Young planets offer a unique window into the early stages of planetary evolution. AU Mic is one of the nearest (9.8 pc) pre-main sequence stars (~20 Myr), hosting two transiting Neptune-sized planets and a debris disk. Previous studies have shown that the rotation of the central star, the debris disk, and the inner planet b are all aligned, suggesting that the system has not undergone violent evolution. Here we report new Rossiter-McLaughlin (RM) measurements for both AU Mic b and c, which happened to transit back-to-back on Aug 24 and 25, 2024, using the Magellan Planet Finder Spectrograph (PFS), accompanioned with contanporaneous photometry from LCOGT and CHEOPS. We confirm the aligned orbit of AU Mic b ($λ_b=1° \pm 12°$) and finding two possible solutions for AU Mic c: we slightly favor an aligned solution ($λ_c=-10° \pm 16°$) but cannot rule out a polar solution ($λ_c=87°\ ^{+36°}_{-29°}$). Broader considerations, including dynamical stability and transit possibility, also support the mutually aligned scenario. An unexpected stellar signal during ingress and the poor TTV predictions of AU Mic c prevent a precise constraint on its obliquity, and various attempts using chromatic spectral analyses fail to outperform simple data exclusion in mitigating the stellar contamination. Our observation highlights the importance of understanding stellar activity across multiple timescales and channels when characterizing young, active systems. A robust solution for the AU Mic architecture will require either a better understanding of stellar activity or future observations fortuitously free from strong stellar contamination.

We compute the low-temperature configurational entropy of a two-dimensional supercooled liquid. Our method, based on a higher-dimensional version of the Grassberger--Procaccia algorithm, can be implemented in a manner that is entirely agnostic with respect to both the dynamics and the theoretical framework, as any genuine notion of order should be. In this construction, entropy is obtained as the decay rate of recurrent structural patterns with increasing patch size, directly linking entropy reduction to the growing persistence of amorphous order. Because the method requires only particle positions, without any knowledge of the interaction potential or even of the particle sizes, it can be applied directly to both equilibrium and nonequilibrium aging configurations. The resulting configurational entropy, together with the higher-order Rényi complexities, agree quantitatively with values obtained from conventional definitions. Remarkably, the entropies measured during aging coincide with their equilibrium counterparts when compared at the same inherent-structure energy.

Strongly simulating a quantum circuit, that is, computing an output amplitude, amounts to summing the circuit's Feynman paths, a weighted count over assignments to the Boolean ``path'' variables. The circuit's gates induce correlations among these variables, forming a graph whose structure determines the hardness of the simulation task. This sum-of-powers viewpoint underlies recent simulators built on knowledge-representation tools from artificial intelligence, namely binary decision diagrams and weighted model counting. We show that the structural quantity most accurately governing the difficulty is the rank-width of the path-variable graph, and we give an algorithm that evaluates the amplitude in time that is exponential only in this rank-width and polynomial in the circuit size. Rank-width can be far smaller than the widths that control competing methods: as corollaries, our algorithm reproduces a recent decision-diagram simulation breakthrough as a special case and matches the Markov--Shi tensor-network contraction bound. To complement this, we exhibit circuit families on which our algorithm provably beats both competing methods. The new method applies to every circuit built from Hadamard and diagonal gates, in particular to circuits over Clifford+T. In practical terms, general-purpose decision-diagram and model-counting tools can serve as the workhorse, with our specialized algorithm dispatched to exploit a small rank-width of the associated graph when it is present.

Magnetic tunnel junction (MTJ)-based magnetic random-access memory (MRAM) is a promising platform for neuromorphic and in-memory computing owing to its non-volatility, high endurance, fast switching dynamics and CMOS compatibility. However, conventional spin-transfer torque and spin-orbit torque MRAM implementations for neural networks often suffer from high critical switching currents, large latency, thermal instability and significant read-write overheads. Here, we demonstrate a unified multistate MRAM-spin-torque nano-oscillator (STNO) architecture that integrates synapses and neurons on a single chip for convolutional neural network (CNN) applications. The system employs 1x8 multistate MRAM arrays as programmable synapses coupled with a vortex-based STNO neuron, enabling both individual and collective programming through fieldline-driven write channels. Multiple configurable resistance states are achieved by tuning internal and external magnetic fields together with bias currents, allowing quantized positive and negative synaptic weights for configurable kernel and pooling operations. The proposed architecture is evaluated through simulation on MNIST, SVHN, CIFAR-10, Google Speech Commands (GSC) and RadioML datasets, achieving accuracy of 99.76%, 87.93%, 78.14%, 87.96% and 56.46% respectively. Based on fabricated device dimensions, the complete architecture occupies ~6171.2 μm2 with an average energy consumption of 200.08 pJ per training and inference cycle for MNIST, highlighting its potential for scalable low-power neuromorphic computing

