Papers

We investigate the nonlinear dynamics of a Bose-Einstein condensate trapped in a double-well potential of a one-dimensional lattice, where the interatomic interactions are periodically modulated in time. In the typical case of a symmetric double-well, we observe collective particle emission under resonant driving, where the excitation regimes are explicitly constrained by the interplay between the drive strength and the hopping amplitude. By introducing a depth asymmetry between the wells, we find that moderate bias specifically enhances the emission rate, while large asymmetry suppresses it. The particle jets can be further controlled by modulating the hopping amplitudes, where the emission is weakened for finite hopping imbalances. These results outline the roles of asymmetry and external driving in precisely manipulating quantum many-body transport, and may offer insights into the design of atomtronic devices.

Scaling multicolor quantum control on chip presents a geometric conflict: each added wavelength traditionally requires another routing corridor, emitter, and electrode opening, consuming trap-surface area and exposing charge-susceptible dielectric near the quantum target. This work introduces an all-planar, vertically stacked silicon-nitride architecture that co-registers independently fed optical transitions within one 24 x 24 $\mu$m footprint. For $^{40}\text{Ca}^+$, the device focuses the 729.4 nm qubit and 854.2 nm repump wavelengths onto a shared site 70 $\mu$m above the upper film. A hierarchical design combines a differentiable cell search for a three-level scatterer, analytic confocal phase synthesis, and deterministic depth allocation across two etches per layer, preserving an explicit 125 nm propagation-axis line-and-space floor without grayscale patterning. Retargeting the upper-layer phase co-registers the focal maxima to within 0.1 $\mu$m in mesh-converged Tidy3D and independently constructed Lumerical FDTD models, retaining >99.9% of each color's peak intensity at the common coordinate with focusing efficiencies of 0.410 and 0.168. At 5 $\mu$m ion spacing, the qubit channel reaches -24.8 dB point crosstalk, remains below -18.0 dB across a 0.5 $\mu$m-radius positioning disk, and yields -23.0 dB symmetric-traceless field-gradient suppression. In the analytic House conductor geometry, the shared footprint provides 15.3 $\mu$m clearance to the nearest radio-frequency rail with zero RF-null displacement. By uniting separate optical inputs and transition-specific wavefronts within one ion-facing aperture, this hierarchy establishes a transferable template for addressing other atomic wavelength pairs and dense multicolor quantum interfaces.

This paper reports on the implementation process of the three-dimensional (3D) edge plasma transport code EMC3-EIRENE on the Divertor Tokamak Test (DTT) facility and the results of its first application, with a focus on assessing the heat load on the Ion Cyclotron Resonance Heating (ICRH) antenna surfaces. Using axisymmetric geometries and the SOLPS-ITER simulation results as a reference, we first evaluate the performance of the EMC3-EIRENE in describing axisymmetric plasmas to ensure correct code modelling setup for later complex 3D applications. We then incorporate the ICRH antenna structure in our 3D simulations, assuming different toroidal symmetry for the antenna to determine whether the heat load assessment can be carried out with reduced computational effort, and to what extent a 3D assessment deviates from a 2D approximation. The predictions of the 3D antenna heat load distribution are obtained and the peak values on the top plate and the two side plates reach 0.9, 2.1 and 3.8 MW/m2, respectively. Finally, 3D gas puffing is included to evaluate its impact on the antenna heat load. The corresponding 3D edge plasma behavior is presented under the coupled effects of gas puffing and the antenna geometrical structure.

We present a directional dark matter search using the MIMAC (Micro-tpc Matrix of Chambers) detector at the Modane Underground Laboratory. Operating a low-pressure gas mixture of i-C4H10 and 50% CHF3 at 30 mbar, without any shielding, the detector allows the reconstruction of the 3D tracks of nuclear recoils produced in the 6-liter active volume. Directionality is a crucial tool to discriminate true WIMP signals from those of background producing identical recoils, such as neutrons. We analyze data from two independent chambers with effective exposures of 495.1 and 354.2 days, respectively. To estimate the background directly from the data, we apply a standard ON/OFF spatial analysis. By projecting the reconstructed tracks onto the galactic map and applying a moving kinematic energy cut depending on the WIMP mass, we compare the event rate in the signal direction with multiple OFF-source regions. Finding no significant excess of events in the direction of the Cygnus constellation, we set an upper limit on the spin-dependent WIMP-protoncross section.

