글로벌 딥테크 최신 학술 논문 스트림

Nearest-neighbor (NN) tight-binding models (TBMs) on plaquette-centered $\{ 10,3\}$ (Schläfli symbol), $\{ 8,3\}$, and $\{ 8,4\}$ hyperbolic lattices on a Poincaré disk with open boundary conditions display a vanishing, a finite, and a diverging density of states (DOS) near zero energy (band center), respectively, yielding a Dirac liquid, a Fermi liquid, and a flat band. Emergent bipartite nature of these lattices within the framework of NN-TBMs, allows us to scrutinize the impact of mass disorder on the electronic states and DOS therein. From extensive numerical calculations of the average and typical DOS using the kernel polynomial method, we show that hyperbolic Dirac liquid remains stable against weak mass disorder, undergoing a semimetal-to-metal quantum phase transition at moderate disorder, followed by an Anderson metal-to-insulator transition at even stronger disorder. The remaining two systems display only the latter transition. Critical exponents near all these transitions are found to be close to the ones mediated by on-site potential disorder.

Quantum impurity models are paradigmatic models of interacting quantum matter, as well as key computational primitives for modern electronic-structure methods. They describe a small subsystem of interacting fermions coupled to a large, noninteracting bath. We perform a comprehensive study of the computational complexity of simulating impurity models, delineating the boundary between classical and quantum tractability for this class of problems. Our main finding is that static properties of quantum impurity models can be calculated efficiently on a classical computer. Specifically, we give classical algorithms that (1) estimate the ground-state energy to additive precision $δ$ in time $\mathrm{poly}(n,δ^{-1})$, and (2) estimate the partition function at inverse temperature $β$ to relative precision $δ$ in time $\mathrm{poly}(n,β,δ^{-1})$, where $n$ is the system size. These results improve the previous best-known complexity for ground-state energy estimation from quasipolynomial to polynomial time, while establishing for the first time rigorous polynomial-time guarantees for simulating impurity models in thermal equilibrium. On the other hand, we find that simulating dynamical properties of impurity models is hard for classical computers but easy on a quantum computer. As a canonical example, we show that computing their nonequilibrium Green's functions captures the full power of quantum computation, even at finite temperature. Taken together, our results rule out superpolynomial quantum speedups for computing static properties, but provide an avenue for quantum advantage in simulating impurity physics out of equilibrium.

Processor pipeline visualization tools are routine inside industry CPU teams, but few of them are described or released publicly. As a result, students, researchers, and other practitioners rarely see the tooling that processor architects use to debug performance before silicon. This paper describes two pieces of Ampere Computing's performance- analysis infrastructure that we have released to the community as open source: event streams, a simulator-output format, and Catscan, an interactive viewer built around that format. Event streams record microarchitectural activity as typed events connected by transaction relationships, so a user can move between a symptom and the instruction, uop, or memory transaction that explains it. Catscan uses that structure to support resource- and transaction-oriented views, persistent highlighting, domain-specific search, comparative trace synchronization, and other workflows used during product development. In this paper we report the design choices that survived production use, the limitations we encountered, and the lessons we think are useful for future microarchitectural visualization tools.

Epitaxial quantum dots (QDs) are widely recognised as one of the best quantum light sources, given their good stability, brightness, quantum efficiency and coherence. To reach such properties, QDs are protected from potentially detrimental surface states by a relatively thick capping layer, typically exceeding 50nm. This prevents the implementation of near-field effects, like plasmonic-based ones, that can dramatically increase the light-matter interaction, since the control of the spontaneous emission dynamics and directionality of the emission can only occur if the emitter is in close proximity (typically tens of nanometers or less) from the metallic structures. In this work, we report the growth and optical characterisation of InAs/GaAs QDs with GaAs capping layer thickness of 10nm, 20nm, and a more standard 95nm. Remarkably, we observe emission linewidths up to 5 times smaller than previously reported, with unperturbed excitonic lifetimes. These results demonstrate that the epitaxial QD's high optical quality can be maintained even when the emitters are at reduced distances from the surface, opening the path for the exploration of near-field light-matter interactions with coherent and stable emitters, suitable for quantum technology applications.

Epitaxial quantum dots (QDs) are widely recognised as one of the best quantum light sources, given their good stability, brightness, quantum efficiency and coherence. To reach such properties, QDs are protected from potentially detrimental surface states by a relatively thick capping layer, typically exceeding 50nm. This prevents the implementation of near-field effects, like plasmonic-based ones, that can dramatically increase the light-matter interaction, since the control of the spontaneous emission dynamics and directionality of the emission can only occur if the emitter is in close proximity (typically tens of nanometers or less) from the metallic structures. In this work, we report the growth and optical characterisation of InAs/GaAs QDs with GaAs capping layer thickness of 10nm, 20nm, and a more standard 95nm. Remarkably, we observe emission linewidths up to 5 times smaller than previously reported, with unperturbed excitonic lifetimes. These results demonstrate that the epitaxial QD's high optical quality can be maintained even when the emitters are at reduced distances from the surface, opening the path for the exploration of near-field light-matter interactions with coherent and stable emitters, suitable for quantum technology applications.

Nonlinear nanophotonics enables the engineering of optical functions using light-matter interactions in nanoscale structures with carefully designed geometries. Phase matching in nonlinear optics is typically essential for realizing high efficiency for desired processes and engineering of sophisticated functions, but it can be challenging to reliably achieve in nanophotonic waveguides. Conventionally, phase matching in nanophotonics is achieved through nanofabrication, e.g., by poling a device's nonlinear material using electrodes with fixed geometry. This approach has two drawbacks: the optical functions a device can perform are fixed at the time of fabrication, and the device's performance can be degraded by fabrication imperfections. Here, we circumvent these limitations by engineering programmable $χ^{(2)}$ holograms inside nanophotonic waveguides, enabling reconfigurable quasi-phase matching that can be updated after device fabrication in approximately one second. By projecting structured optical illumination onto photoconductive electrodes, we generated spatial patterns of electric-field-induced $χ^{(2)}$ to exert spectral, modal, and polarization control over three-wave mixing processes. This programmability also allowed us to employ closed-loop in situ optimization to compensate for phase mismatch in complex waveguide structures, such as width-modulated waveguides and spiral waveguides exceeding 10 cm in length. Furthermore, we show that programmable nonlinearity enables powerful in situ diagnostics, including direct dispersion measurements of various transverse modes and on-chip wavefront phase tomography. Our work opens up the possibility of building cascaded nonlinear nanophotonic systems where yield issues due to fabrication variations can be sidestepped while retaining the benefits of etched waveguides such as confinement and dispersion engineering.

