Papers

Magnetic flux quanta in type-II superconductors are topological excitations of the order parameter whose sensitivity to the local environment makes them probes of current density, magnetic fields, and pinning landscapes. Yet, in planar thin films, individual vortices are difficult to manipulate, often requiring intricate nanopatterning or demanding scanning-probe instrumentation. Here, we show that shaping a superconducting thin film into a three-dimensional curved geometry enables controllable vortex trapping under a spatially uniform applied magnetic field. Employing a conformal formulation of the time-dependent Ginzburg-Landau equation, we simulate vortex dynamics in a cap-shaped superconducting membrane and compare it with a planar reference. Curvature converts the uniform applied magnetic field into a nonuniform local normal component, creating a reconfigurable asymmetric rim-pinning potential tunable by magnetic-field orientation. Rotating the magnetic field therefore controls the number and positions of vortices trapped along the rim. Moreover, the asymmetric pinning produces a superconducting diode effect through current-direction-dependent vortex capture. Three-dimensional curvature thus provides a route to engineer local vortex pinning and realize fluxonic devices with magnetic-field-programmable vortex trapping and transport.

We investigate the sequential version of Shor's order-finding algorithm from the perspective of the imaginarity of quantum channels. By fixing an eigenbranch of the modular multiplication unitary and a target output path, the process is effectively decomposed into a real diagonal factor and a residual phase channel. We find that for the ideal residual phase channel, the three trace-norm induced imaginarity measures are all equal. On good output paths, a smaller residual imaginarity corresponds to a higher single-block success probability. By combining the branch-wise probabilities, we obtain the exact ideal success probability of the sequential order-finding protocol and derive lower and upper bounds in terms of residual phase-channel imaginarity. We further extend the analysis to noisy residual phase channels, and obtain the lower and upper bounds on the noisy success probability. These results clarify the role of imaginarity of channels in Shor's algorithm and provide a refined perspective on quantum-resource behavior in ideal and noisy sequential quantum algorithms.

We study supersymmetric semi-infinite cohomology and its $N = 2$ superconformal structure via the BRST reduction of an $N = {\frac{3}{2}}$ superconformal structure on the super-affine vertex algebra associated to a super Manin pair arising from the Kazama–Suzuki $N = 2$ condition. Moreover, we realize super coset models in terms of relative supersymmetric semi-infinite cohomology.

Despite the importance of the non-uniform Polynomial-Time Hierarchy (PH/poly) in classical complexity understanding the collapse conditions of the Polynomial-Time Hierarchy (PH), a quantum equivalent of PH/poly has yet to be studied in the literature. We introduce the non-uniform computational Quantum Polynomial-Time Hierarchy (QCPH/mpoly), the quantum equivalent of PH/poly, and show that it collapses if and only if QCPH, the quantum equivalent of PH introduced by Gharibian et al. (comput. complex. 2022), also collapses. We also show that QCPH collapses if coQCMA is contained in QCMA/mpoly. These results are analogous to those of Yap (TCS 1983) commonly used to invoke the collapse of PH in classical complexity. QCPH/mpoly is analogous to QCPH with non-uniform quantum verifier circuits.

We present a multi-wavelength study of an extended molecular cloud hosting the LDN 1204, Sh2 145, and Sh2 140 regions to investigate the interplay between stellar feedback, cloud dynamics, and star formation. Infrared images reveal two semi-arc/shell-like structures (extent 14-18 pc) associated with known massive O-type stars. Herschel temperature and column density maps identify one hub-filament system (HFS) candidate toward both LDN 1204A and LDN 1204B sub-regions, with peak column densities of 3.1 x 10^23 and 1.3 x 10^23 cm^-2, respectively. These sub-regions are located at the periphery of the Sh2-145 H ii region. Molecular line data reveal a large arc-/shell-like cloud resolved into two kinematically distinct components spanning -15 to -9.5 km s^-1 and -9 to -3 km s^-1. Each component exhibits an arc-/shell-like morphology, is centered on one of the massive stars, and displays an inverted C-shaped position-velocity structure, indicating expansion driven by its associated H ii region. Both LDN sub-regions are located at the projected interface of the two expanding cloud components. Young stellar objects (YSOs), particularly Class I YSOs, are concentrated toward these sub-regions, while moment 2 maps reveal enhanced velocity dispersion, suggesting increased turbulent motions at the interface. Altogether, the presence of dense filaments, candidate hub-filament systems, and active star formation in LDN 1204 sub-regions demonstrates that feedback driven shell expansion and interaction compressed the gas at the interface, establishing the necessary conditions for filaments and ongoing star formation. These results highlight the important role of feedback-driven cloud interactions in regulating dense structure formation and star formation in molecular clouds.

