Papers

Entangled states of light lie at the heart of photonic quantum technologies, from distributed quantum communication to quantum-enhanced measurement and information processing. Their practical generation, however, remains constrained by the weak interactions between photons, which make the deterministic assembly of large multiphoton entangled states a central challenge in quantum optics. In this work, we use AI techniques to discover heralded linear-optical schemes for path-entangled states and show that the resulting solutions can be elevated from individual circuits to a new scalable family. This family contains previously known constructions as special cases while generally providing exponential and super-exponential improvements over those, and its extension to broader classes of target states shows how automated discovery can reveal transferable physical understanding. By presenting compact experimental proposals for large path-entangled states, our results provide both a theoretical advance in photonic heralding and a route towards a substantial leap in experimentally accessible multiphoton entanglement.

Inspired by matrix techniques in quantum field theory and string theory, we review Permutation Invariant Gaussian Matrix Models (PIGMM), which replace the continuous symmetries of traditional Random Matrix Theory, for $ N \times N$ matrices, with finite permutation symmetry, $S_N$. This symmetry-driven approach reduces highly multivariate $N^2$-variable matrix data analysis problems to a rich but tractable space of parameters. The representation theory of $S_N$ brings a highly correlated quadratic matrix action to a near-diagonal form with $13$ parameters. The invariant observables are parameterised by graphs and their expectation values are computed with Wick contractions implemented algorithmically. We review the successful application of PIGMM for data reduction and anomaly detection in computational linguistics, statistical finance and neural network weights. We conclude with a brief discussion of potential future applications to matrix data analysis tasks that exploit hadronization algorithms and the modular structure of collider-physics data.

Inhomogeneous systems have become increasingly relevant in experimentally engineered quantum many-body systems, where spatially varying interaction strengths can significantly influence nonequilibrium dynamics. Motivated by this, we numerically study the out-of-time-ordered correlators (OTOCs) in inhomogeneous XXZ spin chains. Using two types of spatially varying interaction profiles, namely, linear-gradient and stepwise profiles, we show that spatial inhomogeneity in the interactions can induce pronounced asymmetry in information scrambling, with OTOC operators located at different sites exhibiting distinct dynamical behavior. In particular, OTOCs associated with the strongly interacting side exhibit suppressed scrambling compared to those associated with the weakly interacting side, with the difference becoming more pronounced when the interaction strengths differ significantly. To elucidate the origin of the long-time saturation of OTOCs, we analyze the diagonal matrix elements of the OTOC observables in the energy eigenbasis and their overlap with the Hamiltonian, which explicitly incorporates the spatial interaction profile. The resulting analytical expression is consistent with the numerical results. Finally, we extend our analysis to periodically driven inhomogeneous spin chains and show that the interaction-gradient-induced asymmetry persists under periodic driving.

The gravitational baryogenesis is studied in regularized four dimensional Einstein Gauss Bonnet model with rainbow gravity corrections. This combined framework generates a non vanishing time derivative of the Ricci scalar even during radiation domination era. We derive analytical expressions for the baryon to entropy ratio in both the high curvature and perturbative regimes. The Gauss Bonnet contribution produces nonzero asymmetry precisely at radiation era, where the Einstein Hilbert contribution vanishes. Numerical analysis identifies viable parameter spaces reproducing the observed baryon to entropy ratio, compatible with observations.

Controlling chiral light-matter interactions with nanophotonics is a powerful strategy for amplifying molecular circular dichroism (CD) beyond its natural limits. Here, we present a plasmonic platform that uses superchiral near fields to amplify the optical activity of biological chromophores. Gold nanoparticles (3.6 nm in diameter) are electrostatically coupled with photosynthetic proteins which results in stable hybrid nanobioconjugates in aqueous solution. The Q-band absorption spectrum of the proteins overlaps with the localized surface plasmon resonance of the gold particles. In the visible region, a combination of numerical simulations and normalized CD measurements reveal an enhancement factor of 3 compared to free proteins. This observation reveals three effects. First, there is a local increase in electromagnetic chirality density in the protein environment. Second, there is an increase in the absorption of the proteins. Third, there is plasmon-induced circular dichroism. Our results quantitatively demonstrate that near-field super-chirality directly modulates biomolecular optical activity. These findings open new avenues for chiroptical nanodevices, biosensing platforms, and light-driven asymmetric photochemistry.

