaked model can be attributed to a specific culprit, ensuring robustness even against non-cooperative participants. Extensive experiments on various language and vision-language models demonstrate that EmbTracker achieves robust traceability with verification rates near 100\%, high resilience against removal attacks (fine-tuning, pruning, quantization), and negligible impact on primary task performance (typically within 1-2\%).
Luca Bastioni, Samuel Glandon, Tefjol Pllaha, Madison Stewart, Phillip Waitkevich
The Clifford Hierarchy has been a central topic in quantum computation due to its strong connections with fault-tolerant quantum computation, magic state distillation, and more. Nevertheless, only sections of the hierarchy are fully understood, such as diagonal gates and third level gates. The diagonal part of the hierarchy can be climbed by taking square roots and adding controls. Similarly, square roots of Pauli gates (first level) are Clifford gates (climb to the second level). Based on this theme, we study gates whose square roots climb to the next level. In particular, we fully characterize Clifford gates whose square roots climb to the third level.
Tuğçe Bilen, Ian F. Akyildiz
Sixth-generation (6G) wireless networks are expected to support immersive and mission-critical applications requiring ultra-reliable communication, sub-second responsiveness, and multi-Gbps data rates. Dense small-cell deployments are a key enabler of these capabilities; however, the large number of candidate cells available to mobile users makes efficient user-cell association increasingly complex. Conventional signal-strength-based or heuristic approaches often lead to load imbalance, increased latency, packet loss, and inefficient utilization of radio resources. To address these challenges, this paper proposes a Knowledge-Defined Networking (KDN) framework for intelligent user association in dense 6G small-cell environments. The proposed architecture integrates the knowledge, control, and data planes to enable adaptive, data-driven decision-making. Small-cell conditions are modeled using queueing-theoretic indicators that capture traffic load and waiting-time dynamics. Based on these indicators, a joint optimization objective reflecting latency and packet loss is formulated and solved via Lagrangian relaxation to obtain globally guided association policies. These optimization outcomes are then used to supervise a lightweight Learning Vector Quantization (LVQ) model, enabling fast and scalable inference at the network edge. Extensive NS-3 simulations under varying mobility, traffic load, packet size, and network density demonstrate that the proposed approach consistently outperforms conventional baselines. The framework reduces average latency by 30-45% in high-mobility and heavy-traffic scenarios and decreases packet loss by more than 35% under congestion. The results confirm that combining optimization-driven knowledge with lightweight learning enables scalable, QoS-aware user association for future dense 6G networks.
Sitaram Maity, Nilanjan Roy, Tapan Mishra
Comments 4.5 pages and 4 figures
The Aubry-André model describes a system with quasiperiodic lattice modulation. In one dimension the AAH model is known to exhibit a sharp metal to insulator transition at a self-dual critical point at which all the states in the spectrum are critical or multifractal in nature. While such criticality is immediately destroyed by an additional onsite periodic modulation, we show an emergent criticality in the limit of strong periodic modulation strength under proper conditions. The resulting strong-modulation critical phase exhibits multifractal eigenstates and singular continuous spectra, belonging to the universality class of the critical Harper model. Moreover, we reveal that additional periodic potential of period N in the quasiperiodic chain folds the spectrum into N bands with quasiperiodicity being enhanced by a factor of N, producing N numbers of Hofstadter butterflies in each band. Our results reveal a general mechanism for engineering robust criticality and spectral replication in quasiperiodic systems.
Gaston Giribet, Bruno Sivilotti
Comments 25 pages, 3 figures
We compute the disk 1-point function in timelike Liouville theory. Using the Coulomb gas formalism and analytically continuing in the number of screening operators, we derive an explicit formula, which is shown to satisfy the correct reflection symmetry, to have the expected self-dual properties, to fulfill the bootstrap shift-equations, and to reduce to previous known results in the appropriate limits. In the limit of zero cosmological constant, our result reproduces the one recently obtained in arXiv:2505.09390.
