Little Red Dots (LRDs) appear extremely compact at rest-frame optical wavelengths, yet many show extended rest-frame UV morphology revealing more complex internal structure. We present a combined analysis of VLT/MUSE rest-frame UV integral-field spectroscopy and continuum-subtracted [O III], H$β$, and H$α$+[N II] emission-line maps from JWST/NIRCam imaging at sub-kpc resolution for LRD-204851 at $z=5.482$ in GOODS-S. We find that LRD-204851 hosts a remarkably thin, bipolar, elongated structure passing through the optical continuum centroid and extending several kpc on either side, traced by both the UV continuum and the rest-frame optical emission lines, with a bright [O III] clump-like structure $\sim$2 kpc to the south-east of the centroid. The MUSE observations reveal a double-peaked Ly$α$ profile, with a broad and bright near-systemic red peak and a relatively faint peak blueshifted by $\sim$430 km s$^{-1}$, accompanied by a tentative N V $λ1238$ detection at similar velocity. In narrow-band imaging extracted from the MUSE IFU cube, both the blue Ly$α$ peak and the tentative N V emission lean toward this same south-eastern direction. Independently, radiative-transfer modeling of the integrated Ly$α$ profile favors a biconical low-column-density cavity in a dense, slowly expanding neutral envelope, in support of the bipolar geometry traced by the line maps. Together, these results suggest that the elongated emission of LRD-204851 is connected to radiation and/or gas flow from its central engine through a low-column-density channel with a small opening angle that may trace either a slow outflow or a quasi-static ionization cone. LRD-204851 is one of the first LRDs where the central engine's impact on its host galaxy is potentially directly observable on kpc scales.

There are many different theoretical explanations for the formation of high-density Mercury-like planets, but concrete evidence for any of these formation mechanisms remains elusive. A popular explanation for dense planets is the collisional hypothesis, which states that iron-rich planets can be formed as the products of high-energy, mantle-stripping impacts. Planetesimal collision simulations predict that higher-velocity collisions can form higher-density planets. Motivated by the characteristics of the high-density, short-period (P=0.3d) GJ 367b, we study the results of previously-published smoothed-particle hydrodynamics (SPH) simulations on exoplanet collisions, combining these with models describing the likely collision velocities of these objects, to investigate the relationship between the core mass fractions (CMFs) of exoplanets, their masses, and their orbital periods. We predict that collisionally-produced super-Mercuries should be more common (and more dense) at low masses and short orbital periods. This correlation may enable us to pinpoint the formation mechanism of super-Mercuries as the population of observed targets grows. Afterwards, we connect our hypothesis to the observed Mercury-like population of high-density exoplanets, and find that GJ\,367\,b is the best exoplanetary candidate for collisional formation.

Early JWST spectra revealed galaxies with a strong nitrogen excess challenging galactic chemical evolution models. Using public JWST surveys, we construct a sample of 76 N/O-enhanced galaxies (NOEGs) at 4 $<z<$ 8.5, the largest at high redshift to date. The NOEG fraction rises from $\sim$3% to $\sim$18% between $z\sim$ 4 and 7 - well above the $\sim$2% measured locally - potentially driven by burstier, cluster-dominated star formation. Stacked spectra of the most nitrogen-rich galaxies show signatures of low-metallicity Wolf-Rayet (WR) stars, a likely source of primary nitrogen within the first few Myr of a starburst, with UV and optical continua dominated by young stellar emission and Balmer jumps evident in some cases. Many NOEGs also exhibit ionised outflows: 40% show secondary [O III] and H$α$ components, while stacked spectra of the remainder reveal a broadened, offset H$α$ without forbidden-line counterparts, suggesting dust-attenuated or faded outflows. The continuum in the latter shows a weak Balmer break, indicating these galaxies are past their most recent burst. This suggests that outflows dilute gas metallicity after the first few Myr of the initial enrichment and enable renewed N/O enhancement driven by low-metallicity Asymptotic Giant Branch (AGB) stars. We conclude that NOEGs are caught briefly after a recent starburst: either within $\sim$10 Myr, when WR winds drive nitrogen enrichment, or after 30-40 Myr, when AGB winds take over - following an outflow driven by radiative or supernova feedback, consistent with recent chemical evolution models.

