Papers

Renormalization provides a framework for relating microscopic models of physical systems to effective descriptions at larger length scales. This procedure is studied for the boundary states of non-chiral two-dimensional topologically ordered models. The initial data consist of renormalization fixed points built from representations of finite-dimensional $C^*$-Hopf algebras, which are then perturbed by uniform on-site noise quantum channels and repeatedly coarse-grained. The resulting flows admit an intrinsic algebraic description in terms of completely positive maps on the $C^*$-Hopf algebra or, equivalently, positive linear functionals on its enveloping $C^*$-Hopf algebra. Their iteration is governed by convolution powers, and convergent trajectories yield new matrix product density operator fixed points, described by finite $*$-quantum hypergroups. This provides a concrete physical interpretation of such structures. For finite group algebras and their duals, we provide explicit classifications via Goursat's lemma for groups. Finally, we formulate and prove a quantum generalization of Goursat's lemma for finite-dimensional $C^*$-Hopf algebras, a result of independent interest, which gives an explicit structural description of all convergent renormalization trajectories.

Large imaging surveys in cosmology are detecting orders of magnitude more lens systems than known so far. This unprecedented dataset will lead to robust constraints on cosmology and galaxy evolution models. However, a preliminary careful characterization of the lens and source samples are mandatory. In this work, we report on a VLT/XShooter observation program of 67 lens systems to characterize their spectroscopic redshift distribution. These systems were previously detected on the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys by Huang et al. 2021 and Storfer et al. 2022 with deep residual neural network. We manage to measure redshifts for 58 lenses and 57 sources. We also identify 2 sources with indication of outflow in the shape of the emission lines and 7 sources with rotating disks in $[OII]$ or $H\alpha$. We find no particular bias associated to the redshift measurement operation, meaning that our measured source redshift distribution is likely representative of the true one and can be used to calibrate analyses in large imaging surveys.

The Quantum Scientific Computing Open User Testbed (QSCOUT) has developed a qubit-boson gate set for hybrid continuous-discrete variable (CV-DV) quantum computing. This document outlines how to utilize these gates on QSCOUT using Just Another Quantum Assembly Language, Jaqal\textsuperscript{TM}.

While initially deployed for optical interconnects, silicon photonics is increasingly being explored as a hardware platform for programmable optical systems, including linear optical processors, neuromorphic photonic networks, quantum photonic circuits and multiplexed sensor arrays. Common to most existing implementations is that light is controlled with electronics, and even basic demonstrations wherein light directly controls light remain limited. Here we demonstrate a broadband all-optical silicon photonic phase shifter based on an optomechanically mediated light-light interaction arising from the gradient optical force. Our device concept relies on slot-mode waveguides suspended by subwavelength gratings, which provide mechanical support while preserving optical confinement. We demonstrate all-optical phase shifting using a guided pump beam co-propagating with the signal beam, with only 60 $\mu$W required to achieve a $\pi$ phase shift in a 178.6 $\mu$m-long device. In addition, we measure the required pump power across a wide parameter space and find quantitative agreement with a lumped force-equilibrium model. Since the actuation relies on an all-optical geometric deformation rather than on material-index tuning, the approach avoids local electrical connections to the active element, carries no Kramers-Kronig absorption penalty, and is naturally compatible with cryogenic quantum photonic platforms.

Despite enormous expenditures in the research field, the electron-doped side of nickelate superconductors remains uncharted territory. Substituting the trivalent rare-earth cations by a tetravalent one hitherto failed. Here, we demonstrate by first-principles calculations a disorder-free route to electron dope Ruddlesden-Popper nickelates. When intercalating wide-band-gap insulating layers such as La$X$O$_3$ ($X$=Al, Ga, Sc) into La$_2$NiO$_4$, the extra (LaO)$^+$ layers act as electron donors, releasing carriers into the Ni-3$d$ orbitals. This electron doping puts La$_2$NiO$_4$:La$_2$AlO$_4$ naturally in the optimal region for $d_{x^2-y^2}$-wave superconductivity with T$_c$ exceeding 50 K. The same concept also allows us to electron dope La$_3$Ni$_2$O$_7$, the superconductor in the limelight.