We derive all symmetry-allowed bond-current form factors generated by nearest-neighbor bond-charge interactions on square, triangular, and kagome lattices. We find that the anisotropy of the bond-current susceptibility systematically favors ordering wave vectors that support closed loop-current states, whereas symmetry-related wave vectors with weaker susceptibility generate noncirculating current textures. Near van Hove filling, this correspondence is robust across all lattice geometries considered, producing staggered flux phases on the square lattice, diamond-shaped current patterns on the triangular lattice and both chiral and nonchiral loop-current states on the kagome lattice. Our results establish a direct link between bond-current form factors, susceptibility anisotropy, and real-space current topology, providing a general framework for identifying loop-current orders and interpreting signatures of time-reversal symmetry breaking in correlated electron materials.

X-ray Thomson scattering (XRTS) is a key diagnostic for high-energy-density plasmas, which can exhibit significant quantum effects even at elevated temperatures. XRTS experiments are commonly interpreted using the Chihara decomposition, that was derived in the chemical picture and, thus, separates contributions from bound and free electrons. Despite being the de-facto standard for analysing measurements, a well-known shortcoming is that the standard bound-state treatment in the form of the impulse approximation fails to satisfy fundamental theoretical constraints, most notably the Bethe $f$-sum rule (BFSR). The problem arises due to the usage of plane waves in the impulse approximation as well as non-negligible contributions from bound-bound transitions. In this work, we present a minimal analytical extension of the Chihara decomposition of the dynamic structure factor for matter in the ground state, using hydrogenic bound-free and bound-bound transitions. We demonstrate that compliance with the BFSR is only achieved when both bound-bound transitions are explicitly included and an exact treatment of the bound-free contribution is applied. Finally, detector ray-tracing simulations for atomic hydrogen demonstrate experimentally detectable deviations from the standard Chihara model. The model will be made available in the open source XRTS library xDAVE [Bellenbaum et al., Phys. Plasmas (in print), arxiv:2604.27237].

Colloidal semiconductor quantum dots are promising materials for numerous applications due to their tunable emission and high quantum yields. However, emission instability in the form of luminescence blinking remains a significant obstacle to their practical implementation. While recent advances in synthesis and surface engineering have demonstrated partial or complete blinking suppression, the quantitative assessment of the "quality" of this suppression remains challenging. Existing criteria typically rely on threshold-based classification into ON and OFF states, which becomes inherently ambiguous owing to the continuous distribution of emission intensities in single quantum dots. Here, we propose a threshold-free two-dimensional quantitative criterion based on the variance of the recombination rate and the relative quantum yield, both of which can be extracted from standard time-correlated single-photon counting measurements. We validate the criterion using simulated blinking trajectories covering all major blinking mechanisms and demonstrate that it cleanly separates them into distinct regions of the two-dimensional parameter space while providing a quantitative measure of the degree of suppression. This approach directly quantifies the temporal stability of emission without requiring arbitrary state definitions, thereby providing a robust metric for comparing different blinking suppression strategies.

This study presents a CMOS-compatible, fully integrated three-dimensional island-bridge concept for flexible electronics on silicon planar technology. By embedding metal bridges within trenches in a polyimide-passivated island matrix, the approach localizes mechanical stress to the bridges whereby active components on the islands are protected from mechanical stress, enabling high-performance thin-film transistors (TFTs) on flexible substrates. A concave, arc-shape forming fill in trenches between the islands and backside etching yield freestanding 3D bridges. Numerical simulations to determine the minimum bending radius reveal a characteristic stress distribution in the bridges during bending, with peak stresses at the bridge-island transitions. Variation of trench depth modulates von Mises stress, identifying design parameters for reliability. Experimental validation demonstrates TFT operation under bending, with stable threshold voltage, subthreshold swing, and saturation mobility across a range of bending radii; broader bridges exhibit enhanced mechanical robustness. A 9x9 island-bridge matrix with addressable integration of TFTs across islands demonstrates the scalability of the concept. Overall, the results verify the manufacturability of stretch-free 3D metal bridges where the three-dimensional shape is defined by the topography of the concave trench filling, with integrated active devices, and confirm the mechanical and electrical functionality of the produced flexible substrates.