We investigate experimentally the dynamic phase transition from compressed to buckled phases for thin sheets of rubber. We find that the rubber strips enter a highly compressed, metastable state when compression speed is high. During the compressed phase, higher modes grow, followed by mode coarsening. Mode growth is accompanied by an expansion of length while the system is still being compressed. We measure the forces and length of the sheet to confirm this, and we develop a mechanism for how modes grow and coarsen during dynamical buckling. The influence of crucial control parameters in the experiments, such as the material cross section and compression speed, on the buckling dynamics, are explained theoretically.

Collective behavior in animal groups is routinely described in cognitive language: fish schools sense gradients, swarms compute, colonies decide. These formulations often leave open what the collective is inferring, what computational object is represented, or how that representation arises from microscopic interactions. Here we develop that description quantitatively in a simulation based on the canonical model of collective sensing in fish schools (Berdahl et al., 2013), in which collective gradient sensing emerges from individuals that do not estimate gradients themselves: agents only modulate their speed in response to local light intensity and respond to simple social forces from neighbors. We show that these local rules admit a mesoscopic Bayesian reinterpretation at the level of the school, and hypothesize that the collective dynamics realize approximate inference on a generative model of how darkness gradients drive inter-individual speed differences. The resulting school-level inference process yields a posterior distribution over the local darkness gradient, whose statistics vary with environmental structure and relate systematically to collective motion and sensing performance. The school can therefore be described, in a Bayesian-mechanical sense, as a distributed inferential system without requiring individual agents to perform probabilistic belief updates themselves. This yields a quantitative, falsifiable account of collective sensing as emergent inference, and a concrete bridge from collective behavior to Bayesian mechanics.

Ultraluminous infrared galaxies (ULIRGs) are the remnants of the major mergers of gas-rich galaxies. They are dusty systems and are extremely luminous in the infrared. Both starbursts and active galactic nucleus (AGN) activity supply power in these systems, but it is not clear how these two activities are related to the overall evolution of the merger remnant. Studies suggest that there may be an evolutionary link between ULIRGs and radio galaxies. Radio observations of ULIRGs are a useful tool for understanding this evolutionary path as well as studying the energy contributions from starbursts and AGN. We perform a systematic census of these signatures in 38 ULIRGs using upgraded Giant Metrewave Radio Telescope observations and archival radio data. In the sample, 30 sources have enough frequency coverage to obtain their radio spectrum. Of these, 17 sources show a turnover frequency between 63 and 509 MHz and a spectral age variation from 0.009 to 44 Myr. Also, eight sources have extended structures with projected linear sizes varying from 0.7 to 11 kpc. Our results indicate that the primary energy source in these systems is the AGN rather than star formation. The majority of the ULIRGs in our sample, particularly those in the post-merger stage, exhibit gigahertz-peaked spectrum or compact steep spectrum-like characteristics, suggesting that they are evolving into young radio galaxies. We note that six sources with high star formation activity show a low-frequency turnover and a smaller spectral age; we confirm these six sources host buried AGN. This study enables us to trace the evolutionary link between ULIRGs and radio galaxies.

Spin-1 Bose-Einstein condensates provide a fundamental platform for exploring quantum magnetism and coherent spin dynamics. Their three Zeeman components are coupled by spin-exchange interactions under conserved particle number and magnetization, giving rise to rich magnetic phases and nonlinear spin structures; a rigorous classification of stationary states therefore clarifies the possible spin configurations and their physical origins. In this paper, as a continuation of our previous work \cite{LLWZ23,LLWZ24,LLWZ26}, we study the classification of solution for the spin-1 Bose-Einstein condensates in $\mathbb{R}$, by applying the non-standard Hirota's bilinear method, the determinant formula and the general left-uniqueness strategy, we present some novel explicit solution and give the complete classification of the solutions. In comparison with the classical Hirota's method, the non-standard Hirota's method needs to introduce auxiliary functions to construct Hirota's bilinear form, which essentially adds additional constraint on the wave functions, so that it possible to deal with more complex equations. As far as we know, this is the first systematic study the complete classification of solutions to the spin-1 Bose-Einstein condensates. Our classification results yields experimentally testable predictions for spin populations, relative phases, and magnetic textures