A recent analysis of 15 years of Fermi-LAT data reported a spherically symmetric, halo-like component of the Galactic diffuse emission that peaks near 20GeV. We independently reproduce this cell-aggregated analysis, then extend it to a pixel-level likelihood on the native $0.125^\circ$ maps, adding energy-dependent point-spread-function forward folding and masking bright sources. Both methods replicate the 20GeV halo spectrum, with the pixel-level normalisation ${\sim}20\%$ above the cellwise fit across NFW emissivity scalings $\rho^p$, $p \in 1,2,2.5$. This 20GeV halo is a high-latitude feature, distinct from the inner-Galaxy excess, and consistent with sub-TeV dark matter (WIMP) annihilation. It is centrally concentrated, strongly disfavouring extragalactic emission. Fitting prompt $s$-wave annihilation spectra, best-fit masses are $m_\chi \simeq 0.55$TeV ($W^+W^-$) and $0.72$TeV ($b\bar{b}$) with $\langle\sigma v\rangle \simeq 1\times10^{-24}~\mathrm{cm^3\,s^{-1}}$, in $\sim\!4$-$5\times$ tension with dwarf spheroidal galaxy limits. However, accounting for foreground modelling and $J$-factor systematic uncertainties widens the tension window to $R\simeq1.6$-$9.3$, leaving the $s$-wave interpretation viable. To close the tension, we consider alternative particle dark matter models. $p$-wave annihilation misses relic abundance constraints by $\sim\!7$ orders of magnitude. A decay interpretation evades dwarf limits but is disfavoured by the isotropic gamma-ray background. The only viable velocity structure consistent with dwarf limits, present-day halo rates, and relic density is low-velocity-enhanced annihilation (resonant Sommerfeld or Breit-Wigner). This supplies the required $\approx\!45\times$ boost from a thermal relic. Fully resolving the dwarf tension requires a fine-tuned resonance peaking at the halo velocity and falling for colder systems.

We demonstrate an optimization of angular double-slit interferometry for accurate measurement of orbital angular momentum (OAM) of vortex beams. By scanning the dynamic double slits, the topological charge (TC) magnitude is directly determined from the oscillation frequency of the on-axis intensity. Based on repeated experimental investigations, we establish a critical criterion for slit width selection: to avoid phase truncation or period overlap, the angular width of each slit must exactly match the spiral phase period 2{\pi}/|l|. Under this optimal condition, the interference pattern exhibits the highest visibility and the measurement error is minimized. Experiments for l = 5, 10, and 15 are performed as representative examples, and the universality of this criterion is confirmed. Furthermore, by introducing an additional phase shift, the sign of the TC is unambiguously determined, as demonstrated for l = 10 and l = -15. This simple, robust method provides a high-precision pathway for OAM metrology.

While quantum hardware remains limited, hybrid quantum-classical algorithms with complex control structures, including unbounded loops, are emerging, posing new challenges for quantum program analysis, including the accurate estimation of the resource consumption of a given program. Meanwhile, precise analysis techniques such as symbolic execution have largely left out hybridization and unbounded recursion. On the other hand, current quantum Hoare logics that generally support them are lacking in expressiveness and miss out on efficient computational equational reasoning that could be implemented in a semi-automated tool. This leaves a gap awaiting to be filled. In this work, we answer this challenge with the first semi-automated static analysis solution combining effective functional verification and resource (termination or cost) estimation for hybrid quantum programs with unbounded loops. Towards that end, we introduce integer hybrid path-sums (IHPS), extending path-sums to handle unbounded while loops, as a representation of possible executions of a program. A generic strategy for determining termination and expected resource consumption via loop invariants is also proposed and illustrated on several examples. Finally, the solution is implemented as a semi-automatic Haskell program. This work is the first step toward the design of a complete static resource analysis tool for hybrid quantum programs, essential for the development of real-world quantum computing.

Many real-world networks have the characteristic that they are comprised of distinct groups or communities whose members contain many links within the community but with fewer connections to others. It is important to accurately model these types of networks to correctly predict the outcome of important spreading processes such as disease transmission, or the flow of information etc. Our motivating example is a network of traders within several investment institutions such as hedge funds. We assume an idealised scenario where traders within the same institution have many contacts and can share information quickly and easily but have fewer contacts to traders in other institutions, relying on personal networks, allowing for information to flow easily within a community and less-so between communities. In this paper we investigate a particular spreading process, the spread of a rumour, on a community based network that is characterised by two parameters; the within-group connectivity, and the between-group connectivity. We show that such networks have different characteristics to small-world or random networks that are often used to model the types of systems and that the network topology has a small but not insignificant effect on the spread of rumours on the network.