The X-ray afterglow of several long gamma-ray bursts (LGRBs) associated with broad line type Ib/c supernovae (SNe) exhibits a standard non-thermal afterglow, commonly attributed to synchrotron emission from a relativistic jet, and an evolving thermal component whose physical origin is still debated. We investigate whether these thermal and non-thermal components can be described within a common analytical framework and whether their temporal evolution can provide insight into the physical connection between relativistic jets and SN ejecta. We combine a phenomenological description of the synchrotron emission of the non-thermal energy associated with the relativistic jet with a diffusion model describing the thermal evolution of the jet-affected portion of the SN ejecta. The resulting coupled system is solved analytically, leading to closed-form expressions for both non-thermal and thermal luminosities. We apply the model to the following systems: GRB 060218A/SN 2006aj and GRB 171205A/SN 2017iuk. The proposed formalism reproduces the main features of both thermal and non-thermal light curves. In both systems, the thermal luminosity follows a temporal evolution similar to that of the non-thermal component up to the plateau phase. The inferred thermal energy stored in the jet-affected ejecta is found to be a fraction of the energy coupled to the observed non-thermal emission. The characteristic timescales obtained from the fits suggest a direct link between the evolution of the jet and the thermal response of the expanding ejecta. Although simplified, the proposed framework provides a unified analytical description of LGRB afterglows and their thermal counterparts and offers a useful tool for investigating the physical connection between relativistic jets and SNe Ib/c.

Epidemics on complex networks have been shown to exhibit dynamics that are strongly influenced by the topology of the network. However, it remains unclear how the topology of the network is influenced by epidemic properties, such as waning immunity and disease fatality, coupled with demographic changes. To explore the interplay between epidemic dynamics and network topology, we develop an agent-based model of a fatal infectious disease with an imperfect immunity on an initially scale-free network that evolves via demographic and epidemic-induced changes. We show that this model undergoes an epidemic transition between a phase in which the disease eventually dies out and a phase in which it becomes endemic. Moreover, the network may lose its scale-free property as a result of the epidemic spreading, giving rise to a topological transition from a power-law to a non-power-law degree distribution. We validate our findings using heterogeneous mean-field approximations of the agent-based model. These results highlight the importance of accounting for network evolution in epidemic models and advance our understanding of coevolving dynamical systems, in which disease dynamics and network topology continuously shape one another.

We investigate the thermodynamics of a photon gas within the Magueijo-Smolin formulation of doubly special relativity, a framework that augments the speed of light with an observer-independent energy scale of the order of the Planck energy. We derive the logarithmic grand partition function, and the complete set of thermodynamic quantities for the photon gas, including the Helmholtz free energy, internal energy, entropy, pressure, and heat capacity, and perform their numerical evaluation. Our results smoothly reduce to the conventional special relativistic expressions in the limit where the invariant energy scale tends to infinity. For temperatures approaching the Planck scale, the finite cutoff induces a systematic suppression of all thermodynamic functions relative to their standard special-relativistic counterparts.

The asymmetric expansion of magnetic bubble domains in ultrathin ferromagnets provides a powerful route to probe the interfacial Dzyaloshinskii-Moriya interaction (DMI). While conventional analyses rely on domain wall velocities measured along selected directions as a function of in-plane field, recent approaches have highlighted the additional insight contained in the angular dependence of the velocity, $v(\theta)$. Here, we develop an extended angular creep model that incorporates both the dispersive domain wall stiffness and a chirality-dependent prefactor associated with chiral damping. This generalization captures the full anisotropic dynamics of domain wall motion around a bubble domain. We show that these contributions significantly modify the angular velocity profile and can lead to features not accessible within existing models. Our results establish a more complete framework for interpreting creep-driven domain expansion and provide improved sensitivity for the quantitative extraction of DMI and chiral dynamical effects.