This paper constitutes Part III of a series investigating the excitation of non-modal perturbations in hypersonic blunt-nose boundary layers. Based on the numerical shock-fitting harmonic linearised Navier-Stokes (SF-HLNS) approach presented in Part I (Zhao & Dong, J. Fluid Mech. 2025, vol. 1013: A44) and the asymptotic analysis developed in Part II (Dong et al., J. Fluid Mech., under review), the present work focuses specifically on the influence of nose bluntness (Reynolds number R) and wall temperature T_w on receptivity efficiency through seven detailed case studies. Analysed via the three-step asymptotic model, the downstream perturbation amplitude is governed by two distinct factors: the stagnation vorticity perturbation, determined through shock-perturbation interaction and the slow-down convection mechanism, and the parabolic evolution of non-modal perturbations driven by the lift-up mechanism. Increasing R strongly amplifies the stagnation vorticity response, with only mild enhancement of the lift-up effect. In contrast, decreasing T_w strengthens the stagnation vorticity perturbation, but slightly weakens the lift-up effect; the net result is an overall intensification of the downstream perturbation amplitude with decreasing T_w. Furthermore, explicit scaling laws for receptivity efficiency with respect to R and T_w are established. This study completes the theoretical foundation for non-modal receptivity in hypersonic blunt boundary layers, and serves as a key step toward a physics-based transition prediction framework.

The precise determination of the Higgs boson couplings to electroweak gauge bosons is a key objective of the FCC-ee physics program. In particular, measurements of the Higgs boson couplings to W and Z bosons play a central role in the model-independent determination of its total decay width. This paper presents a study of Higgs boson decays to H -> WW and H -> ZZ in the Higgsstrahlung production process. The analysis focuses on events in which the associated Z boson and the vector bosons from the Higgs decay all decay hadronically, resulting in six-jet final states. The large H -> WW branching fraction leads to high signal statistics in the fully hadronic channel, while for H -> ZZ the much smaller Higgs branching fraction is partly compensated by the large hadronic branching fractions of the Z bosons. Due to the substantial kinematic overlap between the WW and ZZ decay modes, their signal strengths are extracted simultaneously. Jet-clustering and dedicated jet-pairing techniques are employed to optimize the reconstruction of the hadronically decaying gauge bosons and enhance the separation of the two signal components. Assuming a center-of-mass energy of 240 GeV and an integrated luminosity of 10.8 ab^-1, expected relative uncertainties of 1.48% and 8.20% are obtained on the production cross section times branching fraction, sigma(ZH) x BR, for the H -> WW and H -> ZZ decay modes, respectively.

Electrical impedance tomography (EIT) is an ill-posed inverse imaging technique with limited and spatially nonuniform resolution. Conductivity targets located in regions with degraded spatial sensitivity may be reconstructed as a single connected region, resulting in the loss of spatial separability between neighboring structures. In this work, we propose a self-generated local structural prior for suppressing target merging in EIT reconstruction. First, an initial conductivity image is obtained from the measured boundary data using an existing EIT reconstruction method. This reconstruction is subsequently used as a reference image to construct a Gaussian similarity matrix according to the intensity similarity between image pixels. The adaptively chosen eigenvector of the covariance matrix is then employed to extract the principal structural information of the reference image. A localized structural mask is constructed and incorporated into a subsequent EIT reconstruction to preserve the spatial separability of neighboring targets. Numerical and water tank experimental results demonstrate that the proposed method effectively separates neighboring conductivity targets that are merged by conventional EIT reconstruction methods.

