Papers

We construct a continuum model for a one-dimensional moiré superlattice formed by stretching one layer of AB-stacked bilayer graphene along the x direction by a factor s. Following the spirit of the Bistritzer-MacDonald model for twisted bilayer graphene, we treat the interlayer coupling as hopping between several Dirac points. At a critical stretch factor s ~ 1.018 the two bands near the Fermi level touch, forming two degeneracy points along the k_y direction. This gap closing is accompanied by a topological phase transition, in which the Chern number changes from 1 to -1, and by a sign change of the Berry-curvature dipole, which we propose can be detected through the nonlinear Hall effect. We find that uniaxial strain modulates inter-Dirac-valley coupling, which drives band gap collapse and subsequent topological number inversion. This opens a route to engineer topological transport and quantum anomalous Hall effects via strain engineering of moiré heterostructures.

We study a minimal effective field theory description of the three-dimensional Lyman-$\alpha$ forest using the Sherwood and Sherwood–Relics hydrodynamical simulations. We model the Lyman-$\alpha$ flux auto-power spectrum and its cross-correlation power spectrum with the dark matter density field using a tree-level bias model supplemented by the leading counterterms and stochastic contributions. We find that the model describes the simulated auto- and cross-power spectra well up to $k_{\mathrm{max}}=3\,h\,{\rm Mpc}^{-1}$ and $k_{\mathrm{max}}=2\,h\,{\rm Mpc}^{-1}$, respectively. We analyse simulations spanning multiple redshifts, reionisation histories, box sizes and resolutions to assess the robustness of the model. Even within this minimal model, we find strong parameter degeneracies, highlighting the need for independent constraints on nuisance parameters in applications to real data analyses. The redshift evolution of the linear bias parameters is consistent with previous simulation-based studies and is driven primarily by the evolution of the effective optical depth, $\tau_{\mathrm{eff}}$. We also find that the inferred parameters are affected by the resolution of the simulation and, to a lesser extent, by the simulation box size. We also explore the impact of reionisation history, finding that variations mainly affect the linear bias parameters over the range of scales considered. Moreover, we find empirical correlations between model parameters and the Lyman-$\alpha$ forest density bias that show some scatter, indicating that one single parameter is not enough to determine the model parameters. Finally, we compare our results with theoretical predictions from analytical models of the Lyman-$\alpha$ forest.

It has been shown that static black hole event horizons cannot exist in time-dependent backgrounds without becoming naked singularities. In light of this, we are left with the question “how does a black hole horizon evolve in an expanding universe?” Here we offer a solution to this puzzle by showing in full generality that regular black hole apparent horizons tend to become comoving, thus confirming the necessity of a cosmological coupling and raising intriguing possibilities for the early growth of black holes.

The dramatic slowing down of structural relaxation in supercooled liquids is accompanied by the emergence of dynamic heterogeneity. A monotonically increasing dynamical correlation length, measured at the $\alpha$-timescale, is one of the remarkable features of this phenomenon. Here we show that this picture is incomplete: the dynamical correlation length measured in the $\beta$-relaxation regime exhibits a striking non-monotonic temperature dependence, reaching a maximum near the mode-coupling crossover temperature $T_c$ and decreasing upon further cooling, even as local dynamical fluctuations continue to intensify. This behavior suggests a crossover from spatially extended, maximally cooperative motion near $T_c$ to increasingly compact and localized relaxation events below it. We demonstrate that this evolution is quantitatively captured by stochastic beta-relaxation theory, an extension of mode-coupling theory beyond mean-field that explicitly predicts an avoided dynamical transition in finite dimensions. Our results provide the first direct spatial evidence in favor of the avoided-transition picture of the mode-coupling crossover, and establish the peak of the $\beta$-regime correlation length as a robust indicator of the mode-coupling crossover.

