Papers

Over the past decade, semiconductor spin qubits have progressed from few-qubit demonstrations towards larger-scale devices fabricated in increasingly reproducible academic and industrial processes. This progress marks an inflection point: the central challenge is no longer to demonstrate high-fidelity operation in carefully tuned devices, but to discover, verify, and maintain stable operating conditions reliably across many interdependent controls, varied device geometries, and disparate material platforms. In this Perspective, we frame spin-qubit operation as a modular automation problem. We decompose the workflow into five modules: bootstrapping from minimal prior information, configuration tuning, virtualization of physical gates into effective control axes, qubit-level tuning, and an operation layer with drift-aware maintenance. Using recent demonstrations from our work and the broader community, we argue that scalability will depend on explicit interfaces between modules, standardized intermediate data products, and workflow-level metrics such as throughput, success probability, stability time, recovery time, and robustness. We close by outlining the infrastructure needed to move beyond isolated tuning demonstrations toward sustained operation: qubit-performance-aware feedback, reusable software and benchmark tasks, and tight collaboration among experimental, theoretical, and software efforts.

Motivated by the current flavor anomalies and the comparatively less explored nature of the $b\to d$ sector, we present a model-independent study of the rare semileptonic $B_c^{+}\to D^{\ast+}\ell^{+}\ell^{-}$ ($\ell=\mu,\tau$) decay, to investigate its sensitivity to New Physics effects. The analysis incorporates penguin-box contributions, long-distance resonance effects, and the sizable weak-annihilation amplitudes. Using the $B_c\to D^\ast$ transition form factors calculated in the covariant confined quark model and the weak-annihilation form factors obtained within the Bethe–Salpeter approach, we analyze the differential branching fraction, forward-backward asymmetry, longitudinal helicity fraction, and a comprehensive set of normalized angular observables in several one- and two-dimensional New Physics scenarios and compare our results with the Standard Model predictions. Notably, the branching fraction, forward-backward asymmetry, and the normalized angular coefficients such as, $\langle I_{2c}\rangle$, $\langle I_{3}\rangle$, $\langle I_{5}\rangle$, and $\langle I_{6s} \rangle$, show clear sensitivity to New Physics effects. Our results indicate that the decay $B_c^{+}\to D^{\ast+}\ell^{+}\ell^{-}$ serves as a complementary probe of the flavor structure of New Physics and can therefore be investigated in future measurements at LHCb and other high-luminosity flavor experiments.

Unified Dark Matter-Energy models (UDM), a class of models where dark matter and dark energy exist as a single cosmological fluid, are an alternative approach to $\Lambda$CDM. In this work we focus on a model with a fast transition between dark matter-like and dark energy-like behaviour. The epoch and rapidity of the transition are the key features to enable the formation of structure in this model. We have studied its viability using CMB and Weak Lensing data with nested sampling inference methods. We found that the preferred region of the parameter space is the one with early and fast transition models, where it also lies the model's $\Lambda$CDM limit. Our study confirms that this UDM model is able to form cosmological structure compatible with the data used.

We investigate four-dimensional electrostatic systems arising as spatial factors of static Einstein–Maxwell spacetimes with cosmological constant. Assuming that the electric field is everywhere collinear with the gradient of the lapse function, we prove that the harmonicity of one of the (anti-)self-dual components of the Weyl tensor imposes strong rigidity on the underlying geometry. More precisely, we show that the gradient of the lapse function is an eigenvector of the Ricci tensor and that the regular level sets of the lapse function are totally umbilic with constant mean curvature. As a consequence, the manifold is locally conformally flat and admits a local warped product structure with one-dimensional base and three-dimensional fiber of constant curvature.