Chong Ge, Ming Sun, Mpati Ramatsoku, Chris Nolting, Bärbel S. Koribalski
Comments 11 pages, 3 figures, published on ApJ, see https://doi.org/10.3847/1538-4357/ae4226
The merger shocks generated by the collision of galaxy clusters elevate the pressure within the intracluster medium, significantly influencing the evolution of embedded cluster galaxies. We detect a merger shock (Mach number $\sim 1.3$) on the northwest side of the closest rich galaxy cluster Norma (A3627), using XMM-Newton and Chandra data. The textbook ram pressure stripping (RPS) galaxy ESO 137-001 appears to be located in the post-shock region. The shock boosts RPS and may induce the formation of the brightest known X-ray tail behind a cluster late-type galaxy. Another prominent head-tail radio galaxy ESO 137-007, with one of the longest radio continuum tails ($> 500$ kpc), is also likely in the post-shock region. The shock may have reversed the upstream jet to a one-sided radio head-tail morphology. Moreover, the shock can strip and roll the jet cocoon into a vortex ring structure like a `smoke ring' behind the end of the jet as observed by the ASKAP data. Therefore, the cluster merger shock can remarkably change cluster galaxies. Furthermore, Norma is the second brightest non-cool-core cluster following the Coma cluster, with a cool core remnant on its southeast side. Its original cool core may be disrupted by cluster mergers and/or active galactic nuclei.
Yanis Baouche, Mathis Guéneau, Christina Kurzthaler
Comments 9 pages, 3 figures
Accumulation at boundaries represents a widely observed phenomenon in active systems with implications for microbial ecology and engineering applications. To rationalize the underlying physics, we provide analytical predictions for the first-passage properties and spatial distributions of a confined active Brownian particle (ABP). We show that ABPs with absorbing and hard-wall boundary conditions are Siegmund duals, yielding a direct mapping between the propagators of the two problems. We analyze the system across low and high activity regimes -- quantifying persistent motion relative to diffusion -- and show that active motion, together with a favorable initial orientation, typically lowers the mean first-passage time relative to passive diffusion. Notably, the full time-dependent propagator between hard walls approaches a wall-accumulated stationary state given by the derivative of the splitting probability as a consequence of Siegmund duality.
Olga Bantysh, Ramon Reigada, Rodrigo C. V. Coelho, Pau Guillamat, Jordi Ignés-Mullol, Francesc Sagués
Comments Supplementary images and videos available at https://doi.org/10.17605/OSF.IO/6P9B5
The emergence of long-range spatiotemporal order from intrinsic chaos is a central challenge in far-from-equilibrium physics. In active fluids, such as cytoskeletal networks driving cellular motion, self-generated flows typically produce "active turbulence", lacking translational symmetry. Here we show that a chaotic active nematic can self-organize into a spatiotemporal crystal, forming a regular lattice of density, orientation, and vorticity that breaks both spatial and temporal translational symmetry. Using a microtubule/kinesin active nematic interfaced with a lamellar liquid crystal and confined in microfluidic channels, we observe robust spatiotemporal lattices without external forcing. The ordering emerges from spontaneous synchronization of intrinsic flow instabilities, mediated by confinement and feedback between the active layer and the passive anisotropic interface. Continuum nematohydrodynamics simulations support our interpretation, highlighting how intrinsic length and time scales shape the active crystals. These results reconcile chaos and crystallinity in active matter and provide a strategy for engineering order in self-driven, far-from-equilibrium soft materials.
Boris Kupriyanov, Alexander Lazarev, Alexandr Roschin, Frank Werner
Comments 25 pages, 12 figures
The paper discusses several extensions of the recursive representation of the flow shop scheduling problem. It is shown that recursive functions make it possible to describe multiple extensions in a single problem. The paper considers altogether six extensions. The examples consider three types of recursive functions: functions associated with the machine, functions that adjust the procession time based on constraints, and functions that control the feasibility of the schedule. The structure of the superpositions of these functions is presented, and also descriptions of several objective functions by recursive functions are presented. Then the general requirements for a recursive function are formulated and its properties are described. Finally, a demonstration of the formulation of new problems is provided using examples of simple flow shop extensions and branch and bound optimization.
