Papers

We study the quantum dynamics of two interacting anyons in the Anyon-Hubbard model on a four-site plaquette, a system that is exactly mappable to a Bose-Hubbard model. We reveal that static Aharonov-Bohm (AB) caging, induced by only specific statistical phases, emerges in the strongly interacting limit but breaks down under weak interparticle interactions. To address this, we demonstrate that statistical-factor-induced AB caging can be dynamically restored via Floquet engineering. This dynamical mechanism, governed by the synthetic Floquet flux and the anyonic statistical phase, extends the caging effect into the weakly interacting regime across the full spectrum of statistical phases. Furthermore, we show that the external drive enables the selective caging of anyons, providing an efficient approach for manipulating anyons and identifying statistical phases.

We explore the impact of different equations of state (EoS) on heavy ion collision observables using a Chiral Mean Field (CMF) framework constrained by astrophysical and lattice QCD inputs. The investigated family of EoS simultaneously reproduce neutron stars with masses above two solar masses and exhibit a first order phase transition around two times the nuclear saturation density. This is achieved by varying the relative vector and scalar couplings of ${\Delta}$ resonances with the scalar ${\sigma}$ and vector ${\omega}$ fields with respect to nucleons. These EoS are compared to the QCD trace anomaly at finite temperature. We implement both, the default CMF EoS and the modified EoS featuring a phase transition into the UrQMD transport model to study the effects of the phase transition on a qualitative and quantitative level. In particular Au+Au collisions at beam energies of 0.5-3 GeV, the GSI/FAIR energy range of the HADES and CBM experiments, shows visible sensitivity on the EoS. Transverse momentum distributions for protons, the directed flow ($v_1$) and its slope near mid-rapidity for ${\pi}^+$ as well as the $K^+/{\pi}^+$ ratio is analyzed. Clear differences emerge between the results obtained with the default CMF EoS, the modified EoS, and the cascade mode, particularly the slope of $v_1$ of the pions and in strangeness production. These findings demonstrate the sensitivity of heavy ion observables to the nuclear EoS and highlight potential experimental signatures of a phase transition.

Geological fractures exhibit heterogeneous aperture fields that localize flow along preferential pathways and produce nonuniform fluid-matrix contact times. Heat transport combines channelized advection with conductive matrix exchange. For non-Newtonian fluids, shear thinning biases the aperture-to-flux mapping toward larger apertures, while yield stress suppresses flow below the mobilization threshold. A stochastic semi-analytical model represents aperture classes as parallel pathways with constitutive fluxes and superposes their channel-scale advection-conduction solutions for a semi-infinite matrix. Matrix diffusion sets the late-time scalings of breakthrough curves and front moments, while aperture variability and rheology control their amplitudes and crossover. Rheology affects spreading through high-order flux-weighted aperture moments that determine persistent inter-channel variance. For monomial flux laws, the reduced late-time amplitudes collapse onto a single similarity variable, so shear thinning acts as amplified effective aperture variability. Global sensitivity analysis attributes flux reweighting to shear thinning and hydraulic accessibility to yield stress. Two-dimensional simulations verify the construction for Newtonian and power-law flow. A connected rough-field comparison at low aperture variability recovers mean advance and outlet survival but overestimates variance, so Ellis and Herschel-Bulkley results remain independent-channel predictions. The model provides an interpretable reference limit separating rheology-controlled hydraulic selection from matrix-controlled transport.

Gapped chiral phases pose an intrinsic obstruction to projected entangled pair state (PEPS) representations with finite bond dimension $D$, which generically develop spurious long-range correlations despite the gapped nature of the target state. To address this long-standing problem, we take a qualitatively different route by considering the target chiral system together with a completely decoupled time-reversed auxiliary copy. Constraining the finite-$D$ PEPS to the factorized form would simply reduce the problem to representing each chiral layer independently, leaving the original finite-$D$ obstruction unchanged. Unexpectedly, however, we find that finite-$D$ variational optimization generates an emergent residual interlayer entanglement, despite the absence of any explicit interlayer coupling in the Hamiltonian. This emergent entanglement is the key mechanism that bypasses the obstruction, qualitatively changing the PEPS from an effectively gapless representation with long-range correlation tails to one with a finite correlation length. We demonstrate this mechanism for both a free-fermion Chern insulator and an interacting chiral spin liquid. The residual entanglement is systematically suppressed with increasing $D$, approaching the decoupled limit, while the chiral topological information remains accessible through layer-resolved entanglement spectra. Our results thus uncover a previously unrecognized mechanism for bypassing the chiral obstruction through variationally generated auxiliary entanglement.

