Papers

Recent microscopic studies have investigated various features of the spin distributions of fission fragments, but their parity distributions remain largely unexplored. In this Letter, we provide a complete characterization of the spin–parity content of fission fragments within a time-dependent Hartree-Fock-Bogoliubov framework, performing for the first time simultaneous projections on angular momentum, particle number, and parity. Calculations are carried out for the thermal neutron-induced fission of $^{239}$Pu using both the Gogny and Skyrme energy density functionals. We find that dynamical pair breaking during fission populates a significant fraction of unnatural-parity states and generates components with non-zero spin projections $K$. The parity content is found to depend on the number parity of the fragments, with odd-mass nuclei exhibiting pronounced parity staggering and odd-odd nuclei favoring negative parity. These results show that the parity distribution of fragments can depart significantly from the equiprobable partition commonly assumed in statistical de-excitation models, with potential implications for the modeling of fragment decay.

We investigate gravitational wave (GW) emission from periodic timelike orbits of a test particle around a magnetized Ernst black hole and the gravitational waveforms generated by their orbital dynamics. The bound geodesics are systematically classified using the zoom-whirl representation labeled with three integers $(z,w,v)$. Gravitational waveforms are computed within a numerical framework that combines exact geodesic motion with the quadrupole approximation, which is well-suited to extreme mass-ratio inspirals (EMRIs). This analysis is particularly relevant for assessing the capability of future gravitational-wave observations to detect the effects of magnetic fields. Our results show that an intrinsic magnetic field imprints characteristic features on the GW signal, highlighting GW astronomy as a promising avenue for probing magnetized black hole spacetimes.

Relativistic hydrodynamics successfully describes bulk observables in symmetric heavy-ion collisions, but struggles to reproduce charged-particle rapidity distributions in asymmetric systems such as d+Au collisions. To address this challenge, we introduce two key improvements to the initial-state modeling: sampling deuteron configurations from an ab initio wavefunction, and developing a new longitudinal entropy deposition model that incorporates a transverse entropy deposition coefficient $\beta$ and a rapidity loss term scaling with the number of binary collisions $n_{\rm BC}$. Using the (3+1)-dimensional viscous hydrodynamic model CLVisc coupled with the SMASH afterburner, we simulate d+Au collisions at $\sqrt{s_{\rm NN}} = 200$ GeV and successfully reproduce the experimental charged-particle pseudorapidity distributions across five centrality classes with $\beta = 0.35$, as well as the transverse momentum spectra and anisotropic flow $v_n$. The entropy deposition coefficient $\beta$ and the $n_{\rm BC}$-dependent rapidity loss are found to play crucial roles in achieving this agreement. Furthermore, this longitudinal entropy deposition framework demonstrates excellent universality, as validated in p+Au, $^3$He+Au, and Au+Au collisions. Our entropy deposition mechanism could be widely applied to recent light-nucleus collisions such as O+O, Ne+Ne, and asymmetric systems like Pb+Ne at LHC energies, thereby better constraining the nuclear structure of light nuclei through an improved longitudinal description.

In their paper published in Science 392, 221 (2026), Widmann and collaborators reported interferometry experiments to explore the emission coherence decay of a two-dimensional polariton condensate generated in an array of coupled resonators. The authors claim evidence of Kardar–Parisi–Zhang (KPZ) universal scaling in the measured spatio-temporal coherence decay. We argue in the following that the data were not properly analyzed. We re-analyze the experimental data acquired both with the square and the triangular lattices for various values of the excitation power. Instead of stretched exponential decays, in the space (time) windows considered in the paper we find that the measured $|g^{(1)}(\delta {\bf r}, \delta t)|$ at $\delta t=0$ ($|\delta {\bf r}| $ close to $0$) rather show Gaussian (exponential) decay for all excitation powers. As a result, using as temporal and spatial exponents $\beta=0.5$ and $\chi=1$, the data for all pump powers are found to collapse onto a single curve, which is not the KPZ scaling function. In particular, we show that the data collapse onto the KPZ scaling function presented in the paper is an artifact stemming from incorrect data normalization. We thus conclude that the main claim of the paper is not justified as the spatio-temporal decays of the coherence over the space-time windows analyzed in the paper are not well described by the KPZ universal behavior.