Quantifying nonclassicality in continuous-variable systems remains a fundamental problem in quantum information science. The Tsirelson probability, central to the Tsirelson precession protocol, is defined as the average probability that a precessing quadrature yields a positive outcome when measured at $K$ equally spaced times, with the classical bound given by $1/2 \pm 1/(2K).$ In this work, we adopt this probability as a symmetry-sensitive probe to assess the quantumness of superpositions of Gaussian states in harmonic oscillators. We derive analytical constraints on Tsirelson probability arising from rotational and parity symmetries, and show that parity symmetry establishes a universal relation between the maximal and minimal Tsirelson probabilities within parity-related state families. Furthermore, we prove that even-fold rotational circular states cannot exhibit Tsirelson violation due to their definite parity. These results reveal how geometric symmetries of Gaussian-state superpositions determine their nonclassical behavior and provide a symmetry-based framework for probing quantumness in continuous-variable systems.

The astrophysical gamma rays in the MeV energy region have not yet been well-explored due to the limitation of detection technology in the past decades, and the famous gamma-ray "MeV gap" exists. Opening the window of MeV gamma-ray is not only critical for the gamma astronomy but also essential for rich frontier researches in astro-particle physics, such as detecting light dark matter, probing the primordial black hole and better understanding of nucleosynthesis. As a pilot experiment of the project for dark matter detection in space at Shanghai Jiao Tong University, a three-layer Compton camera with the energy resolution better than 4% and position resolution of ~2 mm is developed utilizing the novel scintillators. Here we show the design, detailed calibration and validation results of the novel Compton camera, and demonstrate its good ability of MeV gamma-ray source imaging for the upcoming in-orbit mission.

We prove a Poincaré inequality, uniform in the particle number, for repulsive (one-component) Coulomb gases in dimensions $d\ge3$, with inverse temperature $\beta_N$ that is allowed to depend on $N$. We assume a weak-coupling condition expressed in terms of the effective interaction strength $\Theta_N$ seen by a single particle. This yields exponential relaxation for the associated overdamped Langevin dynamics. The main ingredient is a one-site Poincaré inequality uniform in the number and positions of the Coulomb poles, including coincident poles. A moving-pole estimate and Dobrushin-Wu tensorization yield the many-particle lower bound, while the center-of-mass coordinate gives the matching upper bound.

We prove an integral representation of the $\alpha$-$z$ Rényi divergences for normal states on arbitrary von Neumann algebras. Along each ray $z=c\alpha$, the divergence is a positive average of relative entropies evaluated in a canonical family of escort states. For orders $\alpha$ above one, we require the divergence to be finite, whereas for orders below one support inclusion suffices. An explicit boundary correction removes the lower-order support assumption. The proof uses a compatible weighted Haagerup $L^p$ scale and applies outside the data-processing region. For faithful density matrices, we express the derivative of the escort relative entropy with respect to the Rényi order in terms of a nonnegative fluctuation quantity. Differences of order-one derivatives of the divergence give quantum Fisher information and Wigner-Yanase skew information. For faithful bipartite density matrices, we also express optimized conditional $\alpha$-$z$ entropies at orders above one as averages of ordinary conditional entropies. Further applications concern coherent-state divergences in quantum field theory and the optimizing order for the strong converse exponent in hypothesis-testing.

The experimental observation of large CP violation in charm-meson hadronic decays remains theoretically unexplained within the Standard Model. The data-driven approach which accounts for the rescattering between the final-state pion and kaon pairs provides predictions that fall short of the experimental values. However, it relies on a set of inputs that exhibit large uncertainties. In this work, we make optimal use of the available information on branching ratios and of only one strong-scattering input parameter that is well determined. We find that it remains unlikely to explain the experimental signal within this approach and obtain predictions for sum rules that constrain CP asymmetries of the pion and kaon channels.