We study the conformal scattering of massless scalar waves in Minkowski spacetime. The conformal scattering problem is formulated as a Goursat (characteristic initial-value) problem of the physical wave equation in compactified double-null coordinates, including the neighborhood of spatial infinity $i^0$. As null infinities $\mathcal{I}^\pm$ lie on the domain boundary by construction, asymptotic radiation is directly accessible. We consider three physical scenarios: free wave propagation, scattering off a Pöschl–Teller (PT) potential, and the semi-linear $|\phi|^{n-1}\phi$ wave equation. For multipole numbers $\ell =0,1$, an explicit stencil, averaging along the spatial direction, yields globally second-order convergent results. For $\ell \ge 2$, an implicit stencil averaging along the temporal direction is required for numerical stability. Although the singular $i^0$ reduces the convergence of the radiation data on $\mathcal{I}^+$ to first order, Richardson extrapolation enhances the effective convergence rate to approximately $1.5$. For PT scattering, our method accurately computes scattering quantities, notably the phase shifts induced by the potential. In the semi-linear case, our method captures the physical signatures of a self-defocusing Kerr nonlinearity, including self-phase modulation and spectral broadening. The compactified double-null framework proves to be simple and efficient, suggesting a promising approach to the global evolution of conformal scattering.

The effective-one-body (EOB) framework, originally formulated within the post-Newtonian (PN) expansion, is central to modeling and interpreting gravitational-wave signals. Recent developments have incorporated the post-Minkowskian (PM) expansion into EOB theory. In this work, we focus on the bound state dynamics in the PM approximation up to the third order and construct the core ingredients of EOB: the effective metric. We examine two correspondence strategies, one based on the radial action variable and the other on the precession angle. We demonstrate that the radial action variable provides a consistent correspondence, which is further verified by the correspondence based on the precession angle. Building on these results, we adopt an isotropic gauge with a Schwarzschild-like parametrization to fix the remaining freedom. Within this parametrization, the effective metric coefficients are determined at 3PM order. Our results provide a consistent effective metric for the bound state dynamics.

We benchmarked quantum kernel $k$-means against classical clustering for credit-card fraud detection on real transaction data, at up to \MaxQubits{} qubits, under a protocol with separated selection and reporting data and matched search budgets. We find no robust quantum advantage: the sign of the difference depends on register size, all effect sizes are below $0.013$ ARI, and the single significant advantage we observe is fully explained by the number of configurations searched. We further show that ordinary hyperparameter choices move performance by considerably more than the quantum kernel does, that additional qubits degrade rather than improve performance through kernel concentration, and that the clustering framing itself fails at realistic class imbalance though kernel-based anomaly scoring does not. We regard the methodological contribution as the more durable one. The search-budget ablation in particular is inexpensive and, in our case, decisive: it converted a statistically significant advantage into a procedural artefact. We would encourage its routine use.

The interior structure and bulk composition of giant planets are not directly observable and must be inferred from models. Under the common assumption of a well-mixed, adiabatic envelope, the measured atmospheric metallicity is taken as a proxy for the metallicity of the entire envelope, and hence for the planet's heavy-element budget. JWST now provides precise atmospheric metallicities for a growing number of warm giants, allowing this assumption to be tested for the first time. We quantify the difference between envelope and bulk metallicities of warm giants to assess the evidence for compositional stratification. We assembled eleven warm giants with atmospheric metallicities from published JWST retrievals, computed tailored interior and thermal evolution model grids for each, and performed MCMC retrievals to infer the bulk metallicity consistent with the measured mass, radius, system age, and atmospheric metallicity. Envelope metallicities are smaller than bulk metallicities throughout the sample, with mixing ratios from about 0.02 to 0.90. Eight of the eleven planets have mixing ratios below 0.50, and ten are inconsistent with a fully mixed interior to within one sigma. We tentatively identify a significant anti-correlation between planetary mass and envelope metallicity, but no correlation between envelope and bulk metallicity, nor between envelope and host-star metallicity. Atmospheric metallicity is therefore not a reliable proxy for the bulk composition of warm giants, and incomplete mixing (possibly composition gradients) appears common among the planets accessible to JWST. Bulk composition estimates assuming a homogeneous envelope substantially underestimate the total heavy-element mass. That the solar-system giants are unremarkable within this sample suggests dilute or partially mixed interiors may be a generic outcome of giant planet formation.