We study a Schwarzschild-like black hole embedded in an exponential-sphere (ESM) dark matter halo, characterized by a halo mass $M_0$ and a scale radius $r_0$. We first show that the halo's effect on the marginally bound orbit (MBO) and innermost stable circular orbit (ISCO) is richer than a simple shift: the characteristic radii and energies vary non-monotonically with $r_0$, dipping below their Schwarzschild values before recovering, while the angular momenta decrease monotonically; as a function of $M_0$, the response can even reverse sign depending on how extended the halo is, with only the ISCO energy remaining monotonic throughout. We classify periodic orbits by the rational frequency ratio $q=\omega_\phi/\omega_r-1=w+v/z$ and find that $r_0$ and $M_0$ leave clearly distinguishable imprints on the orbit spectrum. Using the numerical kludge framework, we compute the corresponding extreme-mass-ratio-inspiral (EMRI) waveforms and show that varying $r_0$ produces a strong, monotonic effect enlarging the orbits, lengthening the radial period, and introducing a clear dephasing while comparable variations in $M_0$ leave the signal nearly unchanged unless $M_0$ becomes a sizable fraction of the black hole mass. Together, these results indicate that EMRI waveforms can, in principle, disentangle the total mass of a dark matter halo from its spatial extent, offering a strong-field probe of the dark matter distribution around supermassive black holes.

Modern stellar surveys measure millions of spectra, yet one self-consistent atmosphere and spectrum can require tens of minutes. This cost has motivated grids, spectral emulators, and data-driven models. We present Payne Zero, which reorganizes one-dimensional LTE Kurucz calculations for GPU-native synthesis and multicore atmosphere iteration, and validate it against the original Fortran programs. A 300-1000 nm solar spectrum sampled at a grid resolution of R = 300,000 takes about 14 s on an NVIDIA H100 GPU, while the APOGEE 1500-1700 nm interval takes about 1 s. Physical atmosphere iterations take 2-5 s on 16 AMD CPU threads, and learned initializers reduce the iterations required for convergence. Final spectra remain in practical parity across the tested dwarf and giant regimes. These speeds place direct synthesis inside an optimizer without a label-to-flux spectral emulator. We demonstrate direct many-element fitting of reduced APOGEE spectra and recover multi-element abundance trends broadly consistent with the survey catalog. GPU-resident velocity shifts, broadening, line-spread-function convolution, and detector sampling add negligible cost relative to synthesis. The direct-synthesis search takes less than one minute per star on an H100, while atmosphere verification runs independently on multicore CPUs. The same computational graph calibrates more than 100,000 oscillator-strength and damping corrections jointly against the Sun and Arcturus in about one minute on an H100. Payne Zero therefore brings direct physical fitting and atomic-data calibration to survey scale. The code is available at https://github.com/tingyuansen/payne-zero.

We characterise the interplay between cation-translational and anion-rotational dynamics on the model system $\rm \alpha\text{-}Li_{2}SO_{4}$ through virtual isotopic substitution molecular dynamics (VISMD) simulations. We independently control in turn the lithium translational- and sufate rotational- diffusivity by varying the masses of lithium and oxygen, respectively, showing that both diffusivities exhibit power-law relationships with the masses of each individual component. Changing either diffusivity produces an effect on the other; i.e. there exists a bidirectional coupling between anion and cation diffusive dynamics. From our variable-temperature/variable-mass dataset we demonstrate that the apparent activation energy for lithium diffusion depends strongly on the isotope mass, decreasing with accelerated sulfate dynamics; an observation which provides clear evidence of mode-coupling between cation and anion dynamics.

Under the assumption that black hole horizon area is quantized, each Hawking evaporation step, during which the black hole loses mass and transitions to a lower area level, is interpreted as the erasure of one bit of information. In this paper, by employing Landauer's principle, we test the consistency of various black hole entropy relations with this information-theoretic framework. For the Bekenstein-Hawking entropy, the energy emitted per step saturates the Landauer bound. We extend this analysis to a broad class of generalized entropy models, yielding three distinct outcomes. In the first category, Landauer's principle imposes constraints on the Hawking temperature and, consequently, on the black hole mass. In the second, it restricts the free parameters of the entropy model. The third category, exemplified by Kaniadakis entropy, proves incompatible with Landauer's principle. For all compatible models, we derive the area quantization parameter and the corresponding area spectrum. While this parameter is constant for Bekenstein-Hawking entropy, it becomes level-number-dependent for many generalized models. Nonetheless, the relative spacing between successive area levels vanishes in the classical limit. Our findings point to a deep link between information theory and black hole thermodynamics.