We study the equivalence of canonical and microcanonical ensembles for quadratic Hamiltonians on Euclidean lattices. The answer depends on the arithmetic structure of the energy spectrum: exact-energy microcanonical ensembles converge locally to the canonical Gibbs law in the lattice case, but may retain additional arithmetic information in the nonlattice case. We show that this obstruction disappears after replacing an exact energy shell by any fixed-width energy window. Using uniform local central limit theorems, we also obtain sharp asymptotics for the corresponding state counts and recover Bost's thermodynamic entropy.

Subaru/SCExAO/CHARIS enables near-infrared integral field spectropolarimetry. Quantitative polarimetry is useful for a variety of science cases, particularly measurements related to dust grain properties in circumstellar disks. This capability requires correcting for polarization effects from the optical path via a Mueller matrix model. We present an updated model accounting for the recently installed SCExAO near-infrared wavefront sensor YJH50 dichroic beamsplitter and the major Subaru Nasmyth beam-switcher upgrade. Using internal light source measurements from before and after the beam switcher installation, we find an elliptical retarder model for the image derotator improves polarimetric accuracy over the previous linear retarder model. We additionally find the YJH50 dichroic produces faint polarization effects that we cannot characterize with our Mueller matrix modeling capabilities, and that the Nasmyth beam-switcher has minimal polarization effects other than inducing a sign flip in Q and V polarized light. Using unpolarized standard star calibration measurements, we fit the diattenuation of Subaru's tertiary mirror as a function of wavelength and find that the diattenuation has increased since the previous CHARIS calibration. We calculate that the polarimetric accuracy of the model in the degree of linear polarization ranges from 0.02% to 0.12% for a 1% polarized target. This model update will soon be incorporated into CHARIS's data processing pipeline, and should be used for any polarimetric data taken after the Nasmyth beam-switcher update in October 2025. Additionally, we provide the code for this calibration as part of an open-source Python package for polarimetric calibration called pyPolCal, enabling straightforward re-calibration of the system after any future changes, e.g. the recent recoating of M3.

As quantum systems advance toward interconnected architectures, the ability to identify nodes, manage resources, and support network-level functions becomes increasingly critical. In this work, we propose a lossless source coding scheme for addressing in quantum networks that enables compact, hierarchical, and coherently processable quantum address states. Specifically, we introduce a prefix-suffix address space and develop an isometric hierarchical encoder-decoder that guarantees unique decodability. We further provide a practical Huffman-based procedure that embeds prefix-free, length-eigenstate codewords into the address space, thereby preserving isometry. The scheme is particularly designed for networks with hierarchical structure, heterogeneous cluster sizes, and configurable address assignment to accommodate dynamic network conditions. A numerical example on a 13-node network demonstrates that the proposed hierarchical encoding scheme is feasible and achieves perfect fidelity. This work establishes a rigorous connection between source coding theory and quantum network design, offering a practical framework towards scalable and coherent quantum addressing.

Inverse-designed spectral routers can enable compact snapshot spectral imaging by directing different wavelengths to designated detector sub-pixels without mechanical scanning or absorptive filters. Here, we examine how routing performance varies as the number of spectral channels increases while the visible bandwidth remains fixed. A delay-bandwidth analysis relates channel count, worst-channel efficiency, and device thickness, explaining the growing optical capacity required to generate many spatially distinct spectral outputs. We then use adjoint-based topology optimization and three-dimensional finite-difference time-domain simulations to design TiO2/SiO2 routers with 9, 16, 25, and 36 channels under matched material, bandwidth, and thickness conditions. The average routing efficiency increases with sub-pixel size and approaches a plateau, while the maximum near-plateau efficiency decreases monotonically from 97.0% for 9 channels to 82.3% for 36 channels. At a fixed channel count, compressing the wavelength spacing to 8 nm or rearranging the wavelength-to-sub-pixel assignment changes the efficiency by less than one percentage point. These results indicate that the observed efficiency penalty is governed mainly by the number of wavelength-dependent routing constraints rather than by wavelength spacing or local wavelength arrangement. The findings quantify the trade-off between spectral sampling and optical throughput in compact snapshot spectral imagers.