Circuit cutting runs a quantum computation on processors smaller than the circuit, at the price of classical knitting whose cost grows exponentially with the number of cut gates. Keeping this cost affordable is necessary but not sufficient for an advantage, since knitting classically easy subcircuits is itself classically easy. We formulate three requirements for distributed quantum advantage under a stated budget: affordable knitting, classical difficulty that survives the cut, and, for variational circuits, resolvable gradients. We prove that under stated assumptions knitting stays affordable when subcircuits grow behind a bounded interface and becomes exponentially expensive when fixed-width subcircuits multiply. We turn the requirements into screening criteria and apply them to eighteen circuit families. We identify finite local-depth circuits with bounded interfaces as a setting in which the requirements can coexist, with hardness established only in the worst case. As a classically verifiable proof of principle, we knit one gate joining two field-perturbed toric-code patches on an IBM Nighthawk processor for up to 142 spins, and confirm that the reconstruction can at least resolve the contact correlation beyond independent execution for up to 98 qubits.

We report kilovolt-class vertical (011) e̱ta}-Ga2O3 Schottky diodes utilizing high-permittivity dielectric TiO2/Al2O3 field-plate for high voltage and high temperature applications. A systematic study was performed with Pt/(011) e̱ta}-Ga2O3 Schottky barrier diodes (SBDs) with varied diameters from 100 {\mu}m to 300 {\mu}m, for both with and without field-plate, that revealed excellent consistency of reverse blocking performance regardless of diode area. The field-plate SBDs achieved superior breakdown voltages (3.90 - 4.16 kV) compared to the diodes without field-plate (3.06 - 3.16 kV) owing to effective edge termination. Furthermore, we explored high-temperature performance of the field-plate (011) e̱ta}-Ga2O3 diodes that revealed excellent forward conduction properties and high rectification ratio (~10^9) throughout the temperature range (25 - 150 C). At reverse bias, the field-plate diodes also exhibited kV-range breakdown voltage with no evident increase in leakage current up to the explored elevated temperature of 150 C. The low area-dependence of breakdown voltage, excellent forward transport properties, and minimal reverse leakage at both high-voltage and elevated temperature demonstrate the exciting potential of (011) e̱ta}-Ga2O3 SBDs in high-temperature power switches. Thus, our work demonstrates the strategy of advancing the performance of vertical e̱ta}-Ga2O3 SBDs by utilizing the advantageous (011) e̱ta}-Ga2O3 epilayers with low background doping, reduced killer dislocation effects, and effective field management for high-voltage and high-temperature applications.

Within rainbow-ladder truncation, we identify three contributions to the pion's gravitational form factors—graviton coupling to the quark, to the gluon dressing the quark, and to the gluon binding the pion—and separate them into quark and gluon parts. Using an algebraic quark model with a dynamical basis, we obtain $A(0)=1$, $D(0)=-1$ in the chiral limit, and momentum fractions $\langle x\rangle_q=0.896$, $\langle x\rangle_g=0.104$. The D-term obeys the same partition at the model scale.

Self-propelled particles that only repel one another can still separate into a dense and a dilute phase, a process known as motility-induced phase separation (MIPS). In a clean system the domains coarsen like any conserved mixture: domains grow as $\ell(t)\sim t^{1/3}$. Living and synthetic swimmers, however, move through rough, porous, or patterned surroundings. Using large-scale simulations of active Brownian particles, we ask how frozen heterogeneity changes MIPS coarsening. We introduce disorder in two ways, as a quenched random force field acting on particle positions and as a quenched random torque field acting on their orientations. Both destroy Lifshitz-Slyozov growth. A transient power law with a disorder-dependent exponent gives way to activated dynamics in which the effective dynamic exponent grows without bound and domains grow at most logarithmically. The crossover obeys the scaling form known from the random-field Ising model, and the domain morphology depends on disorder strength, so superuniversality fails. The two kinds of disorder act through different mechanisms. Random forces trap particles in the sinks of a random drift field once the drift beats self-propulsion. Random torques act as a sign-random, quenched chirality that erodes persistence and lowers the local Péclet number toward its critical value. Our results show that quenched disorder is a relevant perturbation for the kinetics of active phase separation and connect MIPS coarsening to the physics of pinned interfaces in disordered magnets.