We investigate the low-energy excitation spectrum of the van der Waals heterostructure superconductor 4Hb-TaS$_2$ using ultra-low-temperature specific-heat and thermal-conductivity measurements with magnetic fields applied parallel and perpendicular to the crystallographic $c$ axis. The specific heat is broadly consistent with a nodeless superconducting gap, but retains a finite residual linear contribution, indicating a small residual low-energy density of states in the superconducting state. In addition, a pronounced upturn appears below approximately 0.3K. Its weak magnetic-field dependence, together with the absence of a corresponding feature in thermal transport, supports an interpretation in terms of localized degrees of freedom, most likely a nuclear Schottky contribution. In contrast to the finite residual thermodynamic density of states, the thermal conductivity extrapolates to a vanishing zero-field electronic linear term within experimental uncertainty for both field orientations. Thus, the residual low-energy states do not form a detectable itinerant heat-conduction channel. In finite magnetic field, the electronic heat transport grows rapidly. For out-of-plane fields, this response is broadly consistent with previous thermal-conductivity measurements and with the behavior commonly associated with multigap nodeless superconductivity. The even steeper increase observed for in-plane fields suggests that the field-induced quasiparticle response of 4Hb-TaS$_2$ is more complicated than the standard multigap picture alone.

In this paper, using a simplified model of the xenon atom, we numerically study the possibilities of efficient generation of coherent pulses in the XUV range through the resonant interaction of atoms with a moderate-intensity laser field, leading to the generation of its harmonics. We demonstrate the interplay of two systems of resonances affecting the harmonic generation efficiency. One is the channel-closing resonances, which arise when the sum of ionization and ponderomotive energies is equal to the energy of an integer number of laser photons. The second is the bound-bound transition resonances corresponding to an integer number of photons with a total energy equal to the energy gap between the Stark-shifted ground and excited states. The harmonic yields in the range of laser parameter values where both resonances occur exhibit a peculiar behavior, namely, near the intersection point of the resonances, a pronounced dip is observed, while the regions of increased generation efficiency due to the combined contribution of both enhancement mechanisms are slightly shifted from this point. We argue that this behavior, which is somewhat similar to the well-known phenomenon of 'avoided crossings', is associated with the formation of Fano-type resonant spectral lines. In contrast to 'avoided crossing' phenomena known in molecular physics, in the found interplay the contribution of one resonance system can be controlled, which is useful for experiments.

The search for nucleon decay in liquid-argon time-projection chambers requires a quantitative description of how the bound nuclear environment reshapes the decay-product kinematics. We present LUNAR, a fast, openly available Monte Carlo generator dedicated to two-body decays of protons and neutrons bound in argon-40, the target nucleus of the DUNE far detector. The parent nucleon is drawn from a selectable nuclear ground state – ten momentum distributions ranging from mean-field Fermi gases to argon spectral functions – and bound off the mass shell by one of three removal-energy prescriptions, including the momentum-dependent optical potential of Juszczak et al. The two-body decay is performed off-shell and boosted to the laboratory frame, and the daughter meson is then propagated out of the nucleus by a semi-classical intranuclear cascade with an optional formation zone for the freshly produced meson. We use the generator to separate the distinct roles of Fermi motion and binding in shaping the observable meson spectrum, to quantify final-state interactions channel by channel, and to translate present Super-Kamiokande limits into expected DUNE event yields for the full set of standard decay modes. Final-state interactions leave the supersymmetry-favored $p\to K^{+}\bar\nu$ signal essentially intact while roughly halving the pion, $\eta$, and antikaon rates – an effect that dominates over the $\pm10\%$ spread induced by the choice of nuclear model. The code is released to the community as a lightweight, extensible tool for signal efficiency and systematics studies.

The $5S_{1/2} \rightarrow 6P_{3/2}$ transition of rubidium at $420$ nm is a promising candidate for a portable warm-vapor all-optical atomic clock. Despite recent precision spectroscopy studies at $420$ nm in Rb, an experimental determination of the saturation intensity of this transition has not yet been reported. The saturation intensity is a fundamental parameter that influences the identification of a potential clock transition frequency in terms of optimizing various intensity-dependent parameters and connected systematics. In this work, we report the first experimental measurement of the saturation intensity of the $420$ nm transition in Rb, obtaining $(23.18 \pm 0.28)$ mW/cm$^2$ for the $^{87}$Rb $F = 2 \rightarrow F' = 3$ transition and $(25.56 \pm 0.37)$ mW/cm$^2$ for the $^{85}$Rb $F = 3 \rightarrow F' = 4$ transition, in excellent agreement with theoretical predictions. We further investigate the temperature dependence of the Doppler-free Lamb-dip amplitude and linewidth over $59.03~\pm~0.37$ - $91.20~\pm~0.90^\circ$C in a $100$ mm commercial vapor cell, identifying around $82.02~\pm~ 0.73^\circ$C as the optimal operating temperature, where the signal-to-noise ratio of the Lamb-dip amplitude with temperature reaches a maximum and the observed Lamb-dip linewidth exhibits a minimum. We also present precise measurements of the magnetic-dipole ($A$) and electric-quadrupole ($B$) hyperfine constants of the $6P_{3/2}$ state for both isotopes, with the measured values being consistent with previously reported values for the hyperfine constants.