Locating periodic solutions of chaotic dynamical systems normally requires an initial guess close enough to the target orbit for numerical continuation or gradient-based search to converge. We show that Physics-Informed Neural Networks (PINNs) trained on sparse, noisy observations without initial conditions recover periodic orbits of the gravitational three-body problem, including orbit families absent from the training data. The method rests on a second-order ODE formulation, fixed-frequency Fourier features, percentile-based adaptive refinement, and a trainable scaling parameter, each validated on forward problems. Across two 100-seed ensembles, $23$–$25\%$ of runs converge to families not present in the training data. We then ask what determines which family emerges. Two $\chi^2$ tests give a consistent answer: changing the training data source significantly shifts the distribution of recovered families ($p < 0.001$, Cramér's $V = 0.339$), whereas switching between the two initialization distributions tested does not ($p = 0.620$, $V = 0.094$). The random seed selects which family a given run recovers; the distribution the weights are drawn from does not shift the aggregate frequencies, but the training data does. The evidence is empirical: we do not characterize the loss landscape analytically, and PINNs remain slower than conventional integrators on well-posed initial-value problems. What the experiments establish is that the recovered orbits are verifiable rather than merely plausible: the identified ones refine to genuine periodic solutions, a network trained on Lagrange data recovers the figure-eight choreography (Li–Liao class I.A.1, matched to seven significant digits in $T^*$), and one trained on figure-eight data recovers a Broucke–Hadjidemetriou–Hénon orbit closing to $\delta_T < 10^{-9}$.

We discuss the $p_T$-differential radial flow $v_0(p_T)$ of charmed hadrons within a Langevin dynamics coupled to relativistic Boltzmann transport approach in an event-by-event basis. We propose heavy flavour $v_0(p_T)$ as a novel observable to probe the strength of the interaction of heavy quarks with the expanding Quark-Gluon Plasma. By comparing different temperature dependence for the spatial diffusion coefficient $D_s(T)$ we show that the $v_0(p_T)$ keep a strong sensitivity to the heavy-quark transport coefficients at intermediate $p_T$. At low $p_T$, the observable is also sensitive to hadronization where we observe a larger $v_0(p_T)$ for $\Lambda_c$ baryons than for $D$ mesons.

The minimal Kitaev chain that emulates a topological superconductor with three quantum dots offers a tunable platform for potentially hosting poor man's Majorana (PMM) modes. Asserting the need to go beyond differential conductance spectroscopy, we introduce current-current correlations as a viable framework for verifying their true non-locality. The robustness of the PMM modes, specifically with respect to delocalization as the system is tuned away from sweet spots, we show, is embedded in the relative magnitudes of the nonlocal transport processes. This aspect is adeptly captured by current cross-correlations, whose features show remarkable stability around the PMM sweet spot, specifically with respect to the detuning of an outer dot. We establish this as a prominent feature and a diagnostic for true PMMs even in the short chain limit. Our results accentuate the need for current cross-correlation measurements as a diagnostic framework for unambiguously verifying true non-locality of entangled states as well as topologically protected states.

We investigate the charged kaon and pion parton distribution functions (PDFs) in the U(3) Nambu–Jona-Lasinio model, considering a novel flavor-mixing interaction arising from vacuum polarization that differs from the instanton-induced 't~Hooft interaction. In this work, the proper-time regularization scheme is employed, and, effectively, it might take quark confinement into account. The gap equations, the meson masses, and the meson–quark coupling constants are calculated in the presence of flavor-mixing interactions. The valence-quark distributions of the charged kaon and pion are calculated and compared with existing experimental data and Jefferson Lab Angular Momentum analysis results at scales $\mu^{2} =$ 4 and 27 GeV$^{2}$. The strength of mixing effects on the PDFs is found to be proportional to the quark effective masses and their differences. We further find that the dominant flavor mixing effects in the pion valence up-quark distribution at scales $\mu^{2} =$ 27 and 4 GeV$^2$ are around $x \simeq 0.3$ and $x \simeq 0.8$, while for the kaon, the effects are shown at around $x \simeq 0.2$ and $x \simeq 0.7$. We also find similar strength of mixing effects on the PDFs at both scales $\mu^{2} =4$ and 27 GeV$^{2}$; however, it certainly improves the pion and kaon PDFs.