The Einstein Probe (EP) has discovered a fast X-ray transient, EP260321a, whose optical counterpart was subsequently classified as a broad-lined Type Ic supernova. Its observed rise time of about 690 seconds is inconsistent with theoretical predictions for shock breakout (SBO) from a Wolf-Rayet star, which is typically regarded as the progenitor of envelope-stripped supernovae. In this paper, we propose that EP260321a arose from a SBO within extended circumstellar matter (CSM), where breakout photons were initially trapped, then diffused out of the unshocked CSM as the ejecta expanded and the opacity decreased. We modeled this photon diffusion process using both Monte Carlo simulations and an analytical approach to describe the temperature evolution. Through Markov Chain Monte Carlo sampling, we obtain the best-fit CSM parameters of log10(Mcsm/Msun) = -3.3 for the total CSM mass, Rin = 160 Rsun for the inner CSM radius, and Rout = 612 Rsun for the outer CSM radius. The presence of such a dense CSM indicates that the progenitor of EP260321a underwent episodic mass loss just days before the explosion, providing new observational constraints on the late-stage evolution of massive stars.

A bubble bursting inside a drop resting on a substrate can eject jet droplets where a bubble at a bath would not. We compute how much liquid it ejects and how the ejected droplets are distributed in size. The volume ejected by the jet grows by more than an order of magnitude as the Bond number decreases from $0.5$ to $0.1$ and then saturates, and the larger the Bond number, the smaller the viscosity that suppresses ejection. At zero Bond number the substrate alone extends the ejection boundary to larger Ohnesorge numbers, contrary to expectation, and yet reduces the volume ejected at the same distance from it. Gravity sets how much liquid the jet carries, not how the jet fragments: scaled with its mean, the droplet-size distribution is independent of the Bond number and has an exponential tail, as for free hollow droplets. The simulations, built on a closed family of sessile equilibria, reproduce the measured velocity of the first droplet within 7\,%, while the volumes emitted in experiments are eight to ten times those computed for the same geometry.

We classify the linear solution spaces of the chordal Belavin–Polyakov–Zamolodchikov (BPZ) equations, which arise in Dubédat's commutation relations for multiple Schramm–Loewner evolutions (SLE). Without imposing growth conditions, we determine the subspaces selected by successive conformal Ward identities and their exact dimensions. For every $\kappa>0$ and BPZ spectral parameter $\lambda\in\mathbb{R}$, we determine the spectrum and Jordan structure of the translation operator. When $\lambda=0$ and $\kappa\in(0,8)$, we further determine all admissible scaling exponents and the dimensions of the corresponding translation-invariant solution spaces. A triangular change of derivative coordinates yields a first-order system of rational Knizhnik–Zamolodchikov type, allowing us to represent the Ward operators explicitly and reduce the classification to finite-dimensional linear algebra. For $2N$ boundary points and $\kappa\in(0,8)$, translation-invariant BPZ solutions with $\lambda=0$ and the homogeneity required by Möbius covariance automatically satisfy the third Ward identity and the usual power-law bound. This recovers, under weaker assumptions, the Catalan dimension formula previously established by Flores and Kleban. At $\kappa=8$, the third Ward identity imposes an additional constraint when $N\ge2$, but the full Möbius-covariant solution space still has Catalan dimension, establishing completeness of the partition functions constructed from uniform spanning trees. Finally, at $\kappa=4$ and $\lambda>0$, we construct an explicit basis of positive BPZ solutions and identify its elements as partition functions for level lines of a Gaussian free field with suitable harmonic means.

Static spherically symmetric asymptotically flat configurations in General Relativity with a minimally coupled scalar field typically possess naked singularities. We study a linear stability of these configurations against radial (monopole) perturbations in case of power-law scalar field potentials. We employ a new shooting method that extracts the eigenvalues corresponding to the exponentially growing modes of the perturbation. The problem is reduced to one second order “master” equation in a divergent form with a regularized effective potential. We confirm our previous results showing that instability modes exist for sufficiently small scalar charges of the initial static configurations.

Quantum networks will rely on intermediate nodes to distribute entanglement, but the same nodes may learn which users are being connected. We introduce a minimal two-call routing primitive in which a user, Alice, establishes an entangled link with one of several clients while testing whether the provider, Bob, has disturbed a coherently encoded request. The construction adapts the hidden-order mechanism of quantum private queries: one call contains a direct request, the other a coherent superposition of the desired and null addresses, and Alice keeps their order secret. A private matching qubit held by the selected client restores the coherent test state after a favorable Bell-measurement outcome, so that Alice can test the returned query without any further operation by Bob. The claim is deliberately limited. The protocol shows that a routing request can carry a physical cheating test, and it detects an explicit destination-reading attack with nonzero probability. It does not yet provide a quantitative information-disturbance tradeoff, composable security, or certification of an unmeasured output against arbitrary attacks. We also characterize the exact perfect-pass limit, in which Bob's residual state, averaged over the private matching states, is independent of the destination.