Low-frequency radio polarimetric observations provide a powerful probe of magnetic fields in astrophysical sources and the intervening medium, as well as magnetospheric emission from compact objects such as pulsars, magnetically active stars, brown dwarfs, and planetary aurorae. With baselines of up to 2000 km, LOFAR offers a unique opportunity to study the low-frequency polarised Universe at sub-arcsecond resolution. However, polarimetric studies with LOFAR have so far been limited to angular resolutions of about 6 arcsec, resulting in stronger beam depolarisation. Here we present a calibration strategy that enables full-resolution polarimetric imaging with the LOFAR pan-European array. Our method applies full-Jones corrections to the international stations using an in-field unpolarised calibrator. In addition, when a sufficiently bright polarised source is present in the field, multi-epoch observations can be aligned in Faraday depth using a visibility-based correction that accounts for polarisation angle and rotation measure offsets. This approach enables deeper combined imaging and deconvolution. We apply this strategy to the LOFAR ELAIS-N1 field, combining four 8 h observations for a total integration time of 32 h. At 0.3 arcsec resolution, we detect two previously known polarised sources identified in lower-resolution studies, resolve additional polarised components, and localise emission regions with sub-arcsecond precision. We also identify a new polarised source and detect circularly polarised emission from the binary M-dwarf system CR Draconis, measuring its proper motion across epochs. These results demonstrate that sub-arcsecond polarimetry at metre wavelengths is now feasible with LOFAR, opening new science opportunities in the LOFAR2.0 era.

Via is a forthcoming all-sky spectroscopic survey that will achieve 100 m s$^{-1}$ radial velocity stability for millions of faint ($G \lesssim 21$) stars while reaching LSST's single-visit depth ($r \approx 24$) for transient spectroscopy, opening new regimes in near-field cosmology and time-domain astrophysics. Via will deploy identical fiber-fed, multi-object spectrographs on the 6.5m MMT and Magellan/Clay telescopes for a five-year, dual-hemisphere survey of $>2{,}000{,}000$ stars beginning in 2027 - timed to complement LSST. Each instrument has 576 robotically positioned fibers over a $1^\circ$ field of view, feeding two spectrographs: Viaspec ($R \approx 15{,}000$; 505-595 nm; 540 fibers) and Boombox ($R \approx 1{,}000$; 360-1010 nm; 36 fibers). Four key goals drive the survey: (1) a comprehensive survey of velocity perturbations in cold stellar streams, sensitive to $M \lesssim 10^7$ subhalos below the threshold of galaxy formation, a stringent test of the particle nature of dark matter; (2) a chemodynamical census of Milky Way satellite galaxies to understand the formation of the faintest galaxies; (3) the first 3D tomographic maps of cold gas in the circumgalactic medium via NaI absorption; and (4) the rapid characterization of thousands of transients to the single-epoch survey depth of LSST. Ancillary science - including the Ly$α$ forest at $z \approx 3$-$4$, polluted white dwarfs, exoplanet host characterization, fast radio burst host galaxies, and extragalactic dwarf galaxies - will leverage spare fibers in every pointing. The Via Project is a collaboration between the Center for Astrophysics $|$ Harvard & Smithsonian, Carnegie Observatories, Stanford University, and Yale University.

We present the Terry Hubble Observations of Roman (THOR) data reduction pipeline and Hubble Advanced Mining Routine for Roman (HAMRR). THOR is designed to reduce HST Wide-field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) imaging data taken as part of program GO-17776: A Precursor Survey of the Roman Galactic Bulge Time Domain Fields (Terry et al, 2024). The primary function of HAMRR is to query the THOR-derived catalog via a typical cone search algorithm. Output products from HAMRR include calibrated photometry and astrometry for detected point sources in the HST catalog. The package supports additional output products such as cutout images, auto-generated color-magnitude diagrams, luminosity functions, and more. The HAMRR tool can be used in coordination with analyses of Roman, Rubin/LSST, and Euclid Galactic Bulge targets in the near future.