We present Hermes, an in situ multiresolution framework for efficient and flexible measurements of cosmic large-scale-structure statistics from discrete catalogues. Hermes reconstructs a catalogue as a continuous density field in a compact scaling-function basis and replaces explicit counting of particle tuples with algebraic operations among window-filtered fields. Standard binning schemes for counts-in-cells, two-point and higher-order correlation functions are thereby expressed through choices of window functions, while new statistics can be constructed by modifying the kernels without redesigning the estimator. We introduce PyHermes, an open-source Python implementation combining multiresolution reconstruction, FFT-based convolution, MPI/thread parallelism, and GPU acceleration. It supports isotropic and anisotropic two-point statistics, marked correlations, standard and multipole three-point functions, filtered statistics, and differential operators for derived physical fields. Tests with cosmological N-body halo catalogues demonstrate a range of clustering measurements and quantify the computational efficiency and scalability of the approach. By separating field representation from statistical windows, a single reconstructed field can be reused for many standard and customised measurements, making Hermes well suited to large data sets from current and future galaxy surveys.

Inelastic neutron scattering (INS) spectra of correlated 4d-4f multiferroic oxides are difficult to interpret because magnetic, crystal-field, and lattice excitations frequently overlap in energy. The hexagonal 6H perovskite Ba3HoRu2O9 provides an ideal platform to investigate this interplay owing to the coexistence of Ru2O9 molecular units and localized Ho3+ moments. To identify the contributions from these different excitations, we combine INS with linear spin-wave calculations, crystal field analysis, Raman spectroscopy, and machine-learned force field (MLFF) phonon calculations. A magnetic excitation below 6.2 meV, observed only in the low-temperature magnetic phase, is reproduced by linear spin-wave theory with intradimer Ru-Ru and Ru-Ho exchange of comparable size and a Ho single-ion anisotropy, and is therefore consistent with a collective spin-wave excitation of the coupled Ru-Ho magnetic network. At higher energies, broad excitations centered near 20, 39, 70, and 90 meV are observed that persist far above the magnetic ordering temperatures. The magnetic part of the 39 meV excitation, isolated by subtracting the Bose-corrected high-temperature data, follows the Ho3+ magnetic form factor. Crystal-field calculations based on the Stevens formalism place a group of strong Ho3+ transitions in this energy range, while Raman spectroscopy and MLFF phonon calculations identify optical phonons with comparable energies. Together, these complementary results show that the broad INS feature near 39 meV arises from overlapping Ho3+ crystal-field excitations and lattice vibrations. These findings establish a microscopic framework for understanding the interplay between spin, crystal-field, and lattice degrees of freedom in this multiferroic 4d-4f compound

We present the first simultaneous fit to deep inelastic scattering (DIS) reduced cross sections from HERA and forward single inclusive hadron production (SIHP) from RHIC and the LHC in which the dipole amplitude is obtained from Balitsky–Kovchegov (BK) evolution within the Color Glass Condensate effective theory. We demonstrate that, using the LO BK equation with running coupling (with or without kinematical constraint) and a constant per-collider $K$-factor accounting for higher-order corrections, a global $\chi^2/\mathrm{d.o.f.}$ close to unity is achieved in both schemes. The required $K$-factors are about a factor of two larger at RHIC than at the LHC, remarkably in agreement with threshold-resummed one-loop studies of forward production. In our setup and with the data available, we find the two observables to be complementary: the SIHP data tighten the constraint on the evolution speed of the dipole amplitude without introducing tension with the DIS description. We further quantify the dependence of the $K$-factors on the fragmentation-function set and the factorization scale, identifying these as the dominant systematic uncertainties to be addressed in future precision analyses of forward hadron production. We perform a full uncertainty analysis using the Hessian method, validated against a Monte Carlo Bayesian inference study.