Abridged. We aim to extend Paper I to the eccentric secondary orbit case and now analyse the elliptic restricted three-body problem (ERTBP). Our secondary masses include Ceres, Mercury, Earth, and Neptune so that we can help infer the presence of both large asteroids and planets through our analysis. We study dust particles on both planar (2D-ERTBP) and non-coplanar (3D-ERTBP) orbits. We computed families of 1/1 resonant symmetric and asymmetric periodic orbits in the 2D-ERTBP and 3D-ERTBP. Doing so produces novel results in their own right and diagnostic tools for precise guidance for our next steps. Based on them, we generated detailed phase portraits. Finally, we run suitably seeded $N$-body simulations to compare with the periodic orbits, and to provide observational links with debris close to WDs. New families of asymmetric periodic orbits, called $E^A_{41}$, $E^A_{42}$, and $E^A_{43}$ in the high-eccentricity 2D-ERTBP regime were discovered. They are generated by the new bifurcation point, $B_T^4$, along the new $A_2$ family, showcased in Paper I. Moreover, new isolated families of asymmetric periodic orbits, namely $E^A_{44}$, $E^A_{45}$, and $E^A_{46}$ were discovered. Families of short- and long- period asymmetric orbits starting from $L_4$, called $E^A_S$ and $E^A_L$, were also computed. In both the 2D- and 3D-ERTBP regimes, highly eccentric motion is exhibited for the dust particles in the majority of the families of either symmetric or asymmetric periodic orbits. The $N$-body simulations reveal that over ten years, the orbital period deviations of the dust are higher than in the circular restricted three-body problem (Paper I); in some architectures, Mercury-mass planets can regularly generate deviations exceeding $\sim$100 s, which potentially aids observational inferences of hidden asteroids or planets orbiting WDs.

We present a minimal, predictive scenario for asymmetric fermionic dark matter (DM) generated through freeze-in. The standard model (SM) is extended by a Dirac fermion $\psi$ that serves as the DM candidate, an auxiliary Dirac fermion $\chi$, a real scalar mediator $\phi$, and a heavier real scalar $S$, all stabilized by a $Z_2 \times Z_2'$ discrete symmetry. The DM asymmetry is generated through the CP-violating out-of-equilibrium decays of the mediator $\phi$, while the heavier scalar $S$ plays a dual role: it generates the physical CP-violating phase required for the asymmetry through its interference with $\phi$, and it mediates the annihilation of the symmetric component of the DM population. We solve the coupled Boltzmann equations for the asymmetric yield $Y_-$ and the total yield $Y_\Sigma$, and identify the scaling relations $Y_-^\infty \propto \mu^2 \varepsilon / m_\phi$ and $\Omega_{\rm DM} h^2 \propto m_\psi \, \mu^2 \varepsilon / m_\phi$, which we verify numerically. The observed relic abundance $\Omega_{\rm DM} h^2 \simeq 0.12$ is naturally reproduced for a wide range of parameters; in particular, for $\varepsilon = 10^{-6}$ and $m_\phi = 200$~GeV, the correct relic density is obtained for $\mu \approx 2.7 \times 10^{-9}$~GeV and $m_\psi \approx 40$~GeV. We further confront the model with current experimental constraints, including direct detection, indirect detection, collider searches, and DM self-interactions, and show that the predicted signals lie far below the sensitivity of current experiments. This scenario provides a self-consistent and testable realization of asymmetric fermionic DM within the freeze-in framework.