The prediction of crystal structures is a key challenge in chemistry and materials science, but evolutionary crystal structure prediction (CSP) remains computationally expensive because it relies on repeated ab initio relaxations and energy ranking. Machine learning interatomic potentials (MLIPs) can accelerate CSP, yet their use is limited by the need for large training sets and by the difficulty of choosing which candidate structures should be labeled by density functional theory (DFT). Here we introduce a self-consistent, foundation-model-assisted CSP workflow that combines evolutionary search with adaptive data selection and fine-tuning. Starting from a pretrained MLIP, the algorithm rapidly explores configuration space while iteratively selecting compact, representative, and physically relevant subsets of structures for DFT labeling, thereby reducing redundant calculations and improving a system-specific potential. We apply the method to the chemically complex Ca–Fe–Ni ternary system. The workflow reproduces the known low-pressure convex hull and enables efficient high-pressure exploration. It predicts a previously unreported compound, Ca$_6$FeNi, which becomes thermodynamically stable above 100~GPa. These results show that foundation-model-based, data-efficient CSP can greatly reduce computational cost while preserving accuracy and enabling the discovery of new materials in complex multicomponent systems.

Many measurements in physics determine a linear transformation from pairs of input and output vectors, where the transformation is known in advance to belong to a matrix Lie group, for example the Lorentz group for the four-momenta measured by two inertial observers, or the unitary group for the states produced by a quantum circuit. Among the classical groups, only the rotation and unitary groups have a well-known closed form solution, given by the Kabsch and Horn algorithms and by the polar decomposition. We extend our previously proposed Lie algebra method from the image of the matrix exponential to the entire Lie group. We derive the projection in closed form for the classical groups over the real and complex numbers, including the indefinite orthogonal and unitary, symplectic, spin, special Euclidean and similarity groups, and we give conditions under which the method is exact for noiseless data, with examples in which it fails otherwise and an extension by a data dependent involution which is exact on the whole group. For noisy data, we bound the error of the method to first order in the noise, and we show that, for the orthogonal and unitary groups, it agrees with the least squares solution over the group to first order when the input vectors are isotropic, but not otherwise. We apply the method to an eight-qubit quantum circuit and to the rigid registration of point clouds, and compare it with Gauss–Newton refinement and direct minimization. A Julia implementation is provided.

As part of the science book of SHARP, we present here the science case of star-disk interaction of low-mass (\Mstar$\leq$2\Msun) young stellar objects (YSOs), in low-metallicity (Z$<$ 0.2 \Zsun) star forming regions (SFRs) and supermassive star clusters, using the SHARP instrument mounted on the ESO-ELT. Extreme adaptive optics (AOs), with a spatial resolution a factor $\sim$3 better than JWST, as well as sensitive multiplexing capabilities, uniquely offered by SHARP, are essential to efficiently survey the whole area of low-Z SFRs and massive clusters in the outer Milky Way (MW) Galaxy and in the Magellanic Clouds (MCs). Using the SHARP exposure time calculator (ETC) we demonstrate that SHARP can achieve the required signal-to-noise, both for the continuum and emission lines, to investigate accretion and outflows in YSOs in distant (d$>$5\,kpc) SFRs, including those relatively embedded. SHARP will be able to observe very faint YSOs ($H\sim$\,24\,mag), allowing us extending studies to very low-mass YSOs in distant SFRs. The performance of SHARP in terms of sensitivity and spatial resolution in the NIR will provide significant insights into the evolution of protoplanetary disks in low-metallicity and massive environments: studies of accretion, jets/winds and photo-evaporation processes, down to the very low-mass ($\sim$0.2\,\Msun) regime in the MCs, and down to substellar YSOs in SFRs of the outer MW Galaxy (d\,$\lesssim$\,10\,kpc), will be possible. SHARP will also be able to observe jets/outflows in targets that are several magnitudes fainter than those reachable with current instruments, and will facilitate studies in low metallicity environments of wide binaries and multiple systems, with separations of $\sim$1600\,au, at a distance $\sim$50\,kpc scale, and of $\sim$150\,au, in regions of the outer MW Galaxy (d $\sim$10\,kpc).