Context. Resonant chains are systems with three or more planets caught in a succession of two- and three-planet mean-motion resonances (2P-MMRs and 3P-MMRs). Most of the observed chains show significant amounts of separation from the nominal commensurabilities. These are lower energy states and therefore suggestive of a process of long-scale dissipation. The most frequently invoked mechanism is active tides affecting the innermost planets, produced by the star. Aims. Simulations of tidal separation are expensive and generally impractical for extensive parameter explorations. Therefore, it is essential to have access to analytical tools that would allow us to inspect tidally separated chains, as probing these systems can give valuable insight into the physical parameters involved in dissipation. Methods. We extended an existing analytical model of the tidal separation of resonant chains with adjacent first-order 2P-MMRs that is meant to be applicable to longer N-planet chains. We have demonstrated how this approach can be used to constrain those parameters involved in the tidal evolution, such as the frequently unresolved Q' factors. Results. We show how this tool can be used to place meaningful bounds over the effective planetary Q' value of long resonant chains, even in the realistic case where the system is poorly characterized, lacking measurements of parameters such as the stellar age or one of the planetary masses. We also show how the magnitude of separation in a resonant chain is specially sensitive to the mass of certain planets. In particular, a more massive second planet will boost tidal separation, while a more massive last planet will inhibit it.

We propose to model spin-orbit resonances that appear in ring systems around minor bodies of the Solar System using a circumbinary approximation. In our model, the ellipsoidal/irregular shape of the minor body is replaced by a binary dumbbell, i.e., two equal masses evolving in circular orbits around their center of mass. This allows us to apply the equations of motion of the restricted circumbinary N-body problem, duly adjusted to mimic the rotation of the central body and its quadruple momentum. The equations also allow for the simple inclusion of other perturbing bodies, like small satellites, enabling the analysis of the simultaneous effect of spin-orbit resonances and mean motion resonances on the ring dynamics. The goal of the circumbinary model is to substitute the study of a given spin-orbit resonance by a surrogate mean motion resonance, allowing for the application of well established numerical and semianalytical models to map the topology and stability of these resonances. We discuss the differences between the circumbinary model and a triaxial ellipsoid. The model is also extended to study the problem of a mass anomaly. We present some applications to the dynamics of Quaoar's ring system, indicating that spin-orbit resonances do not seem to play any relevant role in the present dynamics of the ring particles.

The ionized gas in the Milky Way is a major component of the interstellar medium. Observations of extinction free tracers, such as hydrogen radio recombination lines (HRRLs), have revealed the presence of a dense (electron density 1 to 100 cm$^{-3}$) warm ionized medium. Motivated by advances in radio instrumentation, the existence of fully sampled HRRL maps, and a better knowledge about the population of discrete HII regions in our Galaxy, we have acquired new low-frequency ($\nu\lesssim1$ GHz) observations of HRRLs to characterize the properties of this gas. We target three positions in the Galactic plane, with few or no known HII regions, using the 342 MHz and 800 MHz feeds of the Green Bank Telescope. We detect HRRL emission from all three positions. We combine these with the fully sampled HRRL 5.8 GHz cubes from the GBT Diffuse Ionized Gas Survey (GDIGS) to determine the gas properties using a forward modeling approach. From our analysis we find electron densities between 6 and 15 cm$^{-3}$, and that to determine the gas temperature and emission measure we require informative priors or higher signal-to-noise observations.

We show that the lower edge of the appropriately scaled size $n$ Laguerre beta-ensemble with parameter $a=a_n$ converges to the $\operatorname{Airy}_{\beta}$ process as $n\to \infty$ when $a_n\to \infty$ and $\tfrac{a_n}{n}\to 0$. This completes the picture of the possible edge scaling limits of the Laguerre beta-ensemble with a fixed $\beta>0$. When $a_n\gg (\log \log n)^3$ our proof establishes operator level convergence of the inverse of the scaled Dumitriu-Edelman tridiagonal matrix to the inverse of the stochastic Airy operator. Our methods allow us to prove similar operator level limits for the known soft edge scaling limits of the Laguerre and Gaussian beta-ensembles. For $a_n\le (\log n)^{1/2}$ we give a different argument that relies on coupling and a result of Dumaz-Li-Valko for the transition between the hard and soft edge limits of the Laguerre beta-ensemble.