Pulsar timing arrays (PTAs) are sensitive to the gravitational influence of passing compact substructures, which can produce Doppler timing delays by accelerating pulsars or the Solar System barycenter, and Shapiro timing delays when passing near Earth--pulsar lines of sight. Projections for the complete PTA sensitivity to compact dark matter (DM) substructures, such as primordial black holes and axion miniclusters, are challenging due to the variety of signal types ranging from rare, nearly static encounters, to dynamic flybys, to the stochastic limit of many substructures. We address this challenge with a framework that combines Monte Carlo signal modeling and machine-learned surrogate likelihoods, enabling a unified likelihood-level analysis of signals previously treated only in simplified limiting regimes. We then use this framework to precisely assess the impact of a stochastic gravitational wave background (SGWB), for which evidence was recently found, on the PTA sensitivity to compact DM substructures.The SGWB substantially weakens the sensitivity, and we find that in even the most optimistic observing scenario only a Shapiro search retains sensitivity to subdominant DM components when assuming SGWB parameters inferred from current measurements.

The solar gravitational lens (SGL) is a target-specific observatory: the Sun supplies the wave-optical element, while spacecraft provide occultation, annular photometry, sampling, metrology, and inverse reconstruction. We develop an observability framework for non-exoplanet SGL astronomy. Viability is set by image-plane scale, raster pitch, finite-source gain, source-to-background ratio, temporal coherence, PSF knowledge, calibration, metrology, and focal-line access. We separate the vector Poisson measurement operator from the scalar convolution used for benchmarks. Four analytic scenes are propagated and reconstructed: a solar analog and magnetic white dwarf at 10 pc, an M87*-scale millimeter ring/jet source, and a bright 0.1 AU protoplanetary subfield at 140 pc. Under stated kernel-mismatch, background, calibration-floor, support-mask, sampling, regularization, and imposed information-floor assumptions, the scalar reconstructions give SSIM values of 0.993, 0.918, 0.973, and 0.923. These metrics quantify scalar inverse conditioning, not delivered flight performance; FRC50, support-leakage, and information-floor sensitivity diagnostics expose the dependence on assumptions. Many self-luminous compact targets are not photon-starved relative to a reflected-light exo-Earth reference, shifting the dominant requirements to ring extraction, coronal subtraction, detector dynamic range, PSF knowledge, cadence, spectroscopy, metrology, scan overhead, and access. The strongest bounded cases are white-dwarf surface and magnetic mapping, nearby stellar surfaces, compact AGN/black-hole structure with long-wavelength instrumentation, velocity-resolved broad-line-region mapping, and planet-forming subfields. The priority enabling program is SGL transfer-function characterization: measuring solar-multipole, plasma, extended-Sun, and instrumental response needed for scientifically interpretable imaging.

Substellar objects occupy a unique place in our universe, bridging the gap between the smallest stars and the largest planets, and serving as powerful laboratories for understanding extrasolar atmospheric physics without the contaminating glare of a host star. Previous studies into the atmospheric structure of these objects have revealed clouds, disequilibrium chemistry, thermal inversions, and auroral processes which each contribute to wavelength-dependent brightness variations. HST remains uniquely positioned to address key open questions in the field, such as resolving the vertical atmospheric structure, long term evolution of the atmosphere, and detection of UV aurora in the upper atmosphere, primarily in conjunction with other facilities that probe wavelength regimes that cannot be reached with instruments on HST. We advocate for three large scale initiatives and argue that the study of the atmospheres of substellar worlds directly prepares the community for atmospheric characterization with the Habitable Worlds Observatory.

Learned communication systems may evaluate stochastic channel surrogates millions of times inside differentiable training loops, making diffusion-style reverse sampling expensive. This paper proposes condition-wise Sinkhorn drifting, a one-shot channel surrogate that preserves the transmitted symbol and transports only the conditional output laws \(p(y\mid x)\). We formulate a conditional Sinkhorn objective over repeated outputs at the same transmitted symbol and train the generator with finite-sample barycentric velocities followed by detached particle regression. Experiments on additive white Gaussian noise (AWGN), Rayleigh fading, solid-state power amplifier (SSPA) nonlinearity, and a compact tapped-delay-line (TDL) channel compare direct drifting, joint Sinkhorn drifting, condition-wise Sinkhorn drifting, conditional denoising diffusion probabilistic modeling (DDPM), denoising diffusion implicit modeling (DDIM), and Wasserstein generative adversarial network (WGAN) references. Within the evaluated one-shot drifting-family variants, condition-wise Sinkhorn is strongest under conditional diagnostics and symbolic-coding checks, while diffusion remains strongest on the hardest downstream symbol-error-rate (SER) curves. The resulting operating point is a condition-preserving one-shot simulator for settings where repeated channel calls make diffusion-style sampling too costly.