We use numerical relativity to study the scalar field evolution sourced by hyperbolic encounters of black holes in quadratic scalar Gauss-Bonnet gravity. In this theory, single black holes are known to acquire a scalar hair through scalarization for certain values of their mass and spin. We work in the decoupling limit and evolve the scalar field on top of a background metric. Seeding binary black holes with an initial scalar field, we find that configurations which initially cannot sustain a scalar hair temporarily scalarize during an encounter and thereby exhibit dynamical scalarization. This is possible for both positive and negative couplings between the scalar field and curvature in black hole binaries with zero and non-zero initial spins, respectively. Furthermore, we find that the change in the spin magnitude of black holes during certain hyperbolic encounters can lead to permanent spin-induced scalarization (or descalarization), which we refer to as spin-up (de)scalarization.

A search for physics beyond the standard model using four and three top quark production events is reported. The analyzed proton-proton collision data were recorded at 13 TeV with the CMS detector at the CERN LHC in 2016$-$2018 and correspond to an integrated luminosity of 138 fb$^{-1}$. Events with two same-sign, three, or four leptons (electrons and/or muons) are selected. Constraints on six Wilson coefficients that modify interactions between four third-generation quarks or between top quarks and the Higgs boson in the standard model effective field theory framework are derived. The data are further used to exclude narrow topphilic heavy resonances in the mass ranges between 400 GeV and 1.6 TeV depending on their spin and color states. Finally, the top quark Yukawa coupling is extracted, considering both $CP$-even and $CP$-odd contributions.

Scanning transmission electron microscopy (STEM) is a cornerstone of our understanding of oxide interfaces and superlattices. No other technique provides the same level of insight into structure, chemistry, composition, and dynamics across as wide a variety of material systems. STEM imaging and diffraction, coupled with electron energy loss (EELS) and energy-dispersive X-ray (EDS) spectroscopies, offer unparalleled, high-resolution analysis of structure–property relationships. In this chapter we highlight investigations into key phenomena, including interfacial conductivity in oxide superlattices, charge screening effects in magnetoelectric heterostructures, interface engineering in iron oxides, and the complex physics governing atomic-scale chemical mapping. We also discuss emerging plasma preparation techniques and artificial intelligence-guided approaches to both ex situ and in situ microscopy. These studies illustrate how unique insights from STEM characterization can be integrated with other techniques and theory calculations to develop more predictive models for the behavior of functional oxides.

We investigate the formation of a barrier to evaporation that develops when levitated nanoscale Au nanoparticles are exposed to pulses of 532 nm laser radiation in a high vacuum (pressure $p=10^{-8}-10^{-7}$ Torr) environment. Our data are derived from precision measurements of the charge to mass ratio ($Q/M$) of $\sim$200 nm diameter Au particles confined in a quadrupole ion trap. We characterize the development of the barrier over time as the particle is repeatedly heated with laser pulses and determine the impact of variations of the interval between pulses and of exposure to several gases added to the vacuum chamber. We observe a slow increase in the mass of particles upon prolonged exposure to the vacuum, which we attribute to the growth of a barrier layer. For particles that have acquired a barrier during exposure to CO, we observe a rapid decrease in their mass upon subsequent exposure to O$_2$. These findings are consistent with the growth and subsequent oxidation of a graphene layer on the Au that forms the barrier to evaporation. However, we have not found that the rate of formation of the barrier depends on the pressure of carbon-containing gases (CO, C$_2$H$_4$, CO$_2$) we have added to the chamber. We hypothesize that a rare surface state on the solid Au particle catalyzes the reaction that introduces C to the particle. Repeated laser pulse heating is necessary–either to enable diffusion away from this state or to create fresh states that allow continued C uptake–to facilitate the growth of the surface graphene layer.