We study a dimension-saturating fixed-core ansatz in which four copies of a fixed, non-tunable two-qutrit core $K\in SU(9)$ are interleaved with five adjustable local layers from $L=SU(3)\otimes SU(3)$. Since $\dim SU(9)=80$ and $5\dim L=80$, this is the shortest fixed-core architecture not excluded by parameter counting. We formulate the smooth map $\Phi_K:L^5\to SU(9)$ and use its right-trivialized differential to give verifiable certificates for local universality. We construct an explicit Clifford-word core whose Pauli-label splitting makes the identity-point differential an exact isometry, and we classify all 2304 symplectic actions satisfying the same splitting criterion. We also prove a structural obstruction for an important symmetry class: every complex-symmetric core $K=K^{T}$, including every core generated by a time-independent real-symmetric Hamiltonian in the chosen computational basis, has identity-point differential rank at most 78; hence any full-rank certificate for such a core must occur away from that point. We then assess a hardware-motivated superconducting core generated by a noncommuting, temporally asymmetric drive. Direct calculation verifies $K_{\rm sc}\neq K_{\rm sc}^{\mathsf T}$, and the core achieves $F_{\rm avg}\ge 0.999$ for all 1000 Haar-random targets tested under the stated restart protocol. We also report favorable sampled Jacobian-rank, structured-target, and robustness diagnostics. These results establish local universality at the parameter-counting-minimal, dimension-saturating depth, with an exact Clifford certificate complemented by a hardware-motivated numerical case study. Throughout, we separate exact local certificates from numerical evidence for broader synthesis performance.

We propose Tree Tensor Network Reservoir Computing (TTN-RC), a quantum-inspired reservoir computing framework for time-series prediction that uses the hierarchical structure of Tree Tensor Networks as a random reservoir. To control the exponential concentration or divergence of TTN outputs, we introduce a hierarchical ensemble method that partitions a fixed-size reservoir into multiple independent sub-reservoirs. In the tested NARMA benchmarks, TTN-RC achieves competitive or improved performance compared with conventional Echo State Networks, especially for tasks requiring higher-order nonlinear processing and longer contextual dependence. We also derive an expected contraction rate based on the reservoir Jacobian and develop a mean-field description of the reservoir-state statistics. These analyses identify an asymptotic stability boundary at $\sigma_{T}=\sqrt{2}$ in the large per-tree-size limit, where several theoretical indicators converge. Our results provide a design principle for tensor-network-based reservoir computing and clarify how hierarchical reservoir topology controls stability and nonlinear information processing.

Complex networked systems are prevalent in biology, engineering, and the social sciences, yet their high-dimensional, nonlinear dynamics pose major challenges for analysis and prediction. A mathematically rigorous route to simplification is to represent system behavior on a low-dimensional, smooth invariant manifold known as a spectral submanifold (SSM). Here we present a comprehensive SSM reduction framework and its globalized extension (gSSM) for dimensionality reduction in large-scale nonlinear networks. Our approach yields accurate global and node-level predictions across synthetic and real networks, including highly heterogeneous topologies and systems with higher-order interactions. Crucially, SSM is a robust tipping-point predictor: even at low truncation order (e.g., $O(2)$) it reliably identifies the onset of sustained activity, while higher orders and gSSM capture post-onset amplitudes and saturation. Consistently, the reduction collapses the full network dynamics to a one-dimensional system, offering clarity and efficiency. Across all the realizations, SSM/gSSM consistently outperform classical spectral and mean-field methods in modeling critical transitions at both microscopic and macroscopic scales, establishing SSM-based reduction as a robust, interpretable tool for nonlinear networked systems with broad applicability to epidemiology, ecology, and engineered networks.