The human cerebral cortex, initially smooth, progressively folds during fetal brain development in utero, giving rise to cortical convolutions. Atypical cortical folding patterns can be associated with neurodevelopmental and neurological disorders. To better understand these conditions, it is crucial to first examine the factors governing healthy cortical folding. Computational modeling provides a powerful way for this purpose and has already helped understanding the influence of key biomechanical parameters on the folding pattern. However, most existing models use simplified geometries, limiting calibration and validation with fetal and neonatal brain Magnetic Resonance Imaging (MRI) and neglecting the influence of initial geometry on fold development. On the other hand, simulations on realistic brain geometries introduce additional challenges, including collision handling, fold characterization, and additional computational cost. Furthermore, model parameters are often difficult to interpret, complicating comparison, clinical translation, and calibration. Finally, computational models of cortical folding also remain rarely accessible. In this work, we introduce a novel computational model of cortical folding, developed using the open-source code FEniCS to simulate folding on a whole-brain geometry generated from fetal MRI data. We also propose a modular, interpretable, and scalable simulation framework built around this computational model and openly available to the community. It uses fetal MRI data to generate realistic input brain meshes and estimate key biomechanical parameters such as cortical growth rate. The framework also integrates a spectral metric for cortical surface analysis to optimize folding pattern predictions from an healthy fetal MRI dataset.

The description of the optomechanical systems is commonly based on the quantum Langevin equation formalism. This framework is introduced phenomenologically or based on a model Hamiltonian. However, once dealing with the optomechanical Fabry-Perot cavity or the modified Michelson-Sagnac interferometer with a semitransparent mechanically active membrane inside, a model-free consideration is also possible by using an alternative approach. Such an approach, which is based on the classical wave equations, is popular in the gravitational-wave community where it is termed as input-output relations approach. In this work, using the aforementioned approach, we derived the equations for the ladder operator of the intracavity field, stochastic back-action force, and the relation between the fields at the input mirror. Then we simplified the obtained results down to the range of applicability of the Langevin equation formalism and compared these with the corresponding predictions of the latter formalism. This enabled us to critically assess the validity of the Langevin equation formalism and rectify its range of applicability to find that the latter is more stringent than that intuitively expected. In the case where the dissipative optomechanical coupling is involved we identified appreciable problems with this formalism. It was found that, disregarding the fact that decay rate of the optomechanical Fabry-Perot cavity depends on its length, no dissipative optomechanical coupling is generated. This is in contrast with the prediction of the standard Langevin-equation based treatment. It was found that the Langevin equation formalism misses a phase factor at the input field; this factor turns out to be important for the situation involving the dissipative optomechanical coupling.

Nanofluids, which are composed of insoluble, stable, and well-dispersed solid particles of nanoscale and/or subnanometer sizes suspended in a base liquid, are the next generation of liquids of today. The purpose of this paper is to investigate the one dimensional and three dimensional angle dependent radial distribution functions RDF and ARDF of polymeric nanofluids made up of nonrigid (soft) nanoparticles and a polymer melt (base fluid) using the molecular dynamics simulation approach and to search the shape stabilities by using these results. For this purpose, we use the nanoparticles of three different sizes: 28, 42, and 56 particles. We research them both within the base fluid and without this polymeric medium for instability analysis. We found that the nanoparticles with 28 atoms show the shape instability inside the base fluid when we increase the system temperature from T=1.2 to T=1.8 and hence, the structure of two concentric spherical shell of the nanoparticle breaks down and as a result the empty vacuum between these inner and the outer shells disappears. In contrast to this findings, the nanoparticles with 42 and 56 atoms show the shape stability inside the base fluid by preserving their concentric shell structures when we rise the system temperature and decrease the affinity between the nanoparticles and the base liquid medium.

Light carries angular momentum, but the microscopic pathways that transform it into magnetization remain elusive. Here we establish that crystal-field excitations, historically viewed primarily as equilibrium spectroscopic fingerprints of localized 4$f$ electrons, constitute an active microscopic route through which circularly-polarized terahertz (THz) light creates magnetic polarization. Using wavelength-selective ultrafast Faraday spectroscopy on the paramagnetic insulator CeF$_3$, we show that resonant excitation of localized 4$f$ crystal-field transitions generates a helicity-dependent magnetization that survives for up to about 100 ps. Most strikingly, while the optical helicity is held fixed, the THz-driven response reverses sign as the excitation wavelength is tuned across the crystal-field resonance. The resulting dispersive spectral response follows the crystal-field excitation spectrum rather than that of optical phonons, and is captured by resonant electronic theory of the inverse Faraday effect. Our results identify crystal-field excitations as a previously unrecognized dynamical reservoir for optical angular momentum and broaden the microscopic pathways through which THz light can create and manipulate magnetic states.