AI researchers have been advancing socially intelligent AI agents (Social-AI) across embodiments, from chatbots to physical robots. As Social-AI is increasingly deployed in everyday settings, decisions about the roles these agents should play will depend on how laypeople perceive them. However, public perceptions of social intelligence in AI agents and the acceptability of these agents remain largely understudied. We present a mixed-methods survey of adults in the United States (N=200) that examines social intelligence as a perceived construct in AI agents. Our survey investigates the extent to which participants believe current AI agents have social intelligence, abilities of agents that participants associate with social intelligence, contextual factors influencing participant acceptance of Social-AI agents, and concerns participants hold about these technologies. Participants widely reported having already encountered AI agents they perceived as socially intelligent and grounded their judgments in observable behaviors, more than beliefs about AI agency or intent. We identified a support-adoption gap in acceptability judgments: participants supported the existence of Social-AI agents for others far more than for their own personal use. Our analysis uncovers layperson concerns about Social-AI, informing AI governance regarding appropriate deployment contexts, agent roles, and risks to end users.

Pnictogen-based solar absorbers have gained prominence as promising nontoxic and stable alternatives to lead-halide perovskites (LHPs), but are severely limited by carrier localization, preventing their performance from approaching those of LHPs. Recent efforts have uncovered routes to overcome carrier localization, but these early efforts only considered intrinsic factors. Herein, we push beyond these limited early efforts, examining the role of defects, not only on cold carriers but also hot carriers. Focusing on the structurally one-dimensional pnictogen chalcohalide BiSBr, we find that whilst this material intrinsically does not exhibit carrier localization, vacancies introduced during synthesis or post-treatment lead to pronounced extrinsic self-trapping via the formation of defect-bound hot polarons-excited charge-carriers strongly coupled to local defect-induced vibrational modes. These above-gap defect states divert hot carriers from cooling to the band edge, thus depleting the mobile carrier population. Our findings establish the key role of defect-bound hot polarons in mediating extrinsic localization and offer new mechanistic insights into the interplay between defects, lattice coupling, and excited-state charge-carrier transport, which are critical to designing efficient perovskite-inspired solar absorbers.

Ideal density-functional approximations (DFAs) should account for dynamic, static, and nondynamic correlation. While common DFAs struggle with the latter two, the Ziegler-Rauk-Baerends-Daul multiplet sum method (MSM) provides a pragmatic way to include static correlation. In this article, we use diagrammatic MSM density-functional theory (diag MSM DFT) using the two-orbital two-electron model (TOTEM) to extend MSM DFT to include nondynamic correlation without relying on symmetry arguments. Building on previous formulations [A. Ponra, C. Bakasa, A.J. Etindele,and M.E. Casida, J. Chem. Phys. 159, 244306 (2023); M.E. Casida, A. Ponra, C. Bakasa, and A.J.Etindele, J. Chem. Phys. 162, 144317 (2025)] that lacked relaxation effects, this article incorporates relaxation via nonorthogonal configuration interaction (NOCI). We demonstrate that this modified diag MSM DFT produces an accurate ground-state potential energy curve (PEC) for lithium hydride (LiH), even at the ionic-to-open-shell-singlet avoided crossing characterized by significant charge transfer. This encouraging result suggests that the model can be extended to (at least) other singly and multiply-bonded diatomic molecules, while providing insight into a novel way to include strong correlation in DFT.

We study the quantum chaos bound in the photon ring region surrounding black holes. By evaluating the Lyapunov exponent associated with unstable null geodesics in a broad class of generalized Kerr geometries, as well as the temperature induced by a string probe, we show that the quantum chaos bound is exactly saturated on equatorial circular orbits of the photon ring. We confirm our result by deriving the same exponent from out-of-time-order correlators in the near ring region. As a byproduct, we show that the photon ring saturation of the quantum chaos bound implies the saturation of the Bekenstein bound on the rate of information emission from the ringdown phase through the quasi-normal modes in the eikonal limit. Our results extend the known correspondence between black hole thermodynamics and chaotic dynamics, highlighting the role of the photon ring as a probe of the fundamental limits on thermalization and information scrambling in black holes.