Recent community assessments identify education as a principal barrier to adopting modern machine learning in astronomy. We present Deep Learning for Astrophysics, a freely available textbook at https://deeplearning4astro.com, curated from the NASA Cosmic Origins Artificial Intelligence and Machine Learning Science and Technology Interest Group (AI/ML STIG) lecture series. The book collects 23 chapters by 17 lecturers across six parts, moving from computational foundations and deep-learning architectures through generative modeling, simulation-based inference, reinforcement learning, and large-language-model agents to the practice of AI-laden science. Many include executable notebooks using astronomical data.

This paper presents a curated selection of research questions at the intersection of quantum gravity and quantum information, chosen to highlight issues that we regard as particularly important for researchers in both fields. We organize the discussion into four main themes: the operational characterization of observables, the role of observers, quantum error correction, and the infinite-dimensionality of Hilbert spaces. We hope that addressing these questions will engage researchers across both communities and further strengthen the profound interplay between the two disciplines.

Magnonic systems, which exploit spin-wave excitations in magnetic materials, offer a promising platform for coherent information processing due to their low dissipation, strong nonlinearities, and intrinsic nonreciprocity. However, scaling magnonic circuits remains challenging, particularly with low-loss insulators such as yttrium iron garnet (YIG), which are difficult to pattern. Here, we experimentally realize a synthetic dimension in a magnonic system by coupling multimode magnon resonances in the frequency domain using time-periodic Floquet modulation. This approach enables electronically tunable interactions between discrete modes within a single YIG device, forming a reconfigurable mode-space lattice that supports functionalities such as Bloch oscillation. Our results demonstrate that high-dimensional magnonic dynamics can be achieved without increasing device footprint, establishing synthetic dimensions as a scalable and programmable route for integrated magnonic technologies. This advancement positions magnonic systems as promising platforms for engineering emergent phenomena that are inaccessible at equilibrium.

Massive early-type (B/A) stars and ultracool dwarfs (UCDs) represent two distinct regimes in which ordered, large-scale magnetospheres are observed. In rapidly rotating massive stars, incoherent radio emission is explained by the centrifugal breakout (CBO) mechanism: plasma confined within the rigidly rotating magnetosphere accumulates beyond the co-rotation radius, where centrifugal forces trigger breakout events and magnetic reconnection, generating non-thermal electrons that produce incoherent gyro-synchrotron emission. Empirically, the radio luminosity correlates with the power released by CBO events, establishing a clear link between stellar rotation, magnetic confinement, and radio output. In UCDs, persistent non-thermal radio emission exhibits similar luminosity trends to those of massive magnetic stars, despite the absence of strong stellar winds. This similarity suggests that a CBO-like process may also operate in these fully convective, low-mass objects, though the plasma source and acceleration mechanisms remain uncertain. In both classes, coherent electron cyclotron maser emission (ECME), characterized by strong polarization and rotational modulation, is observed, indicating common magnetospheric processes analogous to planetary auroral emission. The Square Kilometre Array (SKA) will be able to deeply observe about 70% of the sky. We expect to observe $\sim 1000$ UCDs, enabling better statistical analysis of their emission and a test of the CBO hypothesis.

We aim to characterize the post-collapse evolution of accretion-induced collapse (AIC) remnants of rapidly rotating, magnetized white dwarfs, focusing on their rotational, magnetic, and thermal structure, as well as the development of instabilities and their energy content. We perform nine axis-symmetric general-relativistic neutrino magnetohydrodynamic (MHD) simulations of collapsing, rapidly rotating, magnetized white dwarfs. The simulations follow the system from collapse through bounce and up to $\sim$1 s post-bounce. The simulations are performed by the conformally flat general relativistic neutrino MHD code Gmunu. The collapse produces a rapidly rotating proto-magnetar surrounded by a persistent accretion disk lasting at least $\sim 1$ s after bounce. The remnant mass and spin span 1.15–1.45 $M_{\odot}$ and 2.9–4.9 kHz, respectively, with stronger initial magnetic fields generally leading to lower rotation rates. During the first $\sim 10$ ms, the proto-magnetar exhibits global oscillations that drive both gravitational-wave emission and coherent modulation of the poloidal magnetic field energy. The magnetic energy evolution, normalized to its bounce value, follows an approximately universal behavior across all models. The remnant interior remains strongly magnetized ($\gtrsim 10^{13}$ G) and hot ($\gtrsim 20$ MeV) up to 1 s after bounce, with maxima of both quantities co-located in the inner $\sim 10$ km. The magnetic field topology shows surface poloidal fields of ${\sim}10^{12}$ G and toroidal fields of ${\sim}10^{14}$ G, with strong toroidal components extending into the equatorial region. When the magnetic energy exceeds the rotational energy ($\sim 10^{52}$ erg), the remnant core becomes unstable, leading to episodic magnetic flux expulsion, mass ejection, and flare-like activity in which magnetic energy is released and thermalized in the surrounding material.

