Papers

Pipe and channel flows of viscoelastic fluids display chaotic dynamics at unusually low speeds, a phenomenon referred to as elasto-inertial turbulence, EIT. First reported in experiments a century ago, recent theoretical studies and model computations predict a variety of scenarios for the phenomenon's origin, ranging from hoop stress modes to center modes and to Tollmien-Schlichting waves. Lacking experimental confirmation, the relevant scenario in actual flows of polymer solutions remains unknown. We here determine the transition threshold of EIT in pipe experiments, covering three decades in elasticity number. Across this entire parameter range, the transition features center mode structures at onset. Eventually the instability diverges at a lower inertia (upper elasticity) limit, which is a robust signature of this center mode scenario. Finally, we report the first experimental observation of a traveling wave in viscoelastic pipe flow, and the sequences of localized structures found, are in excellent agreement with a center mode traveling wave, the "arrowhead" solution, discovered in model simulations.

The random-cluster model with cluster parameter \(0<q<1\) is conjectured to exhibit negative dependence, but even pairwise negative correlation between distinct edges remains open on general finite graphs. We first establish a reduction showing that the pairwise conjecture is equivalent to its restriction to regular graph sequences of diverging degrees $(d_n)$, even for edge pairs at distance \(o(d_n/\log d_n)\). We then prove strict pairwise negative correlation for a broad class of high-degree regular graph sequences satisfying a two-scale edge-isoperimetric condition. More precisely, for every fixed \(p\in(0,1)\), all sufficiently large graphs in the sequence have strictly negative covariance between any two distinct edge indicators at distance \(o(d_n/\log d_n)\), uniformly in \(q\in[0,1)\) and in the choice of the two edges. In particular, the result includes the \(q=0\) endpoint, corresponding to Bernoulli bond percolation conditioned to be connected. The isoperimetric hypothesis is satisfied by high-degree expander families and, with probability tending to one, by uniformly random regular graphs of diverging degree; its two-scale form also allows product geometries such as hypercubes and fixed-side high-dimensional discrete tori. The proof is based on a polymer representation and cluster expansion, together with a geometric identification of the leading contribution to the two-edge correlation.

For non-Hermitian Hamiltonians, gain, loss, and non-reciprocity produce complex eigenvalues which, in turn, facilitate different kinds of topological phases. One example is the imaginary line-gap phase, where eigenvalues cannot lie on the real line. This notion was recently shown to explain the robust temporal localisation of waves in photonic quantum walks and time-varying metamaterials. In these systems, waves localise around a time interface between topologically inequivalent mediums. At the core of this phenomenon is a $\mathcal{PT}$-symmetric two-mode model, where the non-trivial topology arises due to the $\mathbb{Z}_2$ classification of the AI symmetry class. In this work, we study two-mode models in all non-Hermitian symmetry classes. We find that robust temporal localisation generically follows as a physical consequence of imaginary line-gap topology according to a simple diagnostic: at least one of time-reversal symmetry ($\mathcal{T}^{\hspace{0.05em}2} = 1$) and particle-hole symmetry ($\mathcal{C}^2 = 1$) must be present. Our results provide a comprehensive symmetry-based guide to the observation of the topologically protected temporal localisation of waves.

Linear response is cheap to measure; the bistability boundaries it organizes are not. For a passive network with one localized cubic, the driving-point receptance $G$ fixes the period-one cusp set at fundamental-harmonic order: cusps lie on a fixed phase contour of $G$, a tangency of that contour under parameter variation creates a pair, and its curvature separates a gap opening from an isolated loop. For a two-mode absorber the linear prediction locates a benchmark birth coupling to $0.3\%$, and to $0.03\%$ once a third-harmonic correction of scale $|G(3\Omega)/G(\Omega)|$ is included.