Localization is essential in ensemble-based data assimilation because finite ensembles produce noisy covariance estimates, causing spurious updates and excessive loss of ensemble variance. In subsurface applications, localization is usually based on spatial distance, but this criterion can be hard to justify when parameter-data relationships are controlled by flow dynamics, nonlinear operators, non-local parameters, or prior conditioning effects. This work investigates correlation-based localization as an alternative strategy in which tapering coefficients are computed from the statistical reliability of estimated model-data correlations. We interpret localization as a shrinkage problem in correlation space and propose three tapers: a generalized power-law taper motivated by mean-square-error correction, a logistic taper derived from a Bayesian spike-and-slab formulation, and a discrepancy-based taper inspired by Morozov's principle. The tapers are evaluated using synthetic reservoir data assimilation problems involving scalar and grid-based parameters, localized flow responses, non-trivial correlation patterns, and increasing model dimension. The results show that correlation-based localization can suppress spurious correlations while preserving meaningful parameter-data relationships. In several cases, the proposed power-law and logistic tapers retained more posterior ensemble variance than distance-based localization while maintaining acceptable data-match quality. The logistic taper provided the strongest variance preservation, whereas smoother tapers favored better data matches. Overall, the results indicate that correlation-based localization is a statistically motivated alternative to distance-based localization, especially when spatial distance is unavailable or misleading.

We study spaces of conformal blocks associated with line bundles over elliptic curves, with coefficients in a vertex algebra. For vertex algebras satisfying suitable finiteness and semisimplicity conditions, which are met by all admissible affine vertex algebras as well as admissible W-algebras associated with nilpotent elements of standard Levi type, we prove the holonomicity of the sheaf of conformal blocks over the moduli space of bundles. Furthermore, we show that the space of flat sections of the associated Jacobi-invariant connection is spanned by trace functions on modules. This result provides a substantial generalization of the celebrated theorem of Yongchang Zhu to quasi-lisse vertex algebras. As a special case, we deduce that for affine vertex algebras at admissible level, the dimension of the space of conformal blocks coincides with the number of admissible weights at that level.

We consider Subtraction Nim, where two players have exactly the same options, but which is partizan in the sense that at the game ending, a partizan rule is applied for the decision of the winner. We consider the following example: Let $S$ be the set of removable numbers, which is a non-empty finite subset of positive integers greater than or equal to $2$, applied for both players Left and Right. At the end of the game, Left wins if the number of remaining tokens is even, and Right wins if the number of remaining tokens is odd. We computed the outcomes for many $S$, and found surprising phenomena that in most examples of $S$ (almost $98\%$ of some samples), the outcomes are $\mathcal{L}$-positions for all large enough $n$. In comparison, $\mathcal{R}$-positions appear only occasionally. The main theorem explains why this phenomenon occurs. We prove that $n+1$ and $n-1$ are $\mathcal{L}$-positions when $n$ is an $\mathcal{R}$-position. Similarly, $\mathcal{L}$-positions appear whenever $\mathcal{P}$-positions or $\mathcal{N}$-positions appear. Only $\mathcal{L}$-positions can last forever.

We evaluate FALQON parameter transfer for Max-Cut, transferring sequences from small donors ($n \in \{8,10,12\}$) to 14-node recipients. Using 3-regular and Erdős-Rényi families, we show that transfer success is dictated by the recipient graph, not the donor. Transfer excels for dense recipients -- achieving high approximation ratios regardless of the donor -- but remains challenging in sparse cross-family cases. Crucially, performance is highly resilient to donor size, with 8-node donors matching larger instances. Thus, cheap small graphs can provide robust parameters for larger targets, significantly reducing the measurement overhead of the feedback loop.

Let $g$ be a smooth metric on $\mathbb R^3$ with non-negative scalar curvature. We show that if $g$ satisfies $\vert g(x)-g_{\text{euc}}(x)\vert = O(\vert x\vert^{-1-τ})$ for some $τ> 0$ then $g$ must be flat.