Quantum feedback control requires acting on noisy continuous measurement records without direct access to the underlying quantum state. We propose Kraus-Parameterized Belief Reinforcement Learning, a pipeline in which a recurrent encoder, constrained to the Stiefel manifold, produces density-matrix estimates that are guaranteed positive-semidefinite and trace-normalized by construction, embedding quantum state geometry directly into the learning loop. A Proximal Policy Optimization (PPO) actor then maps these physically valid belief states to continuous control actions. On a simulated continuously monitored qubit, the resulting policy achieves stable feedback control, maintaining a measurement-conditioned belief fidelity of approximately 0.77-0.80 and exhibiting substantially lower return variance than a parameter-matched LSTM-history baseline across both nominal and out-of-distribution conditions. Although gains in raw target fidelity are modest, the geometric constraint guarantees a physically valid, interpretable belief representation and yields markedly more stable control under measurement inefficiency and abrupt dynamics switches. These results indicate that physics-informed neural memory is a practical inductive bias for reliable quantum feedback control.

A few dozen previously radio-quiet active galactic nuclei (AGN) have been observed to transition to radio-loud at 1-3 GHz frequencies over timescales of more than a decade, and this has has been interpreted to be due to newly launched jets. We identified 101 compact radio sources out of a sample of 64,972 non-blazar AGN which increased in flux density by 80-1800% over 1-6 years in the 887.5 MHz Australian SKA Pathfinder Variables and Slow Transients survey. We obtained optical spectra and radio SEDs using new observations and archival survey data. We determined 60 sources were consistent with extrinsic variability due to refractive interstellar scintillation and 41 were variable due to intrinsic causes, with 26 continuously brightening and two transitioning from radio-quiet to radio-loud. We concluded that young radio jets launched by either tidal disruption events or changes in the accretion properties were responsible for the continuously brightening AGN. These sources were non-variable at higher frequencies over the same time period, as expected for an expanding emission region. Fourteen sources had inverted or peaked SEDs initially which either flattened below the turnover or evolved into steep SEDs, consistent with young, expanding jets. Twelve sources had non-variable steep or gigahertz-peaked SEDs, which suggested these hosted more slowly evolving jets. We investigated the previously discovered AGN with newly launched jets, and found several have faded at multiple frequencies, which suggested the observed radio-loudness was temporary, rather than the onset of a sustained period of radio activity.

Technologies, products, platforms, and behavioral routines often compete through gradual adoption, reinforcement-dependent use, and temporary multi-homing. We formulate a homogeneous, well-mixed, three-state agent-based model of competition between an incumbent option (X) and a challenger (Y). Agents are exclusive users of (X), exclusive users of (Y), or dual adopters (Z). Adoption is memory-based: an exclusive user adds the alternative only after enough adoption-relevant encounters within a finite learning window. Retention is also memory-based: a dual adopter continues to use both options only if each is sufficiently reinforced within a finite retention window. This microscopic mechanism reproduces aggregate usage signatures analogous to the four Adner–Kapoor technology-substitution regimes—creative destruction, robust coexistence, the illusion of resilience, and robust resilience—without explicitly representing ecosystems, complementors, prices, or strategic investment. Starting from the same small challenger seed, the benchmark simulations differ only in adoption burden, retention burden, post-adoption usage preference, and the teaching role of dual adopters. Rolling usage shares reproduce the four aggregate substitution patterns, while state-resolved trajectories and phase portraits reveal distinct microscopic pathways. Thus, similar market-level substitution curves need not have unique causal interpretations: although ecosystem mechanisms may be essential in many empirical cases, finite-memory learning and retention alone can generate qualitatively similar regimes. The model provides a compact baseline linking technology-substitution trajectories to observable individual-level adoption, multi-homing, and discontinuance.