We study the spherical collapse of a homogeneous dust cloud on a three-brane in the Shtanov–Sahni braneworld, in which the extra dimension is timelike. In the high-energy regime the brane Friedmann equation acquires a negative quadratic term in the matter density, controlled by a critical density $\rhoc=2\lambda$, where $\lambda$ is the magnitude of the negative brane tension. For a spatially closed interior we integrate the dynamics exactly. Every turning point of the scale factor lies above $\astar=\sqrt{3/4\pi\lambda}$, a bounce exists if and only if a simple condition on the comoving density holds, and all curvature invariants stay below bounds fixed by $\lambda$ alone along the entire cycle. Comoving worldlines are geodesically complete. We then match the cloud across a comoving boundary to a spherically symmetric exterior with a trace-free effective source and solve the Israel conditions in closed form. The exterior is a charged Vaidya geometry whose mass function and tidal charge are fixed by the boundary radius. The tidal charge is positive, opposite in sign to the Randall–Sundrum case, and the exterior cannot be static. A trapped region forms on the boundary if and only if the mass exceeds $2/(3\sqrt{\pi\lambda})$, and in that case the bounce still takes place in an untrapped neighbourhood of the boundary. For trapped clouds we construct an exterior over the full contraction, bounce and re-expansion by joining an advanced and a retarded charged Vaidya patch through a static wedge. The matched metric is of class $C^{1,1}$, the effective energy conditions hold, and the cloud re-emerges through a white hole region into a second asymptotic region. In the general relativistic limit $\lambda\to\infty$ the Oppenheimer–Snyder solution is recovered.

We present two decades of X-ray monitoring of the eclipsing accreting pulsar Hercules X-1 with Fermi/GBM, Swift/BAT and MAXI/GSC, centred on the extended low state (ELS) that began in 2025 May (the first such event in 22 years) and is still ongoing at the time of writing, $\sim$480~d after its onset. The 35-d superorbital clock does not simply stop in the ELS; it fades. The surviving modulation stays phase-locked to the pre-ELS clock until the flux of the main high state (the bright phase of the 35-d cycle) has decayed to a few per cent of its normal level. The in-phase coherence is then lost, around 2026 January–March. We classify the pre-ELS pulse-frequency history into three torque states: spin-up, spin-down and flat. The spin derivative correlates positively with the main-high hard X-ray flux (Pearson $r\simeq0.7$), and the ELS hosts the longest sustained spin-down of the record, $\dot{\nu}\approx-4.7\times10^{-13}$~Hz~s$^{-1}$ over the $\gtrsim$380~d of \fer/GBM coverage. The 8–50 keV pulse-profile morphology is statistically indistinguishable across the torque states at fixed superorbital phase, and the shape parameters show no secular drift over the 18-yr record. These results show that the precessing warped accretion disc keeps its rhythm while the pulsar fades from direct view: the clock keeps its phase, the torque keeps tracking the accretion flux, and the beam keeps its shape. No free precession of the neutron star is required by the current monitoring data.

In this letter, we demonstrate that employing the Lens Aperture as a Knife-Edge (LAKE) with two identical LEDs has the distinct advantage of obtaining schlieren images along two cutoff orientations. It is possible to control LED brightness to obtain a desirable weighted sum of both horizontal and vertical schlieren cutoff images on each camera frames. Powering the LED sources by an affordable and programmable Arduino board enables a rapid switch between the horizontal and vertical schlieren cutoff that is exactly synced to the camera frames, resulting in crosstalk-free schlieren image sequence. Furthermore, with a little postprocessing, this monochrome image series can be easily transformed into a colorful sequence of bidirectional schlieren images.

Calibrating microscopic traffic models for digital twins is an expensive black-box optimization problem: tuning car-following and lane-changing parameters requires a full simulation run, affording only a tight budget per recalibration window. Matching raw trajectories yields a rugged objective that sparse surrogates cannot learn, reducing sequential acquisition to near-random probing. We present FLAT, which couples what to optimize with where to sample next. An eight-dimensional behavioral fingerprint smooths the parameter-error landscape, making the objective learnable from a few dozen samples; annealed lower-confidence-bound (LCB) acquisition then spends each remaining run where it most reduces error. The surrogate, interchangeable among a Gaussian process (GP), random forest (RF), or multi-layer-perceptron (MLP) ensemble, plugs into the same LCB loop. Across six heterogeneous real-world scenes, FLAT-GP achieves the lowest scene-averaged behavioral error, winning 6/6 scenes against SPSA, GA, and CMA-ES and 5/6 against TPE under the matched budget. Some baselines need up to 4.4 times more simulations to match. Ablations show objective choice shifts final behavioral error by 81% on average, removing sequential LCB raises the six-scene mean by 20%, and surrogate choice shifts it by at most 4.2%, confirming gains trace to objective geometry and sequential allocation rather than surrogate capacity.