The thermochemical evolution of planetesimals is an underprobed stage of volatile delivery to terrestrial planets during their formation, and may contribute to the volatile depletion of the Earth relative to primitive chondrites. We have developed a model of C outgassing from porous, chondritic planetesimals. Our model tracks the thermal evolution and the production of CO/CO2 gas using the redox states of ordinary and enstatite chondrites (OC and EC, respectively, collectively the "NCs"), and CI and CV carbonaceous chondrites ("CCs"). We posit the formation of global fractures when local gas pressure exceeds confinement levels, which vent the excess directly to space, leading to efficient C depletion. We also account for sintering and the enthalpy of dehydration from wet carbonaceous chondrite bodies. We find that C depletion is more efficient on CC planetesimals than NCs due to the former's oxidized environment: for 10-100 km planetesimals formed at 2 Myr after CAI formation, > 50% of C is depleted in almost all CC bodies while < 50% is depleted in almost all NC bodies. Both the largest and the smallest bodies tend to preserve more C, the former due to sintering locking condensed C in against escape, while the latter due to efficient conductive cooling. Earlier accreted planetesimals deplete more C: bodies formed before ~ My deplete most of their C. Our results favor NC planetesimals as the C carriers during terrestrial planets' accretion. Terrestrial planets likely accreted from a mix of C-depleted and C-rich bodies from both CC and NC reservoirs.

The Euclidean paradigm that spheres optimize mean curvature variational problems breaks down in the sub-Riemannian Heisenberg group: neither the Pansu sphere nor the Korányi sphere is optimal for the variational problems associated with the Minkowski and Heintze-Karcher inequalities. Motivated by this phenomenon, we develop a variational theory for geometric problems driven by the horizontal mean curvature, focusing on the total mean curvature functional and the related Minkowski inequality. To investigate this phenomenon, we establish first and second variation formulas for general mean curvature functionals in arbitrary Riemannian manifolds, and then obtain corresponding formulas in Heisenberg groups through a Riemannian approximation scheme. We subsequently specialize to the optimization of total mean curvature under area constraint in the first Heisenberg group, introducing suitable notions of non-characteristic stationarity and stability. We identify a new one-parameter family of rotationally invariant critical surfaces, which we call Pansu-Minkowski spheres. Among them, we show that a distinguished member, the optimal Pansu-Minkowski sphere, emerges as the unique critical point of the Minkowski quotient, and uniquely minimizes it among Pansu-Minkowski spheres. We prove non-characteristic stability and local minimality of Pansu-Minkowski spheres under rotationally invariant perturbations, while showing their instability under unrestricted perturbations.

Superluminous supernovae (SLSNe) are a rare class of transients with peak luminosities 10-100 times greater than those of standard core-collapse supernovae (SNe). The mechanisms powering their extreme brightness remain debated, with circumstellar medium (CSM) interaction, or energy injection from a central engine like a magnetar wind nebula being the most plausible scenarios. To further constrain the underlying mechanism, we carried out a systematic search for GeV gamma-ray emission using the Fermi-LAT telescope from a sample of nearby hydrogen-poor (Type I) and hydrogen-rich (Type II) SLSNe over the past 16 years. Among the sample, only SN 2017egm shows significant gamma-ray emission, with likelihood test statistic (TS) values of 26-33 (i.e., >5$σ$) depending on the adopted time window. The signal arises between 50 and 160 days after explosion and is well described by a power-law spectrum with index $Γ=2.17 \pm 0.23$. The emission is consistent both in terms of its light curve and its spectrum, with predictions from magnetar models requiring either low nebular magnetization or faster spin-down than dipole losses. The CSM shell interaction scenario can reproduce the observed flux level but not the observed timing of the gamma-ray signal. In addition, the observed ratio, $L_γ/L_{opt} \sim 1$, is inconsistent with theoretical expectations and not in line with ratio measurements in other interacting CSM-dominated objects (e.g., novae or SNe) where this ratio is less than $10^{-2}$. Our study strongly suggests that a central engine like a magnetar plays a key role in this SLSN and could explain the bulk of the optical and gamma-ray light curves properties. Finally, simulations of 50 hours of CTAO observations indicate that a SN 2017egm-like event would be detectable up to 140 Mpc in the magnetar model but not in the CSM model due to strong gamma-gamma absorption.