We investigate the quasinormal modes (QNMs) of scalar perturbations and strong cosmic censorship (SCC) in regular Ayón-Beato-García-Bronnikov-de Sitter (ABGB-dS) black hole spacetime. The main motivation of this work is to clarify whether the regularization of black hole core, which removes the central singularity, can also change the fate of SCC connected to the Cauchy horizon. We first study the dependence of the scalar QNM frequency (QNF) on the scalar mass and black hole parameters. For angular number $l=0$, a small scalar mass can give rise to a slowly decaying mode which is purely imaginary, while it will become complex for large enough scalar mass and we call it dS-like mode. We also find that the black hole charge and cosmological constant affect the QNM spectrum in qualitatively opposite ways. We then examine SCC under massless and massive scalar perturbations. For massless perturbations, the QNMs spectrum can be organized into photon sphere (PS), de Sitter (dS) and near-extremal (NE) families. Compared with the SCC in the Reissner-Nordström-de Sitter (RN-dS) case, SCC is generally more easily violated in the ABGB-dS spacetime, although this tendency is reversed for sufficiently large cosmological constant. For massive scalar perturbations, we find that the scalar mass does not restore SCC. Instead, it can enhance the violation by driving the system into the regime $\beta>1$. At last, we discuss what we may expect from the violation of SCC in a regular black hole spacetime.

Free-space quantum key distribution (QKD) provides crucial advantages, including mobility and deployment exibility, for securing next-generation communication networks. However, atmospheric turbulence and beam wander severely degrade single-photon coupling effciency and link stability over outdoor channels. In this work, we experimentally demonstrate a free-space decoy-state BB84 QKD system operating at 803 nm with a 100 MHz repetition rate over a 2 km outdoor link. By employing an active beam-wander correction based on fast-steering mirrors (FSMs) and position sensitive detectors (PSDs) with a 500 Hz control loop, we enhance the ?ber coupling effciency and achieve an average ?nite-key secure key rate of 110 kbps with an average quantum bit error rate (QBER) of 3.28 %, representing a 2.5 times secure key rate enhancement under an active beam stabilization. This work demonstrates the indispensability of active beam stabilization and provides an operational reference for robust, long-range free-space quantum communication.

Mobile infrared-visible imaging typically pairs a compact infrared sensor with a high-resolution visible camera for complementary perception. While cross-sensor misalignment caused by different optics, viewpoints, fields of view, and exposure timings hinders practical deployment. In this paper, we propose BeyondFusion, a unified latent diffusion framework for calibration-free visible-guided infrared super-resolution and infrared-visible fusion tasks. The proposed framework supports both task-specific training and joint training where two tasks are optimized and executed as two readouts of the same generative process. Instead of relying on explicit registration or geometric warping, BeyondFusion introduces a cross-modal self-aligning (CMSA) module into the denoising U-Net. CMSA reorganizes infrared and visible latent tokens into a shared attention space to learn content-adaptive cross-modal correspondence during the denoising process. Together with misalignment augmentation module, the model is facilitated to exploit visible structural and semantic cues while preserving thermal consistency, enabling high-frequency infrared reconstruction and informative fused-image generation under uncalibrated conditions. Extensive experiments on public benchmarks and a mobile infrared-visible imaging system show strong performance across aligned inputs, low-resolution infrared observations, synthetic misalignments, and real mobile captures with unsynchronized sensors. Ablation studies, unified training analysis, and downstream pedestrian detection further validate the effectiveness of BeyondFusion for calibration-free multimodal imaging.

Forecasting how aftershocks evolve in space and time after a large earthquake is a central problem in statistical seismology and underpins operational earthquake forecasting. Existing forecasting methods rest on statistical point-process models such as the epidemic-type aftershock sequence (ETAS) and Reasenberg-Jones models, which prescribe a fixed decay in time and an isotropic kernel in space. They match the average Omori-Utsu and Gutenberg-Richter statistics well but do not capture the fault-controlled spatial patterns of real sequences or the productivity that varies among sequences. Neural point-process models relax these fixed forms but keep the event-by-event view and have not consistently surpassed ETAS on common benchmarks. Rather than modeling individual events as a point process, we recast aftershock forecasting as conditional generation of a spatiotemporal field. We develop QuakeGen, a diffusion model that generates the evolving fields of aftershock rate and maximum magnitude conditioned on recent seismicity and the forecasting horizon. The same conditional generative framework can be trained on rich seismic catalogs to forecast global aftershock sequences and regional daily seismicity, and could further condition on physical fields such as fault geometry or geodetic deformation. On global sequences, the data-driven approach outperforms the operational USGS Reasenberg-Jones forecast, recovering the fault-controlled, anisotropic spatial structure that fixed kernels cannot express. On daily forecasting, QuakeGen also matches the well-tuned ETAS baselines, which neural point-process models have yet to surpass on the regional benchmark. Conditional generative modeling, which has transformed prediction in fields as diverse as weather forecasting and protein structure prediction, holds the potential to forecast more accurately how earthquake sequences unfold in space and time.