Prior to the version 1.3.1 update on CRAN in December 2025, gsynth, a popular R package for estimating Interactive Fixed Effects (IFE) models, could drastically and systematically underestimate standard errors. This underestimation would occur when two estimation options (inference = "parametric", and EM = TRUE) were used together, in which case the package would apply a parametric bootstrap procedure to Gobillon and Magnac (2016)'s IFE-EM estimator. The package ceased supporting this combination in December 2025, and the latest documentation now describes the parametric bootstrap as not suitable for use with the IFE-EM estimator due to a theoretical incompatibility. Our focus is an implementation error we identified in the pre-1.3.1 versions of gsynth: the parametric bootstrap used when EM = TRUE did not match the algorithm proposed in Xu (2017), using in-sample residuals instead of out-of-sample errors. We show that this implementation error alone can cause underestimation by orders of magnitude. We conduct an empirical Monte Carlo study using randomly assigned placebo treatments on a series of state-level panel datasets, and show that gsynth could yield high false positive rates in realistic settings. We identify three papers published in the American Political Science Review that are affected by this behavior. Reanalyzing the relevant sections of these papers, we show that (i) correcting the implementation error renders most findings insignificant, and (ii) using Xu (2017)'s Generalized Synthetic Control method in place of IFE-EM renders every finding insignificant.

How should recommender systems be designed when recommendations shape access to scarce, short-lived opportunities? We study this question in a production setting: Timee, Japan's largest platform for spot work, where workers favorite job templates and receive notifications when firms post shifts from those templates. Maximizing predicted favoriting can generate misdirected concentration: recommendations accumulate on popular templates that create few viable job openings, while templates with unmet labor demand receive too little exposure. We design exposure-control mechanisms for favorite-list management, reallocating template exposure based on posting activity and unfilled capacity. The proposed recommender, thresholded eligibility control (TEC), is fully parallelizable and suitable for large-scale digital platforms. In simulations calibrated to Timee data, TEC raises the per-round job-finding rate from 57.6% to 70.0%. A prefecture-level randomized field experiment increases realized matches and exposure per active template, reduces the share of low-exposure templates, and improves impression-level favoriting and downstream matching.

Deploying Large Language Models (LLMs) requires exploring a large configuration space spanning parallelization strategies, batching techniques, and scheduling policies. Exhaustive measurement across this space is impractical, making latency prediction essential for system optimization. While NPUs have emerged as accelerators designed for LLM inference, no prediction methodology has been established for them. Specifically, applying prior work to LLM inference latency prediction on NPUs faces three challenges: undisclosed microarchitecture of commercial NPUs, unpredictable compiler optimizations, and latency non-linearity induced by bucketing. We present LENS, a latency estimator that predicts NPU inference latency without information on the microarchitecture or compiler, and captures the non-linear latency induced by bucketing. LENS profiles each bucket with two end-to-end (E2E) measurements and composes the results to predict latency for arbitrary input-output length combinations. We validate LENS across NPUs from multiple vendors, several LLMs, and diverse workloads, achieving a mean prediction error of 2.15\%. We further compare LENS against two methodologically related baselines, confirming the validity of its approach.

Despite rapid advances in UAV technologies, current deployments remain limited due to several gaps in UAV systems research. To address these challenges, we propose OmniDroneX, a unified Drone-as-a-Service ecosystem, in which drones are transitioned from fixed function platforms into dynamically composable entities that can be integrated with external infrastructures to offer omni-capabilities. OmniDroneX bridges low-level physical primitives with high-level mission intent through a unified vendor-agnostic interface (libUAV) and a formal physical-service abstraction model (PT-SOA). A core innovation is the diverse application of large language models (LLMs) across multiple layers of the OmniDroneX architecture. LLMs are used to assist in identifying and formalizing primitive device functions and abstract service definitions, supporting automated service composition and workflow generation, and enabling interactive, natural-language mission specification and refinement. OmniDroneX also incorporates important categories of composition techniques that are essential in dynamic UAV systems, including physical layer composition for drone capability augmentation, as well as spatiotemporal, functional, collaborative, exception-aware, and QoS-based service compositions. Collectively, these features allow OmniDroneX to serve as a foundation for scalable, resilient, and self-evolving UAV ecosystems operating in complex and dynamic environments.