We explore the similarities and differences between the Gibbs phenomenon in partial Fourier representations of discontinuous signals and Friedel oscillations in the electron density of a solid near an anomaly. Inspired by the apparent similarities of the two phenomena, we perform a detailed exploration of both from the viewpoint of an engineer being introduced to a concept from solid-state physics. Focusing on the density of an one-dimensional electronic gas confined by a square potential, we show that, despite the similarities, Friedel oscillations cannot be attributed to the inability of a partial Fourier series to describe a discontinuity. Nevertheless, the two phenomena do exhibit similarities, which can be exploited to develop intuition. By adopting an educational style, we hope to establish some common language between electrical engineers and condensed-matter physicists, hoping that this can further inspire the two communities to seek intuition and further comprehension within neighbouring but different disciplines.

Resonant spin-precession experiments in storage rings are sensitive to two distinct axion and axion-like particle dark-matter couplings: an oscillating electric dipole moment (EDM) primarily driven by the axion-gluon interaction, and the axion-wind (derivative) coupling acting as an effective pseudomagnetic field on the spin. Both effects produce a vertical polarization buildup at the same resonance frequency and are therefore degenerate in this standard observable. It is shown that the two couplings enter the vertical build-up and the spin-precession phase walk as the difference and sum of their resonance strengths, respectively. Measuring both observables simultaneously at fixed energy in a multi-bunch configuration allows the individual coupling strengths to be extracted up to a two-fold sign ambiguity. As a complementary approach, the ratio of electric to magnetic bending fields in a combined storage ring can be varied while keeping the resonance frequency fixed. This leaves the axion-wind contribution unchanged while modifying the EDM contribution in a calculable way, enabling a clean separation of the two effects. Both approaches can be used in future storage-ring facilities dedicated to EDM measurements.

Nuclear magnetic moments are sensitive probes of nuclear structure. However, their accurate quantitative description poses significant challenges, demanding both accurate nuclear and electromagnetic interactions as well as rigorous control of algorithmic uncertainties. Here, we present the first systematic calculation of magnetic dipole moments for selected light nuclei and aluminum isotopes within nuclear lattice effective field theory (NLEFT), an ab initio framework applicable to medium-mass and heavy nuclei. Our calculations employ a lattice next-to-next-to-next-to-leading-order (N$^3$LO) chiral interaction together with electromagnetic currents consistently derived up to the two-body level. To achieve controlled predictions, we incorporate recently developed NLEFT algorithms and perform a comprehensive assessment of algorithmic uncertainties. Within the estimated uncertainties, our results are in good overall agreement with experiment and demonstrate that two-body currents are essential for reproducing the observed magnetic moments. We further benchmark our predictions against other ab initio calculations for light nuclei ($A\leq12$). Our work establishes a solid foundation for ab initio studies of electroweak observables using methods that scale efficiently to medium-mass and heavy nuclei while demonstrating state-of-the-art accuracy.

We develop a basis-resolved covariance framework for investigating the organization of low-energy many-body wavefunctions in the spin-$1/2$ Kitaev–Heisenberg model. By constructing covariance matrices from local-spin, bond-correlation, and plaquette-flux representations of the low-energy states, Principal Component Analysis (PCA) is employed to identify the dominant collective covariance modes. We find a systematic evolution of the covariance geometry across the phase diagram: magnetically ordered phases are described by an essentially one-dimensional covariance manifold, conventional magnetic phase boundaries exhibit competition between leading covariance modes, whereas the Kitaev regimes develop intrinsically multidimensional covariance geometry. Furthermore, the same many-body wavefunction produces distinct covariance geometries in different operator representations, demonstrating that covariance geometry is determined jointly by the quantum state and the physical observables used to probe it. Shannon entropy and the participation ratio provide quantitative measures of this evolution. The present framework establishes basis-resolved covariance geometry as a complementary statistical perspective for characterizing frustrated quantum many-body systems beyond conventional order parameters.