All-solid-state batteries (ASSBs) promise high energy density and enhanced safety, but their development is hindered by instability and incompatibility at solid-solid interfaces. In Li-metal ASSBs, lithium penetration occurs despite stiff ceramic electrolytes via grain boundaries, often initiated by minor Li/SE interfacial irregularities. Here we introduce a two-dimensional continuum model with electro-chemo-mechanical coupling to investigate interfacial current distribution in Li ASSBs with surface-roughened argyrodite electrolyte under stack pressures and applied current density. Our theoretical analysis and simulation studies highlight the critical role of mechanical stress in interfacial current distribution. We find that prominent stress variations around elongated surface protrusions are the key to nonuniform Li deposition, without which Li deposition becomes uniform even on a rough surface. Moreover, our parametric study elucidates that stress effects dominate the overpotential and current distribution under low interfacial current density to exchange current density ratios, otherwise the high interfacial resistance due to surface-roughness-induced interfacial area becomes dominant. With these insights, we also discuss the potential of engineering artificial interlayers to modulate interfacial current distributions, offering guidance for improving the long-term performance and reliability of ASSBs.

According to the Belinski-Khalatnikov-Lifshitz (BKL) conjecture the dynamics of general relativity near singularities is highly chaotic. However, since general relativity breaks down at singularities, it is generally expected that a more fundamental theory, such as quantum gravity, is needed to describe the spacetime dynamics in regions with large spacetime curvature. In the absence of a widely accepted theory of quantum gravity, it remains unclear how exactly quantum effects may modify the classical evolution. Taking a conservative point of view, in this paper we study the classical dynamics of a gravitational collapse, starting from a strong-field (though classical) scenario up to the Planck scale to quantify how much chaos is generated during the time the Einstein equations can be trusted. Specifically, we use the Shannon entropy and Kullback-Leibler divergence, as well as Fourier analysis, to find that, when the Planck scale is reached, the chaotic features of the model remain relatively underdeveloped. This suggests that, at least during the classical regime, chaos is not strong enough to erase all information about the initial state of the universe, or about a previous classical universe in the context of bouncing cosmologies. In addition, we also characterize the final invariant phase-space distribution for the chaotic Bianchi IX dynamics in general relativity, which provides a novel description of its invariant repeller.

In this work, we study finite-time effects in ultracold atomic systems by considering time-dependent modulations with variable waveforms and durations. These two characteristics can be controlled by adjusting only a single parameter. For arbitrarily short pulses, our model recovers the paradigmatic kicked rotor while maintaining the impulse transmitted per period and unit amplitude constant. Furthermore, we demonstrate that finite-time effects have a profound impact on dynamical localization, a result that cannot be captured by the {\delta}-kicked-rotor model. Through a detailed analysis of the effects of different modulation amplitudes, periods, and waveforms, we identify the conditions for which dynamical localization is significantly enhanced. We show that the strength of dynamical localization increases sharply as the system approaches the {\delta}-kicked-rotor limiting case. Moreover, we establish the existence of an optimal value of the period that maximizes dynamical localization for given values of the amplitude and shape parameter.

We prove that the system of Favre-filtered compressible Navier–Stokes equations with subgrid-scale closure terms, written in the coordinates $(Lt,Lx_1,Lx_2,Lx_3)$ for an arbitrary parameter $L>0$, is obtained from the system written in standard coordinates $(t,x_1,x_2,x_3)$ by the action of a smooth diffeomorphism of the underlying spacetime manifold. The proof begins with a self-contained treatment of infinite-dimensional manifolds and the Fréchet manifold of smooth field configurations. We then define the one-parameter dilation group $\{\phi_L\}_{L>0}$, verify that each $\phi_L$ is a diffeomorphism, and compute its tangent and cotangent actions. The induced pullback action on sections of the configuration bundle is shown to commute with the total derivative operator, which implies that the first-jet prolongation of $\phi_L$ maps the equation submanifold of the system onto itself. Equation-by-equation verification—continuity, momentum, and energy—confirms that every residual is multiplied by the common nonzero factor $L^{-1}$ (or, equivalently, is identically zero in the transformed coordinates), so that the solution set is preserved. We conclude that the family of systems parameterised by $L>0$ satisfies the diffeomorphism transformation expression and that solution spaces are canonically isomorphic for all $L$.