Weak shock reflection at nearly glancing incidence is governed, after the transonic weak-shock scaling, by a self-similar unsteady transonic small-disturbance (UTSD) free-boundary problem. We derive and differentiate the first finite-strength perturbation of the corresponding isentropic potential-flow problem along paths of fixed canonical incidence $a=\alpha/\delta$, where $\mu=\delta^2=2(M^2-1)$. A second-order refluxed adaptive finite-volume method, exact discrete tangents and adjoints, and a Rankine–Hugoniot-constrained fitted principal front give the fixed-$a$ canonical sensitivity $H_{2,a}^{\PF}(0.5;1.4)=-0.217\pm0.012$; a fully differentiated physical back-map gives the diagnostic fixed-$a$ coefficient $K_{2,a}^{\PF}\simeq-0.266$. We derive the exact chain rule that converts these quantities to the distinguished fixed-$\lambda$ path $\lambda=(M-1)/\alpha^2$, showing explicitly that the conversion requires the independent incidence derivative of the leading UTSD branch and therefore cannot be inferred from the fixed-$a$ calculation alone. A matched-boundary self-similar Euler study with strength-dependent refinement contains 21 qualified nonlinear states and 252 evaluations of a common front-functional family. Coupled extrapolation gives $g_0^{\Eul}=0.510\pm0.006$ and the physical leading-angle coefficient $G_0^{\Eul}=0.256\pm0.004$, consistent with the shock-fitted UTSD limits. A separate same-strength phase-bracket audit using 18 Euler states shows that the captured-shock subcell phase is comparable to the desired cubic signal. The resulting finite-resolution Euler secants are compatible with the potential-flow correction, but their $\rho=h_\eta/\sqrt\mu\to0$ extrapolation is not model-stable. Thus leading-order Euler–UTSD correspondence is numerically verified, whereas cubic-order Euler correspondence remains unresolved.

The monochromatic 5.49 MeV solar axions induced by the isovector coupling $g_{3aN}$ can be searched for at the dark matter direct detection experiments. In this paper we estimate the prospects of the relevant axion couplings for axion mass $m_{a} <$ 1 MeV with xenon targets. Given the axion-electron coupling $g_{ae}$, the signal is dominated by the axion-induced $e^+ e^-$ pair production whose cross section is largely enhanced when the axion mass approaches twice of the electron mass. Furthermore, the cross section depends on the atomic number squared $Z^2$. This allows the next-generation xenon experiments to surpass the current Borexino constraints and provide sensitivities competitive with those of the large neutrino detectors such as JUNO and Hyper-Kamiokande. With an exposure of 200 and 1000 ton$\cdot$yr, the couplings $|g_{3aN} g_{ae}|$ can be probed down to $1.59\times10^{-14}$ and $7.12\times10^{-15}$ at 90% C.L., respectively. If the axion couples to photons, the projected sensitivities on $|g_{3aN}g_{a\gamma}|$ can touch down to $6.76\times10^{-12}$ GeV$^{-1}$ and $3.02\times10^{-12}$ GeV$^{-1}$, respectively.

Helium is the second most abundant element in the Universe, yet helium-dominated atmospheres are rarely considered as environments for life. Two assumptions have contributed to this neglect: helium is expected to escape from rocky planets together with hydrogen, and Earth itself lacks a substantial helium envelope. Recent observations and atmospheric evolution models, indicate that rocky exoplanets can retain helium-dominated atmospheres. Here we make the case for life in such environments by synthesizing a largely overlooked body of laboratory research on life in helium-dominated atmospheres. Every organism studied, including bacteria, fungi, protozoa, microalgae, plants, and animals tolerates helium-dominated atmospheres when supplied with essential metabolic requirements. Across a range of pressures, helium has shown no demonstrated toxicity and no fundamental barrier to metabolism, cell division, photosynthesis, nitrogen fixation, or coordinated multicellular activity, including in humans. Helium-dominated atmospheres therefore constitute a viable and underrecognized planetary environment for life. Helium is chemically inert and spectroscopically unobtrusive, so the bulk atmosphere would neither contribute to the chemical destruction of biosignature gases nor strongly obscure their spectral features. Helium-dominated atmospheres also have low mean molecular weights and large scale heights, strengthening spectral features in transmission and improving remote detectability.

Conventional retinal flicker endpoints quantify changes in diameter, mean velocity, or flow but do not capture the modal concentration of the cardiac velocity waveform during neurovascular stimulation. Here, beat-resolved retinal Doppler holography and low-rank modal decomposition are combined to derive compact arterial endpoints from unfiltered arterial segment-velocity waveforms sampled across beats and vessel locations. For each acquisition, locally centered waveforms are assembled into a common matrix and decomposed by singular-value decomposition (SVD). Robust summaries quantify total pulsatile scale, modal amplitude, residual amplitude, mean-to-pulsatile balance, and singular-spectrum dimensionality; the same construction can also be applied descriptively to individual beats. We demonstrate the framework using 33 temporally ordered Baseline~1/Flicker/Baseline~2 acquisitions from one eye. Relative to the pooled baselines, 13-Hz flicker was associated with lower centered-waveform RMS scale $R_0$ and leading-mode amplitude $A_1$, and with higher robust residual-amplitude ratios $\rho_1$ and $\rho_2$, mean-to-pulsatile ratio MPR, effective rank, and participation ratio; these contrasts showed exploratory within-session separation after Holm adjustment. No evidence of differences in the absolute residual amplitudes $R_1$ and $R_2$ was detected; together, these observations are consistent with reduced concentration in the leading acquisition-specific arterial pulse mode rather than an increase in absolute residual pulsatility.