Nonlinear nanophotonics enables the engineering of optical functions using light-matter interactions in nanoscale structures with carefully designed geometries. Phase matching in nonlinear optics is typically essential for realizing high efficiency for desired processes and engineering of sophisticated functions, but it can be challenging to reliably achieve in nanophotonic waveguides. Conventionally, phase matching in nanophotonics is achieved through nanofabrication, e.g., by poling a device's nonlinear material using electrodes with fixed geometry. This approach has two drawbacks: the optical functions a device can perform are fixed at the time of fabrication, and the device's performance can be degraded by fabrication imperfections. Here, we circumvent these limitations by engineering programmable $χ^{(2)}$ holograms inside nanophotonic waveguides, enabling reconfigurable quasi-phase matching that can be updated after device fabrication in approximately one second. By projecting structured optical illumination onto photoconductive electrodes, we generated spatial patterns of electric-field-induced $χ^{(2)}$ to exert spectral, modal, and polarization control over three-wave mixing processes. This programmability also allowed us to employ closed-loop in situ optimization to compensate for phase mismatch in complex waveguide structures, such as width-modulated waveguides and spiral waveguides exceeding 10 cm in length. Furthermore, we show that programmable nonlinearity enables powerful in situ diagnostics, including direct dispersion measurements of various transverse modes and on-chip wavefront phase tomography. Our work opens up the possibility of building cascaded nonlinear nanophotonic systems where yield issues due to fabrication variations can be sidestepped while retaining the benefits of etched waveguides such as confinement and dispersion engineering.

Equivariant machine learning interatomic potentials (MLIPs) have revolutionized atomistic modeling, but accurate treatment of complex materials and molecular systems demands expensive models. This limits simulation length- and time-scales, with tensor products a key computational bottleneck. The recent emergence of foundation-scale MLIPs further exacerbates this challenge. We present Branch Interatomic Potential (BranchIP), a single-model framework for learned adaptive tensor product computation, trained with a novel distillation loss. In our experiments on two systems of physical interest, a heterogeneous catalysis system and a proton-conducting solid acid electrolyte, BranchIP accelerates MLIPs across model sizes by up to $2.4\times$ while reducing memory usage by up to $2.6\times$. This is achieved while maintaining physical fidelity. Furthermore, the learned adaptive computation provides model interpretability by revealing which interactions demand deeper computation and showing how computational depth relates to chemical complexity and dynamics.

Equivariant machine learning interatomic potentials (MLIPs) have revolutionized atomistic modeling, but accurate treatment of complex materials and molecular systems demands expensive models. This limits simulation length- and time-scales, with tensor products a key computational bottleneck. The recent emergence of foundation-scale MLIPs further exacerbates this challenge. We present Branch Interatomic Potential (BranchIP), a single-model framework for learned adaptive tensor product computation, trained with a novel distillation loss. In our experiments on two systems of physical interest, a heterogeneous catalysis system and a proton-conducting solid acid electrolyte, BranchIP accelerates MLIPs across model sizes by up to $2.4\times$ while reducing memory usage by up to $2.6\times$. This is achieved while maintaining physical fidelity. Furthermore, the learned adaptive computation provides model interpretability by revealing which interactions demand deeper computation and showing how computational depth relates to chemical complexity and dynamics.

Throughput in DSP and machine learning workloads is often limited by two temporal structures, i.e., loop-carried recurrences and long-latency, multi-cycle compute nodes. On spatio-temporal coarse-grained reconfigurable arrays (CGRAs), both bottlenecks can be addressed by overlapping iterations across the multi-context modulo configurations. Yet, existing CGRA mappers schedule a fixed dataflow graph (DFG) that treats recurrence-aware scheduling and operator-level pipelining separately, limiting inter-iteration overlap and inflating routing pressure. To tackle this, we present CONFERM, a recurrence-aware temporal mapper that uses the dominant temporal con-straint to guide the DFG representation and expose opportunities for loop-carried pipelining. CONFERM identifies and prioritizes bottleneck regions during scheduling. The regular loop-carried offsets across interleaved iterations allow the emitted control sequence to repeat at a shorter cadence than the original initiation interval, thus delivering higher throughput with lower CGRA configuration overhead. Across ten benchmark kernels, CONFERM improves throughput by 2.18x over state-of-the-art mappers. Its uniform iteration offsets shorten the emitted initiation interval by 46%. CONFERM's mapper pass also converges faster by 5.07x on average with the same heuristic mapper backend.

Compact ground-state preparation circuits are essential for early fault-tolerant quantum chemistry. We introduce Variational Imaginary-time Majorana Evolution (VIME), a classical pre-training algorithm that extends operator-projected variational quantum imaginary-time evolution (OVQITE) to molecular electronic structure using a single compiled Majorana-propagation (MP) surrogate graph. We pair VIME with a compressed tiled Unitary Product State (c-tUPS) ansatz that we develop to reduce both classical simulation and quantum state-preparation costs. In the strongly correlated ruthenium complex TLD-1411, active-space calculations requiring up to 52 qubits achieve chemical precision against DMRG reference energies, with energy errors approximately $400\times$ smaller than those from ADAPT-VQE-based variational Majorana-propagation (ADAPT-VMPE). Across the strongly multireference acene series up to heptacene (60 qubits), VIME matches or improves on the MP-reported energy accuracy of the ADAPT-VMPE comparison points with up to $26\times$ fewer CNOTs and $167\times$ lower two-qubit depth. These results establish imaginary-time classical pre-training of compressed variational ansätze as a promising route to resource-efficient molecular ground-state preparation.

Sparse expert activation reduces MoE models' computation, yet expert weights can exceed limited device memory. Offloading makes inference feasible on a compact AI appliance but exposes host-to-device transfers to the inference path. We present MoE-CORE, a system that coordinates expert offloading and residency for memory-constrained MoE inference. It stages complete expert layers in alternating buffers during prefill. During decode, it combines nonuniform layer-wise cache capacity, domain-informed initialization, routing-history-aware replacement, and cross-layer prefetching. The main configuration executes router-selected experts exactly; an optional score-based substitution path handles eligible low-score misses. The main comparison uses 1K- and 128-token output caps for MoE-CORE and vLLM Prefetch, respectively. Across five workloads per model, MoE-CORE records a mean time per output token (TPOT) of 38.0-44.8 ms versus 1268.9-1269.1 ms for the evaluated vLLM Prefetch configuration on DeepSeek-V4-Flash-W4A8; the corresponding values on GLM-5.2-W4A8C8 are 206.6-220.5 and 5941.5-5941.8 ms. Under an 84-GB NPU-memory cap, the best measured DeepSeek GSM8K configuration achieves a TPOT of 21.5 ms with approximate expert substitution and multi-token prediction (MTP) at depth 2. These results support coordinated expert residency and transfer scheduling under a device-memory constraint. The code is here.

The timing behavior of a mapped circuit depends on both its logic implementation and the physical environment in which that implementation is realized. Revisiting mapping decisions after placement therefore requires a search procedure that accounts for surrounding timing constraints, fanout loads, and interconnect effects. We study local remapping in this setting and develop a framework that couples discrete mapping search with physical implementation feedback. Timing-critical regions are isolated through bounded windows whose interfaces retain the context of the surrounding circuit. Within each window, a mixed-integer formulation jointly selects logic cuts, signal polarities, and library cells under a delay model informed by estimated locations and interconnect parasitics. A continuous relaxation filters the search space before discrete optimization produces alternative implementations with similar modeled timing and different structural choices. These implementations are reconstructed and assessed through legalization, routing-based parasitic estimation, and timing analysis. Physically validated improvements are incorporated into the design, and the updated context guides subsequent searches. The framework provides a systematic way to revisit local logic implementations while accounting for their interaction with an existing placement.