Enrico Fermi in 1932 used classical Gauss equation to derive the Coulomb density–density interaction from the longitudinal electromagnetic potential. In this work we extend the Fermi procedure to the transverse component of the vector potential. By using a fully quantum canonical transformation, we replace the transverse vector potential with a current–current and current–current–density interactions. The transformed Hamiltonian is, then, projected in the fermionic space providing a matter–only, totally incoherent and gauge respecting Hamiltonian. The removal of coherence will avoid the breakdown of perturbation theory predicted by Haag's theorem, and make possible to introduce, in the transformed space, the diagrammatic approach. After discussing the implications of the transverse interactions on the current theories based on the Fermi procedure, we conclude by showing how the transverse Hamiltonian provides the quantum origin of the electromagnetic longitudinal–transverse splitting of phonons and other elemental excitations.

We show that an emergent geometric symmetry generates non-trivial topology in quantum-dot-based multi-terminal Josephson junctions. It confines same-spin Andreev bound state crossings to an analytic one-dimensional manifold of the synthetic Brillouin zone, where interdot coupling selects Weyl nodes of charge $\pm1$ in the singlet sector and doubly degenerate cones of charge $\pm2$ in the doublet sector, at gate-tunable locations. The mechanism yields a spectroscopic detection protocol and a design principle for fabricating devices with non-trivial topological signatures.

Deducing the properties of the host neutron stars from thermonuclear (type-I) X-ray bursts remains a challenge, due to incomplete data, multidimensional parameter space, and dearth of suitable models and analysis tools. Here we describe further development of the BEANSP package, with a new "ensemble" analysis mode utilising the consistent and regular "clocked" bursting exhibited by some sources. This mode requires only one model evaluation per epoch, and so is much more efficient than the previous "train" mode. We apply the code to the best-known source exhibiting "clocked" bursting, GS 1826-24, utilising a grid of KEPLER models pre-calculated for this purpose, and find good agreement with a previous study. We performed experiments on simulated data, and recovered input parameters related to the burst ignition with reasonable accuracy, but less so for the system distance, emission anisotropy and neutron star mass and radius. Finally, we assembled a set of 14 daily burst epochs covering the 2024 outburst of the accretion-powered millisecond pulsar SRGA J144459.2-604207, and attempted to constrain the system properties of this object by comparing to SETTLE model predictions. We find reasonably good agreement between the observations and model predictions for a mildly sub-solar fuel composition, with H-fraction $X\approx0.54$ and CNO metallicity $Z_{\rm CNO}\approx0.01$. However, we note that the inferred H-fraction is in excess of the limit of 0.4 established separately, and the adopted model may not provide sufficiently accurate predictions for this burst ignition regime. The inferred distance depends on assumptions about the system inclination and corresponding anisotropy of the persistent emission, and is likely in the range 6-11 kpc. Future applications with more physically realistic models are a promising avenue for this and other sources with H-rich bursts.

We investigate the impact of high-energy QCD resummation on Higgs-boson production processes relevant for Higgs-pair studies at the Large Hadron Collider. We present the first dedicated study of Higgs boson production in association with a bottom-quark pair and two additional hard jets in the gluon-fusion channel at high energies as a background to vector-boson-fusion Higgs-pair production. The resummation can significantly modify the QCD contribution in VBF-like regions of phase space, indicating that fixed-order calculations overestimate the contamination from gluon-fusion backgrounds. We then extend existing High Energy Jets (HEJ) predictions for Higgs boson production in association with jets by including quark-pair resummation effects for the first time.

Astrophysical binaries formed by a stellar-mass compact object and a massive black hole are among the most promising sources for future space-based gravitational-wave detectors. These extreme mass-ratio inspiral (EMRI) systems are tracked coherently over more than $10^{5}$ orbits, encoding detailed information about strong-field gravity. Translating a detection into physical parameters requires models of comparable precision. One outstanding difficulty is the treatment of transient orbital resonances. In this work we address the problem at the level of the Koopman operator, where the waveform is promoted to an observable and the evolution over one radial cycle is a linear operator. Removing the fast timescale without a singularity at a crossing is then a matter of choosing a function of that operator. We demonstrate the approach on a Kerr geodesic driven through the 3:2 crossing by a modelled forcing term. There the coefficient of the standard near-identity transformation diverges, while the finite-window generator attains its analytic bound to better than one part in $10^{6}$. Averaging over twice the crossing duration recovers the resonant jump with its predicted magnitude and phase dependence.