The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) introduces increased demands on the ATLAS Muon Spectrometer, particularly in terms of data throughput, timing distribution and system reliability. The Phase-II Chamber Service Module (CSM) is a key component of the upgraded Monitored Drift Tube (MDT) trigger and readout system, providing a high-speed interface between the front-end electronics and the backend systems. This paper describes the design and implementation of the Phase-II CSM, together with its validation. The results show that the CSM supports two independent optical uplinks, each operating at a line rate of 10.24 Gbps, together with clock distribution and slow control in the expected operating environment. Integration with small-diameter MDT (sMDT) chambers and tests with the prototype L0MDT trigger system are also presented. The CSM boards are now in production and will be used for installation and integration during the upcoming LHC Long Shutdown.

In a fusion device plasma-wall interactions \edit{on the sheath scale} can be modeled as a collisionless problem. When modeling these regions particle-in-cell codes suffer from statistical error originating from undersampling the velocity space. On the other hand, Vlasov codes do not have this issue as they evolve the full distribution function. Here, we present a new finite-volume Vlasov code, kobra, equipped with adaptive-mesh refinement to reduce computational effort. Currently, the code solves the Vlasov-Poisson equations. We validate our code in 1d1v and 1d2v using established benchmarks, i.e. the two-stream instability, Landau damping, the Dory-Guest-Harris instability, and also a classical electrostatic plasma sheath. We find that the code reproduces the theoretical properties of these problems well. More importantly, the adaptive grid provides a computational gain that is likely to scale to higher dimensional, plasma-wall simulations.

The scatter in elemental abundances among stars of similar age and metallicity reflects chemical inhomogeneity in their birth environments, making abundance scatter a key observable for chemical-tagging studies of Galactic formation and evolution. Using a large sample of subgiant stars with precise ages and elemental abundances derived from LAMOST low-resolution spectra, we investigate the intrinsic chemical abundance scatter of the low-$\alpha$ thin disk near the solar neighborhood ($7 < R < 10$ kpc). We model the abundance ratio [X/Fe], for each of the 19 elements of concern, as a function of age, [Fe/H], and [Mg/Fe], and deduce the intrinsic dispersions with a forward modelling technique. Our results confirm previous findings that the intrinsic scatters are small, typically $\lesssim0.05$~dex, for light elements (C, Al), $\alpha$-elements (O, Mg, Si, Ca, Ti), and iron-peak elements (Mn, Ni). A dedicated analysis of M67 yields similarly small scatter values for these elements, implying limited discriminatory power from light-element abundances alone. In contrast, neutron-capture elements exhibit substantially larger scatters, typically $\gtrsim$0.1 dex, which are significantly larger than those of M67 member stars ($\sim$0.07~dex). In particular, our analysis suggests that the abundance variations of individual neutron-capture elements cannot be explained by a single tracer such as [Ba/Fe]. These findings clarify the utility of neutron-capture elements for chemical tagging and highlight the potential of low-resolution spectroscopy in such studies.

Using in-situ observations from Solar Orbiter, STEREO-A, and Wind, we investigate the heliospheric evolution of an interplanetary coronal mass ejection (ICME). The magnetic ejecta (ME) shows a magnetic-cloud-like (MCL) configuration: a front region in which the magnetic field rotates and its magnitude declines, followed by a weakly rotating "back region" of nearly constant field magnitude. Near-Sun EUV and white-light observations reveal two fast CMEs launched in rapid succession and interacting at low coronal heights, providing direct evidence that an MCL ejecta can arise from interaction between two closely spaced CMEs sampled near their apex. Using near-radially aligned Solar Orbiter and STEREO-A observations, we find that the sheath expands more rapidly than the ME, consistent with the "snow-plow" effect, while the ME properties broadly follow trends reported in previous ICME studies. Comparison of STEREO-A and Wind observations, separated by only 9.2 degrees in longitude, reveals measurable mesoscale variability within both the sheath and the ME. We identify dual polytropic behavior within both substructures, consistent with the merging of two interacting CMEs to form the observed MCL ejecta. This dual behavior in the ME is most pronounced in the inner heliosphere and weakens with heliocentric distance, indicating thermodynamic homogenization during radial expansion, whereas the sheath maintains thermodynamic contrasts from the inner heliosphere to 1 au. Our findings suggest that polytropic diagnostics can help reveal thermodynamically distinct plasma populations associated with interacting CMEs, providing additional evidence for CME-CME interaction in MCL ejecta where conventional in-situ signatures show no clear evidence of such interactions.