In recent years, crystal generation models have enabled the design of massive numbers of candidate materials. However, the lack of dynamical stability among generated structures has become a major bottleneck preventing their translation into practical materials discovery. To address this challenge, we propose PhononScore, a phonon-aware scoring function for crystal generation. Unlike computationally expensive explicit phonon calculations, PhononScore predicts a unified stability score from crystal structures, enabling ranking of candidate materials dynamical stability with second-level computational cost. We construct a multi-fidelity phonon dataset containing 157,463 crystal structures. On the PhononBench benchmark, PhononScore improves the average dynamical stability rate of candidate pools generated by nine crystal generation models from 30.7% to 83.7%, achieving a 2.72-fold enrichment of stable structures, while the average stability rate of the Top-10 candidates reaches 97.5%. On a high-fidelity DFT-PBE phonon benchmark, the DFT-finetuned PhononScore-DFT increases the Top-100 stability rate to 93.0% and achieves 5-6-fold enrichment of dynamically stable structures under an extremely imbalanced hard-screening scenario. As a materials-screening tool analogous to scoring functions in drug discovery, PhononScore can serve directly as a dynamical-stability feedback signal for crystal generation, active learning, and reinforcement learning, enabling second-level stability-aware reranking without explicit phonon calculations and providing a unified and efficient dynamical stability evaluator for high-throughput materials discovery, active learning, reinforcement learning, and closed-loop inverse design. The online PhononScore platform is available at: http://phononbench.cn/phononscore/

We study one-way quantum communication lower bounds for search problems. Unlike decision problems, search problems can have many valid outputs, which pose a fundamental barrier to standard quantum lower-bound techniques. We overcome this by developing a novel method based on matrix discrepancy, which allows us to bound the output measurements of a quantum protocol jointly. As applications of our method, we establish the first tight quantum lower bounds for two fundamental search problems in some natural parameter regimes: collision finding and triangle finding. For collision finding, we prove a tight $\Omega(N^{1/4})$ one-way quantum communication lower bound. Previously, the best-known quantum communication lower bound for collision finding was $\Omega(N^{1/12})$ due to Göös and Jain (RANDOM 2022), and no stronger bound was known even under the one-way restriction. For triangle finding in graph streams, we prove a one-pass quantum streaming space lower bound of $\Omega\left(\sqrt{\Delta_V}\right)$ for graphs with $m$ edges, $\Theta(m)$ triangles, and constant $\Delta_E$, where $\Delta_V$ and $\Delta_E$ denote the maximum number of triangles sharing a common vertex and edge, respectively, under the condition that $1\le \Delta_V\le m^{2/3}$. This constitutes the first nontrivial quantum space lower bound in this regime, matching the classical upper bound of Jayaram and Kallaugher (RANDOM 2021) up to logarithmic factors. Notably, our method also recovers the classical lower bound of Kallaugher and Price (SODA 2017) through an entirely different argument, avoiding their Boolean-Hidden-Matching reduction that breaks down for quantum protocols.

Entanglement distribution is the overarching purpose of quantum networks. While communication over long distances can use deployed fiber infrastructure, it requires photons in the telecom band. However, advanced quantum network nodes do not operate at such wavelengths. Here we overcome this limitation with two tailor-made low-noise quantum-frequency converters to distribute entanglement between a single atom and a resonant photon over 14km line-of-sight via 24km of a deployed commercial fiber. The photon at wavelength 780nm is first entangled with the atom, then converted to the telecom S-band, and finally back-converted after propagation through the fiber. This link enables a photon transfer efficiency of 1.7% while affecting the atom-photon entanglement fidelity by less than 1%. This brings integration of atomic quantum nodes with existing long-distance fiber networks into reach, enabling novel applications in quantum information processing.