The chirality-induced spin selectivity (CISS) effect, the coupling between structural chirality and electron spin polarization, has been experimentally observed across many diverse systems. However, despite extensive theoretical effort, a unified mechanistic understanding remains elusive. In this perspective, we demonstrate how some of the basic properties of the fascinating effects of CISS can be understood based on straightforward symmetry considerations commonly employed in fundamental particle physics. In particular, we show that CISS does not violate any fundamental symmetries including parity and time-reversal. By anchoring CISS within the universal language of symmetry, we offer a robust conceptual foundation for interpreting experiments and guiding future theoretical and experimental designs.

The chirality-induced spin selectivity (CISS) effect, the coupling between structural chirality and electron spin polarization, has been experimentally observed across many diverse systems. However, despite extensive theoretical effort, a unified mechanistic understanding remains elusive. In this perspective, we demonstrate how some of the basic properties of the fascinating effects of CISS can be understood based on straightforward symmetry considerations commonly employed in fundamental particle physics. In particular, we show that CISS does not violate any fundamental symmetries including parity and time-reversal. By anchoring CISS within the universal language of symmetry, we offer a robust conceptual foundation for interpreting experiments and guiding future theoretical and experimental designs.

Low-precision inference is widely adopted in edge AI to reduce computational cost and memory footprint. However, existing open-source accelerator platforms provide limited end-to-end support for CNNs following the standard TensorFlow Lite integer inference scheme. This paper presents ZTA-Q, an open-source RISC-V-based platform that enables accurate deployment of TensorFlow Lite INT8 models. In addition to extending operator support, ZTA-Q provides a configurable post-processing datapath for studying how circuit-level approximations, including reduced multiplier precision, shared shift scaling, and simplified rounding, affect model accuracy. The proposed system is implemented on a Digilent Arty A7-100T FPGA and operates at 83.3 MHz. Evaluations on representative CNN models show that with LUT, register, and DSP overheads of 26.3%, 12.6%, and 150%, respectively, ZTA-Q limits the degradation in both top-1 and top-5 accuracy to within 0.25 percentage points.

Nonreciprocal supercurrents in interacting nanostructures can arise when the positive and negative critical currents probe inequivalent portions of a phase-dependent many-body spectrum. We study this mechanism in a parallel double-quantum-dot Josephson junction with strong intradot Coulomb repulsion, where local and non-local Cooper-pair transfer coexist. Using exact diagonalization of a zero-bandwidth Hamiltonian with explicit superconducting orbitals, we show that orbital flux and the gauge-invariant tunnel-sign parity control the interference between local Josephson processes and non-local exchange. For detuned dots, this produces flux-tunable singlet, triplet, and doublet ground-state spectral branches and two rectification regimes. Near the boundaries of the charge sector with singly occupied dots [(1,1) sector], doublet branches compete with singlet or triplet branches, yielding diode efficiencies approaching 40%. Within the triplet-dominated (1,1) sector, nearby singlet crossings asymmetrically reshape the ground-state envelope even when both critical-current extrema lie on the triplet-like branch, producing a broader response of order 10-15%. Finite temperature generally suppresses charge-crossover rectification, however, for intermediate temperatures we find an enhancement of both the normalized efficiency and the absolute critical-current asymmetry in the triplet regime. These results establish phase-dependent many-body branch competition as a gate-, flux-, and tunnel-parity-sensitive source of Josephson nonreciprocity.

Nonreciprocal supercurrents in interacting nanostructures can arise when the positive and negative critical currents probe inequivalent portions of a phase-dependent many-body spectrum. We study this mechanism in a parallel double-quantum-dot Josephson junction with strong intradot Coulomb repulsion, where local and non-local Cooper-pair transfer coexist. Using exact diagonalization of a zero-bandwidth Hamiltonian with explicit superconducting orbitals, we show that orbital flux and the gauge-invariant tunnel-sign parity control the interference between local Josephson processes and non-local exchange. For detuned dots, this produces flux-tunable singlet, triplet, and doublet ground-state spectral branches and two rectification regimes. Near the boundaries of the charge sector with singly occupied dots [(1,1) sector], doublet branches compete with singlet or triplet branches, yielding diode efficiencies approaching 40%. Within the triplet-dominated (1,1) sector, nearby singlet crossings asymmetrically reshape the ground-state envelope even when both critical-current extrema lie on the triplet-like branch, producing a broader response of order 10-15%. Finite temperature generally suppresses charge-crossover rectification, however, for intermediate temperatures we find an enhancement of both the normalized efficiency and the absolute critical-current asymmetry in the triplet regime. These results establish phase-dependent many-body branch competition as a gate-, flux-, and tunnel-parity-sensitive source of Josephson nonreciprocity.

Propagating the electronic and nuclear degrees of freedom of a molecule simultaneously is a challenging task, because the number of vibronic states grows exponentially with system size. We use the adaptive time-dependent density matrix renormalization group to perform simulations of the extended Hubbard-Peierls Hamiltonian, in which both the electronic and nuclear degrees of freedom are quantized. We describe our approach, and demonstrate it through converged calculations of the nonadiabatic dynamics of hexatriene. This simulation predicts a lifetime of the `bright' $\mathrm{1B_u}$ electronic state of approximately 40 fs. Our predictions for the population of the $\mathrm{1B_u}$ electronic state are in qualitative agreement with those obtained using the linear vibronic coupling model derived from the extended Hubbard-Peierls Hamiltonian in previous work.

Heterogeneous high--performance computing architectures expose numerical algorithms to perturbations arising from the non--associativity of floating--point arithmetic. In Large--Eddy Simulation (LES), similar numerical effects may become relevant when they affect the filter--width entering the subgrid scale (SGS) model. This work investigates this mechanism for the least--squares (LSQ) based filter--width formulation, focusing on how floating--point effects are generated, transmitted, and coupled with the resolved flow. We show that, for fixed resolved kinematics, the LSQ filter--width is logarithmically non-expansive but not strictly contractive with respect to perturbations of the mesh metrics. Consequently, small disturbances may be transmitted with little attenuation through strongly directional filter-width responses. To mitigate this sensitivity, we introduce a scalar max--min compression of the directional mesh scales together with a bounded modulation based on the resolved velocity gradient. The resulting formulation reroutes floating--point perturbations through the filter-width operator, improving robustness while preserving the flow--dependent character of the original LSQ construction. The framework is assessed on heterogeneous CPU and GPU architectures for flow past a circular cylinder at Re=3900 and the Taylor--Green vortex at Re=1600. In the former, nearly one--to--one transmission of relative metric disturbances can become relevant when the transmitted perturbations interact with shear-layer transition. By contrast, on orthogonal Taylor--Green vortex grids, the accumulation pathway is structurally absent and no comparable macroscopic response develops. These results suggest floating--point sensitivity matters for LES filter--width formulations in heterogeneous computing environments.