Ferroelectric switching is among the most fundamental and widely studied symmetry-breaking processes in physics. However, the Landauer paradox asserts that an ideal single-domain ferroelectric should be kinetically unswitchable, because a three-dimensional reversed nucleus would carry a prohibitive depolarization penalty, leading to unphysically large coercive field (the electric field required to switch the polarization). Here we show that this long-standing paradox is resolved by topology. In defect-free PbTiO3, large-scale molecular dynamics simulations reveal that the intrinsic critical nucleus is a three-dimensional polar skyrmion. Its continuous polarization rotation and Néel-type boundary walls self-compensate bound charge, suppressing the depolarization energy by orders of magnitude and bringing the predicted coercive field into agreement with experiment. This topological nucleus further overturns the 60-year-old Janovec-Kay-Dunn law. We derive an analytical thickness-dependent coercive-field law governed by field-induced softening of the parent ferroelectric state and controlled by a single material descriptor. This framework captures diverse experimental trends across ferroelectric families and recasts the Kay-Dunn exponent of -2/3 as an effective finite-window behavior. These results establish polar topology as an organizing principle for intrinsic switching and suggest that hidden topological transition states may broadly shape nonequilibrium phase transformations traditionally understood as Landau-type symmetry breaking.

Two-dimensional type-IV collinear magnets combine nonrelativistic spin degeneracy with spin-orbit-coupling-enabled magnetic responses. Here we establish a one-dimensional counterpart through altermagnetic confinement. A Lieb-based construction connects three-dimensional altermagnets to two-dimensional type-IV magnets and extends the same principle to one-dimensional ribbons. In a symmetric $[110]$ ribbon, a sublattice-exchange operation preserves the longitudinal momentum and enforces nonrelativistic spin degeneracy. {Spin-orbit coupling (SOC) ties spin to the lattice, so the Néel orientation determines whether the remaining symmetries protect the doublets or allow them to split.} First-principles-derived Wannier calculations for Ta$_2$TeSeO ribbons reveal spin-polarized propagating channels with an ideal right-moving-mode polarization of approximately $35\%$ at finite conductance for the parent easy-axis orientation $\mathbf N\parallel[100]$. Direct DFT calculations of Ta$_2$Te$_2$O ribbons resolve the contrast between spin-split $[100]$ and spin-degenerate $[001]$ SOC spectra. Assembling the same isolated Ta$_2$Te$_2$O ribbons into a transversely periodic array restores spin splitting without SOC. This conversion parallels the recovery of three-dimensional altermagnetism through suitable periodic stacking of two-dimensional type-IV magnets. One-dimensional type-IV magnetism thus provides a route to spin splitting through the interplay of antiferromagnetic order and SOC, distinct from conventional Rashba splitting driven by structural inversion asymmetry.

Cryogenic buffer-gas cells are widely used to produce cold molecular beams, but the microscopic dynamics governing beam formation remain challenging to model. Here we present fully kinetic simulations of a cryogenic buffer-gas cell using the Direct Simulation Monte Carlo method implemented in the PICLas framework, treating the buffer gas and ablated molecules within a single unified model. We capture characteristic features of cryogenic buffer-gas sources, including plume cooling, directed transport toward the aperture, and the formation of a slow molecular beam, while also resolving energy transfer from the hot ablation plume to the helium buffer gas that is inaccessible to existing approaches relying on the background-gas approximation. Our results demonstrate that fully kinetic simulations can provide detailed insights into buffer-gas cell dynamics and open a route toward a systematic optimization of such sources.