Galaxy clusters are key probes of cosmology and structure formation, yet their dynamical classification traditionally relies on spectroscopic redshifts, which do not scale efficiently with survey size. As large photometric surveys such as LSST become available, photometric redshifts offer an attractive alternative, but their impact on velocity-based diagnostics remains poorly constrained. We quantify the sensitivity of two Gaussianity diagnostics - the Anderson-Darling (AD) test and Gaussian mixture modeling (Mclust) - to different photometric redshift error prescriptions. Propagating Gaussian and Student-t uncertainties through SDSS photometric velocity distributions, we assess how the error model affects recovery of cluster dynamical states established by the independent $\Gamma$ morphological proxy. Using 1672 SDSS clusters with pre-existing $\Gamma$, we perform Monte Carlo resampling under Gaussian and Student-t errors, the latter mimicking heavy-tailed uncertainties and catastrophic outliers, plus a spectroscopic control experiment with mock photometric redshifts from spectroscopic data. Under Gaussian errors, relaxed clusters are recovered in ~95% of realizations, while unrelaxed ones in only ~5%, revealing a strong bias toward relaxed classifications. Student-t errors drop relaxed recovery to ~60-70% and raise unrelaxed to ~30-45%, though still incomplete. Paired Wilcoxon tests confirm these differences are significant. This has direct implications for large photometric surveys: dynamical studies based primarily on photometric data may significantly underestimate disturbed cluster fractions without robust spectroscopic calibration, outlier mitigation, and validation with realistic mock catalogs.

We calculate the nucleon axial form factor in relativistic chiral perturbation theory with $\Delta(1232)$ up to next-to-next-to-leading order (NNLO). Relevant low-energy constants are determined by fitting to recent lattice-QCD results at several pion masses, while accounting for the uncertainty associated with the truncation of the chiral expansion. We obtain a good description of the lattice data for momentum transfers up to $\sqrt{Q^2}\simeq0.6$ GeV and pion masses up to $M_\pi\simeq400$ MeV. We find that the explicit inclusion of the $\Delta$ resonance is required to reproduce the lattice-QCD pion-mass dependence of the axial charge and axial radius, as well as the momentum dependence of the form factor. At the physical point we obtain $g_A=1.257\pm 0.011$ and $\langle r_A^2\rangle=0.312\pm0.037~\mathrm{fm}^2$. Our analysis provides a model-independent and systematically improvable parametrization of the pion-mass and momentum dependence of the axial form factor, offering a framework for extrapolating lattice-QCD results to the physical point and for improving predictions of low-energy weak interactions involving nucleons.