Conceptual density functional theory (CDFT) defines chemical reactivity descriptors as derivatives of the electronic energy with respect to the number of electrons and the external potential, or combinations thereof; in practice, however, researchers almost always replace these derivatives with finite-difference and frontier-orbital approximations, and no common software exists for their analytical evaluation. We present PyCDFT, to our knowledge, the first standardized, open-source, and scriptable code that analytically computes the descriptors of conceptual density (matrix) functional theory for ground and excited states up to second order, including the orbital hardness, the Fukui function and Fukui matrix, and the linear response function, from a single converged mean-field wavefunction imported from virtually any electronic-structure package. The descriptors are obtained from matrix-free, preconditioned Krylov-subspace solutions of the coupled-perturbed self-consistent-field equations for both spin-unpolarized and spin-polarized references, with the work distributed over MPI ranks and all data flowing through a single HDF5 checkpoint file that supports restart, post-processing, and the export of real-space descriptors as cube files for visualization. The design delegates integrals, grids, and exchange-correlation kernels to PySCF and Libxc, keeping the library compact, user-friendly, and interoperable. Worked examples on the ground state of H$_2$O and a broken-symmetry $Δ$SCF excited state of NH$_3$ show that a complete second-order CDFT analysis requires only a few lines of user code.

Bismuth telluride (Bi2Te3) is a prototypical V-VI semiconductor of interest for both thermoelectric and topological applications; however, phase-selective synthesis and thermal stability across the bismuth-telluride homologous series remain poorly understood. We report a facile and phosphine-free colloidal synthesis approach for a phase-selective synthesis of Bi2Te3, BiTe, and Bi4Te5 nanosheets with well-defined hexagonal morphology. By controlling precursor chemistry and reaction temperature, we achieved the selective formation of different phases within the (Bi2)m(Bi2Te3)n homologous series. Based on in situ heating studies, BiTe and Bi4Te5 nanosheets transform into Bi2Te3 at about 340 degree C, followed by preferential Te sublimation under vacuum or oxidation in air at higher temperatures. We discuss plausible mechanisms for these phase transformations. EDS analysis and FFT analysis of STEM images provide direct evidence for the temperature-dependent compositional and structural changes and highlight the close thermal relationship among these phases. These results not only advance fundamental understanding of phase stability and thermal behavior in bismuth-tellurides at the nanoscale but also establish a framework for understanding structural evolution in related homologous series, providing insights into their potential future applications in thermoelectric, spintronic, and topological systems.

Control of molecular angular momentum orientation enables state-resolved studies of molecular interactions and provides a basis for quantum information processing. Here we propose all-optical Autler-Townes state-selective adiabatic passage (ASAP) to prepare molecules in a single $|J,M\rangle$ sublevel. An Autler-Townes branch created by a strong coupling field is selectively populated and adiabatically mapped onto the target vibrational state. We resolve detuning-dependent rovibrational Autler-Townes splitting in $^{13}$CO$_2$, establishing the spectroscopic basis for the selective excitation of the target dressed branch. The density-matrix model calibrated by these spectra predicts transfer approaching 90\%. The scheme can exploit millisecond vibrational radiative lifetimes within the electronic ground state and extend to polar and nonpolar molecules with infrared-active vibrational modes.

We demonstrate the complete observation of a black-hole lightring resonance in an optical analogue. To do so, we generalize the concept of the photon sphere to non-stationnary systems by showing that the lightring is associated to a spatiotemporal caustic and that its complex frequency is determined by the propagation and divergence of this caustic. For an optical soliton acting as an analogue black-hole potential, we predict a characteristic spectral plateau whose boundaries are set by the real part of the lightring frequency, while its spectral decay is governed by the imaginary part. Using a pump-probe experiment in a 5-km-long dispersion-shifted fiber, we observe these signatures for two distinct pump wavelengths. The measured spectra agree with numerical simulations and with the predicted lightring-mode profile, providing direct access to both the oscillatory and decay properties of the resonance. Our results establish a direct experimental connection between black-hole lightrings, spacetime caustics, and quasinormal-mode spectroscopy in a dispersive analogue system.

Several ad hoc dispersion models for density-functional theory are based on the use of Hirshfeld (or "stockholder") partition of a molecular charge density, which provides an in situ definition of atomic size. We show that a recently introduced "optimized" quantum Drude oscillator model for dispersion admits a closed-form solution in terms of the Lambert $W$ function, whose branches identify the compact and diffuse oscillator solutions. The compact solution determines the $C_8$ (dipole-quadrupole) dispersion coefficient analytically from the free-atom polarizability, $C_6$ coefficient, and van der Waals radius, without any reference $C_8$ data. Next, we provide a formal basis for a relativistic version of the atoms-in-molecule Hirshfeld partition. Using four-component Dirac-Hartree-Fock densities for isolated atoms defines a strictly positive deformation field that carries the relativistic changes in atomic density into the Hirshfeld partition. A uniqueness theorem for the non-relativistic case is extended to relativistic Hirshfeld atoms and admits an asymptotic expansion through quadratic order in the fine-structure constant. Normalization requires the relativistic density correction to reshape the reference atom while preserving its population. Finally, four-component polarizabilities and C6 coefficients are reported for closed-shell atoms and ions, which supply the reference data required to extend atoms-in-molecules dispersion models into the heavy-element regime. Periodic trends are observable in a scalar contraction factor that measures relativistic effects.

Wearable ultrasound probes must transfer increasingly large acquisition payloads while maintaining compact, low-power electronics. In TinyProbe, the current bottleneck in data transfer occurs between the acquisition FPGA and the wireless system controller. This work presents an open-source, multi-wire SPI readout interface that uses serial command and address phases followed by a build-time-selectable dual- or quad-lane payload phase that is intended to address this bottleneck by increasing the potential bandwidth over the wifi limit while retaining compatibility with the Microcontroller-centric wearable US architecture. The interface emulates a serial flash memory, enabling compatibility with a broad range of microcontroller families and their existing peripheral interfaces. On the FPGA, the data path connects the existing acquisition FIFOs to the SPI interface through clock-domain crossing, sample reshaping, and packing into 32-bit words. Dual-SPI readout is integrated into the existing IGLOO2/SiWG917 TinyProbe architecture and verified at an SCLK frequency of 5 MHz. A separate Kria K26 testbed is used to characterize the FPGA SPI interface independently of the acquisition and wireless subsystems, demonstrating error-free transfers at SCLK frequencies up to 66 MHz. These measurements identify the SiWG917 multi-lane SPI implementation as the next bandwidth-limiting component and motivate a future upgrade of the system controller. The HDL and MCU implementations are released under a permissive open-source license.