Phase-field modeling has achieved great success in predicting pattern formation in materials, such as the formation of ferroelectric domains. However, because it is typically based on continuum mechanics, conventional phase-field modeling cannot be straightforwardly applied to atomic-scale pattern formation, such as dopant segregation and vacancy ordering, which are driven by chemical potentials. Here, we extend the phase-field concept to the atomic scale by formulating the free energy of atomic systems within stochastic self-consistent harmonic approximation (SSCHA) theory to allow fractional site occupations. Our methodology enables us to directly calculate the derivative of the free energy with respect to site occupation and thereby obtain the chemical potential, successfully reproducing Ag distributions in bulk Cu as well as the resulting lattice expansion. Furthermore, we applied our methodology to investigate dopant segregation around a {\Sigma}5(310)[001] Cu grain boundary doped with Ag atoms. We found that Ag atoms preferentially segregate at the vertices of the triangular motif of a grain boundary. As the number of dopants increases, excess Ag atoms segregate near the vertices and then at the bottom sites of the triangular motif. This study extends the phase-field concept to discrete atomic systems, enabling the identification of preferential dopant-segregation sites and thereby visualizing atomic-scale pattern formation.

Quantum emitters coupled to nonlinear one-dimensional waveguides provide a route for quantum-state engineering by utilizing parametric gain accumulation along with modified waveguide-mediated interactions. Since the accumulated squeezing depends on propagation distance, different emitter separations can experience different effective gain, making the spatial structure of connected quantum correlations a central feature of the dynamics. Here we investigate the transient and steady-state connected correlations of emitter arrays coupled to a parametrically driven waveguide. Using an effective master equation for nonlinear waveguide QED, we analyze second- and third-order connected correlations as functions of the squeezing parameter and interparticle distance. In the two-emitter limit, accumulated squeezing drives excitation buildup and generates a nonzero connected second-order correlation. For many-emitter arrays, tuning the interparticle distance switches the dominant local second-order correlation between the bulk and boundary regions, and enables an analogous spatial control of genuine third-order connected correlations. In the steady state, the averaged second-order correlation exhibits sign-changing and nonmonotonic behavior in the squeezing–interparticle distance parameter space, whereas the third-order connected correlation is strongly enhanced by increasing the squeezing parameter. These results identify nonlinear waveguide QED as a tunable platform for spatially controlling connected quantum correlations and provide insights into correlation engineering in open quantum optical arrays. We further show that this local contrast remains visible in both odd and even number of atomic arrays.

Astronomical interferometry is a cornerstone technique for high-resolution stellar imaging and observational astrophysics, extracting spatial information from the coherence of light collected by separated telescopes. Since the degree of coherence is complex, a genuine imaging task requires the joint recovery of the modulus and the relative phase, instead of independent singleparameter estimations. We investigate the simultaneous estimation of both parameters based on direct interferometry scheme and continuou-svariable quantum teleportation scheme. We find that in simultaneous estimation the direct interferometry scheme consistently yields a lower quantum Cramér-Rao bound, demonstrating its superiority over the continuous-variable quantum teleportation scheme. Furthermore, we establish the conditions under which the classical Cramér-Rao bound for Gaussian measurements saturates the quantum Cramér-Rao bound, identifying heterodyne detection as a near-optimal measurement scheme in the large mean photon number regime. An analysis of transmission loss reveals that the direct interferometry scheme yields superior precision in the short-baseline regime, whereas the continuous-variable quantum teleportation scheme outperforms it at longer baselines.