During drop coalescence, a connecting bridge of fluid forms and rapidly expands due to surface tension. For spherical drops, these dynamics are well understood in both the viscous and inertial regimes. However, under strong confinement, fluid motion is fundamentally altered by geometric constraints, leading to dissipation on small lengthscales. We investigate the coalescence of drops confined in a Hele-Shaw cell (two parallel plates separated by a narrow gap). In this geometry, the depth-averaged flow is governed by Darcy's law while surface tension drives the interface motion. We identify two distinct temporal regimes in the evolution of the bridge radius that evolves as a power law ($R_b$). At early times, the bridge grows as $R_b \sim t^{1/2}$, which results from a confinement-dependent meniscus instability that determines the initiation of contact between droplets prior to bridge formation. At later times, the bridge growth slows substantially and follows $R_b \sim t^{1/5}$, consistent with recent theoretical predictions for Darcy-governed coalescence. We show that the transition between these regimes is controlled by several geometric lengthscales. In particular, the onset of the Darcy regime occurs when the interface radius of curvature becomes comparable to the plate spacing, such that the flow becomes fully confined. Using a boundary integral formulation, we find that both scaling laws for $R_b$ are determined by the bridge width. Together, these results identify a new universal regime of drop coalescence in a broad class of fluids obeying Darcy's law.

This work advances a fundamentally new approach to space-based construction by using liquid self organization in microgravity as a generative design and fabrication principle. Building on the LiquiFab method, we demonstrate how minimal surface architectures - traditionally dependent on complex additive manufacturing - can instead emerge directly from the physics of fluid interfaces shaped by programmable boundary conditions. We present a simulation-to-fabrication workflow, that includes a boundary-driven minimal-surface solver integrated in Grasshopper/Rhino, and an experimental system that implements in a neutral buoyancy environment simulating microgravity. This enables the generation of customizable Schwarz-P-inspired with tunable geometry and thickness, illustrating a scalable pathway for material-efficient, on-orbit fabrication. To validate performance in true microgravity, a flight experiment on the International Space Station is scheduled for the first quarter of 2027 and we here detail the additional considerations required for this experiment.

Bell-state measurements are essential ingredients in many protocols for quantum information processing, ranging from quantum teleportation and dense coding to entanglement distribution in quantum networks. Their power relies on the fact that they are measurements in an entangled basis of a two-particle system and that the used Bell-state basis can be generated from a single Bell state by local unitary transformations. How can these measurements be generalized to more particles? We develop a general framework for this state-to-measurement problem: We introduce a hierarchy of classes of measurement bases, distinguished by the local transformations the parties may use for their generation from a single state. This leads to a generalization of the concept of maximally entangleable (or weighted hypergraph) states and the identification of a novel maximally entangled basis of four qubits, being a candidate for data-hiding tasks or distillation protocols. Finally, we prove that not all forms of entanglement can be encoded in an entire measurement basis.