Miniaturized ultrasound (US) probes require programmable and synchronized transmit (TX) excitation across multiple elements, while existing compact platforms often rely on limited microcontroller (MCU) pulse generators or closed-source fixed-function pulser devices. We present U-Sonic, an open-source digital US TX peripheral integrated into a 32-bit RISC-V system-on-chip (SoC). The implemented SoC integrates 8 pulser cores, while the parameterized architecture supports up to 16 channels. Each core generates single- or dual-tone bursts with programmable period, duty cycle, pulse count, polarity, and idle level, together with optional inverted stop pulses for active damping. A shared memory-mapped Open Bus Interface (OBI) enables synchronous start and stop of arbitrary channel subsets and supports composite bipolar, gated, and three-level excitation schemes. Functional correctness was verified in Verilator against a Python golden model over 4379 checked cycles across directed and randomized configurations, and confirmed on a Terasic DE10-Lite field-programmable gate array (FPGA). The design was synthesized and placed-and-routed in IHP 130 nm. The post-layout area in kilo gate equivalents (kGE), scales as 1.65 kGE plus 1.66 kGE per channel. The 8-channel instance occupies 14.9 kGE, corresponding to approximately 14.3% of the 104 kGE SoC. The register-transfer level (RTL), register descriptions, verification collateral, and software support are released as open source.

Wearable ultrasound enables continuous deep-tissue monitoring, and a single programmable probe can operate in multiple complementary modes, such as structural A-mode and Doppler flow measurement. However, each operating mode requires dedicated measurement parameters and peripheral states, with no single configuration serving all modes on resource-constrained devices. Time multiplexing of operating modes introduces reconfiguration latency that lowers the effective mode repetition rate. To address this limitation, we present an open-source, transition-aware control stack for low-latency, in-session reconfiguration of the 32-channel TinyProbe wearable platform. Operating modes are described as hardware configurations, and host-side shadow registers track the peripheral states, enabling transition-specific register updates. Transition sequences are executed either by the host (over Wi-Fi 6) or by a firmware loop on the probe MCU. We validate the stack on a pulsatile-flow phantom by interleaving blocks of 25 to 100 pulsed-wave Doppler shots at 1.43 kHz PRF with single 16-channel A-mode acquisitions, changing channel configurations at every transition. Compared to full reconfiguration, the overhead per transition decreases from 30.2 ms to 11.6 ms (host-scheduled) and 3.1 ms (MCU-scheduled). For 75-shot Doppler blocks, the multi-mode repetition rate reaches 16.0 Hz (MCU-scheduled), 90.1% of the theoretical maximum of 17.7 Hz. Concurrent reconstruction of a Doppler spectrogram and a lumen-diameter trace demonstrates the functionality of time-multiplexed flow and structural monitoring.

In polar semiconductors the Fröhlich interaction is the dominant electron--phonon coupling, yet excitonic resonances in materials such as halide perovskites remain anomalously sharp. We show that standard frozen-center-of-mass treatments of the exciton--phonon problem miss the decisive kinematic degree of freedom: restoring the exact center-of-mass (COM) recoil reveals a universally open, parameter-free $1s\to1s$ absorption channel at recoil momentum $q_*=\sqrt{2M_{\rm ex}\hbarω_{\rm LO}}/\hbar$, whose rate scales as $N_{\rm LO}(T)$. We prove that this recoil channel is controlled by destructive electron--hole interference: the recoil linewidth vanishes with the mass asymmetry as $γ_{\rm LO}^{\rm recoil}\propto\mathcal{F}_{1s,1s}(q_*)^2$, and the elastic dressing obeys the exact suppression law $S_X/S_{\rm ind}=η^2(6-η^2)/5$ within the hydrogenic Fröhlich model. The theory establishes a hierarchy of scattering regimes. In mass-asymmetric materials (GaAs, $η=-0.74$) the recoil channel is active ($γ_{\rm LO}^{\rm recoil}=2.2$~meV); in mass-symmetric materials (FAPbI$_3$, $η=0$; MAPbI$_3$, $η=-0.11$) it is killed by interference (0.00 and 0.12 meV), showing that the observed 27--40 meV perovskite linewidths cannot be accounted for by COM recoil and therefore require internal-state-changing and other inelastic channels, of which the constructive, $η$-robust $1s\to np$ resonance is the leading candidate within the present model. The Fröhlich constant $α$ alone is therefore insufficient as a figure of merit: after projection onto the correlated exciton, the controlling parameters are $η$, $q_*a_X$, and the Rydberg detuning.

Intracule pair densities provide insight into electron correlation, but their routine analysis in extended systems is limited by the cost of numerical integration and the restriction of analytical methods to Gaussian basis functions. We present an efficient multicenter integration scheme for intracule densities and their moments. By adapting the topological fuzzy Voronoi cell formalism, we partition intracule space around interatomic displacement vectors, concentrating quadrature points near secondary density maxima that standard single-center grids poorly resolve. Benchmarks on linear alkanes show improved convergence with increasing molecular size, achieving relative errors below 0.02% in electron-electron repulsion energies with fewer quadrature points than single-center methods. The partitioning also enables the decomposition of global two-electron properties into spatial contributions associated with short- and long-range electron-pair separations. Coupling the multicenter grid with kernel density estimation reconstructs smooth radial intracule distributions at large interelectronic distances without the dense angular grids required by conventional surface integration. Validation on the S22 dataset supports the reliability of the method across diverse molecular systems. These developments facilitate intracule analysis in polyatomic systems and the investigation of electron correlation and dispersion interactions.

The Rayleigh-Plateau instability predicts that infinitesimal perturbations of a liquid jet grow only for kR < 1, with kR = 1 marking the classical stability boundary. Here, we show that femtosecond-laser-induced cavitation generates a localized, impulsive recoil perturbation on a flowing liquid jet, enabling a two-dimensional map of jet breakup across the (kR, epsilon/R) plane. The perturbation's spacing (wavelength) and strength (amplitude) are set independently by the laser repetition rate and pulse energy, respectively. At low amplitudes, tuning the repetition rate recovers the classical Rayleigh-Plateau dispersion relation and its kR = 1 cutoff, while increasing the wavelength enables controlled generation of monodisperse droplet trains, bidisperse droplet populations, and ultimately isolated single droplets. Along the amplitude axis, low pulse energies produce a seed that amplifies only the imposed wavenumber, whereas above a critical energy Ec, the seed broadens to excite many wavenumbers simultaneously. At still higher amplitudes, we demonstrate deterministic breakup for kR > 1, extending to kR = 1.9, with laser-synchronized droplet production rates up to 0.2 MHz. These results establish localized femtosecond-laser-induced cavitation as a route to controlled Rayleigh-Plateau breakup both within and beyond the classical linear-stability boundary.

In a polar material, a neutral exciton couples to phonons through the sum of the electron and hole deformation potentials. Because the total source vanishes by charge neutrality, the elastic exciton-phonon vertex is regularized by electron-hole interference. Here we determine the non-perturbative fate of this interference by exact diagonalization of a Holstein-exciton model. By parameterizing the mass asymmetry to decouple it from the small-polaron atomic limit, we map a regime map comprising an internal dressing crossover and a dissociation boundary. We prove analytically and verify numerically that for equal masses, the symmetric exciton ground state is protected from phonon dressing by an exact exchange selection rule, provided the phonon source is odd under electron-hole exchange (the neutral case). As mass asymmetry increases, this selection rule is broken and the exciton acquires a strong local polaronic cloud. We show that the dissociation boundary, conversely, is set by a global energy balance between Coulomb binding and polaronic stabilization, and is nearly independent of the internal dressing. Paradoxically, the very symmetry that protects the exciton from dressing denies it polaronic stabilization, driving it toward dissociation at strong coupling. We discuss these results in the context of lattice exciton-polaron models and their implications for sharp versus broad excitonic lines in mass-symmetric versus mass-asymmetric polar semiconductors.