The precise characterization of the spatial degree of coherence of a radiation field is important for assessing its suitability for specific applications in optical communications, advanced imaging, and quantum information processing. However, measuring the full coherence matrix traditionally requires complex, phase-sensitive interferometric setups that are highly susceptible to noise and difficult to scale on integrated platforms. To address this, we propose an architecture-agnostic approach for analyzing partially coherent light that is compatible with any universal programmable photonic unitary circuit, regardless of its internal topology. Leveraging the Schur-Horn theorem, our method diagonalizes the output coherence matrix, enabling direct extraction of its eigenvalues from output power measurements alone. We numerically validate this framework across various universal topologies and demonstrate its efficacy even in under-parameterized, non-universal architectures with only minor loss in precision. Finally, our black-box optimization approach proves inherently resilient to arbitrary optical losses and component deviations, paving the way for robust, lower-depth, and programmable spatial coherence analyzers.

Hyperuniformity in active matter is usually treated as a property of a prescribed density or continuum field. This view misses a basic feature of hydrodynamic active matter: an incompressible fluid does not respond equally to every microscopic force. Longitudinal forcing is absorbed into pressure, whereas transverse forcing drives flow. The relevant question is therefore not only whether particles are uniformly arranged or whether the total activity is small, but which sector of the active forcing is selected by the physical response. Here we introduce response-selected hyperuniformity, in which long-wavelength order is a property of a source-response pair. In a reversible valence-one fluid with no prescribed partners, locally neutral clusters screen the signed active-moment sector that controls transverse flow, producing a first-moment spectrum that vanishes quadratically at low wavenumber. Locally unscreened moments instead generate a nonzero infrared plateau. The resulting transverse-force spectrum has a universal crossover from fourth- to sixth-order scaling, with the crossover set by the ratio of the unscreened residual to the screened analytic contribution. Complete partner renewal preserves this normal form, establishing exchangeable multipole inheritance, while turnover tunes the residual through an independently measured local defect density. The zero-residual limit yields strictly hyperuniform velocity fluctuations; any finite residual causes defect-controlled infrared leakage and sets a finite screening length. Thus microscopic exchange need not destroy hidden hyperuniform flow order, but rare unscreened moments determine how far the quiet-flow regime survives.

We combine the axiverse with a negative cosmological constant $\Lambda$, both originating from the string landscape, and apply an observation-time-weighted anthropic argument. Adopting a uniform prior on $\Lambda$ and a typical string-motivated axion decay constant comparable to the reduced Planck scale, this framework predicts a $\sim 40\%$ probability of observing $0.1 < \Omega_m < 0.9$, thereby naturally resolving the long-standing fine-tuning and coincidence problems of dark energy. Unlike many scalar-field dark energy models, the anthropic Lambda-axion universe (ALAverse) statistically disfavors slow-roll dynamics, as slow-roll requires fine-tuning of the initial field displacement. Moreover, the negative cosmological constant renders fast-roll scenarios anthropically unfavorable, since they typically yield only a very brief observational window with positive dark energy density. Having ruled out both extremes, the ALAverse characteristically predicts a moderate-roll dynamics. We derive a two-parameter parametrization in terms of $\delta_\Omega$ and $|\varepsilon_s|$ that covers ALAverse solutions as well as a broad class of canonical and phantom field models. Current observational data yield $\delta_\Omega = -0.0498 \pm 0.0186$, corresponding to a $2.7\sigma$ rejection of $\Lambda$CDM ($\delta_\Omega = 0$) and single-field thawing phantom models ($\delta_\Omega > 0$). The data also show a mild preference for the ALAverse over slow-roll quintessence, a trend that can be conclusively tested with future high-precision measurements of the Hubble diagram.

Within the framework of stochastic first-passage time thermodynamics (TFPT) and power-law distributions (Mittag-Leffler and Levy), the appearance of fractional Caputo derivatives in hydrodynamic equations is substantiated. The developed framework is applied to the problem of explosive boiling of a superheated liquid: an integral formula for nonlocal entropy production is derived and the critical index of dissipation intensity is calculated, along with qualitative changes in these parameters upon introducing external pressure. It is found that dissipation at a given instant is strictly determined by the integral history of the macroscopic matter flow J(t) over the entire evolutionary interval up to the moment of phase explosion. The calculated critical dissipation index z strictly describes the kinetic catastrophe and the violation of Prigogine's minimum entropy production principle near spinodals.