Temperature-dependent electrical resistivity $\rho(T)$ is one of the most common types of experimental data analyzed in condensed matter physics. For one group of pure metals, the actinides, experimental $\rho(T)$ curves differ radically from one another to the point that there is no unified theoretical approach to understanding and fitting $\rho(T)$ data in these elements. First-principles calculations result in $\rho(T)$ curves that differ from experimental data, even qualitatively. In an attempt to unravel this long-standing problem, here I propose a simple model that accurately fits the $\rho(T)$ data for nine phases of elemental actinides (from thorium (Th) to curium (Cm)) for which experimental data are publicly available to date. The model is based on the concept of two parallel conduction channels: one is described by the Bloch-Grüneisen equation, which is associated with the classical electron-phonon dissipation mechanism, and the other by the Arrhenius equation, which is associated with the nearest-neighbor hopping (NNH) conductivity. Debye temperatures $\Theta_D$ obtained by applying the model to the $\rho(T)$ data for nine elemental actinide phases are in good agreement with published values deduced from heat capacity measurements. For neptunium (Np) a maximum Arrhenius activation energy (among all actinides) of $E_a=15.9$ $meV$ was derived. The model was also successfully applied to $\rho(T)$ data measured on $\delta$-phase plutonium-based alloys Pu-Ce and Pu-Ce-Ga.

We introduce the pair second-order correlation function $g_{\textrm{pairs}}^{\left(2\right)}=\left\langle \left(P^{\dagger}\right)^{2}P^{2}\right\rangle /\left\langle P^{\dagger}P\right\rangle ^{2}$, defined through the pair operator $P^{\dagger}=a^{\dagger}b^{\dagger}$, to characterize second-order correlations and pair bunching and antibunching in photon-pair creation processes. This quantity directly probes correlations between pair-generation events within a single two-mode quantum state, providing access to the intrinsic pair-generation process beyond conventional single-mode or heralded second-order correlations, which do not directly capture correlations between pair events. Values of $g_{\textrm{pairs}}^{\left(2\right)}$ greater than, equal to, or less than unity correspond respectively to pair bunching, Poissonian pair statistics, and pair antibunching. Using the Cauchy–Schwarz inequality, we further show that all classical two-mode fields described by a positive Glauber–Sudarshan \ensuremath{P}-function satisfy $g_{\textrm{pairs}}^{\left(2\right)}\geq1$, so that pair antibunching is classically forbidden and constitutes an unambiguous signature of nonclassicality. We evaluate $g_{\textrm{pairs}}^{\left(2\right)}$ for several representative quantum states and show, in particular, that even arbitrarily weak two-mode squeezed vacuum states exhibit pair bunching. Comparison with heralded second-order correlations highlights the complementary information provided by these observables. The proposed correlation function is experimentally accessible via standard coincidence measurements, requires no phase reference or state reconstruction, and remains invariant under uniform loss.

The $\alpha$-induced reactions on silver isotopes leading to the production of the medically relevant radionuclides $^{108m,109g,110m,110g,111g}$In have been systematically analyzed using the TALYS~2.0 code. A total of 192 combinations of nuclear reaction model parameters, comprising level-density models (LDM), $\alpha$-optical model potentials ($\alpha$OMP), and pre-equilibrium (PE) models, were evaluated through $\chi^2$ minimization against the available experimental data. The results reveal pronounced channel-dependent sensitivities of the statistical-model ingredients. The $^{107}$Ag($\alpha$,3n)$^{108m}$In and $^{109}$Ag($\alpha$,3n)$^{110g}$In reactions are primarily governed by the LDM. For the $^{107}$Ag($\alpha$,2n)$^{109g}$In reaction, the sensitivities to the LDM and PE mechanism are comparable, indicating that both contribute nearly equally to reproducing the experimental data. In contrast, the $^{107}$Ag($\alpha$,n)$^{110m}$In and $^{109}$Ag($\alpha$,2n)$^{111g}$In reactions are dominated by the PE mechanism, while the $\alpha$OMP plays a secondary role and the LDM has only a minor influence. These findings demonstrate that the relative importance of the statistical-model ingredients varies significantly among the investigated reaction channels. Differences between the present TALYS calculations and the TENDL-2023 evaluation are attributed to the absence of parameter optimization in the present study. Overall, the analysis shows that no single parameter combination provides the best description of all investigated reactions. The observed channel-dependent sensitivities provide useful guidance for selecting and evaluating TALYS model ingredients for the studied reaction channels and motivate future work incorporating additional experimental data and model-uncertainty quantification.