The no-cloning theorem, the no-deleting theorem, and other no-go theorems play a crucial role in quantum mechanics and quantum information. In this paper, we show that it is impossible to conjugate or reflect an unknown quantum state or conjugate or reflect the bit-flip (the phase-flip) of an unknown state via a universally unitary evolution. We also indicate that the partial conjugating operations are not anti-unitary and it is impossible to universally partially conjugate an unknown state via a unitary evolution. We compute the fidelities of the optimal physical approximations to conjugating and conjugating the bit-flip and phase-flip operations.

Magnetic reconnection in the solar atmosphere drives energetic phenomena such as Ellerman bombs, UV bursts, and surges. We used coordinated observations from the Swedish 1-m Solar Telescope (SST), IRIS, SDO, and the Hinode/X-ray Telescope (XRT) to analyze an active region with strong magnetic flux emergence. This region displayed long duration UV burst activity, occurrence of multiple Ellerman bombs, and recurrent ejection of surges. Chromospheric imaging show sthe presence of a dome-like structure that overarched the region where magnetic flux was emerging. The curved chromospheric fibrils were closely associated with bright and similarly curved extensions from a UV burst in the IRIS 1400 A channel. We observed an episode of formation of a bright sheet along the curved fibrils in H-beta that subsequently fragmented into plasmoid-like blobs with peak emission at a Doppler offset of +43 km/s. IRIS Si IV lines in the same region show complex and non-Gaussian line profiles that display asymmetric extensions to high Doppler offsets. Some profiles have clear components with Doppler offsets in excess of 150 km/s on both sides of the nominal line center. The optically thin SDO/AIA channels, including 94 A, show intermittent and repeated occurrences of the burst. Emission measure and filter ratio analysis indicate that the burst is multi-thermal and can attain temperatures beyond 1 MK. AIA and Hinode/XRT observations reveal a localized EUV and soft-X-ray counterpart of the burst/dome system, supporting the presence of intrinsically multithermal plasma that reaches coronal, and likely multi-MK, temperatures.

The observation of a near-side enhancement in long-range correlations within high-multiplicity pA and pp collisions, commonly referred to as the ridge, has motivated significant efforts to quantify possible collective effects in small systems. Estimation of non-flow contributions in two-particle correlation measurements in small systems at the LHC typically relies on the assumption that jet-induced non-flow correlations are independent of event multiplicity. Consequently, this assumption allows the high-multiplicity non-flow to be estimated and accounted for by directly using low-multiplicity events. In this paper, the validity of this assumption is studied examining the multiplicity dependence of non-flow contributions estimated via two-particle correlation functions in pp collisions at RHIC energies $\sqrt{s} = 200$~GeV using the PYTHIA event generator. It is observed that selecting any specific multiplicity range inherently biases jet production dynamics. These biases introduce a non-trivial multiplicity dependence of the non-flow contribution at RHIC energies. The dependence of jet fragmentation and $p_{\text{T}}$-differential cross sections on event multiplicity is studied using a variety of commonly used multiplicity estimators, including mid-rapidity charged-particle multiplicity, forward multiplicity, and underlying-event activity. The results indicate that non-flow contributions do not exhibit simple multiplicity scaling and challenge the applicability of standard subtraction procedures utilized at LHC energies at lower RHIC collision energies.

We construct and study possible astrophysical signatures of the rotating counterparts of two charged regular black holes, namely the Ayón–Beato–García (ABG) and Balart–Panotopoulos–Rincón (BPR) spacetimes – obtained using the Newman-Janis algorithm. After verifying the regularity of the rotating metrics, we study massless scalar perturbations, compute the quasinormal mode (QNM) spectra, and characterise their dependence on the spin and charge parameters. Grey-body factors (GBFs) are computed, and the QNM-GBF correspondence is verified. The low-frequency superradiant amplification factor is also examined via matched asymptotic expansions. The Lyapunov exponents are used to connect the eikonal QNM damping rate to photon-orbit instability. Additionally, from shadow profiles, we constrain the parameter space of rotating regular black holes using the Event Horizon Telescope (EHT) observations. Across all the probes, we find that the rotating BPR and Kerr–Newman black holes behave almost indistinguishably from one another, while the rotating ABG geometry exhibits distinct perturbative, scattering, and geometric properties, particularly at larger values of spin and charge. Our analysis indicates that differentiating between charged rotating regular black hole models may be possible using gravitational wave and shadow observations.