High-Level Synthesis (HLS) relies on transforming original C specifications into synthesizable HLS-oriented C (HLS-C) implementations. Functional consistency verification between original C specifications and HLS-C implementations is a critical yet labor-intensive task in HLS design flows. While Large Language Models (LLMs) have recently shown promise in automated testbench generation, their stochastic nature often leads to insufficient coverage, inconsistent verification environments, and unreliable equivalence checking results. To address these limitations, we propose a knowledge-augmented, agent-driven shift-left verification framework for automated functional consistency checking between original C and HLS-C implementations before synthesis. The framework introduces a Dual-Tier Consistency Checking mechanism that jointly enforces static structural alignment and dynamic behavioral equivalence between paired testbenches, while integrating symbolic execution and coverage-driven refinement to improve verification completeness. Furthermore, we construct a heterogeneous HLS Verification Knowledge Graph to provide topology-aware reasoning priors for testbench generation, and design an autonomous verification agent to orchestrate iterative refinement and failure diagnosis across heterogeneous toolchains. Experimental results on 107 HLS benchmark pairs demonstrate that the proposed framework achieves 0.9826 average coverage and 0.9533 dynamic consistency, outperforming representative AST-based, retrieval-augmented, and iterative agent-based baselines. https://github.com/cz-5f/HLS-LeVeri.git

In this paper, we propose a general-purpose multi-dimensional symbol construction for computing an arbitrary symmetric function with digital over-the-air computation (OAC) and discuss the practical aspects of coherent aggregation. For our first contribution, we discuss the categorical representation of a symmetric function. By using this representation and leveraging the sufficiency of the histogram to evaluate a symmetric function, i.e., inspired by type-based multiple access (TBMA), we introduce a general approach to design a single set of OAC symbols to compute any digital function. For our second contribution, we use a comprehensive platform based on low-cost nodes that maintain synchronization in time, frequency, phase, and amplitude via a trigger mechanism, enabling coherent OAC experiments without Global Positioning System (GPS) or cable-based synchronization. Using measurements from the platform, we characterize the phase and amplitude statistics of the composite channel to derive a realistic impairment model for coherent OAC. Through a comprehensive analysis, we demonstrate the effectiveness of the proposed scheme under impairments captured by the proposed model

In this article, we develop a multi-dimensional two-layer thin film model extending the thin film model proposed in \cite{barthwal2025hyperbolic}. The model considered in \cite{barthwal2025hyperbolic} considered a very specific Marangoni scale by choosing Marangoni numbers in both layers to be $1$. We relax this condition here and prove that the obtained system possesses a full set of Riemann invariants. Based on these findings, we develop a Riemann Invariant-based Local Characteristic Decomposition WENO (RI-WENO) method for the two-layer thin film model in one and two dimensions. The method is built upon a specially designed variable transformation constructed from the derived Riemann invariants of the system. This transformation partially diagonalizes the governing equations and yields a sparse structure in the transformed eigenvector matrices. As a result, the proposed RI-WENO framework significantly reduces the computational cost of the standard Local Characteristic Decomposition WENO approach while retaining its strong capability to suppress spurious oscillations. Numerical experiments, including new benchmark test cases, demonstrate that the RI-WENO method achieves an effective balance between accuracy and computational efficiency, making it a promising and practical choice for solving the two-layer thin film model.

In this paper, we study the information-theoretic characterization of simultaneous signalling and control over channels modeled by partially observable Markov decision processes (POMDPs). The problem is formulated as an optimization over randomized control strategies that maximize the directed information from actions to observations, subject to an average-cost constraint. We derive a novel dynamic programming framework in which the state is defined on the space of conditional probability distributions, leading to a high-level ``meta'' dynamic program. Specifically, we show that two coupled information states, namely, the posterior distribution of the system state and a distribution over such posteriors, satisfy Markov recursions and provide sufficient statistics for optimal control. This structure enables the decomposition of optimal strategies into separated randomized policies that depend only on these information states. Our results establish necessary and sufficient conditions for optimality and unify classical stochastic control and information-theoretic formulations. In particular, we show that in the absence of signalling, the proposed framework reduces to the standard dynamic programming equations for POMDPs. The developed approach provides a principled foundation for analyzing and designing control systems with intrinsic information constraints.