Ultralight scalar dark matter can make space-based gravitational-wave detectors respond through both the scalar charge of freely falling test masses and scalar-induced changes of local solid length scales. Existing space-detector forecasts usually model the former as a center-of-mass force, while ground-based interferometer studies show that scalar fields can also act through material and optical-path transduction. We ask which part of a local material response survives after one-way Doppler measurements are assembled into delayed time-delay-interferometry observables. To this end, we formulate center-of-mass motion and endpoint-size breathing in a common link-response notation for LISA-, Taiji-, and TianQin-like detectors. The main result is a projection rule: in the equal-arm, identical-endpoint, common-field limit, endpoint breathing enters Michelson-$X$ as a common-mode link perturbation and is removed from the retained channel. Its leading leakage is controlled by finite scalar wave vector, unequal or time-dependent arms, nonidentical endpoint response, or auxiliary readouts, and carries extra geometric and delay suppressions beyond the local size response. We then give reproducible noise, sensitivity, and network-combination formulas, and quote multi-mission improvements only under explicit independent-stream and scalar-coherence assumptions. The result provides a controlled baseline for deciding when test-mass breathing can be neglected and when instrument-specific material response must be modeled.

Vertical gradient of mean turbulent electromotive force (expressed by the dynamo coefficient, alpha, caused by the penetrating convection into the tachoclines of Sun-like stars leads to the non-propagating alpha-mode patterns, which result in the periodic variations of magnetic field horizontal components. The aim of the paper is to study the influence of the latitudinal variation of the dynamo coefficient on the linear dynamics of large-scale waves in the overshoot layers of the tachoclines in Sun-like stars. We use the linear magnetohydrodynamic (MHD) equations with the dynamo coefficient in a simple rectangular geometry. It is shown that the vertical gradient of the alpha coefficient has the same appearance in the induction equation as the Coriolis force in the momentum equation. Therefore, the latitudinal variation of alpha parameter excites new large-scale waves similar to the Rossby waves on a rotating sphere. The dispersion properties of the waves depend only on vertical and latitudinal gradients of the alpha parameter, therefore the modes are basically different from the ordinary dynamo waves. The alpha_theta waves may have either prograde or retrograde propagation depending on the signs of the gradients. The time scales of the waves may vary from hundreds of days to tens of years in various parameters of the solar tachocline. These waves are coupled with the Rossby waves on a rotating sphere in the existence of the large scale magnetic field, which may lead to the mutual transformation of convective and rotation energies.

Flood-monitoring sensors are often placed according to coverage, access, or expected inundation. However, the value of a measurement depends on the prediction or decision it is intended to inform. Using tRIBS-Urban simulations and a neural-network surrogate of the August 2014 metropolitan Detroit flood, we examine how this learning target changes single-sensor placement. Across 2,576 candidate locations, we compare parameter-oriented optimal experimental design (PO-OED), which values expected information gain (EIG) about model parameters, with goal-oriented optimal experimental design (GO-OED), which values EIG about specified flood predictions. We also examine how parameter EIG evolves during the event, and illustrate that parameter learning translates unevenly into reductions in predictive uncertainty across locations and lead times. Under GO-OED, point-depth targets favor nearby locations, whereas regional-average and regional maximum-depth targets can favor nonlocal locations. Weighted multi-point objectives retain similar broad spatial patterns, although their computed max-EIG locations differ. Public geospatial data further provide illustrative feasibility and contextual classifications for deployment screening. These results show how monitoring objectives shape sensor placement in optimal experimental design, and motivates an objective-first workflow that defines the intended prediction and priorities, applies field-verified restrictions, and ranks locations by EIG.

The electron Parton Distribution Functions (PDFs) are essential components in the calculations of cross sections within a collinear-factorisation framework at lepton colliders. We compute them at the next-to-next-to-leading order (NNLO) in QED by working in two different factorisation schemes, namely the standard $\overline{\rm MS}$ one and the so-called $\Delta$ scheme, which was originally defined at the next-to-leading order, and which we generalise in this work by extending its definition to all orders. We present analytical results relevant to the large-$z$ behaviour of the PDFs in both factorisation schemes, and thus show how the soft-logarithm enhancement of the $\overline{\rm MS}$ electron PDF is completely absent in the $\Delta$ scheme. The latter therefore constitutes a natural choice that helps significantly reduce the complexity not only of numerical simulations in phenomenological applications, but also that of analytical computations necessary to achieve the soft resummation of physical observables. We argue that NNLO PDFs are necessary to attain relative-precision targets of $10^{-4}$ or better, for colliders whose centre-of-mass energies are in the hundred-GeV range.