We study static, spherically symmetric self-gravitating non-Abelian 't Hooft-Polyakov monopoles in Einstein-scalar-Gauss-Bonnet gravity for two classes of scalar-Gauss-Bonnet coupling functions. We demonstrate that the branch structure of the monopole solutions depends sensitively on the choice of the coupling function. For the polynomial coupling, we show that, for sufficiently large values of the coupling parameter, the principal part of the field equations becomes locally degenerate at a critical radius, leading to a critical solution that signals a geometric phase transition. By contrast, the exponential coupling acts as a natural regulator, preventing the degeneration of the principal part and preserving smooth field profiles. Finally, we discuss a possible physical interpretation of the critical solution, in which spacetime separates into an inner region where quantum-gravitational effects may become important and an outer region that remains well described by classical general relativity.

Photonic-crystal surface-emitting lasers (PCSELs) can combine high-power operation with narrow-divergence surface emission, but optimizing coupled parameters requires costly full-wave simulations. Deep Q-network (DQN) optimization can reuse simulated transitions to guide edits, yet which value-learning mechanisms remain reliable under tight simulation budgets is unknown. We address this gap by comparing baseline DQN and six value-based variants for a seven-variable PCSEL design under a shared objective, simulator, 83-call budget, and four matched initializations. Beyond endpoints, we analyze sample efficiency, policy behavior, and physical response to separate learning gains from favorable starts or exploratory jumps. Dueling DQN is the only variant to improve all four seeds. Relative to the first evaluated designs, its selected structures increase the mean quality factor () from to (), reduce wavelength error by 64%, and increase upward power by 47%; compared with baseline DQN, they achieve a higher mean under the same budget. Other variants yield no consistent improvement; Double DQN reproduces baseline trajectories, while Rainbow-lite shows high upside but strong seed dependence. These results identify Dueling DQN as the most reliable configuration tested for simulation-budget-limited PCSEL inverse design and provide a reproducible framework for attributing algorithmic gains in scientific optimization. The source code is publicly available at https://github.com/Longying-Wen/PCSEL-RL.

We propose a Purcell-engineered notch-filter hybrid coupler for superconducting controlled-$Z$ (CZ) gates that combines coherent interaction engineering with leakage-selective dissipation. The architecture integrates a nonlinear transmon coupler with a coupled Purcell-filter and notch-resonator subsystem, providing additional control over both the coherent interaction pathways and the engineered dissipative environment. The filter branch reshapes the effective interaction pathways, while the notch resonator further tailors the frequency response of the coupled filter network and preserves strong leakage-selective dissipation. Using dressed-eigenstate analysis together with Lindblad master-equation simulations, we show that the proposed architecture substantially reduces leakage and retains high-fidelity, low-leakage operation compared with an optimized single-transmon coupler while remaining robust over a broad range of coherence assumptions and device parameters. The gate analysis reconstructs the projected computational quantum channel and therefore retains the phase information required to distinguish a CZ operation from identity. The nominal operating point occurs at $t_{\rm CZ}=327.46~\mathrm{ns}$ with $F_{\rm avg}^{\rm CZ}=99.714\%$, $L_{\rm avg}=8.78\times10^{-4}$, and $L_{\rm max}=2.04\times10^{-3}$. A minimax timing-robust operating point at $327.20~\mathrm{ns}$ maintains $F_{\rm avg}^{\rm CZ}\geq99.590\%$ over a $\pm0.50~\mathrm{ns}$ timing window. These results demonstrate that engineered dissipation complements conventional coherent interaction engineering and provides an additional design degree of freedom for realizing robust, high-fidelity superconducting CZ gates.