High-stability frequency stabilization between lasers is essential for applications such as precision metrology, frequency dissemination, and quantum communications. We demonstrate the use of code-based multiplexing of a passive fiber-based interferometer for frequency stabilization and transfer between lasers separated by 85 GHz in frequency using a single shared passive reference. Out-of-loop characterization places an upper bound of sub-kHz/$\sqrt{\text{Hz}}$ on the transferred frequency noise at Fourier frequencies above 40 mHz, with a differential fractional stability of $7\times10^{-13}$ at 1 second. We also demonstrate continuous laser tunability and characterize the residual length noise coupling. Finally, we provide a framework for scaling the architecture to higher laser counts, offering a pathway to scalable, frequency agile stabilization of multiple light sources without the overhead of an optical frequency comb.

Magnetic skyrmions are promising nanoscale information carriers because their position can be manipulated by electrical currents. The additional ability of deterministic control of the spin structure would allow the use of magnetic skyrmions as multi-state bits, expanding the capabilities of skyrmion devices further. Such control could be realized by coupling all-optical helicity independent switching of magnetization (AO-HIS) to magnetic skyrmions. This is realized in a Pt/Ir/CoB/Gd/Pt multilayer that is engineered to stabilize magnetic skyrmions and, at the same time, enable AO-HIS by single ultrafast laser pulse. Laser excitation is used to write skyrmionic textures, whose polarity is selected by a small applied out-of-plane field. A single 30 fs laser pulse is then used to toggle the magnetization of an illuminated region containing skyrmionic textures, reversing their polarities without requiring any magnetic field or current pulses. This establishes deterministic optical switching of the skyrmion spin structure as a new manipulation channel, distinct from previously reported optical nucleation and annihilation. The material is then patterned into a wire, to combine the optical manipulation with current-induced skyrmion motion. These results establish a route toward opto-spintronic skyrmion devices in which light programs the internal state of a skyrmion and electrical currents control its position.

Nuclear quantum effects are critical for describing proton transfer and hydrogen bonding, but their incorporation into quantum chemistry calculations is often computationally prohibitive on classical hardware. A promising alternative are quantum computers due to their linear scaling in the space requirements with system size. We introduce a novel hybrid quantum-classical algorithm for ab-initio molecular dynamics that incorporates nuclear quantum effects via the nuclear-electronic orbital method. The proposed algorithm evaluates ground state energies and forces on the quantum computer using a variational quantum eigensolver, while the molecular geometries are updated classically. We validate our approach through simulations of $\text{H}_2$, $\text{H}_2\text{O}$ and the Zundel ion $\text{H}_5\text{O}_2^+$, comparing the simulated vibrational spectra with experimental data. Upon inclusion of nuclear quantum effects, the proton shuttling movement in the Zundel ion becomes effectively barrierless, and errors in the simulated frequencies improve significantly. Employing compact hardware-efficient ansatz circuits we achieve results comparable to the more accurate UCCSD ansatzes, which hints towards the feasibility of executing our algorithm on near-term quantum devices.

Sagnac interferometers are important tools for precision measurements. Cancellation of common-path noise ensures a high degree of stability against external perturbations, while their sensitivity to rotations provides the basis of laser gyroscopes. Here we highlight another, less explored feature of Sagnac interferometers: the fact that optical elements are traversed in reverse order for clockwise and counterclockwise propagating light components. This provides the opportunity to explore a classical realization of indefinite causal order, where the order of events within a sequence is not fixed. We explore this concept to identify the geometric phase associated with two non-commuting polarization operations with a single measurement. This idea may have applications for the rapid determination of polarization manipulations or optical activity within chiral media, but foremost it provides a geometric illustration of indefinite causal order.

Orbital angular momentum (OAM) multiplexing provides an infinite-dimensional discrete Hilbert space ideally suited for high-capacity free-space quantum key distribution (QKD). Nevertheless, pure scalar spatial modes carrying topological charge ($|\ell| \ge 1$) undergo severe decoherence when transmitted through terrestrial atmospheric turbulence. Turbulent refractive-index eddies split high-order vortex singularities, induce catastrophic intermodal crosstalk across adjacent topological channels, and rapidly drive the quantum bit error rate (QBER) well above the unconditional 11% security threshold associated with individual cloning attacks. Here, we demonstrate that hybrid polarization-OAM entangled states, known as vector vortex beams (VVBs), provide intrinsic, hardware-free immunity against turbulent perturbations. Because the optical anisotropy of terrestrial air is exceedingly small ($Δn < 10^{-9}$), refractive-index fluctuations couple symmetrically to orthogonal circular polarization modes as an identical common-mode scalar phase screen that cancels in the relative polarization-phase degree of freedom. By numerically propagating modal fields through modified power-spectral phase screens over turbulence strengths ranging from $D/r_0 = 0$ to $3.0$, we show that the VVB encoding protocol suppresses the asymptotic QBER from 42.0% to 4.8%, yielding an error-suppression factor of approximately 11.6 without requiring active adaptive optics or deformable mirrors.

Most proposals for $Z_3$ parafermions in fractional quantum Hall-superconductor structures used the spin-unpolarized $ν= 2/3$ Halperin $(1,1,2)$ state. The fractional quantum anomalous Hall (FQAH) states of twisted MoTe$_2$ and rhombohedral graphene are believed to be spin- and valley-polarized Jain states, with the same topological order but a different spin structure. We analyze a trench between two polarized $ν= 2/3$ edges. Among the pairing and tunneling bilinears of the edge-mode electrons, exactly two of each have zero conformal spin. Pairing is compatible only with the neutral-mode superconductivity channel and tunneling only with neutral-mode backscattering, whereas in the unpolarized state singlet pairing and tunneling select the same channel. Since the two channels condense the same neutral anyon up to a local operator, the domain walls carry $Z_3$ parafermions, with 3 protected states per pair, whether or not the neutral channel changes between regions; fixing the fermion parity does not enlarge this count. Before the neutral gap forms, pairing is at best marginal for repulsive inter-edge coupling unless an attractive neutral coupling favors its channel; once the gap has formed, both charge terms are relevant for an inter-edge Coulomb coupling below 7/25 of the intra-edge one. The superconductor must supply even-frequency, equal-spin, intravalley pairing, which an s-wave singlet superconductor with only Ising spin-orbit coupling does not provide at leading order, whereas chiral $p+ip$ and $f+if$ states do. The $Z_3$ label is carried by a quasiparticle of the FQAH state, so no process confined to a junction whose tunneling segments are not FQAH can change it, and we expect a $6π$-periodic Josephson current with or without fixed fermion parity.