To better understand the role of AGN-driven outflows as a mechanism for heating or sweeping up gas over distances comparable to the size of the galaxy in its evolution, and to explore their physical characteristics as a function of AGN and host galaxy properties, it is necessary to have a statistical sample of AGNs selected from a uniform sample of galaxies with spectroscopic coverage of key restframe optical emission lines. To assess the impact of AGN-driven outflows on their host galaxies, we need to derive the mass and energy carried by the outflows, as well as correlations of these quantities with both AGN and host galaxy properties, in order to reveal their effects on the galaxy population and constrain the physical mechanisms driving the outflows. The availability of adaptive-optics-assisted 3D spectroscopy with the ELT multi-IFU instrument SHARP/VESPER enables the construction of spatially resolved outflow property maps, providing instantaneous outflow rates across the entire field of view without assuming outflow geometry, and thus significantly reducing the uncertainties compared to methods based on longslit spectroscopy. Furthermore, combining these maps with resolved star formation rate (SFR) maps allows a direct comparison between outflow properties and star-formation activity across the galaxy, providing key insights into how AGN feedback regulates star formation down to sub-kpc scales. By applying this approach to a representative sample of galaxies at cosmic noon ($1.5 < z < 2.5$), spanning a wide range of stellar masses from low-mass systems ($M_\star = 10^{8-10}\,M_\odot$) to the massive end ($M_\star > 10^{10}\,M_\odot$), we aim to systematically investigate the interplay between AGN activity, outflows, and star formation in the galaxy population as a whole.

We present a study of ionised hydrogen ($\textrm{H}\scriptstyle\mathrm{II}$) regions in the Galactic Plane using data from the SARAO MeerKAT Galactic Plane Survey (SMGPS). The SMPGS is a wide-field, wide-band 1.3 GHz radio continuum survey ($251^\circ \leq l \leq 358^\circ$ and $2^\circ \leq l \leq 61^\circ$ at $\quad |b| \leq 1^\circ.5$) that has enabled us to trace the diffuse emission enveloping recently formed massive stars. Our multifrequency synthesis images reveal faint and extended emission that was previously overlooked by $\textrm{H}\scriptstyle\mathrm{II}$ region surveys. We report the distances and Lyman-photon flux ($N_{\mathrm{Ly}}$) measurements for 1,327 Galactic $\textrm{H}\scriptstyle\mathrm{II}$ regions from which we characterise the spectral types for candidate ionising stars. The spectral types range from B2 to O4. The typical stellar spectral type responsible for ionisation is the B0, which constitutes about $\text{16%}$ of our catalogue, corresponding to a mean $\log(N_{\mathrm{Ly}}) = 47.5\ \mathrm{s}^{-1}$. Moreover, as a result of the lack of radio recombination line (RRL) velocity measurements for faint $\textrm{H}\scriptstyle\mathrm{II}$ regions, we identify the effective completeness limit at $\log(N_{\mathrm{Ly}}) \approx 47.6\ \mathrm{s}^{-1}$. The multiwavelength approach reveals that the physical radius at 1.3 GHz and in the mid-infrared are well correlated with a slope of $1.15 \pm 0.02$. We find clear power-law relations between $N_{\mathrm{Ly}}$ and physical radius, and an inverse correlation between electron density and radius ($n_{\rm e} \propto R^{-0.73}$). However, no significant correlation is observed between the $N_{\mathrm{Ly}}$ and Galactocentric distance, suggesting that the observed trends are governed primarily by local star-forming environments rather than large-scale Galactic gradients.

Wind shear and wind veer (gradients of wind speed and direction, respectively) are ubiquitous in the atmospheric boundary layer (ABL), and wind turbines therefore routinely operate in sheared and veered conditions. Previous field campaigns have observed statistically significant variations in power production efficiency (quantified by a power coefficient) upwards of 15% due to shear and veer. However, it is not yet clear how non-uniform inflow conditions alter rotor aerodynamics and drive these efficiency variations. In this study, we perform concurrent-precursor large-eddy simulations (LES) of an actuator disk-modeled wind turbine across stratified ABL conditions to demonstrate that shear and veer can reduce wind power efficiency by more than 20%. To support these ABL simulations, we perform simplified inflow LES where shear and veer are controlled independently. Using these controlled simulations, we demonstrate that shear and veer effects can be decomposed into: (1) geometric effects, due to changes in rotor-equivalent wind speed, and (2) inductive effects, which change the rotor aerodynamics and induced velocities. Inductive effects of wind shear modulate the power coefficient through changes to the local induction, while inductive effects of wind veer reduce the power coefficient by generating an adverse pressure gradient at the rotor scale. The geometric and inductive effects of shear and veer approximately linearly superimpose, with increasing losses as shear and veer magnitudes increase. Inductive effects account for a significant fraction of the observed losses, and the induction of a turbine is affected by shear, veer, and wall proximity through processes that are neglected in existing engineering models. Revealing the mechanisms through which shear and veer affect rotor performance establishes a framework that can enable improved power prediction in realistic ABL conditions.