An upper homogeneous (upho) poset is a poset whose every principal filter is isomorphic to the whole poset. Fu--Peng--Zhang conjectured that every finitary upho poset admits a compatible left-cancellative, invertible-free monoid structure whose left-divisibility order coincides with the given order. We disprove this conjecture. For every vertex-transitive graph $G$, we construct a finitary upho poset $P(G,v_0)$ from walks starting at a fixed vertex $v_0$. Applying this construction to the Petersen graph, we show that multiplicability of $P(G,v_0)$ would force the automorphism group of $G$ to contain a regular subgroup. This would imply that $G$ is a Cayley graph, contradicting the fact that the Petersen graph is not Cayley. Hence $P(G,v_0)$ is a non-multiplicable finitary upho poset. We also show that the analogous poset associated with the line graph of the Petersen graph is multiplicable, demonstrating that non-Cayleyness of the underlying graph alone does not determine multiplicability.

Understanding the scrambling of quantum information is central to many areas of quantum physics, including quantum thermalization, entanglement growth, and quantum information processing. Insights from these studies have, in turn, inspired the development of novel quantum protocols and algorithms. Recently, a bidirectional teleportation protocol was proposed to implement a digital SWAP operation between qubits by leveraging chaotic Hamiltonian evolution combined with measurement and post-selection. In this work, we provide a comprehensive study of two central quantities that characterize the protocol, the post-selection probability and the fidelity, taking into account possible errors in time-reversed dynamics. We show that these quantities can be expressed in terms of standard diagnostics in quantum dynamics, including the Loschmidt echo and its subsystem variant. The results unveil (1) the initial-state dependence of the fidelity and (2) the stability of the post-selection probability in integrable models. Our findings offer practical guidance for the implementation of the protocol on realistic quantum devices.

We use temporal unitary transforms to generate 16-QAM up to 220 GBd using only 50-GHz electrical bandwidth. The technique is theoretically lossless and can generate arbitrary optical waveforms beyond the bandwidth of the constituent modulators.

This paper presents a measurement of photon plus two-jet events in $pp$ and Pb+Pb collisions, i.e. events in which the transverse momentum of a single photon is balanced by two distinct jets. The measurement was performed using $pp$ data taken in 2017 with an integrated luminosity 260 pb$^{-1}$, and Pb+Pb data taken in 2018 with an integrated luminosity 1.72 nb$^{-1}$, both at $\sqrt{s_\mathrm{NN}}$ =5.02 TeV, as recorded by the ATLAS detector. Events with photons in the transverse momentum range 90-180 GeV and at least two anti-$k_t$ $R = 0.2$ jets with a $p_\mathrm{T}$ > 30 GeV are selected, and three observables are measured: ${\mathrm{x}}_{\mathrm{JJ}γ}$, $\mathrm{A}_{\mathrm{JJ}γ}$, and $ΔR_{\mathrm{JJ}}$. These observables characterise the overall energy loss of the multiparton system from medium interactions (${\mathrm{x}}_{\mathrm{JJ}γ}$), the relative energy loss between the two colour-charge carriers ($\mathrm{A}_{\mathrm{JJ}γ}$), and medium-induced modifications to their opening angle ($ΔR_{\mathrm{JJ}}$). The observables are corrected for uncorrelated combinatoric background contributions using a novel multijet mixing technique, for photon purity, and for detector resolution effects via iterative unfolding. Final results are presented per photon, and the ratio ($I_\mathrm{AA}$) is taken between measurements in Pb+Pb and $pp$ collisions, for Pb+Pb centrality intervals of 30-80%, 10-30%, and 0-10%. Significant suppression of per photon two-jet yields in all three observables, $I_\mathrm{AA} < 1$, is observed as a result of parton-medium interactions. The experimental measurements are compared to three different jet quenching models: JEWEL, JETSCAPE, and LBT.