Indentation experiments can be used to mimic real-life damage events of glasses that lead to surface flaws and thus lower practical strength. Conventional indentation studies often focus on the surface deformation after unloading. However, to understand the link between the surface deformation and structure, it is crucial to characterize the sub-surface deformation during the indentation process. The indentation-induced deformation, consisting of both elastic and plastic zones, is governed by the glass composition and structure, indentation and atmospheric conditions, and stress state. However, only a few experimental methods exist for characterizing the sub-surface indentation deformation mechanism during indentation. In this study, we use synchrotron X-ray nanoscattering to probe the deformation mechanism in situ during indentation of four types of oxide and oxynitride glasses with distinct structural features. This is done by measuring the variation in the position and intensity of the first sharp diffraction peak of the X-ray structure factor with a high spatial resolution down to ~100 nm. We find that the deformation zones of these glasses, which are characterized by the shape, size, and relative contribution between densification and shear flow under different indentation loads, vary with Poisson's ratio. Thus, our work provides new insights into the mechanical behavior of oxide glasses, contributing to the design of more damage-resistant glasses.

We estimate the reddening of the broad-line region and continuum of the active galactic nucleus NGC 7469 during the 1996 International AGN Watch multi-wavelength monitoring campaign using seven different reddening indicators. As was found for NGC 5548, these indicators support velocity-integrated broad hydrogen line ratios being close to Case B values. All the indicators point to substantial reddening of E(B-V) = 0.44 +/-0.03 for NGC 7469 during mid-1996. We find evidence for a gradual increase of about 10% in the reddening during the seven weeks of the 1996 campaign. Decades-long optical monitoring before and after the campaign is also consistent with modest changes in the extinction from year to year.

Different field species can begin with finite anisotropic propagation geometries whose principal axes need not coincide. We ask whether local Yukawa interactions on a finite graph can nevertheless generate one common infrared spatial cone, even when the interactions that drive the locking become marginally irrelevant. Retaining the full finite mismatch between positive-definite spatial kinetic matrices, we derive the one-loop nonlinear matrix flow and show that its Thompson diameter is globally nonexpansive. On a connected graph, persistent normalized edge activity upgrades this to a uniform finite-window contraction, so all interacting sectors asymptotically share one relative propagation geometry. An explicit two-channel Pauli-Dirac Yukawa-quartic completion realizes the persistence conditions on an open weak-coupling set of finite-mismatch initial data. In four dimensions the Yukawa couplings vanish in the infrared, yet their accumulated interaction time diverges, leaving a Gaussian endpoint with a common spatial cone. For a controlled two-plateau extremal class, graph distance also fixes the first nonzero short-time order of the diameter decrease. Thus common-cone locking can emerge from renormalization-group dynamics rather than being imposed as a microscopic common structure.

The effect of deflection of a light signal that propagates through the gravitational field of a solar system body at rest is considered in the case that the source and the observer are at a finite distance from the body. The observer is assumed to be located somewhere nearby the Earth, for instance at Lagrange point L2 of the Sun-Earth system, while the spatial position of the celestial light source is arbitrary. The gravitational fields in the exterior of the bodies are described by the full set of time-dependent mass-multipoles and spin-multipoles of these bodies. So the gravitating bodies can be of arbitrary shape, inner structure and rotational motion. The unit tangent vector of the light trajectory at the position of the observer is determined in the 1PN and 1.5PN approximation of the post-Newtonian (PN) scheme. A simplified expression for the unit tangent vector is obtained, where all terms are neglected that together contribute less than 10 nano-arcseconds in light deflection for all astrometric configurations between source, body and observer. It is shown that in the case of an axi-symmetric body the unit tangent vector of the light ray as well as the light deflection are given in terms of Chebyshev polynomials. This fact allows for determining the effect of light deflection in the gravitational fields of the bodies up to any order of the mass-multipoles and spin-multipoles. It is shown that the total light deflection, that is the angle of light deflection where source and observer are located at infinite spatial distance from the body, represents an upper limit of the effect of light deflection. These investigations are aiming at astrometric measurements on the sub-micro-arcsecond level of accuracy.