This work presents a new numerical code for solving the time–dependent Gross–Pitaevskii–Poisson (GPP) system using adaptive mesh refinement (AMR). The code is designed to study the nonlinear dynamics of self–gravitating bosonic matter in three spatial dimensions under periodic boundary conditions. It combines high–order spatial discretization, explicit time integration, and dynamic refinement driven by the magnitude of the gravitational potential. The implementation is validated through a set of test problems in the nonlinear regime. These benchmarks demonstrate that the solver accurately preserves global conservation laws, resolves strong wave interference and phase singularities, and maintains consistency across refinement levels in highly dynamical scenarios.

When two initially entangled photons each undergo Compton scattering, the scattered electrons become correlated. However, the final reduced density matrix of one scattered pair is not influenced by the other scattered pair due to unitarity. Herein, we keep unitarity up to tree level for Compton double scattering and obtain different results than recent literature. The initial four particles, where the initial photons are entangled, are written as a superposition of two states with a relative phase. The final density matrix has two area divergences that are regularized with unitarity. The regularization procedure, i.e. solving for the roots of a polynomial that represents the probability for no scattering, suggests a novel definition of the scattering cross-section. Vieta's formulas relate these divergences to finite cross-sections. For an initial pure state, the formulas for the final density matrix and the correlation of final electronic polarizations are given. The correlation implies double scattering is analogous to Young's diffraction experiment. The two initial superposed states are the circular apertures while the Feynman amplitudes are the interfering complex light fields.

Bouncing cosmologies offer an alternative to the standard $\Lambda$CDM model by avoiding the problem of the initial cosmological singularity by construction. In these models, the universe undergoes a contraction phase that begins in a nearly flat and dilute state, followed by a bounce, after which the universe transitions into the expanding phase described by the $\Lambda$CDM model. During contraction, most large-scale structures are expected to be erased. Black holes, however, as shown by several previous investigations, may persist through the bounce. The goal of this work is to analyze the evolution of a black hole population throughout the contraction, bounce, and expansion phases. Additionally, we investigate how the presence of black holes influences the properties of the background cosmological fluid. To this end, we develop a cosmological model involving two interacting fluids. Our findings indicate that the cosmological fluid alters its properties in a spacetime with fixed geometry.

We classify AdS$_3$ solutions of the U(1) invariant sector of minimal $d=7$ supergravity. We find two classes of solutions preserving ${\cal N}=(2,0)$ supersymmetry for which the internal space M$_4$ is either a negative curvature Kahler-Einstein manifold or a circle fibration over $\Sigma\times \mathbb{R}$. For the later, in the case that $\Sigma$ has constant curvature, we reduce finding a solution to solving a single ODE that admits polynomial solutions. Among these are interesting solutions whose uplifts to $d=11$ describe M5 branes wrapping various $d=4$ orbifolds. These include a topological $\mathbb{CP}^2$ with 2 orbifold fixed points that we identify as the weighted projective space $\mathbb{WCP}^2_{[k,k,\ell]}$. We are also able to construct solutions with M5 branes that wrap a spindle fibred over constant curvature Riemann surfaces of arbitrary genus. Such solutions should provide holographic duals to the ${\cal N}=(2,0)$ SCFT associated to the M5 brane compactified to $d=2$ on these orbifolds. We match the holographic central charges of these solutions to a field theory computation in terms of anomaly polynomials and c-extremisation.

We derive the exact image-dipole potential of a point dipole inside a closed cuboidal superconducting trap. The construction generalises the parallel-plate result to a geometry that confines every translational degree of freedom, and we prove that the image lattice satisfies the Meissner boundary condition on all six walls. For a centred dipole the orientational energy reduces to a diagonal quadratic form whose three coefficients are Epstein-zeta-type lattice sums. We show that in both the infinite and finite rectangular traps the dipole orientation aligns with the short cross-sectional axis over a finite range of aspect ratios. The equilibrium orientation in both cases is described by a phase diagram whose degeneracies we classify. Every prediction is verified against finite-element solutions of the same boundary-value problem, with agreement better than $0.16\%$.