Quantum game theory investigates the influence of quantum resources on strategic decision-making. In this work, two-player quantum games based on the Transverse Field Ising Model(TFIM) are investigated under amplitude-damping decoherence. The TFIM Hamiltonian naturally produces a family of entangling gates, enabling a physically motivated implementation of quantum games. The effects of noise on Nash equilibria, players' payoffs, concurrence and coherence of the quantum states for different initial states and strategy pairs are analyzed. The results show that decoherence progressively suppresses quantum strategic advantages, with maximum damping driving all outcomes to identical classical payoffs. The concurrence and coherence analysis of the states generated in the quantum game reveal initial state and strategy dependent quantum correlation dynamics, including entanglement sudden birth and death.

Spin qubits in gate-defined quantum dots provide a highly programmable platform for simulating condensed-matter phenomena. In this work, we introduce a digital-analog quantum simulation protocol for extracting the single-particle spectrum of a Kitaev chain. The Kitaev chain is mapped onto qubits via the standard Jordan-Wigner transformation and implemented as a drive-engineered, $N$-site transverse-field Ising model (TFIM) in a linear array of quantum dots. We show that periodically toggling the analog-simulation parameters conditioned on the state of a control qubit causes the dynamics of this control qubit to stroboscopically match the output of the one-clean-qubit (DQC1) model of computation, thereby yielding the full spectrum of the TFIM from measurements of a single spin. Classical postprocessing can then be used to isolate the $N$ single-particle energies of the Kitaev chain from the $2^N$ eigenenergies of the TFIM. By varying the strength of the Rabi drive used to engineer the synthetic transverse field, the spectral signature of the crossover from the trivial to the topological regime of the Kitaev chain could then be mapped out with measurements of just one spin.

The recent observation of a 220 PeV neutrino event (KM3-230213A) by the KM3NeT observatory presents a formidable challenge to standard astrophysical source models. We investigate the hypothesis that this ultra-high-energy signature originates from the terminal evaporation burst of a Primordial Black Hole (PBH). Since PBH evolution spans cosmic history, static vacuum approximations fail to capture early-universe dynamics. Embedding the PBH in a cosmological background via the McVittie spacetime, we demonstrate that early-universe cosmological accretion and expansion-suppressed Hawking emission shift the required initial mass window for a terminal burst occurring today. We show that although the early universe environment dictates the black hole's overall lifespan, its final explosion today ($z \approx 0$) is governed by standard Schwarzschild thermodynamics. This mechanism naturally produces the intense 220 PeV local flux while suppressing early emissions, thereby satisfying diffuse isotropic background limits. Consequently, this dynamical framework alters the mapping between current ultra-high-energy neutrino observables and the primordial curvature perturbations that seeded them.

Extensive Euclid satellite imaging at low surface brightness has revealed that most nearby galaxies are diffuse-looking spheroids, where the stellar radius increases for over three decades in luminosity. We argue this Diffuse Galaxy sequence results from internal stellar diffusion by Wave Dark Matter ($\psi$DM), as wave energy is transferred to star orbits over time. In particular, the soliton random motion scatters central stars onto radial orbits that become enhanced with each passage through the centre, slowly “puffing up" the stellar profile. Heating is greater within massive galaxies as $\psi$DM fluctuations are stronger and more frequent, reproducing both the Diffuse Galaxy sequence and the rising velocity dispersion along the sequence, from Ultra-Faint to Dwarf Spheroidal and Ultra Diffuse galaxies, favouring a light boson, $m_\psi=2.88^{+0.14}_{-0.13}\times10^{-22}$eV. Winding back this diffusion, we predict the stellar content of Diffuse Galaxies, including globular clusters, formed near the centre, as anticipated by $\psi$DM simulations, where gas cools efficiently within the dense soliton. This predicted $\psi$DM evolution from compact beginnings towards diffuse spheroidal galaxies today can now be fully charted from JWST to Euclid.