The dark axion portal provides a well-motivated framework for new physics beyond the Standard Model (SM), in which an axion-like particle (ALP) couples simultaneously to a photon and a dark photon, leading to distinctive collider signatures. In this work, we investigate the sensitivity to the $a$–$\gamma$–$\gamma'$ interaction via the mono-photon channel arising from $\mu^{+}\mu^{-} \to a \gamma'$ with $a \to \gamma \gamma'$ at the $1.5~\mathrm{TeV}$ muon collider with an integrated luminosity of $\mathcal{L}=500~\mathrm{fb}^{-1}$ for the polarized and unpolarized beam configurations, $P(\mu^+,\mu^-)=(-100\%,+100\%)$ and $P(\mu^+,\mu^-)=(0,0)$, using detector-level simulation. The signal is characterized by a single energetic photon accompanied by missing energy as the dark photons escape detection. The projected sensitivity reaches the $\mathcal{O}(10^{-5})~\mathrm{GeV}^{-1}$ level for ALP masses in the range $1~\mathrm{GeV}\leq m_a\leq1200~\mathrm{GeV}$ for $P(\mu^+,\mu^-)=(-100\%,+100\%)$, while for $P(\mu^+,\mu^-)=(0,0)$ the projected sensitivity reaches the $\mathcal{O}(10^{-4})~\mathrm{GeV}^{-1}$ level for the same ALP mass range. These results demonstrate that the mono-photon signature at a muon collider provides a sensitive probe of the $a$–$\gamma$–$\gamma'$ interaction over a wide mass range.

We introduce Rand-SEMI-QAOA, a finite-budget QRAO–QAOA ensemble for MaxCut based on a $(3,1)$-QRAC relaxation. The method samples labels uniformly without replacement from the product-$X$ family of an implemented Galois stabilizer mutually unbiased basis (MUB) system. Each selected state–mixer pair is optimized independently for relaxed QRAO energy and then evaluated by deterministic Pauli-sign decoding. Exhaustive scans of the implemented noncomputational MUB catalog place the product-$X$ family first in 18 of 20 validated family-mean cells and in every tested cell for $r=5,6,7$. On a complete cohort of $2{,}400$ random connected 3-regular MaxCut instances with $n\in\{18,20,22\}$, the capped matched-cardinality schedule attains a graph-mean decoded best-of-set approximation ratio of $0.9421$ with one QAOA layer, while the $K=r^2$ schedule attains $0.9319$. These statistics are conditional on the disclosed frozen selector pools and do not estimate variability over selector seeds. An exact gauge identity shows that product-family labels generate the orbit of the QRAO Hamiltonian under an $r$-dimensional sign-gauge group. For common angles and relaxed energy, deterministic syndrome analysis proves branchwise dephasing, while an anisotropic Gaussian surrogate controls the coherent label-averaged response on the scale $\beta=b/r$. The theory does not order independently optimized decoded maxima. The results are finite-size and resource-explicit and do not establish quantum advantage.

We investigate the charging of a harmonic-oscillator quantum battery by a propagating two-photon quantum pulse coupled through a two-level-system charger. Excitation-number conservation reduces the dynamics to a sequential response of the first and second excitation sectors, whose effective non-Hermitian generators exhibit two exceptional points separating overdamped, mixed, and underdamped regimes. We derive the exact full-charging amplitude and the response-matched two-photon temporal mode that achieves perfect charging in the ideal resonant single-channel model. For experimentally accessible Gaussian pulses, moderate temporal anticorrelation or a finite photon delay can enhance charging, whereas positive correlations generally suppress it. States with equal Schmidt number can nevertheless show different charging efficiencies, demonstrating that temporal-mode structure and response matching, rather than nonseparability alone, determine charging performance.

Scalable arrays of identical single-photon sources are a central resource for photonic quantum information processing, quantum networks and quantum metrology. Neutral atoms provide intrinsically identical emitters that can be assembled and rearranged in optical tweezers, but a many-channel fiber interface to individually trapped atoms has remained a major technical challenge. Here we demonstrate a chip-interfaced single-photon source array based on 50 individually addressable $^{87}\mathrm{Rb}$ atoms. A glass waveguide fan-out converts the \SI{5}{\micro m} pitch of the optical-tweezer array to the \SI{127}{\micro m} pitch of a commercial fiber array, mapping each atom to its own waveguide, fiber and single-photon detector. We resolve all 50 channels with an average nearest-neighbor cross-talk of $0.4\%$ and a uniform insertion loss of \SI{2.9}{dB}, and verify single-photon emission with $g^{(2)}(0)=0.29$, presently limited by detector dark counts and residual cooling-light scattering. Combining per-channel atom discrimination, rearrangement and reservoir replenishment, we prepare source subarrays of up to 24 atoms with a $93\%$ fill fraction. For small target numbers, atom loss is repaired from the reservoir at the detection-limited rate of \SI{118}{Hz}. We further fabricate a 784-channel waveguide chip, showing that the photonic interface can be extended well beyond the present number. This architecture establishes a fiber-native neutral-atom platform for larger arrays of identical single-photon sources.