Parameter inference and state estimation in stochastic and partially observed biological systems remain major problems in mathematical biology. In this work, we introduce a two-dimensional lattice graph model for the spread of infectious diseases. Estimating states and parameters in graph-based stochastic epidemic systems is particularly challenging because of randomness and incomplete observations. To address these issues, we propose a particle filter based data assimilation framework for the sequential estimation of both model states and unknown parameters. Two methodologies are developed: one based on the number of infected agents and another based on partial spatial location's information of infected agents on a two-dimensional lattice. The performance of the two methods are firstly analyzed and validated using synthetic data, and the first method is then applied to influenza data collected from different prefectures in Japan between July 2024 and December 2025. One-week-ahead forecasting simulations are also performed using current weekly data. The findings highlight the effectiveness of the proposed PF framework for real-time epidemic monitoring, forecasting, and adaptive public health decision-making.

We generalize the classical Ceva's and Menelaus's theorems to curvilinear triangles bounded by circular arcs. We introduce trilinear coordinates associated with such triangles and develop several geometric constructions. In particular, for any proper Möbius triangle we define the incenter, excenters, and orthocenter.

The spectrum of Ramanujan's partial theta function $θ(q,x):=\sum _{j=0}^{\infty}q^{j(j+1)/2}x^j$, $q\in \mathbb{D}_1$ (the unit disk centered at the origin), $x\in \mathbb{C}$, is the set of values of the parameter $q$ for which $θ(q,.)$ has a multiple zero. We show that there is no spectral value in the set $\mathbb{S}\cup \mathbb{D}_{c_0}$, $c_0=0.2078750206\ldots$, where $\mathbb{S}$ is the sector $\{ 0<|z|<0.6,{\rm arg}(z)\in [π/4 ,7π/4 ]\}$. There is a single spectral value in the set $\mathbb{S}\cup \mathbb{D}_{0.31}$ which equals $0.309249\ldots$. For $q\in \mathbb{S}\cup \mathbb{D}_{c_0}$, the moduli of the zeros of $θ$ are separated by the negative half-integer powers of $|q|$.

We present a lattice QCD calculation of the charged-neutral pion mass splitting $M_{π^+} - M_{π^0}$ at $\mathcal{O}(α_\mathrm{em})$ using a recently proposed framework based on a Pauli-Villars (PV) regulated photon propagator defined in the continuum and infinite-volume limit, with $Λ$ acting as an additional UV cutoff scale. The use of this propagator avoids power-law finite-volume effects, allowing for a straightforward treatment of the infinite-volume limit. We perform the calculation using CLS ensembles, studying finite-volume effects, the continuum limit and the extrapolation to the physical point for several values of the scale $Λ$. By means of the Cottingham formula, we further decompose the result into elastic and inelastic contributions at fixed $Λ$. Our final result, after removing the cutoff scale $Λ$, is $M_{π^+} - M_{π^0} = 4.56(22)$ MeV, in good agreement with the experimental measurement. This calculation serves as a validation of the formalism in a well-controlled setting and offers useful insights into the application of electromagnetic corrections to other observables.

Six challenges for the standard cosmological model $Λ$CDM are listed, which arise when comparing theoretical predictions with observational data on scales of ~1 Mpc. Different parameters of luminous and dwarf galaxies in the local sphere with a radius of 12 Mpc are presented. The average densities of stellar matter and dark matter are reproduced depending on a distance in the Local volume. Observational data on distribution of angular momentum of nearby galaxies are considered. A comparison of the dark matter mass estimates for systems of galaxies based on motions of their internal (virialized) members and neighboring galaxies is given. The reasons for the low derived value of the dark matter density, $Ω_m = 0.08\pm0.02$, in the Local Universe with respect to the global value $Ω_m = 0.30\pm0.02$ are discussed

The asymptotic Karush-Kuhn-Tucker (AKKT) optimality conditions are distinguished from other approaches in the literature by virtue of their capacity to be effectively derived through numerical methods, such as the utilization of an appropriate version of the augmented Lagrange method. These tools are of a theoretical nature, yet they possess practical utility in the identification of candidate solutions to continuous-time programming problems. While this type of optimality condition is valid without imposing any constraint qualification, it is not sufficiently robust to generate good candidate solutions. In some cases, solutions satisfying AKKT conditions are not even stationary. In this study, we investigate conditions that effectively refine this set of candidate solutions with the same precision as the classical Karush-Kuhn-Tucker (KKT) conditions. This is achieved by introducing a novel constraint qualification, designated AKKT-regularity. It has been demonstrated that, under AKKT-regularity, each local optimal solution is shown to satisfy the KKT conditions. In addition, it is demonstrated that this constraint qualification is the weakest possible to ensure such a property. Furthermore, sufficient conditions are provided for its applicability.