In this work, we study the gravitational lensing of gravitational waves (GWs) by extending the geometric-optics approximation to higher order. With the help of the Newman-Penrose formalism, we reexpress the GW propagation equations as a series of scalar equations and present explicit expressions for the Weyl scalars that describe the GW polarizations. By combining the approaches of solving geodesic deviation and transport equations, we construct a solvable system of equations that describes the evolution of GW polarization along null geodesics. This framework fills the gap left by the leading-order geometric optics and the Kirchhoff diffraction integral, neither of which captures the polarization characteristics of GWs during the lensing process. This work applies the above framework to a Schwarzschild lensing configuration. Through a rigorous theoretical formulation and detailed numerical analysis, our results reveal the emergence of apparent vector and scalar modes in lensed GW signals, which originate from the smearing of the polarization plane and distortion of the wavefront and do not represent genuine dynamical degrees of freedom but rather arise as the propagation effects imposed by gravitational lensing.

Strong electronic correlations in narrow-band systems provide a promising route to realize emergent quantum phases. While ferroelectricity in van der Waals materials is typically associated with inversion symmetry breaking driven by lattice distortions, interlayer sliding, or moiré reconstruction, the possibility of generating ferroelectricity directly from electronic interactions remains largely unexplored. Here, using molecular beam epitaxy, scanning tunneling microscopy, and ab initio calculations, we investigate two stacking geometries of bilayer 1T-TaSe$_2$, A-C and A-C$'$, formed by coupled Star-of-David charge density wave phases. We show that both stackings realize quasi-one-dimensional interacting chains, but are governed by distinct interaction mechanisms. In the A-C stacking, strong interlayer hybridization leads to dimerization and the formation of a band insulating state. In contrast, the A-C$'$ stacking is dominated by interlayer Coulomb interactions, producing a spontaneous charge imbalance between layers that gives rise to an out-of-plane ferroelectric polarization. Furthermore, we demonstrate that ferroelectric and antiferroelectric interchain configurations can be stabilized and electrically switched by an external field. Our results prove that bilayer 1T-TaSe$_2$ is a platform for interaction-driven electronic ferroelectricity, establishing an overlooked family of charge-ordered correlated states in 1T-TaSe$_2$ multilayers.

Ultrafine-grained (UFG) aluminium alloys are promising lightweight structural materials for space applications, where a high grain-boundary density can act as sinks for irradiation-induced defects. Their deployment, however, is contingent on thermal stability: aluminium components in low-Earth orbit can reach $\sim$200 $^\circ$C under solar irradiation, close to where severely deformed aluminium alloys recrystallise. Accurate, bulk-representative determination of recrystallisation onset is therefore essential, yet conventional in situ transmission electron microscopy (TEM) heating is compromised by thin-film effects, ambiguous grain-boundary contrast, and small sampling volumes. Here, a UFG AA6061 (Al-Mg-Si) alloy produced by high-pressure torsion was studied by a direct comparison of in situ TEM heating and in situ electron backscatter diffraction (EBSD) heating, complemented by differential scanning calorimetry (DSC), analytical scanning transmission electron microscopy (STEM-EDX) and microhardness. In situ EBSD sampled $\sim 10^{3}$ grains from bulk material and resolved the microstructural evolution into sequential recovery, recrystallisation and grain-growth regimes, placing the onset of instability at $\sim$198 $^\circ$C. Calorimetry, microhardness and nanoscale elemental mapping showed that grain refinement suppresses GP-zones formation and shifts precipitation to lower temperatures, with precipitation neither retarding recrystallisation nor restoring strength once the UFG structure is consumed. Revisiting the Brailsford-Bullough-Hayns sink-strength theory with a KAM-informed, temperature-dependent internal sink strength, we show that the grain-boundary sink strength collapses as recovery and recrystallisation proceed. We establish in situ EBSD heating as an in operando method for bulk-representative determination of microstructural instabilities in advanced metallic systems.

Bridging the sim-to-real gap is a central problem in robotics, and the prevailing approach is to build increasingly accurate simulators. Here, we propose another approach based on renormalization: using effective, resolution-dependent parameters to absorb details omitted by the simulator and reproduce real behavior. These parameters may differ from measured physical values because they compensate for what the simulator leaves out. We demonstrate this mechanism analytically for proportional–derivative (PD) control at finite simulation frequency, where proportional feedback changes the effective derivative gain and derivative feedback changes the effective inertia. We then interpret dynamic rope manipulation and underwater swimming through the same perspective. Finally, we present a practical procedure for choosing observables, identifying omitted physics, and determining effective parameters. Renormalization offers robotics a complementary path across the sim-to-real gap: effective parameters, real behavior.