Precessing binary black-holes generically produce an imbalance of right- and left- handed gravitational waves, reflecting the breaking of mirror symmetry by the merger dynamics. We study this phenomenon using the observer-independent quantity $V_{\rm GW}$, a gravitational analogue of the optical Stokes parameter that quantifies the intrinsic handedness of the emitted radiation. Using 91 LIGO-Virgo-KAGRA black-hole mergers from the O1-O4a observing runs, we find that $92\%$ of the analyzed events favour non-vanishing $V_{\rm GW}$, indicating a predominance of precessing dynamics across the events. Through a recently established relation between $V_{\rm GW}$ and the remnant black hole recoil, we further constrain the retention of merger remnants in dense stellar environments, finding that at most $8\%$ could remain gravitationally bound to globular or nuclear star clusters and subsequently participate in hierarchical merger channels. We finally investigate the cosmological distribution of black-hole merger handedness. The observed $V_{\rm GW}$ distribution is consistent with symmetry under $V_{\rm GW}\rightarrow -V_{\rm GW}$, and yields an average value $\langle V_{\rm GW}\rangle=-1.9^{+6.1}_{-6.6}\times10^{-3}$ ($90\%$ credibility), consistent with the absence of a preferred handedness and with expectations from large-scale statistical isotropy. In particular, the inclusion of O4a events reduces uncertainties in $\langle V_{\rm GW} \rangle$ by $\sim 40\%$ with respect to O1-O3 events. These results establish black-hole merger handedness as a unified probe of orbital precession, remnant recoil, hierarchical formation, and cosmological mirror symmetry.

Classical critical collapse provides a dynamical route from smooth initial data to a naked singularity, representing a sharper violation of predictability than ordinary black hole singularities. We argue that this distinction is erased by quantum backreaction. Building on the semiclassical interior analysis, where quantum self-energy of the collapsing matter generates a universal growing mode and a finite mass gap, we study the exterior naked singularity region that determines global visibility in the Einstein-scalar system. We analyze controlled exterior models in both $2+1$ and $3+1$ dimensions. In the former, smooth matching and physical boundary conditions analytically select a vacuum polarization state, whose backreaction cloaks the classically naked region by a quantum trapped branch. In the latter, numerical horizon tracing shows that near a quantum-shifted threshold the exterior develops finite-mass marginally trapped surfaces rather than a zero-mass naked endpoint. These results suggest a global quantum picture in which the Choptuik naked singularity shares the fate of an ordinary black hole singularity: quantum effects push the putative Cauchy horizon behind a quantum-generated horizon, thereby reducing the loss of predictability to the standard black hole evaporation problem.

The optical binding of gold nanoparticles has conventionally been explored within the Rayleigh limit using dipole approximations. But the field is increasingly focusing on the Mie regime for particles in the 100-500 nm range, where the dipole approximation is insufficient, and a complex landscape of multipolar resonances must be considered. This can be leveraged to engineer more complex forms of optical matter. To this end, we computationally study the optical binding force landscapes experienced by a pair of AuNPs using generalized multiparticle Mie theory. We calculate the total optical binding forces and mechanical trap stiffness values ($dF_i/di$) at the specific resonance wavelengths where the electric dipole, quadrupole, or octupole modes reach their respective scattering peaks and dominate the mechanical response. We demonstrate that the plasmonic mode symmetry greatly influences the spatial distribution of zero-force nodes and the rigidity of the optically bound dimer. By aligning these multipolar phenomena with standard experimental configurations, this work provides a mechanical framework for programmable metafluids and reconfigurable micromachines, bridging the gap between fundamental electrodynamics and reconfigurable nanomanipulation.

Moiré multi-layers of transition metal dichalcogenides have been shown to exhibit optical responses that are endowed with a richness that is absent in single monolayers. Much of this can be attributed to the Moiré superlattice that modulates the electronic landscape of these heterostructures. Strongly coupled layer-hybridized excitons in $\text{MoSe}_2 / \text{WS}_2$ heterobilayers have been shown to exhibit enhanced optical nonlinearities. In this work we strongly couple layer hybridized excitons and trions in n-doped $\text{MoSe}_2 / \text{WS}_2$ heterobilayers inside an optical microcavity. We find that the additional Lindhard screening from dopant electrons and the formation of trions result in a strikingly non-monotonic nonlinear response. The absence of electron capture in the Moiré superlattice plays a crucial role, promising very large second-order nonlinearities. In this work, trion polaritons manifest as high velocity hot polaritons, reaching nominal diffusion lengths approaching 100 microns.

In this work, we formulate self-similarity from the perspective of scale invariance, where a self-similar form is understood as the transformation of a function into a form invariant under scale transformations. By applying this formulation to physical parameters, which consist of numerical values and units, it is demonstrated that dimensional analysis works for physical problems because scale invariance is partially shared between units and physical parameters. This naturally leads to the distinction between similarity of the first kind and similarity of the second kind according to whether the scale functions induced by units and those associated with physical parameters are equivalent or not. Self-similar solutions of the second kind can be further classified according to whether the power exponents of the similarity parameters include functions of dimensionless numbers. This leads to the conclusion that there are three kinds of self-similar solutions. The present work provides a unified framework for understanding dimensional analysis and a universal classification of self-similarity in physical problems.