Product-formula Hamiltonian simulation is naturally suited to near-term quantum processors, but its accuracy is set by two competing errors: finite-step Trotter bias and physical hardware noise. We introduce a joint extrapolation strategy that ties the tunable per-layer noise strength to the Trotter step size, $\lambda(s)=c(sT)^{p+1}$ for a $p$-th order product formula. Along this one-dimensional path, the leading physical-noise and Trotter corrections over the full evolution both enter at order $s^p$ and can be canceled by a single Richardson extrapolation. Building on a previously established finite-order Baker–Campbell–Hausdorff truncation bound, we derive a provably commutator-scaling resource guarantee for the joint extrapolation. For local Hamiltonians with local Lindbladian noise, the protocol mitigates physical noise together with Trotter error with only a constant asymptotic overhead relative to noiseless Trotter extrapolation, provided the required noise strengths lie above the intrinsic device-noise floor. We experimentally demonstrate the protocol for Ising dynamics on a superconducting quantum computer using learned noise amplification. Complementary 100-qubit Sparse Pauli Dynamics (SPD) simulations achieve comparable accuracy to two-dimensional Richardson extrapolation with fewer circuit settings.

Semimetal elemental antimony (Sb) nanostructures show great potential for applications where nanophotonic properties play a key role, such as phase-change optical memories, non-linear optical elements, photothermal therapy agents, photodetectors and photocatalysts. However, designing advanced Sb-based photonic devices critically requires an accurate and reliable knowledge of the optical response of bulk and nanoscale Sb. Herein, we report for the first time a fully consistent and accurately measured dielectric function for Sb nanoscale films in a wide spectral range from the ultraviolet to the far infrared (4 - 0.04 eV, i.e. ~ 0.3 - 30 $\mu$m), surpassing previous reports that explored a limited spectral range. It is found that the Sb spectral response is driven exclusively by giant interband transitions in the visible up to mid infrared (4 - 0.4 eV, i.e. ~ 0.3 - 3 $\mu$m), and that their contribution dominates over that of free carriers down to 0.12 eV (i.e. ~ 10 $\mu$m). Such spectral response enables Sb nanostructures to display spectrally selective and tunable nanophotonic resonances. First, we showcase interband plasmonic resonances in the visible-to-near infrared for Sb nanogratings. Second, we report giant refractive index dielectric resonances in the mid infrared for nanostructured Sb/dielectric/metal resonant cavities. These findings open a pathway to optimized planar Sb nanoscale designs enabling a tailored light-matter interaction, which will be useful for integrated data, telecom, medical, optoelectronic and energy conversion devices operating in a broad spectral range.

Rest-frame ultraviolet emission lines are diagnostics of hard ionizing spectra and highly ionized gas in galaxies resembling the sources of cosmic reionization. Nebular CIV emission traces both intrinsic line production and resonant scattering through its velocity-resolved profile. Previous studies have treated CIV empirically, using integrated fluxes, equivalent widths, and line ratios rather than modeling the radiative transfer (RT) shaping the emergent profiles. We present the first systematic RT modeling of resonantly scattered CIV emission profiles in 18 local star-forming galaxies observed with HST/COS. Using the clumpy RT framework PEACOCK, idealized experiments show that profile morphology is governed by column density, gas kinematics, intrinsic equivalent width, and aperture-dependent recovery of scattered emission. We fit continuum-normalized spectra corrected for stellar contributions with a neural-network-accelerated Bayesian pipeline, reproducing P-Cygni-like, double-peaked, double-peaked with two absorption troughs, and blue-bump plus red-peak morphologies. Emission infilling connects these profile classes and complicates kinematic inferences, while aperture losses decouple observed net equivalent widths from intrinsic line production. Combining RT-inferred intrinsic equivalent widths with rest-UV diagnostics, we find that most galaxies are consistent with stellar photoionization, although some may require harder spectra or more extreme ionization conditions. Comparison with CLASSY reveals stronger associations of stellar mass and star formation rate with gas kinematics than with CIV column density. Our results establish CIV as both a tracer of hard ionizing radiation and a resonant-line probe of gas structure and kinematics, with velocity-resolved profiles providing information beyond integrated line strengths in local reionization analogs.