The theoretical foundation of combining external nonequilibrium thermodynamics, the nonequilibrium statistical operator method, and stochastic first passage time thermodynamics are explored. It is shown that including a random lifetime of a metastable state in the generalized distribution function allows the first passage time to be considered as a fully - fledged macroscopic coordinate. A microscopic justification for this approach is provided, and a generalized thermodynamic potential is introduced. A procedure for closing the transport equations based on on thermodynamic consistency conditions is developed. It is shown that in the generalized Maxwell - Catteneo equation, the classical relaxation time is strictly replaced by the mean first passage time, which imparts internal macroscopic nonlinearity to the system. Using renewal theory, the exact mathematical structure of transport memory kernels for non-Markovian processes is derived. A qualitative comparative analysis of various approaches to the thermodynamic description of nonequilibrium phenomena is presented.

We use luminous red galaxies (LRGs) and background quasar spectra from DESI DR1 to measure the mean MgII equivalent width around massive quiescent galaxies as a function of projected radius and azimuth relative to the projected major axis. Our forced-measurement approach assigns a MgII doublet-window EW to every LRG-quasar pair, including spectra without individually detected absorbers, and subtracts a redshift-matched random-control signal measured from the same normalized quasar spectra. The all-angle profile declines smoothly over $r_p=0.01$-$1.0$ proper Mpc and shows stronger inner absorption at $0.4<z_{\rm LRG}<0.75$ than at $0.75<z_{\rm LRG}<1.1$. Superposed on this radial and redshift dependence, sightlines near the LRG major axis show enhanced absorption relative to the minor axis at $r_p\simeq30$-$80$ kpc. For the full $0.4<z_{\rm LRG}<1.1$ sample, the integrated fiducial major-minus-minor difference over $r_p=0.03$-$0.077$ Mpc is $0.184\pm0.075$ Angstrom, with a position-angle randomization probability $p=0.013$. The redshift split shows no significant evolution in the anisotropy amplitude, even though the inner EW profile itself evolves. Our results provide evidence for a localized major-axis enhancement of MgII-bearing cool/warm gas around LRGs, showing that azimuthal CGM structure is measurable in massive quiescent halos as well as in star-forming systems.

Systems composed of interacting bistable elements are commonly described by transition graphs that determine which state changes are accessible under an external drive. Under quasistatic loading, accessibility is constrained by the equilibrium structure of the system, often resulting in sparse transition networks and unreachable stable states. Here, we show that dynamic loading of dissipatively-coupled hysteron networks enhances accessibility by enabling transition pathways that are forbidden under quasistatic driving while preserving the underlying equilibrium states. In particular, we consider pulse actuation and derive a control map linking pulse amplitude and duration to state transitions. For suitable dissipative couplings, individual hysterons become independently addressable using a single scalar input, increasing transition-graph connectivity and enabling access to otherwise unreachable states. We validate the framework experimentally using pneumatic hysterons and find good agreement with theory. More generally, the framework applies to dissipatively coupled networks of bistable elements across fluidic, mechanical, and electrical domains.

We investigate quark-antiquark entanglement in heavy quarkonium within a nonperturbative light-front Hamiltonian framework. By tracing over the antiquark degrees of freedom in the hadronic state vector, we construct the reduced density matrix of the quark subsystem and compute the associated von Neumann entropy. For spin-0 quarkonia, we show that this entropy reduces to the Shannon entropy of the unpolarized transverse momentum dependent parton distribution (TMD), up to constant color and spin contributions. For spin-1 quarkonia, we derive the explicit polarization dependence of the entropy and connect it to polarized and tensor-polarized TMDs. Using light-front wave functions obtained via basis light-front quantization (BLFQ), we evaluate the entanglement entropy for charmonium and bottomonium states, revealing a pronounced sensitivity to the polarization of vector mesons. Furthermore, we resolve the infrared parameter by matching the momentum-space entropy to a harmonic-oscillator representation. Ultimately, these results establish entanglement entropy as a novel probe of nonperturbative quarkonium structure, forging a direct link between quantum information measures and partonic observables.