Atomic-scale understanding of the surface elementary processes in metalorganic vapor phase epitaxy (MOVPE) of GaN has so far relied on static density-functional-theory (DFT) energetics and on first-principles molecular dynamics (FPMD) limited to a few tens of picoseconds. Here we combine FPMD with a universal machine-learning interatomic potential (MLIP), UMA, to follow the dynamics of growth-related adspecies on GaN(0001) over time scales inaccessible to purely first-principles approaches. FPMD simulations of a GaNH admolecule coexisting with H adatoms reveal a hitherto unrecognized diffusion mode, in which the N atom lifts the Ga atom of the GaNH unit off the surface layer during migration, and show that the lifted Ga abstracts an H adatom from the surface, events invisible to static DFT. Single-point UMA calculations on FPMD snapshots reproduce the first-principles relative energies along the trajectory (RMSE of about 8.5 meV/atom) without any retraining. Long-time MLIP-based MD (150 ps) then reveals dynamics never observed within the FPMD window: site-to-site H-adatom hopping, which gates the migration paths of the growth unit, and reversible dissociation of the GaNH unit into independently migrating Ga and NH adspecies. This work constitutes, to our knowledge, the first application of an MLIP to the molecular dynamics of GaN MOVPE.

Vincent van Gogh's prolific artistic output and personal correspondence offer a unique window into the psychological trajectory of a 19th-century artist. This study applies computational methods to analyze emotional patterns across van Gogh's final decade through sentiment analysis of over 700 letter segments and fractal dimension analysis of 569 paintings. Using critical slowing down (CSD) theory from dynamical systems, we examine whether van Gogh's psychological system exhibited mathematical signatures of approaching tipping points. Our analysis reveals a statistically significant correlation between visual complexity and death sentiment ($r = 0.193, p < 0.001, n = 524$), alongside evidence for CSD patterns in multiple psychological dimensions before major crises. The 1888 ear incident shows coordinated variance spikes across acquired capability, desire for death, and visual complexity preceding the event, followed by stabilization before the crisis. These findings demonstrate that mathematical approaches can detect psychological transition signatures in historical figures while revealing the complex multi-modal nature of psychological systems.

Despite its promise as a lead-free alternative, the practical application of Cs2AgBiBr6 in optoelectronics is limited by its wide band gap and detrimental intrinsic defects. To overcome these challenges, we synthesized Cs2AgBi0.5Fe0.5Br6 single crystals via a modified hydrothermal method. While both pristine and Fe-doped crystals undergo a structural phase transition near 125 K, Fe incorporation fundamentally alters its impact. The dopant simultaneously narrows the band gap in the high-temperature phase and suppresses the associated cryogenic structural instability. Our optical and X-ray structural studies establish Fe doping as a powerful strategy for tailoring the properties of Cs2AgBiBr6 , advancing its potential for high-performance, low-temperature optoelectronic and spintronic devices.

We review the temperature dependence of Bloch equations. The temperature dependence of nuclear magnetization in thermodynamic equilibrium and relaxation are reviewed, and relations are developed to account for the temperature effects in a nuclear magnetic resonance experiment. It is found that the temperature dependence of the Bloch equations precisely accounts for the temperature effects observed in a nuclear magnetic resonance experiment.

We prove a strong converse for quantum communication over Pauli channels within the class of stabilizer codes. If a code whose code space is a full joint eigenspace of a stabilizer group transmits above the coherent information of its own input state, its entanglement fidelity decays exponentially in the block length; the encoder may be any isometry onto that space and the decoder any channel. For memoryless channels this determines the $\varepsilon$-quantum capacity of the class for every $\varepsilon < 1$, so that tolerating a constant error buys no rate; for antidegradable channels, such as the depolarizing channel with error probability $p \in [1/4, 3/4]$, that capacity is zero, while for $p \in [1/4,1/2)$ partial-transposition bounds provably cannot certify a strong converse. The proof uses neither additivity assumptions nor semidefinite relaxations: optimal decoding succeeds precisely on an event in a product probability space, so the blowing-up lemma of Ahlswede, Gács and Körner applies, and the side information it produces is charged against the coherent information. The argument also constrains near-deterministic decoding for codes of any kind, and we isolate the encoder-side statement that would extend it to all of them.