The plasma channel of the AWAKE plasma wakefield acceleration experiment is created by laser ionization of rubidium vapor in a 10~m long vapor source. Verifying the properties of the channel --- the radius of its fully ionized core and the width of its boundary sheath --- that are vital for ensuring good-quality wakefields is important as is validating numerical models of ionizing pulse propagation. Near-resonant schlieren imaging can detect the plasma channel in the low-density vapor, but there is no direct inversion to obtain channel parameters from the images. We use symbolic regression to find compact analytical formulas that connect measurable properties of the schlieren signal to plasma profile parameters. Using databases of simulated signals generated with three different plasma edge-profile families, we obtain formulas with one and two fitting constants to predict the equivalent channel radius with an accuracy below twice the camera pixel size and formulas to predict the sheath width. Re-evaluating previous measurements with these formulas, we confirm a theoretically predicted power-law relationship between the channel radius and the energy of the ionizing laser pulse. The formulas can be adapted to new experimental conditions by refitting the constants on a modest set of new samples, providing a lightweight, interpretable alternative to evaluation with deep neural networks.

Tracking seasonal change in crops and forests requires observing the same plants repeatedly. Ground robots can do this at close range, and a manipulator gives their sensors more viewpoints. Yet the robots behind long-term field datasets are rarely released with their design files, and how a robot's own structure limits arm reach and occludes its sensors is seldom compared between builds. We present ALFRED, an open-source mobile manipulator built from commercially available components. It carries a six-degree-of-freedom arm, LiDAR, RGB-D cameras, RTK GNSS and an IMU on an Ackermann-steered base, all mounted on a reconfigurable aluminium strut frame, and runs containerised ROS software. It was developed through four builds against six requirements for repeated outdoor deployment: durability, modularity, repairability, sensing reach, endurance and reproducibility. Model-based analysis of the last three builds shows the usable share of the arm's reachable poses rising from 34.0% to 60.0% and then 66.1%, and ray casting shows that only the final build keeps the frame-mounted LiDAR's horizontal view clear both forwards and backwards. ALFRED completed a year of monthly forest surveys (528 traversals) without missing a scheduled collection. This was despite battery degradation, reconfiguration for another researcher's study, and the parallel development of ALFRED 2.0 for autonomous crop-row operation, with each switch between builds taking about six hours. The deployment also showed that mechanical modularity is only as dependable as the robot description that tracks it.

We numerically study exciton-photon coupling in a hybrid structure composed of a period-doubled Si3N4 photonic crystal slab and an hBN-encapsulated MoSe2 monolayer. Period doubling folds quasi-guided modes into the light cone and produces spectrally separated photonic branches whose radiative character is controlled by the symmetry of the doubled unit cell, resulting in one bright and one bound state in the continuum (BIC)-like mode at normal incidence. We then use the hBN thickness as an independent tuning parameter for the vertical field profile. Increasing the hBN thickness redistributes the resonant field toward the MoSe2 monolayer and enhances the Rabi splitting from about 3-4 meV to 8.5 meV, corresponding to an increase in the coupling strength from approximately 1.5-1.7 meV to 4.3-4.4 meV. Comparison between bright and BIC-like configurations shows that the quality factor primarily determines radiative visibility and linewidth, whereas the coupling strength is mainly governed by the field amplitude at the monolayer. We further show that the hBN layer controls the hybridization of folded TE-like modes at finite momentum, leading to an additional photonic gap whose size can be tuned by the hBN thickness and closes at an hBN thickness of approximately 113 nm. In the hybrid structure, we observe finite-momentum exciton-polariton states that, depending on the hBN thickness, form either through coupling to an isolated photonic branch or through coupling to two nearly degenerate photonic modes. These results identify period-doubled photonic crystal slabs as a flexible platform for controlling radiative coupling, exciton-photon overlap, and polariton dispersion in hybrid structures based on transition-metal dichalcogenide monolayers.

Structured light can generate electronic dc currents with azimuthal winding, yet the rules governing their winding order $m$ remain unclear. Here we identify sector-resolved winding selection rules using graphene as a clean two-dimensional platform. By decomposing the current response into local and gradient sectors at the current-operator level, we show that the winding order is determined not by the optical orbital angular momentum $\ell$ alone, but by the angular structure of the corresponding current operators together with projection onto the azimuthal direction. For scalar Laguerre-Gaussian beams, linear polarization yields $m=|\ell\pm1|$ in the local sector and $m=|\ell|,|\ell\pm2|$ in the gradient sector, whereas circular polarization with helicity $σ=\pm1$ selects $m=|\ell-σ|$ in the local sector and $m=|\ell+2σ|$ in the gradient sector. Numerical time-evolution calculations verify these rules and further show that helicity can select an $m=0$ branch, producing an azimuthally uniform circulating current whose radial profile determines the axial magnetic field $B_z(z)$. Our results provide a sector-resolved organizing principle for classifying and controlling structured-light-driven dc currents with tailored winding structures.

Structured light can generate electronic dc currents with azimuthal winding, yet the rules governing their winding order $m$ remain unclear. Here we identify sector-resolved winding selection rules using graphene as a clean two-dimensional platform. By decomposing the current response into local and gradient sectors at the current-operator level, we show that the winding order is determined not by the optical orbital angular momentum $\ell$ alone, but by the angular structure of the corresponding current operators together with projection onto the azimuthal direction. For scalar Laguerre-Gaussian beams, linear polarization yields $m=|\ell\pm1|$ in the local sector and $m=|\ell|,|\ell\pm2|$ in the gradient sector, whereas circular polarization with helicity $σ=\pm1$ selects $m=|\ell-σ|$ in the local sector and $m=|\ell+2σ|$ in the gradient sector. Numerical time-evolution calculations verify these rules and further show that helicity can select an $m=0$ branch, producing an azimuthally uniform circulating current whose radial profile determines the axial magnetic field $B_z(z)$. Our results provide a sector-resolved organizing principle for classifying and controlling structured-light-driven dc currents with tailored winding structures.

The photostability of DNA nucleobases relies on ultrafast nonradiative relaxation following ultraviolet excitation. In thymine, the competition between internal conversion (IC) and intersystem crossing (ISC) determines the balance between ultrafast energy dissipation and potentially long-lived photochemistry. However, the precise molecular mechanisms linking early singlet-state electronic and structural evolution to the formation of long-lived triplet dark states remain unresolved. Here, we investigate the gas-phase photodynamics of thymine using time-resolved multi-center X-ray photoelectron spectroscopy (tr-mc-XPS) supported by state-of-the-art ab initio quantum calculations. By simultaneously probing multiple carbon 1s core levels, we track site-specific electronic and nuclear dynamics. We discover that the long-lived dark state is not initially a pure triplet; rather, it exists as a mixture of singlet and triplet states for the first 240 ps before transitioning fully to the $^3ππ^*$ state. On the femtosecond timescale, we resolve atom-specific vibrational coherence at $\sim$730 cm$^{-1}$ (a ring-breathing mode with a period of 46 fs) that survives the initial $^1ππ^*$ to $^1nπ^*$ IC. Furthermore, we identify a critical dual role for the methyl group (C9H$_3$). During singlet relaxation, the methyl group acts as an inertia spectator, and its mass hinders direct internal conversion to the ground state. Upon $^3ππ^*$ state formation, however, state-dependent hyperconjugation couples the methyl group to the pyrimidine ring, turning it into a highly sensitive electronic reporter of ISC. These findings establish tr-mc-XPS as a powerful approach for disentangling the complex, multi-timescale photodynamics governing nucleobase stability.