Field-tunable reconstruction of crystalline electric field (CEF) doublets offers a promising avenue for inducing multipolar character, while its observation in real materials has been little explored so far. Here we establish the honeycomb rare-earth chalcohalide NdOF as such a platform. Raman spectroscopy identifies four CEF excitations at 1.7, 15.6, 19.2, and 80.9~meV, and a Zeeman--CEF analysis reproduces their nonlinear field splitting into seven branches. Magnetization and susceptibility over 0.1--9~T are well described by a CEF model for the total angular momentum $J = 9/2$ manifold, confirming the robustness of the extracted CEF scheme. These results demonstrate a field-driven continuous evolution of the ground-state doublet from dipolar to dipolar-multipolar character, with pressure providing a complementary tuning knob, establishing NdOF as a model system for exploring the controlled induction of multipolar components in rare-earth magnets.

Little red dots (LRDs) are compact high-redshift objects, newly discovered by the James Webb Space Telescope. Although LRDs exhibit broad Balmer emission lines suggestive of the presence of active galactic nuclei (AGN), their spectral features differ significantly from those of ordinary AGN. Recent studies suggest that their characteristics can be explained if accreting supermassive black holes (SMBHs) are embedded within dense gaseous envelopes and surrounded by compact stellar clusters. In this scenario, stars in the cluster can scatter onto plunging orbits that intersect the envelope and collide with its surface. Here we investigate the observational properties of such star-envelope collisions as luminous transient events. We find that collisions involving red supergiants with radii of $\sim 10^{3}~R_\odot$, together with gaseous envelopes whose masses are comparable to those of the central SMBHs, are the most promising targets due to their high luminosities and long durations. For compact clusters with sizes of $\lesssim 10~{\rm pc}$, such massive stars can participate in star-envelope collisions within their lifetimes at event rates reaching $\sim 0.3~{\rm yr}^{-1}$ per LRD. We show that these transients are detectable with future wide-field surveys such as the Nancy Grace Roman Space Telescope if they occur at relatively low redshifts ($z \lesssim 1$). Detection of such transients would provide strong evidence for the envelope+stellar-cluster scenario of LRDs and offer a unique probe of the envelope mass, which is otherwise difficult to constrain from LRD spectra alone.

This paper studies a type of rank-based mean field game in which competing agents strategically switch among multiple effort regimes. We propose an entropy regularized auxiliary problem where the switching decisions are randomized to the control of transition probability for a continuous-time finite-state Markov chain. We first establish the existence of regularized equilibrium in this auxiliary problem. Assuming the convexity of reward scheme, we then prove that the equilibrium is unique and can be approximated by a fictitious play iteration scheme. Furthermore, as the entropy regularization vanishes, we establish the convergence analysis of the regularized equilibrium towards the relaxed equilibrium in the original MFG of optimal switching. The uniqueness of the population ranking distribution under the relaxed equilibrium is also obtained given a strictly convex reward scheme.

Nontrivial topological spin-textures, such as skyrmions, merons, bimerons, and skyrmioniums, are envisioned as robust building blocks for future memory and logic devices. Controllable transformations between these states require a quantum-mechanical description of electronic degrees of freedom and atomic-scale insight beyond existing phenomenological models. Here, we report an atomic-scale investigation of topological phase transitions and their protection in the two-dimensional van der Waals ferromagnet Fe$_3$GeTe$_2$ (FGT) using a combined experimental-theoretical approach. Synchrotron-based Fourier transform holography directly images labyrinth domains, isolated skyrmions, mixed labyrinth-skyrmion phases, and skyrmion bags with high spatial resolution. We compare these observations to simulations based on an electronic lattice Hamiltonian that captures both metallicity and relativistic spin-orbit coupling in FGT. By systematically exploring a broad range of temperatures and magnetic fields, we map the mechanisms governing topological transitions and their stability. This sequential-integrated experimental-theoretical framework advances understanding of spin-texture interactions and enables precise control of external tuning parameters. Our results establish a platform for creating, stabilizing, and manipulating topological states, paving the way for engineered spin-texture transitions in next-generation spintronic technologies.