Resilience denotes the capacity of a system to withstand shocks and to recover from them. We distinguish between two different types of dynamics. The first allows for a separation between phases of normalcy and phases of rapid breakdown followed by slow recovery. The second applies to volatile organizations in which such phases are intertwined. Breakdown is often self-inflicted. Situation awareness is impaired by psychological mechanisms that lead to incorrect expectations regarding societal dynamics. Through positive feedback, the failure of a few elements is amplified into a failure cascade. However, positive feedback can also be harnessed to enable recovery. In volatile systems, resilience must be understood as an emergent property arising from the interaction of agents. This necessitates a data-driven approach to inform agent-based models, drawing on repositories, knowledge graphs, or tools from artificial intelligence. Such models help demonstrate that resilience represents a compromise between robustness and adaptivity. Maximizing performance frequently comes at the expense of resilience, and second-order solutions aimed at transforming the system prove more promising than attempts to reconstruct past conditions.

We propose a universal diffuse-interface modeling framework for surfactant transport in two-phase flows, applicable to all solubility scenarios and to any conservative phase field method. The foundation of our framework is a general three-scalar non-equilibrium model governing the surfactant concentrations in each bulk phase and at the interface, which builds on our prior consistent scalar transport framework and is locally and globally conservative, leakage-free, Galilean-invariant, and reduction-consistent. Assuming thermochemical equilibrium, we derive two one-scalar models: one for a surfactant in full equilibrium between both bulk phases and the interface, and one for a surfactant confined to a single bulk phase and the interface. All models are coupled to the Navier-Stokes equations through a surface tension force that incorporates the Marangoni stress arising from non-uniform interfacial surfactant distributions. While diffuse-interface surfactant models have been developed for the Cahn-Hilliard equation and, more recently, for the conservative Allen-Cahn (CAC) equation, existing models for CAC address only the insoluble and single-phase-soluble cases, leaving the general scenario of partial solubility in both bulk phases unaddressed; furthermore, these models lack Galilean invariance and reduction consistency, and are not applicable beyond the CAC setting. The framework is validated against analytical solutions in one-dimensional transport tests, assessed for convergence in two-dimensional advection-diffusion simulations, and demonstrated in fully-coupled drop-in-shear flow simulations covering insoluble, soluble, and partially-soluble surfactant scenarios.

Deformations of sandwich gravitational waves are considered. Squeezing a wave with pure displacement (DM) parameters to an impulsive wave, the DM property is lost, leaving us with the velocity effect (VM). For each fixed value of the deformation parameter $p$, DM can be restored by further increasing the amplitude which however diverge when $p\to\infty$, and no impulsive wave is obtained.

We report the experimental realization of minimal chimera states in a system of three uncoupled oscillators driven solely by frequency-modulated forcing. Unlike conventional scenarios where chimera states emerge due to interactions among oscillators, here the coexistence of coherent and incoherent dynamics arises entirely from a common external modulation of a system parameter. By tuning the modulation amplitude and frequency, the system exhibits transitions between global synchronization, global incoherence, and minimal chimera states. The stability of these regimes is quantified using the maximal Lyapunov exponent, while a synchronization order parameter is employed to characterize the degree of coherence. A systematic exploration of the parameter space reveals well-defined regions associated with distinct dynamical behaviors. To provide analytical understanding, we employ a phase-reduction approach and derive the corresponding phase dynamics, which elucidate the mechanisms underlying phase locking and desynchronization. The robustness of the proposed mechanism is further demonstrated in a time-delayed chaotic system. Finally, experimental results obtained from an electronic circuit realization confirm the emergence of minimal chimera states under frequency-modulated driving. These findings establish external modulation as a viable route to chimera formation without coupling, offering a new perspective on collective dynamics in driven nonlinear systems.

The problem of finding lower and upper bounds on multivariate homogeneous polynomials is both difficult and important given its applications to questions ranging from dynamical stability in complex potential landscapes to data analysis. From the standpoint of tensor eigenvalue theory, the question is equivalent to finding the smallest and the largest eigenvalues of the coefficient tensor corresponding to the given polynomial. Standard approaches outlined in the literature amount to running nonlinear iterations in search for the optimal rays along which the growth of the polynomial is fastest or slowest. Unlike the case of matrices (or their corresponding multivariate quadratic forms) convergence of such algorithms for higher-rank tensors is capricious due to the complex topography of polynomial objective functions. In this essay, a very different strategy, inspired by quantum-mechanical variational methods, is introduced for finding bounds on polynomials. The original polynomial is replaced by an operator acting in a suitably chosen (large) space of states, such that in an appropriate "classical" limit this operator approaches the original polynomial expression made of commutative variables. As a result, approximating the smallest and largest eigenvalues of the coefficient tensor, and thus finding bounds on polynomials, amounts to diagonalizing the resulting quantum operator, represented as a large matrix, and then inspecting the smallest and largest eigenvalues of this matrix. This approach is then successfully applied to standard test examples from tensor eigenvalue literature and other problems of interest in mathematical physics including Strichartz-type inequalities.