It is shown that the ELM energy loss normalized by the plasma stored energy ({\Delta}EELM/Wplasma) for high-density small/QCE ELM regimes scales inversely with the separatrix turbulence parameter a_t. In contrast, the neoclassical electron collisionality at the pedestal top, nu*e,neo, expected to regulate {\Delta}EELM/Wplasma according to the Loarte scaling (Plasma Phys. Control. Fusion 2003 45 1549), does not adequately capture {\Delta}EELM/Wplasma data for peeling-ballooning-limited type-I ELMs and ballooning-limited small/QCE ELMs, limiting its applicability for extrapolation to one scenario window. A multi-machine database including seven tokamaks and with {\Delta}EELM/Wplasma ranging from 0.5% to 14%, has been analyzed. A regression analysis on only type-I ELMs yields (({\Delta}E_ELM)/W_plasma )_(Type-I ) [%]=6.8*T_(e,ped)^0.03 n_(e,ped)^(-0.4) ąppa}^(-0.4) R_major^0.4, corresponding to {\Delta}EELM/Wplasma =4.5% for nominal SPARC pedestal parameters and 12% for the ITER D-T Q=10 scenario. For the small/QCE ELM class, however, as a_t increases, the pedestal moves toward a ballooning-limited boundary, the toroidal mode number increases, the ELM frequency rises following the scaling f_ELM=46e^((2.25*a_t)), and {\Delta}EELM/Wplasma decreases via the relation ({\Delta}E_ELM)/W_plasma [%]=1.6e^(-({\alpha}_t/2)). For SPARC QCE-relevant a_t=0.86 and ITER high-fueling scenario a_t = 0.64, the scaling favorably predicts {\Delta}EELM/Wplasma of 1.0% and 1.2%, respectively, with values below 1% if the small/QCE ELM regime is pushed beyond a_t >1. The small/QCE ELM-fitted results represent an initial step toward future analysis on broader datasets, which will be necessary to improve the accuracy of projections for future reactor-relevant scenarios.

In a recent paper \cite{Chu:2026dhx}, the quantum stability of the fuzzy sphere was established at large but finite $N$, where a tadpole was also identified for the scaling fluctuation mode of the matrix geometry. Here we show that this tadpole generates a positive area-conjugate microscopic response, which in isolation energetically favors contraction of the fuzzy sphere. However, when the horizon is coupled to gravity, the tadpole requires the bulk geometry to adjust according to the junction condition of general relativity. Taking the exterior geometry to be Schwarzschild, we show that the junction condition requires a positive interior cosmological constant. Imposing a static, spherically symmetric, regular vacuum interior then selects pure de Sitter space. The matching further determines a soldering relation between the interior de Sitter time and the exterior Schwarzschild time, with a relative lapse growing as $C = O(N)$. We also propose a matrix realization of the de Sitter interior in which fuzzy-sphere representation sizes determine the angular geometry while condensates of off-diagonal link fields determine the emergent radial metric. This provides a concrete consistency test for spacetime emergence from the matrix degrees of freedom. Potential cosmological implications are discussed.