Yunxiao He, Xiaonan Ning, Bo Guo, Jianfei Hua, Yuqiu Gu, Wei Lu
Comments 15 pages, 5 figures
Wavelength-tunable ultra-intense femtosecond lasers may enable breakthroughs in diverse areas of science spanning attosecond science, particle acceleration and beyond. Conventional crystal-based methods are limited by gain bandwidth and damage thresholds, which restrict their wavelength tunability. Plasma-based frequency conversion, unconstrained by material damage, offers a promising alternative. Here, a novel scheme named Frequency Downshifting Stair (FDS) based on plasma bubble filling control is presented. The FDS enables arbitrary frequency down-conversion of ultra-intense femtosecond pulses and yields chirp-free laser pulses. It can achieve near-100% photon conversion efficiency, approaching the physical limit. This is attributed to the linear control by the FDS of laser chirp evolution during the photon deceleration in the plasma wake bubble. For a laser pulse with an arbitrary wavelength λ_0 (e.g., λ_0=800nm), proof-of-concept PIC simulations demonstrate that a single-stage FDS enables continuous wavelength tuning from λ_0 to {2λ}_0 (800-1600nm). Moreover, a three-stage cascaded FDS achieves more than tenfold frequency (10λ_0) downshifting to a central wavelength of 8.5μm. The FDS scheme thus provides a universal pathway for generating high-energy, few-cycle pulses across the broad infrared regime, offering a powerful new tool for wavelength-dependent ultrafast science.
Yining Hu, Zili Feng, Takashi Kurumaji, Linda Ye, Chunyu Mark Guo, Philip J. W. Moll
Comments 25 pages, 13 figures
In multiferroics, new physical responses and functionalities emerge when symmetry-distinct order parameters couple. This conventionally occurs when lattice and magnetic degrees of freedom order independently in a material. Here, we report an all-magnetic analogue of multiferroic behavior in the antiferromagnet Co$_{1/3}$TaS$_2$, where topological scalar spin chirality and nematicity coexist on the same spin lattice. While the chiral spin texture generates an anomalous Hall effect (AHE), the nematic order breaks threefold rotational symmetry and dominates longitudinal transport. Crucially, in zero field these symmetry-distinct orders merely coexist yet magnetic fields induce strong coupling between them, thus realizing a new type of multiferroic bebhavior via tuning of the coupling itself instead of direct manipulation of secondary orders. In sub-domain sized devices with achiral geometry, we demonstrate that nonreciprocal transport serves as a symmetry-based probe of the global spin chirality, co-aligned with the strong topological AHE of the system. In Co$_{1/3}$TaS$_2$ the topological Hall state inherits a large resistance anomaly via chiral-nematic coupling, thus our results showcase how hybrid magnetic orders can achieve advanced functionalities by merging symmetry-forbidden material responses.
J. V. Sales-Silva, K. Cunha, V. V. Smith, S. Daflon, D. Souto, R. Guerço, V. Loaiza-Tacuri, A. Queiroz, C. Chiappini, I. Minchev, S. R. Majewski, B. Barbuy, D. Bizyaev, J. G. Fernández-Trincado, P. M. Frinchaboy, S. Hasselquist, D. Horta, H. Jönsson, T. Masseron, N. Prantzos, R. P. Schiavon, M. Schultheis, M. Zoccali
Comments 26 pages, 13 figures, 2 tables; accepted for publication in ApJ
The Milky Way bulge-bar is composed of multiple populations. Using chemical and kinematical planes, we segregate six populations in a bulge-bar sample observed by the APOGEE survey: two with bar-driven orbits, two with eccentric orbits, and two with low-eccentricity orbits, each composed of low- and high-[Mg/Fe] stars. Our sample spans $-2.0\lesssim$[Fe/H]$\lesssim+0.5$ and Galactocentric distance $R_{Gal}$ $<6$ kpc. We use chemical abundances from APOGEE DR17 for the elements Mg, Si, Ca, Al, K, Mn, Co, Ni, and Fe, and from the BAWLAS catalog for Ce and Nd. We find that the low- and high-[Mg/Fe] stars with low-eccentricity orbits, which exhibit chemical and orbital characteristics similar to those of the low- and high-[$α$/Fe] disks, display slightly negative and positive metallicity gradients, respectively. This result for the low-[Mg/Fe] low-eccentricity stars indicates a break in the global thin disk metallicity gradient. The high eccentricity populations with both low- and high-[Mg/Fe] show approximately flat metallicity gradients. In general, the [X/H] gradients of all elements for all populations follow Fe, except for the neutron-capture elements Ce and Nd. For all elements, the high-[Mg/Fe] bar population shows a much steeper positive [X/H] gradient than the nearly flat gradient for the low-[Mg/Fe] bar stars. The positive [X/H] gradients observed among our high-[Mg/Fe] bar stars probably reflect an age variation along the peanut structure. This interpretation agrees with the N-body simulations. Such steep positive gradients have also been reported in some high-redshift (z$\sim$4--10) galaxies.