The rapid neutron-capture process (r-process) is widely regarded as the dominant mechanism responsible for the synthesis of heavy elements in the universe, yet its astrophysical sites remain an open question. Recent studies suggest that the high-entropy, rapidly expanding baryonic material ejected by magnetar giant flares may provide favorable conditions for r-process nucleosynthesis, while the late-time gamma-ray emission observed from the magnetar SGR 1806-20 offers direct observational support for this scenario. In this work, we perform nuclear reaction network simulations to investigate the nucleosynthesis yields of magnetar giant flares and to characterize the associated nuclear gamma-ray line emission arising from the radioactive decay of heavy nuclei. The nuclei synthesized in magnetar giant flares are found to be mainly distributed near the first and second r-process abundance peaks. Owing to this nuclide composition, the gamma-ray opacity is found to be strongly energy-dependent with the opacity in the keV band exceeding that in the MeV band by approximately three orders of magnitude. The nuclear gamma-ray emission is dominated by MeV photons at early times and gradually extends toward the sub-MeV and keV bands as time progresses, thereby offering a diagnostic of heavy element enrichment in the ejecta. The gamma-ray spectrum exhibits a peak near 1 MeV with major contributions from $^{88}$Kr and $^{92}$Sr, whose radioactive decays produce several bright gamma-ray lines with fluxes exceeding $\sim10^{-8}$ erg cm$^{-2}$ s$^{-1}$, making them the most promising lines for detection by MeV gamma-ray detectors. Because magnetar giant flares occur in the Galaxy at a rate roughly three orders of magnitude higher than neutron star mergers and their gamma-ray lines are accessible to current MeV instruments, they offer new and valuable science opportunities for MeV gamma-ray astronomy.

We develop a data-driven reconstruction programme for the dark-energy equation of state within VCDM, a minimally modified gravity framework in which both background and linear perturbations can be consistently evolved across the phantom divide. Using CMB, BAO, and type-Ia supernova data, we first perform a Bayesian spline reconstruction of $w(a)$, finding a preference for smooth, monotonic phantom-crossing trajectories. Bayesian evidence disfavors increasingly complex spline models, indicating that current observations exhibit a statistical preference for low-complexity dark-energy dynamics. Motivated by this result, we apply Exhaustive Symbolic Regression, an interpretable machine-learning technique that systematically searches over analytic expressions of fixed complexity, identifying the remarkably simple one-parameter form $w(a)={w_0}/{\sqrt a}$, which reproduces the reconstructed behaviour and fits the data at a level comparable to standard two-parameter parametrizations such as CPL. The model naturally crosses the phantom divide for $w_0<0$, suppresses early dark energy, and predicts a transient accelerating and phantom phase without a future big-rip singularity. As a one-parameter model, it is highly predictive, being a genuinely dynamical deformation of the cosmological constant rather than containing it as a limit. Bayesian model comparison yields mild-to-moderate support for this parametrization relative to standard two-parameter alternatives, and stronger evidence relative to $Λ$CDM. Our results suggest that current observations favour surprisingly simple dark-energy dynamics and illustrate how Bayesian reconstruction and symbolic regression can be combined into a principled model-discovery framework for cosmology.

The formation mechanism of spicules is fundamentally important for understanding mass and energy transport from the chromosphere into the corona. Recent studies suggested that spicules may be powered by microfilament eruptions. However, direct observational evidence remains limited due to insufficient spatial resolution. Using high-resolution H$α$ broadband observations from the Visible Broadband Imager (VBI) onboard the Daniel K. Inouye Solar Telescope (DKIST), we identify 30 spicule events triggered by microfilament eruptions in a quiet Sun region near the solar disk center on 2023 August 29. The detected microfilaments have an average length of $0.93\pm0.46$ Mm and a minimum length of 0.17 Mm, substantially smaller than previously reported minifilaments. We identify two distinct morphological classes of ejecta: individual spicules associated with smaller microfilaments, and enhanced spicular activities associated with larger microfilaments. Moreover, some events exhibit apparent twisting motions. All these high-resolution observations provide compelling evidence that spicules can be triggered by microfilament eruptions.