The radiative transfer equation (RTE) governs thermal radiation in participating media, which is critical to modeling combustion, atmospheric, high-temperature, and radiative thermal management applications. However, due to the inherently high-dimensional nature of radiative transfer, numerical solutions to the RTE induce significant computational cost. This work develops a Fourier neural operator (FNO) as a fast, discretization-invariant, surrogate model for predicting the absorbed heat flux field in participating media. A dataset is generated on a benchmark 2-dimensional problem modeling thermal surface emission into a participating medium with spatially varying properties using Monte Carlo simulations. The FNO is trained to learn the solution operator, mapping the input property fields and geometry to the resulting heat flux field. The trained FNO provides up to 26-times computational acceleration compared to Monte Carlo simulation at equivalent error. Furthermore, as the FNO learns the solution operator and not an image-to-image mapping, the trained FNO accurately generalizes to various spatial discretizations, including those not seen in the training dataset. A spectral analysis of the spatial frequencies present in the heat flux prediction demonstrates the FNO's ability to suppress the high-frequency noise present in the training dataset, while preserving the physically meaningful low-mid frequency spectrum. These results demonstrate the Fourier neural operator surrogate model can provide accurate, computationally efficient, and discretization-invariant predictions for radiative transfer in a participating medium. By learning the underlying solution operator, this approach moves toward the development of surrogate models for radiative transfer capable of generalizing across a broad range of geometries, discretizations, and boundary conditions.

Adhesion between NaI(Tl) single crystals and the walls of quartz ampoules remains a major limitation for Bridgman growth under sealed conditions, particularly for applications requiring ultra-radiopure scintillators for dark matter searches, where sealed handling is essential. In this study, ammonium iodide (NH4I) was used as an additive to generate HI in situ, thereby suppressing the NaOH-SiO2 reaction that forms adhesive sodium silicate phases. Small-diameter crystals (8 mm) were first grown to determine the NH4I concentration required to eliminate adhesion. The optimized condition was then applied to the growth of a large NaI(Tl) crystal. A crack-free and bubble-free NaI(Tl) crystal with dimensions of 3 inches in diameter by 3 inches in length was successfully grown. The crystal exhibited a light output of 59,000 photons/MeV, which is higher than that of the commercial NaI(Tl) crystals used as references in this study.

We develop a Bayesian formulation of diffusive quantum-classical dynamics by treating the wave function and classical variables as components of an ordinary stochastic process. The joint probability density P(psi,x,t) obeys a classical Fokker-Planck equation, while the quantum state appears as its second moment. Requiring autonomous second-moment evolution and trace preservation, together with a full-column-rank quantum-classical noise correlation matrix, forces the ensemble dynamics into hybrid Lindblad form. The same result also determines the general class of diffusive stochastic unravelings compatible with this hybrid evolution. Notably, this construction makes positivity immediate and does not take complete positivity or an underlying unitary quantum dilation as assumptions, but instead relies on the presence of a sufficiently coupled classical sector. We formulate quantum measurement, filtering and smoothing of hybrid quantum-classical dynamics as standard Bayesian inference and show how to correlation between the quantum and classical noise fully explains the differences between quantum smoothing and smoothing in classical time series models. We recover the stochastic master equation from the Kushner-Stratonovich equation with correlated noise and show how the quantum effect operator is related to the Bayesian backward message through the adjoint dynamics of the linear unraveling. The Bayesian posterior also defines a smoothed density matrix and, more generally, a posterior distribution over latent quantum-classical trajectories. These quantities can be approximated with standard particle filtering and smoothing methods. Numerical examples show that smoothing improves reconstruction of a hidden quantum-classical trajectory and that the full trajectory posterior can retain structure, such as multimodality, that is absent from its density-matrix second moment.

Metabolic networks play pivotal roles in understanding the evolution of organisms, microbiome dynamics and disease prevention and treatment. This study presents a comprehensive analysis of metabolic network properties across 10912 organisms spanning Bacteria, Archaea, and Eukarya domains. A novel method for the network construction is introduced, emphasizing the chemical transformations of metabolites. Unlike conventional approaches that link every substrate to every product in all chemical reactions, this method aligns more closely with metabolic pathways, linking products only to their generating substrates. Emphasis is placed on investigating the community structure within metabolic networks, employing the Surprise quality function that better addresses some limitations of previous approaches. Through comparisons between real and randomized versions of the networks, we identify characteristics that cannot be explained solely by the network degree distribution, thus identifying topological properties and community structures that arise from additional evolutionary pressures. This highlights the need for evolutionary models to incorporate additional mechanisms beyond the replication of the degree distribution.