Passive and active photonic components are central to the continued development of astronomical photonic integrated circuits (PICs), although achieving broadband achromatic performance remains a significant challenge. This work presents broadband evanescent tri-couplers, tapered directional couplers, and a chromatically controlled achromatic intensity modulator for astronomical interferometry in the J- and H-bands. Silicon nitride and silicon oxide provide complementary low-loss platforms, while customised tapered components enable broadband operation across the 0.95-1.8 microns range. For the silicon nitride platform developed by STMicroelectronics, tapered tri-couplers and directional couplers were designed as replacements for conventional components in a pairwise beam combiner for the PLANETS project. Optimised tapered tri-couplers achieve less than 1% excess loss across the J-band, while tapered directional couplers provide broadband 40:60 splitting suitable for beam combination. For the silicon oxide platform from Enablence, a two-dimensional tapered tri-coupler was investigated for nulling interferometry. The device provides broadband starlight suppression while limiting exoplanet throughput loss to less than 2.2% across the H-band and simultaneously retaining broadband phase-sensing capability for fringe tracking. The chromatically controlled achromatic intensity modulator is introduced as a combination of a tapered directional coupler with a thermo-optic phase shifter, the device provides programmable broadband intensity control for applications including null-depth balancing in interferometric PICs. Future work will extend these concepts to lithographically fabricated chalcogenide glass platforms operating in the mid-infrared, enabling compact photonic beam combiners for future ground- and space-based nulling interferometers targeting Earth-like exoplanets.

We develop a light-front Faddeev description of baryons in two-dimensional QCD at $N_c=3$, in which an exact coupled-channel representation identifies the quark–diquark picture as a single-channel truncation, and solve it variationally with exact matrix elements. In the chiral limit we find an exactly massless lightest baryon, in agreement with the classic valence solutions, DLCQ, and bosonization; the excitation tower reproduces Webber's spectrum state by state and sets the valence gap $1.371\,M^{\ast}_{\rm mes}$. The channel content distinguishes these states: the massless baryon is single-channel, the gapped states are genuinely multi-channel, and all baryon Regge trajectories are of the meson class. The calculation is anchored at both ends of the coupling range: the meson-to-baryon mass ratio agrees with strong-coupling bosonization to $0.3$–$4.3\%$, while the valence masses reproduce the full discretized light cone quantization (DLCQ) masses to $0.04\%$ (meson) and $0.15\%$ (baryon) at weak coupling. Extending to two degenerate flavors, we find the massless baryon to be the $\Delta$-like quartet, while the $N$-like doublet at $0.977\,M^{\ast}_{\rm mes}$ is an exact $50\!:\!50$ superposition of good- and bad-diquark channels. Adding a massive strange quark, we obtain, to our knowledge for the first time at the valence three-quark level, the hyperon spectroscopy of QCD$_2$: $\Sigma$-like states fall below $\Lambda$-like ones, inverting the four-dimensional ordering, the chiral thresholds count two kaon units per strange quark, and the Gell-Mann–Okubo relation is protected in mass squared. With all three quark masses non-degenerate, the proton-like state falls below the neutron-like one, $\Sigma^0$–$\Lambda$ mixing appears, and the Coleman–Glashow relation holds at the percent level.

In this note, we consider the Sherrington–Kirkpatrick model with deterministic external field. Let $q=q(\beta,h)$ denote the solution of the replica-symmetric self-consistency equation \[ q=\mathbb E\tanh^2\!\left(h+\beta\sqrt q\,Z\right), \qquad Z\sim N(0,1), \] where $\beta$ and $h$ are inverse temperature and external field, respectively. By refining Lata\la' s argument, previously limited to \(\beta < \frac{1}{2}\), and using the Kearns–Saul inequality, we prove overlap concentration and convergence of the free energy to the replica symmetric formula with error \(O(N^{-1})\) whenever \[ \beta^2\frac{q}{{\rm arctanh}q}<1. \] Note that for any $\beta<1$ and $h\in \mathbb R$, the condition above is satisfied. Moreover, for every nonzero $h$, this region contains a nonempty interval with $\beta>1$.

We develop a unified algebraic framework for nonlocal derivative nonlinear Schrödinger (DNLS)-type hierarchies based on loop algebra splittings. Within this framework, nonlocal and reverse space-time reductions are realized through algebraic constraints, leading to the corresponding integrable hierarchies. By constructing simple elements and establishing the associated factorization theory, we derive Darboux transformations (DTs). And apply DTs to construct explicit solutions.