Science is often portrayed as a universal and self-contained system, driven solely by the internal logic of knowledge accumulation and isolated from the turbulences of the socio-political world. In this paper, we challenge this narrative by providing systematic quantitative evidence that the global scientific ecosystem is deeply shaped by geopolitical transformations. Using a large-scale dataset of scientific publications drawn from the OpenAlex database, spanning over five decades and covering virtually all countries and disciplinary areas, we track the evolution of national research profiles and show that geopolitical dynamics shape scientific agendas at multiple scales. At the global level, intrinsic scientific change is slow and cumulative, but exogenous shocks, such as Chernobyl, September 11, and COVID-19, produce rapid disruptions that synchronously reconfigure the priorities of many countries at once. At the country level, we document a broad globalization of knowledge, yet deeply heterogeneous: while Global North countries converge toward a shared international agenda, Global South countries display strong dependence on international resources alongside locally distinctive research interests. Among emerging Southern economies, scientific power is increasingly asserted through specialized and independent agendas. Finally, we observe a reorganization of global scientific influence toward a more polycentric structure, with the emergence of a Southern cluster gravitating around Brazil and Indonesia as new regional hubs.

This paper investigates the behaviour of a fluid characterized by a viscosity simultaneously depending on pressure and shear rate within a Hele-Shaw cell featuring a sharp corner geometry. The study extends previous analyses conducted on purely pressure-dependent (piezo-viscous) and yield-stress fluids, providing a new perspective on confined complex flows. Motivated by practical applications related to designing biomedical devices and flows of relevance to biomedicine area, thin film technologies, injection molding – to name only a few – the flow configuration considered here can highlight essential features of complex fluid behavior in narrow-gap geometries around a sharp edge. Starting from the governing equations for an incompressible generalized Newtonian fluid and employing an appropriate rheological model, we derive the modified flow equations adapted to the Hele-Shaw flow. A particular solution is obtained near the corner region. Numerical simulations complement the theoretical results, illustrating the influence of the rheological parameters on the flow behavior.

Quantum gate teleportation is a key technique in fault-tolerant quantum computation that uses resource states to implement logical gates. Here, we develop a theory of magic gate teleportation (MGT), a form of quantum gate teleportation that uses non-stabilizer resource states to implement non-Clifford unitary gates on arbitrary input states without revealing information about those states. This setting is motivated by the canonical approach to implementing logical non-Clifford gates in fault-tolerant quantum computation. We uncover a hidden structure within MGT—after backpropagating the Pauli measurements, MGT protocols can be viewed as encoding the input state into a stabilizer code heralded by the measurement outcomes, followed by a logical non-Clifford gate. Using this structure, we construct MGT protocols for any resource state obtained by applying commuting Pauli rotations to a stabilizer state, and provide an efficient algorithm for synthesizing their circuit implementations. Conversely, we prove that directly useful single-qubit resource states are necessarily Clifford-equivalent to diagonal states, and establish the same constraint for multi-qubit resource states used in a broad class of MGT protocols. In particular, the output state distilled from the $[\![5, 1, 3]\!]$ protocol is not directly useful for any MGT protocols, though it can be probabilistically converted into directly useful states. Finally, we identify conditions under which the feedforward operators can be implemented by Pauli operators, shedding light on the paradigm of algorithmic fault tolerance and simplifying the feedforward operations needed for quantum computing.

The theory of quantum filtering (of quantum continuous measurements) was developed by V.P. Belavkin about 40 years ago. Since then it attracted attention of numerous investigators including mathematicians, theoretical and experimental physicists. However, the rigorous mathematical theory of the filtering equations for mixed states in basic infinite-dimensional quantum systems remained an open problem, which was resolved by the author recently. This survey paper presents in full the mathematical theory of quantum filtering equations, their rigorous derivation from basic principles, the corresponding law of large number limits (propagation of chaos) and related topics. Applications to feedback control, quantum dynamic and mean-field games are discussed.

We investigate generative diffusion models as denoising samplers for two- and three-dimensional lattice $\phi^4$ theory across the symmetric, near-critical, and broken phases. Validated against ensembles generated by Fourier-accelerated HMC combined with Wolff cluster updates, the reverse-SDE sampler reproduces scalar observables and the momentum-space propagator $G(|k|)$, with residual bias concentrated in the zero-mode and, in three dimensions, the action density. We introduce two local diagnostics and an HMC-referenced effective sample size (ESS), which probe the learned drift directly, through a Metropolis-adjusted Langevin acceptance rate, and through observable-level bias and variance. Exploiting a fully convolutional architecture with weights shared across different volumes ($V=L^D$), we show that cross-volume training transfers to unseen sizes, matching or slightly improving in-distribution training in the two-dimensional symmetric and broken phases. A three-dimensional model trained on $L \in \{4, 8, 16, 32\}$ reproduces the propagator and most scalar observables at the unseen lattice size $L = 64$ across the phase diagram, with the residual susceptibility excess in the broken phase as the main exception, and improves several critical observables relative to in-distribution $L = 64$ training. This establishes cross-volume generalization as a viable mechanism for large-volume sampling, and the score learned from many cheap small-lattice configurations transfers to the target volume without retraining.