In this work we propose a local geometric wetting boundary condition for a conservative Allen–Cahn-based lattice Boltzmann framework. The prescribed contact angle is imposed through ghost phase-field values constructed from a locally reconstructed wall normal and a donor-fluid extrapolation. The ghost-node wetting update is local, geometrically consistent, and compatible with thread-safe large-scale implementations, while phase-field mass is controlled through a separate global volume correction. Validation includes static contact-angle tests, short-time droplet spreading, impact on a hydrophobic surface, and gravity-driven motion through a sharp-edged orifice. The simulations recover the imposed equilibrium angles, reproduce contact-angle-dependent spreading exponents between approximately 1/2 and 1/4, and follow the classical W e1/4 maximum-deformation scaling. The model also captures the transition between capture, release, and release with breakup. The proposed approach provides an accurate and scalable framework for wetting-controlled flows in complex geometries.

Objective: To evaluate retroOpt, a novel organ-level tube current modulation (TCM) method that minimizes effective radiation dose while preserving diagnostic image quality for liver metastasis detection. Methods: In this retrospective, IRB-approved study, 22 patients with 68 liver lesions (38 malignant, 30 benign) underwent portal venous phase contrast-enhanced chest-abdomen-pelvis CT. Using projection-domain noise emulation, five series were generated per patient: original full dose (Orig-100), uniform dose reduction to 40% (UD-40) and 60% (UD-60) of the original effective dose, and organ-level TCM at the same levels (Opt-40, Opt-60). Three abdominal radiologists independently detected and classified lesions and rated image quality (5-point Likert). Per-lesion sensitivity was compared by McNemar test. Malignant lesion-size thresholds for 50% and 90% sensitivity (x50, x90) were estimated by logistic regression. Image quality was compared by Wilcoxon signed-rank test. Results: At the 60% level, Opt-60 achieved mean malignant lesion sensitivity comparable to full-dose CT (82% vs 80%) and exceeded uniform reduction (67%). At the 40% level, Opt-40 improved mean sensitivity over UD-40 from 52% to 68%. Mean all-lesion sensitivity rose from 54% (UD-40) to 64% (Opt-40) and from 65% (UD-60) to 77% (Opt-60), remaining comparable to full dose (76%). All optimized-versus-uniform differences were significant (p <= 0.003). Opt-60 lesion-size thresholds closely matched Orig-100 (x50 3.3 vs 3.7 mm; x90 15.7 vs 16.8 mm). Median Opt-60 image quality ranged from 3 to 4.5 across readers. Conclusions: Organ-level TCM preserved liver metastasis detection at 60% of the original effective dose, outperforming uniform dose reduction. Task-specific organ-level dose optimization may enable greater CT dose reduction than uniform strategies for patients requiring repeated metastasis surveillance.

We record the Calabi-Yau version of Kontsevich's formality morphism from deformation quantization. As a special case we find that any unimodular holomorphic Poisson Calabi-Yau has a canonical closed deformation quantization of its resolved algebra of functions. A broader motivation is to find an explanation of Kontsevich's deformation quantization in the setting of Calabi-Yau categories via Sen-Zwiebach's string vertices.

Driven by contributions from academia, industry, and open-source communities, the quantum software ecosystem is rapidly growing. Across this ecosystem, new concepts often emerge through software artefacts accompanying scientific publications as well as through sustained development in larger communities. However, many repositories receive development efforts only over a limited period of time, raising the question whether their concepts persist beyond individual repositories. In this paper, we apply established empirical software engineering techniques to analyse a set of foundational quantum software repositories. We combine cross-repository activity with contributor relationships to study the evolution of communities. Our analysis provides empirical evidence of contributor migration patterns and indications of cross-project knowledge transfer. We observe multiple development paths: projects may evolve into sustained communities, contributors may integrate concepts into established ecosystems, or activity may continue through new and follow-up software artefacts. Our observations provide an initial empirical perspective on how concepts and influence persist across repository boundaries in quantum software ecosystems.