We develop a semi-analytic extension of the Web-Halo Model (WHM) to Hu-Sawicki $f(R)$ gravity, with the aim of linking nonlinear matter clustering to the successive stages of cosmic-web collapse. The cylindrical sheet and filament windows of the original WHM are replaced by axisymmetric ellipsoidal top-hat windows, yielding a modest improvement around the perturbative-to-nonlinear transition without introducing additional fitting parameters. Modified gravity is incorporated through environment-dependent chameleon spherical collapse, from which the collapse threshold and virial overdensity are obtained and propagated through the sheet, filament, and halo contributions. For $|f_{R0}|=10^{-5}$ and $10^{-6}$, the predicted nonlinear enhancement is broadly consistent with the scale-, redshift-, and field-strength dependence seen in the e-MANTIS emulator, with closer agreement for the weaker field and at higher redshift. The component responses show that sheets and filaments contribute substantially around the transition regime, while the halo response becomes increasingly important at smaller scales. As complementary diagnostics, no displacement of the BAO peak is resolved, whereas tomographic weak-lensing spectra retain a percent-level response to the modified matter power spectrum. The extended WHM therefore provides a physically interpretable framework for tracing screened modified-gravity effects across the cosmic-web collapse hierarchy.

Observations of the reactive ions OH+, H2O+ and H3+ in the Galactic interstellar medium reveal large sight-line-to-sight-line scatter in their column densities, commonly interpreted as evidence for substantial variations in the cosmic-ray ionization rate (CRIR). We revisit this interpretation using high-resolution three-dimensional magneto-hydrodynamic simulations of the multiphase ISM with time-dependent chemistry for H, H2, H+ and electrons, building on the fiducial model of Godard et al. (2023). We find that a single CRIR of ~2 10^{-16} s^{-1}, together with standard Galactic-scale parameters, naturally produces broad column-density distributions for all three tracers in good agreement with the observed medians and percentile widths, with no fine tuning. Reaching this match requires that the post-processing of OH+, H2O+ and H3+ retain the time-dependent H2 field generated by the turbulent flow rather than assume chemical equilibrium: turbulence drives long-lived H2 enhancements in the unstable neutral medium where OH+ and H2O+ predominantly reside, and an equilibrium treatment under-predicts their columns substantially. H3+, which receives most of its column from denser CNM gas closer to equilibrium, is much less affected. Our results caution against interpreting sight-line-to-sight-line scatter as direct evidence for large CRIR fluctuations, and motivate a shift from independent 1D equilibrium analyses toward 3D dynamical frameworks when inferring ionization conditions in the ISM.

Neural representations have become a central tool for studying the internal mechanisms of modern AI models, yet their complex high-dimensional structure makes them difficult to interpret. We show that classification tasks give rise to a universal representational geometry, shared across state-of-the-art models in vision, audio, and language processing. The key structure is that within-class variability is not random in representation space. Instead, its classifier-relevant component has strong and structured correlations with the class's own centroid and with the centroids of its competing classes. Building on this observation, we derive an analytical mean-field theory governed mainly by the variability along true-class and rival-class centroid coordinates, together with a global renormalization of the class radius that compensates for the non-Gaussian statistics of real representations. The theory accurately predicts classification accuracy across architectures and modalities. The relevant geometric quantities improve systematically with model scale, mirroring the observed gains in accuracy. A striking feature of the theory is its sparsity: accurate prediction requires only a small set of centroid coordinates associated with the true class and its strongest rivals - connecting our framework to sparse-feature extraction approaches such as sparse autoencoders. Together, these results provide a parsimonious predictive theory of neural representations and suggest that classification in deep networks is governed by a sparse, centroid-aligned structure embedded within the full high-dimensional representation space.