The $^{12}$C + $^{12}$C fusion reaction plays a key role in several astrophysical phenomena. However, it is difficult to determine its cross sections in the relevant energy region because of both low cross sections and strong resonant structures. On the other hand, the $^{12}$C + $^{13}$C system shows a much smoother energy dependence of fusion cross sections. To simultaneously analyze the $^{12}$C + $^{12,13}$C systems, we here develop a reaction model that explicitly treats the entrance channel and the compound nucleus states. For this purpose, we combine the discrete basis model for the entrance channel and the shell model for the compound nuclei. The coupling strengths between the entrance channel and the compound nucleus states are determined so that the fusion cross sections for these systems match with each other at the resonance energies for the $^{12}$C + $^{12}$C system, as has been observed experimentally. The model successfully reproduces the significantly different behaviors of fusion cross sections in these systems.

A critical requirement for MITICA – a full-scale prototype of the heating Neutral Beam Injectors hosted at the Consorzio RFX Neutral Beam Test Facility for the ITER experiment – is the capability to withstand a continuous voltage of 1MV across the vacuum gaps insulating the beam source from the grounded vessel. To validate such feature, a dedicated voltage-holding test campaign was conducted throughout 2024 and 2025 using a full-scale mock-up of the beam source. The tests also involved an accurate characterization of the associated breakdown events: vacuum dielectric failures which result in rapid potential drops and generate strong current discharges. This contribution will present a relative time reconstruction architecture based on cost-effective, embedded RedPitaya (Zynq-7000 FPGA) devices repurposed as timing hubs. These nodes function as configurable trigger multiplexers while simultaneously recording trigger signals as transients to facilitate the offline reconstruction of event sequences. The method allows self-calibration through measuring the static intrinsic delays of the optical fibers and internal logics, generating delay offsets to synchronize acquired waveforms across a sparse, connected-graph topology of both acquisition devices and hubs themselves.

We study eigenfunctions of quantum star graphs in the large edge number limit through the edge-mass distributions associated with their semiclassical measures. For generic edge lengths, we show that these distributions can realize every admissible multifractal scaling law along suitable subsequences of eigenvalues. We also prove a constructive result for quasi-equilateral star graphs. Starting from prescribed probability measures, we construct graphs and locate eigenvalues inside spectral clusters whose eigenfunctions reproduce the same scaling behavior. These results show that quantum star graphs form an explicit model realizing the full range of admissible multifractal behavior between localization and equidistribution.

A limiting case is worked out in which the causal action principle for causal fermion systems describing Minkowski space gives rise to the linear Fock space dynamics of perturbative quantum field theory, including non-abelian gauge fields and Dirac fields.

Quasi-periodic fast-mode magnetoacoustic waves are often detected during solar flare events, although they are not observed in every flare, due to observational signal-to-noise limits and differences in flare magnetic topology and energy release strength. These structures propagate along magnetic configurations and supply effective diagnostics for coronal magnetic environments and flaring regions. Periodic signatures seen in fast-mode QFP wave trains carry physical information about excitation processes and propagation conditions. These signatures support quantitative studies of flare cores and magnetic channel properties. This work focuses on a well-documented event involving two oppositely oriented QFP waves simultaneously excited by a GOES-class M6.0 solar flare that occurred in active region NOAA 11261 on August 3, 2011. These QFP waves can be categorized into broad and narrow wave trains, with the narrow one propagating along funnel-like loops and the broad one moving through the low corona. Observational results suggest that both broad-wave and narrow-wave QFP phenomena can be simultaneously triggered by a single flare eruption. This study also indicates that such multi-path QFP wave events can be utilized to diagnose the magnetic field and the flare's core, and demonstrates the capability of multi-path QFP waves for robust coronal magnetic field and flare core diagnostics.