In the early universe, neutrinos undergo many interactions with the particles in the plasma. Key processes are the scattering of neutrinos by free electrons and positrons. In this paper, we derive general expressions for the electron neutrino-electron scattering kernel in isotropic media, analytically simplifying the 5D collision integral to two dimensions. We follow a procedure that is similar to the derivation of the Compton scattering kernel to reduce the angular integrals, yielding a compact analytic expression in terms of elementary functions that can be easily evaluated. We illustrate the properties of this kernel and also compute its first moments analytically, providing insights into the energetics of the redistribution process. For comparison, we consider the photon-electron scattering kernel, highlighting differences and similarities. We then explain how the obtained expressions can also be applied to the $\nu_{\mu/\tau}$-electron and neutrino-positron scattering processes. The results presented here may be useful in the context of Big Bang Nucleosynthesis and were added as an extension to the Compton scattering library CSpack for more general applications.

We challenge the widespread consensus that mean-field theory fails to describe long-range open quantum systems in the presence of symmetry breaking and/or when starting from strongly correlated states (e.g., macroscopic superpositions). While recent literature relies on cumulant expansions to capture such systems, this approach rests on truncations with no clear justification. Here, we show that it is, at best, conceptually redundant in the strong long-range regime. We show that the evolution can be decomposed into, and fully reconstructed from, independent mean-field dynamics. This decomposition generates the entire hierarchy of cumulants and, as a byproduct, identifies—to our knowledge, for the first time—a regime in which cumulant expansions exactly predict low-order cumulants. We illustrate the power of our findings with two applications: we compute the moment generating function for nonequilibrium $\mathcal{Z}_2$ symmetry breaking, and construct states restoring time-translation symmetry in time crystals. In both cases, our method fully reproduces the exact many-body dynamics, which is out of reach of cumulant expansions. Our results reclaim the exactness of mean-field theory, offering a transparent framework for large-scale open quantum systems.

Air entrainment often plays a crucial role in determining impact loads exerted by free-surface wave flows interacting with structures, yet its modelling is often oversimplified in numerical approaches. In this study a two-phase numerical model, based on the Lattice Boltzmann Method coupled to a conservative Allen–Cahn interface-capturing equation is employed to perform direct numerical simulations of dam-break waves propagating over a dry bed and impacting on vertical walls. Access to high-resolution simulations enables a detailed assessment of how accurately resolving both air–water and solid–water interfaces affects local and overall dynamics, as well as quantities of extreme engineering interest. Indeed, the magnitudes and locations of the pressure peaks are strongly affected by wave front deflection and local aeration induced by a small corner vortex. Additionally, comparisons between no-slip and free-slip implementations suggest that the large air cavity formation, commonly observed as trapped inside the reflected jet falling back onto the incoming flow, may be the result of modeling assumptions rather than intrinsic flow physics, again highlighting the key role of near-wall shear in jet breakup dynamics.

Coastal Louisiana is sinking, amplifying flooding and land loss, yet the seasonal component of this motion remains difficult to attribute. Satellite geodetic records from Baton Rouge spanning 2004-2024 reveal long-term subsidence of -2.69 +/- 0.69 mm/yr, with a superimposed annual oscillation of 10-15 mm that is in phase with river stage and confined-aquifer hydraulic head. This positive correlation is diagnostic of poroelastic deformation rather than surface loading. A poroelastic model of a semi-confined aquifer driven by hydraulic-head variations reproduces both the long-term and seasonal signals. The seasonal amplitude decreases logarithmically with distance from the intersection of the Baton Rouge Fault and the Mississippi River, as expected for radial pressure diffusion from a flux source. Fault-river intersections therefore act as seasonal conduits into deep aquifers, representing an underappreciated control on coastal land motion that is likely to strengthen as hydrological extremes intensify.