Metsaev exhibited generic and decoupled formulations of conformal Yang–Mills theory in $(A)dS_6$, $(A)dS_8$, and $(A)dS_{10}$, and conjectured the corresponding relations in higher even dimensions. Motivated by the low-dimensional matrices in Appendix C, we identify and diagonalize a natural all-$N$ Bezoutian continuation of the three generic Gram forms. The monic Hankel cutoff, the evaluation pattern in Appendix C, and the conjectured mass nodes determine this continuation uniquely. Its vector and radical Gram-form diagonalization identities hold for every $D=d+1=2N+4$, $N\geq1$. The continuation is the Bezout matrix of $z\prod_{i=1}^N(z-\rho i(2N+1-i))$ and $1$; evaluation at its simple roots produces the Vandermonde congruence appearing in the field redefinition. The same calculation gives closed formulas for the inverse, determinant, and inertia, and identifies the normalization weights with Johnson-graph multiplicities. Any nonlinear coefficient algebra already specified in the generic formulation is transported by this change of basis. The result does not construct such an algebra in arbitrary dimension. At $N=4$, we impose associativity, Frobenius invariance, and a fixed flat specialization; these algebraic constraints still admit a one-parameter family of pairwise distinct products in a fixed generic basis.

We show that intercalating a WSe$_2$ monolayer into bilayer graphene mediates wavefunction hybridization of the two graphene layers at the Fermi level. These delocalized states entangle both graphene layers, creating a synthetic bilayer graphene with interlayer coupling comparable to the proximity-induced spin-orbit interaction. By analyzing transport properties of a four-terminal device, we demonstrate equal entangled parallel charge currents in both graphene layers, allowing us to unlock the hidden Rashba states via layer-selective chirality manifested in opposite-signed local Rashba-Edelstein signals. We also show nonlocal Rashba-Edelstein and spin Hall effects activated in one graphene layer when a charge current is driven in a spatially adjacent graphene layer. This effect is robust to the twist angle modulation between graphene and WSe$_2$, and to the applied electric field, suggesting its durability.

Photonic quantum networks require error-correction architectures that remain useful with finite-energy bosonic states, pure-loss fiber transmission, and explicit resource accounting. In this light, we study a concatenated architecture in which each physical rail is a finitely squeezed Gottesman–Kitaev–Preskill (GKP) qubit transmitted through a pure-loss fiber segment, corrected by teleportation-based GKP error correction with finitely squeezed ancillae, and decoded by an outer quantum parity code (QPC). The GKP layer converts continuous homodyne syndromes into effective rail-level Pauli marginals, while the QPC layer suppresses the residual qubit-level errors. For the concatenated code family considered here, we find a finite-squeezing threshold of $5.06\,\mathrm{dB}$ at zero propagation loss. In the memory setting, the QPC layer lowers the squeezing at which repeated error correction becomes beneficial from $6.7\,\mathrm{dB}$ for bare GKP correction to $5.2\,\mathrm{dB}$ for QPC$(3,3)$ and $4.3\,\mathrm{dB}$ for QPC$(5,5)$, and improves the average-fidelity ratio by up to $75$–$90\%$ in the relevant intermediate-noise regime. In the repeater setting, avoiding pre-amplification gives larger secret-key fractions at moderate squeezing, but also produces an optimal squeezing because highly squeezed GKP peaks become sensitive to loss-induced inward displacement. Resource-normalized rates show that QPC concatenation can exceed the repeaterless PLOB benchmark by orders of magnitude and extend the communication reach, at short repeater spacing, to distances of order $10^4$km with $14$dB squeezing. However, QPC concatenation becomes detrimental when each elementary hop is too lossy. These results provide quantitative design rules for finite-squeezing GKP–QPC quantum memories and repeaters.

Machine-learning detectors for power-system cyberattacks are themselves attack surfaces, and quantum machine learning has been proposed for them. We benchmark fidelity-kernel SVMs and variational classifiers against six tuned classical models on public power-system attack data (Mississippi State/ORNL), across white-box, transfer, decision-based black-box, and poisoning attacks. Our headline finding is methodological: the benchmark's answers are set by the evaluator's choices before the models. Eight choices – six in the evaluation protocol, two in the tuning the benchmark itself runs – each reversed or moved a conclusion at fixed models. The largest is the split: the row-level protocol scores 0.905 macro-F1 where holding whole source files out leaves 0.594, and in the capped matched-dimensionality regime the quantum arm sits within noise of chance with the classical arm 0.024 above it. A fidelity kernel looks most robust until attacked directly (retention 0.886 to 0.064); a mis-fitted surrogate manufactures a 10x asymmetry; an unseeded black-box attack moves 75% between restarts. A positive control explains the accuracy null: the labels, not the pipeline. We give the control that catches each choice and release the seeded benchmark.