Recent advances in generative world models have increased interest in digital models that reproduce both the appearance of real objects and their response to physical interaction. Three-dimensional reconstruction techniques, including 3D Gaussian Splatting, capture detailed surface geometry and appearance from images and videos. However, extending these representations beyond plausible animation to mechanically interpretable models for constitutive behavior, boundary conditions, and inverse parameter identification remains less explored. In this work, a differentiable Lagrangian-coupled 3DGS-smoothed particle hydrodynamics (SPH) model is proposed for forward simulation and inverse analysis of deformable solids. The observed object is first reconstructed from multi-view calibrated visual dataset as a 3DGS rendering model. An envelope-based procedure then generates an independent SPH support for the solid-mechanics model, avoiding the direct use of rendering primitives as mechanical particles. A reference-configuration Lagrangian transfer maps SPH deformation to Gaussian positions and covariances, thereby coupling the physical model and the image observation model while preserving a differentiable computational path. The SPH formulation supports linear elastic, hyperelastic, and Kelvin–Voigt viscoelastic responses, together with fixed, free, and Robin-type boundary conditions. Numerical studies validate the SPH response against finite-element results, assess accuracy and efficiency against a conventional model using Gaussian centers as surface SPH particles, and demonstrate forward simulations on beam, bridge, and liver-shaped examples. Inverse analyses further estimate constitutive and boundary parameters from rendered deformation observations, including noisy cases, demonstrating the feasibility of the proposed model for mechanics-based parameter identification from image data.

Seismic hazard and structural analyses require broadband ground-motion time histories, yet the high-frequency band (above 1~Hz) is the hardest to obtain: physics-based simulations are too costly at these frequencies, and stochastic methods lose the deterministic phase, directivity, and long-period coherence that control structural demand. We present HighFEM-2, a latent denoising-diffusion waveform model trained with rectified flow matching on a multi-modal diffusion transformer. It synthesizes three-component acceleration up to 50~Hz, conditioned on a low-frequency waveform below the source corner frequency and on magnitude, hypocenter and station location, and $V_{S30}$. The low-frequency waveform supplies the deterministic source, path, and directivity, so the network learns only the regional high-frequency scattering. Conditioning each station on its own waveform lets HighFEM-2 generate records for all stations of an earthquake that share its source and low-frequency path terms. Trained on 195{,}138 Italian INSTANCE records ($M_w$ 1.4–6.5, within 200~km), HighFEM-2 produces realistic waveforms: it reproduces observed peak amplitudes with small bias ($0.042 \pm 0.088$ log units for PGA, $0.057 \pm 0.090$ for PGV) and matches observed envelopes, Fourier spectra, and integrated velocity and displacement. The conditioning waveform can come from a simulation or a filtered record, and ensembles of realizations sample the high-frequency variability given that input. HighFEM-2 thus provides fast, regionally calibrated broadband time histories for hazard and risk assessment, including near-fault scenarios where recordings are scarce.

We study the effect of repulsive interactions on skin modes and entanglement in the unidirectional Bose–Hubbard model. Although the ground state of this integrable model undergoes a superfluid–Mott transition with suppressed skin accumulation, the corresponding change in entanglement depends on the selected many-body state. We compare the ground state with the steady state, defined as the largest-imaginary-energy eigenstate in the zero-momentum sector. For sixteen sites at unit filling, we find that the ground-state density approaches uniform filling and its entanglement decreases toward the Mott limit, whereas the steady states exhibit a nonmonotonic entanglement crossover. At intermediate interaction ($U/t=10$), the second Rényi entropy of the steady state develops four spatial maxima. We show that these maxima are accounted for by competing subsystem-number sectors within a dominant configuration manifold of four doublons and four holons, but not by the subsystem particle-number variance alone. The dominant global onsite-pair manifold retains the same entropy peak structure. At strong interaction, projection onto the one-doublon–one-holon manifold closely reproduces the full entropy profile and its two edge peaks. Furthermore, we demonstrate that the many-body winding about the origin remains nonzero at strong interaction; an exact two-site example shows how it becomes ill-defined in the singular projected $U/t\to\infty$ limit. Our results distinguish ground-state skin suppression from state-selective entanglement and point-gap topology.