The simplified lattice Boltzmann method (SLBM) is a recent development in the lattice Boltzmann method (LBM) community, addressing the intrinsic limitations of the traditional LBM by directly evolving macroscopic quantities and maintaining numerical stability in high Reynolds number simulations. However, fundamental understanding of the numerical dissipation and dispersion of SLBM is still lacking, and the origin of its good numerical stability remains unknown. In this work, a generalized formulation is developed, revealing that the SLBM recovers modified macroscopic equations containing both intrinsic physical deviations and numerical truncation errors. To remove these deviations, the macroscopic equation derived from the standard BGK-LBM is adopted as a reference model and solved by the predictor corrector strategy, which constitutes the reformulated SLBM. The proposed method uses the generalized SLBM formulation in the predictor step with tunable high-order parameters, while the corrector step is realized by the finite-difference discretization. Linear wave analysis clarifies the roles of these parameters in controlling numerical dissipation and dispersion, which is then validated in more complicated numerical examples. It is demonstrated that the reformulated SLBM preserves the second order accuracy, improves the dispersion and dissipation performance, enhances numerical stability, and resolves fine vortex structures on relatively coarse grids. Thus, the proposed method combines improved numerical properties with the simplicity of SLBM, offering a high fidelity and stable scheme for incompressible flow simulations.

We consider three-dimensional (3D) lattice Abelian Higgs models, with compact U(1) gauge variables coupled to a doubly-charged $N$-component complex scalar field (CLAH). We focus on their phase transitions between the disordered-confined (DC) and ordered-deconfined (OD) phases. When they are continuous they belong to the 3D Abelian Higgs (AH) universality class associated with the stable charged fixed point (CFP) of the renormalization-group flow of the 3D AH field theory, or scalar electrodynamics, describing $N$-component complex scalar fields minimally coupled to a U(1) gauge field. This CFP exists only for a sufficiently large number of components, i.e., $N \ge N_d^*$, where the integer $N_d^*$ depends on the spatial dimension $d$ (for example $N_4^*=183$). To estimate $N_3^*$, we look for the minimum number $N_{\rm cL}$ of scalar components of 3D doubly-charged CLAH models developing continuous transitions along their DC-OD transition line. For this purpose, we present finite-size scaling analyses of Monte Carlo simulations for $N\in[4,10]$, up to lattice sizes $L\approx 100$. The results provide evidence of continuous DC-OD transitions for $N=10$, and weak first-order transitions for $N\le 7$. They are not conclusive for $N=8,\,9$. Therefore, we estimate $N_{\rm cL}=9(1)$.

We consider a non-spherical neutral particle spinning in free space and interacting with the electromagnetic quantum vacuum. When the rotation axis is orthogonal to the particle symmetry axis, the scattered field develops frequency sidebands that induce the parametric emission of dynamical Casimir photon pairs. Under the structural constraint of a maximum tip velocity, the emission rate is maximized for a nearly spherical geometry and is further enhanced near a polaritonic resonance. For realistic material parameters, even these optimized upper bounds remain exceedingly small, setting stringent quantitative limits on free-space rotational dynamical Casimir emission with a single nanoparticle.

A 75 nm-thick Fe0.5Pt0.5 film is a ferromagnetic metal showing striped magnetic domains in remanence at room temperature. The magnetoresistance is characterized by varying the external temperature and the in-plane magnetic field intensity, thereby affecting its magnetic structure. Qualitatively, the resistivity is well described by using the generalized Ohm's law. High-field magnetotransport properties are successfully explained by considering the competition between the expected metallic behavior and the electron-magnon interaction. In the low-field condition, we size the contribution of the magnetic texture to the macroscopic magnetotransport response by introducing a new quantity. Consistent with the microscopic modulation of the lateral conduction, low-field measurements reveal inhomogeneities attributed to the spatial distribution of ferromagnetic domains and domain walls. By carefully analyzing the macroscopic response near the coercive field, the additional contribution to the resistivity is attributed to the domain walls themselves. In fact, this term could surpass the anisotropic term at low temperatures. In summary, this study demonstrates that spatial magnetic inhomogeneities are not only macroscopically measurable but also comparable in magnitude to other regularly considered terms, mainly at low temperatures.