Existing schemes for synthesizing graph states in quantum networks are essentially edge-by-edge constructions, so quantities such as the time-slot depth and the resource overhead grow significantly with the edge density of the target graph. This paper proposes a new method. Exploiting the mathematical equivalence between joint Pauli-X measurements and graph pivot operations, we formulate graph state synthesis as a rank-2 reduction process of a difference matrix over GF(2), and give an upper bound floor(N/2) on the number of steps for synthesizing an arbitrary N-node graph state, independent of the edge density of the target graph state. At the physical level, the joint Pauli-X measurement of each step is mapped to a dual-star concurrent distribution. We model the protocol on Waxman physical topologies with fiber attenuation and give a heuristic algorithm, and evaluate it against a strengthened Steiner baseline through Monte Carlo experiments. The experimental results show that our protocol is superior in time-slot depth almost everywhere. The entanglement resource overhead, the total number of CZ gates, and the number of Pauli measurements drop below the baseline near edge density p approximately 0.3, and are superior across the board thereafter. The denser the target graph state, the more significant the advantage.

The quantum Fisher information (QFI) is widely used to characterize quantum phases and transitions, but its diagnostic power sometimes relies on selecting special generators based on prior knowledge of the underlying physics. We ask whether this requirement can be relaxed in nonequilibrium systems by studying the QFI of the long-time asymptotic state of a two-dimensional p+ip superfluid following an instantaneous quench of the coupling strength, using the particle number within a large subextensive subsystem as the generator. In equilibrium, the ground-state QFI is continuous across the topological transition between the weak-pairing BCS and the strong-pairing BEC phases, showing no direct signature of the transition. After the quench, however, the QFI associated with the same generator distinguishes the three dynamical phases and can encode the topology of the pre-quench state. In phase I, with a vanishing order parameter, the QFI Fourier spectrum consists of a single zero-frequency spike determined by the nonequilibrium distribution function. In phase II, with a constant nonzero order parameter, the QFI spectrum contains a zero-frequency spike and two continua separated by a gap set by the minimum asymptotic quasiparticle energy. The continuum edge behavior reveals whether this minimum occurs at zero or finite momentum. In the former case, the spectral weight vanishes at the edge, with the sign just inside the continuum encoding the pre-quench topology for large subsystem. In phase III, with a time-periodic order parameter, the QFI spectrum exhibits discrete peaks at integer multiples of the oscillation frequency, together with continua associated with the Floquet quasienergy spectrum. Our results show that driving the system out of equilibrium can enhance the diagnostic power of the QFI for a standard physical observable, revealing information inaccessible in equilibrium.

Sliding ferroelectricity widely exists in various van der Waals bilayers or multilayers, which is induced by asymmetric stacking of commensurate interface. The greatly reduced switching barriers via interlayer sliding lead to high speed with low energy cost, while they are still much higher compared with superlubric sliding of incommensurate interfaces. The polarizations of such incommensurate interfaces are not switchable, which is the major obstacle of combing superlubricity and sliding ferroelectricity for ultralow barriers. Here we propose a design of such combination based on previous synthesis of lateral heterojunctions of 2D materials, which can be extensively applicable to various systems including PN junctions. In such long-distance superlubric ferroelectricity, the vertical polarization can be continuously controlled by superlubric sliding of incommensurate interfaces between lateral heterojunction bilayers, where the series of multiple stable states are long-sought for artificial synaptic devices. The unconventionality of our findings does not only include unprecedented barriers down to the magnitude of mu-eV, but also unprecedented long ion displacements distinct from the small deviations in classical paradigm of ferroelectricity. Our predicted superlubric sliding electrically driven by low vertical voltage is also hitherto reported, much more efficient compared with previously reported sliding mechanically driven by tips, resolving a major issue for practical applications.