Modelling retinal haemodynamics is crucial for understanding retinal microcirculation but is computationally demanding because it involves coupling between the vasculature and surrounding tissue across multiple scales. This computational burden has been substantially alleviated by a recent analytic solution on the planar disc that enables lumping the capillary bed and surrounding tissue into an effective resistor. However, that formulation treats the retina as a flat surface, whereas the retina is a curved surface with a finite anterior aperture. In this work, we develop a nontrivial and physiologically necessary extension to spherical-cap tissue domains with varying apertures, where surface curvature and finite-aperture boundaries complicate solving coupled Darcy equations on a curved manifold. Using a stereographic projection and a decoupling transformation, we derive an analytic solution for the capillary-tissue system on the spherical cap that represents flow in both the capillary bed and interstitial tissue more realistically while retaining the efficient resistor formulation, a key advantage of the planar-disc formulation. This solution is coupled to one-dimensional (1D) arteriolar and venular flows to obtain a multiscale description of retinal haemodynamics. Using a vasculature model designed to capture retinal vascular features, we show that the multiscale model's predictions are consistent with experimental data. We further explore aperture effects using both a fixed hemispherical vasculature and aperture-dependent vasculature. The aperture affects retinal haemodynamics mainly through changes in the constructed vasculature itself, whereas the surface-averaged pressures and relative terminal flow distributions remain nearly unchanged. This framework provides a foundation for studying retinal pathophysiology on more anatomically realistic domains.

The C IV $\lambda\lambda1548,1551$ resonance doublet is a key tracer of warm gas ($T\sim10^5\,{\rm K}$) within and around galaxies. Recent observations have detected this line in both absorption and emission, revealing asymmetric profiles in galaxies and spatially extended haloes around active galactic nuclei (AGNs). Resonance scattering can strongly modify the emergent spectra and spatial distributions, complicating their interpretation. Using 3D Monte Carlo radiative transfer simulations, we study C IV resonance scattering over a broad range of column densities, intrinsic emission-line widths, and outflow velocities. We find that multiple scattering broadens the line profile and, in outflowing media, modifies the doublet ratio, $R_{\rm CIV}$, defined as the flux ratio of the K and H components at 1548 and 1551 $\mathrm{\mathring{A}}$, respectively. When the outflow velocity approaches or exceeds the doublet separation ($\simeq500\,{\rm km\,s^{-1}}$), K-line photons are redistributed around the H component, driving $R_{\rm CIV}$ below its intrinsic value and, in optically thick fast outflows, even below unity. We also combine photoionization models with resonance scattering to investigate extended C IV haloes around AGNs and compare them with He II $\lambda1640$ emission. Simple photoionization models do not produce C IV emission more extended than He II, whereas resonance scattering redistributes locally produced and central-source C IV photons to larger radii. These results demonstrate that the C IV doublet ratio and spatial distribution provide complementary diagnostics of warm gas.

The origin of fission-fragment spin remains unresolved. For $^{236}$U fission, we combine deformation-dependent finite-temperature pairing with a multidimensional scission-spectrum analysis. Near the pairing-quenching boundary, pair breaking exposes near-Fermi high-$\Omega$ intruder orbitals and opens high-$K$ channels. The resulting maximum spectroscopic capacities range from a few to more than a dozen units of $\hbar$. Rapid neck rupture acts as a non-adiabatic projection freeze-out, where pairing serves as a dynamical gate: its critical attenuation does not generate angular momentum but allows existing high-$K$ projections to be retained diabatically as local fragment-$K$ components while total angular momentum remains conserved.

Net-proton multiplicity distributions obtained by the STAR collaboration are analyzed in the grand canonical approach. A method of finding the baryon chemical potential $\mu_B$ immediately from such distributions is applied for the first time. The obtained values of $\mu_B$ are consistent both with those determined earlier using the statistical thermal model and with the results of the fit based on the Hadron Resonance Gas (HRG) model. We propose a criterion of thermalization of fireballs produced in heavy-nuclei collisions.