Francesca Marafini, Giacomo Zini, Alberto Barontini, Nuno Mendes, Alice Cicirello, Michele Betti, Gianni Bartoli
Comments Submitted for peer review to Data Centric Engineering, Cambridge University Press
The availability of a dataset for validation and verification purposes of novel data-driven strategies and/or hybrid physics-data approaches is currently one of the most pressing challenges in the engineering field. Data ownership, security, access and metadata handiness are currently hindering advances across many fields, particularly in Structural Health Monitoring (SHM) applications. This paper presents a simulated SHM dataset, comprised of dynamic and static measurements (i.e., acceleration and displacement), and includes the conceptual framework designed to generate it. The simulated measurements were generated to incorporate the effects of Environmental and Operational Variations (EOVs), different types of damage, measurement noise and sensor faults and malfunctions, in order to account for scenarios that may occur during real acquisitions. A fixed-fixed steel beam structure was chosen as reference for the numerical benchmark. The simulated monitoring was operated under the assumptions of a Single Degree of Freedom (SDOF) for generating acceleration records and of the Euler-Bernoulli beam for the simulated displacement measurements. The generation process involved the use of parallel computation, which is detailed within the provided open-source code. The generated data is also available open-source, thus ensuring reproducibility, repeatability and accessibility for further research. The comprehensive description of data types, formats, and collection methodologies makes this dataset a valuable resource for researchers aiming to develop or refine SHM techniques, fostering advancements in the field through accessible, high-quality synthetic data.
Simon Köhnes, Jiongning Che, Barbara Dietz, Thomas Guhr
Comments 10 pages, 5 figures
At lower energies, the resonances in scattering experiments are often isolated. In quantum chaotic many-body, disordered or generically stochastic systems, the resonances overlap at larger energies. Eventually, the Ericson regime is reached in which the cross section behaves like a random function. The scattering matrix elements then follow a universal Gaussian distribution. For more than sixty years, the emergence of this robust additional universal behavior on top of the universal system stochasticity awaits a concise analytical treatment. We derive the transition to the Ericson regime in the universal Heidelberg approach and prove the universal Gaussian distribution by a proper asymptotic expansion. We also obtain explicit formulae for the moments of the distributions. We compare with microwave experiments and numerical simulations.
V. Vanga, G. Alatteili, E. Iacocca
Artificial spin ices are metamaterials that can host several ferromagnetic resonances as well as spin waves. As the field advances towards the creation of three-dimensional geometries, a trilayer square artificial spin ice has been already found to exhibit many interesting properties. Here, we numerically investigate a strongly-coupled trialyer square artificial spin ice under the effect of interfacial Dzyaloshinskii-Moriya interaction (DMI). This interaction affords non-reciprocity to waves, leading to changes in the standing wave modes established in confined geometries. We find that the interplay between the non-reciprocity, an applied field, and the stray field within the artificial spin ice results in frequency split additional edge modes. The edge modes are favored by the DMI sign and exhibit destructive and constructive interference depending on both the DMI magnitude and the external magnetic field. Our results demonstrate the non-reciprocity in small nanoislands can affect the long-range states stabilized in the artificial spin ice due to the strong coupling between layers.
Eric Jedermann, Piotr Kulpinski, Martin Strohmeier, Vincent Lenders, Jens Schmitt
The Iridium Low Earth Orbit (LEO) satellite constellation remains a unique provider of global communications for critical industries, governments, and private users, serving over 2.5 million active subscribers despite recent market competition. In contrast to terrestrial wireless standards such as 3GPP, Iridium protocol specifications are proprietary and have not undergone rigorous, public, and systematic security evaluation. In this work, we present the first comprehensive security analysis of Iridium authentication and radio link protocols. We reverse engineer Iridium SIM-based authentication mechanism and demonstrate that the secret key can be extracted from the SIM card, enabling full device cloning and impersonation attacks. Leveraging a month-long dataset of Iridium up- and downlink satellite traffic, we further show that nearly all signaling and radio communication protocols currently in use lack encryption, resulting in the exposure of sensitive information in cleartext over the air such as login credentials and large volumes of personal data. Finally, we develop custom software-defined radio (SDR) tools to carry out spoofing and jamming attacks, revealing that modestly equipped adversaries can inject falsified messages or disrupt the Iridium service locally due to the absence of source authentication. Our findings uncover systemic vulnerabilities in the Iridium radio link and highlight the urgent need for users of critical applications to transition to more secure communication radio links.
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