Co-propagating chiral Majorana edge modes are predicted to exist in proximity-coupled quantum anomalous Hall systems. They combine the exciting prospects of edge vortices as flying non-Abelian Ising anyons, with their fully electrical detection through anyon fusion processes. In this setup, electrical transport arises from the interference of a pair of Majorana edge states. By bosonizing the model with an additional replica sector, we generalize previous treatments to fully asymmetric configurations. We analyze a Mach-Zehnder interferometer and show that while the DC conductance does not exhibit signatures of edge-vortex interference, at low frequencies, this interference manifests as an effective capacitance. This quantity is sensitive to the non-Abelian anyon statistics of edge vortices and, in particular, carries signatures of their topological spin and nontrivial conformal dimension. We demonstrate that the thermal length $l_T = \hbar v/(πk_B T)$ is the relevant scale at low temperatures $T$, analogous to quasiparticle transport in conventional quantum Hall edge states with velocity $v$. As long as the interferometer arm lengths match within this length scale, transport signatures of the non-Abelian statistics of edge vortices remain visible.

We have theoretically investigated the stochastic switching dynamics of a charged microparticle in a quadrupole trap near the principal parametric resonance at atmospheric pressure. We show that this behavior arises from a balance of thermal noise-activated escape and dissipative return between linear and nonlinear dynamical regimes of the particle motion. The switching follows an effective Gibbs distribution with an effective potential barrier between the regimes and effective system temperature, which are both experimentally accessible. Because the effective barrier depends on particle mass and charge, and since thermal noise reveals rather than obscures the transition, this exponential dependence could provide the foundation to precision noise-aware detection schemes. The system further offers a highly adjustable platform for studying activation dynamics in non-equilibrium parametric systems.

Peptide sequence governs both the structures formed through supramolecular assembly and the dynamics by which they emerge, but predicting either requires resolving slow collective processes among many interacting molecules. Molecular dynamics (MD) provides microscopic insight into these processes, yet the long timescales of assembly and the vast peptide sequence space make systematic exploration computationally demanding. We introduce SupraTITO, a transferable generative molecular dynamics (GenMD) framework for supramolecular systems, demonstrated through peptide self-assembly. SupraTITO learns transferable implicit transfer operators (TITO) conditioned on peptide sequence, molecular topology, and periodic geometry, allowing configurations to be propagated over physical intervals much longer than an MD integration step. On a comprehensive dipeptide benchmark, SupraTITO generalizes to held-out sequences and reproduces sequence-dependent structures and dynamics while maintaining molecular integrity over long rollouts. Compared with direct ensemble prediction trained on the same trajectory data, SupraTITO more accurately reproduces assembly structures while also resolving their temporal evolution. The learned dynamics generalize across peptide concentrations, including dilute conditions not represented during training. These results extend transferable GenMD to collective dynamics in periodic supramolecular systems and provide a foundation for modeling related processes beyond peptide assembly.

A system has a nonreciprocity when the light propagating through it in opposite directions encounters different optical adventures. This effect lies in the origin of various applications, including signal processing, noise reduction, unidirectional propagation, and sensing. Here, we experimentally demonstrate the detection of nonreciprocity in plasmonic metasurfaces and a method to determine its direction. We use the Inverted Leakage Radiation Microscopy setup to show that the non- reciprocity is linked to a false chirality of the medium. The setup behaves as an equivalent of the classical Sagnac loop providing an interference pattern at the image plane. The non-reciprocity is then detected by examining the topological order of the resulting image. Our system represents a compact and versatile method to detect false chirality in plasmonics and suggests a variety of potential areas of implementation in nanophotonics, chemistry and applied physics.

Average atom (A-atom) potentials provide a mean-field description of a chemically disordered alloy and are used to predict the properties of solid solutions without short-range order. Such potentials are usually averaged from an existing interatomic potential and are therefore only as accurate as the parent model. Accurate interatomic potentials are themselves difficult to parameterize and can require large training datasets. Here we benchmark a recently developed formalism that computes an exact A-atom potential directly from a linear atomic cluster expansion (ACE). We first fit a linear ACE to Fe-W data generated with an embedded atom method (EAM) potential. The resulting A-atom potential reproduces the properties of the disordered phase computed from an explicit random supercell and from a conventional A-atom potential averaged from the same EAM potential. We then fit a linear ACE to energies and forces computed from electronic structure calculations for about 1500 small Mo-Nb structures with an average of 7 atoms per structure. The A-atom potential derived from this ACE reproduces the DFT elastic constants, lattice parameter, mixing enthalpy, and Bain path of special quasirandom structures. Of the three chemical site bases, only the occupation basis also reproduces the DFT surface energies of the alloy. For Mo-Nb, the A-atom potential also predicts that the ideal solution entropy outweighs the destabilizing vibrational contribution to the finite-temperature free energy of the disordered phase. These benchmarks show that the properties of disordered alloys can be recovered from small training datasets when the chemical site basis is chosen carefully.

Topological spin textures in antiferromagnets inherit the compensated magnetic order of the host material, resulting for skyrmions in the suppression of the skyrmion Hall effect and enabling ultrafast dynamics that make them attractive for low-power spintronic devices. In intrinsic antiferromagnets, the two sublattices are identical, but synthetic antiferromagnets offer additional control mechanisms by enabling independent tuning of the properties of two ferromagnetic layers. Analogous to a ferrimagnet, the total magnetic moment can be adjusted by compensating the two-layer moments. Here, we demonstrate that tuning the effective magnetic anisotropy difference between the two layers drives a spin-flop transition where one layer reorients and thus stabilizes an orthogonal configuration with one layer oriented along the out-of-plane direction and the other in-plane. In this transition, an antiferromagnetic skyrmion undergoes a homotopic reconfiguration into a complex spin texture comprising a skyrmion coupled to an in-plane bimeron. Element-specific X-ray microscopy resolves this texture layer by layer: one hosts an out-of-plane skyrmion coupled to an in-plane bimeron in the other. We refer to this previously unexplored three-dimensional spin texture as a skymeron. By using time-resolved pump-probe X-ray microscopy, we discover unique polarity ,dependent dynamics during current pulses: a short post-pulse inertia-like continuation of the motion, and a slower return towards the pinned initial state. Micromagnetic simulations reveal that the inertia-like propagation originates from the finite-time relaxation of reorientation of the skymeron. Our results establish layer-selective anisotropy engineering as a route to uncharted composite spin textures with internal dynamical degrees of freedom, not possible in conventional antiferromagnets with identical sublattices.

Characteristic X ray generation is essential for producing X ray sources and for investigating light matter interactions. Here, we demonstrate that characteristic X ray generation can also be employed to determine the thickness of van der Waals thin films in a non destructive manner. Specifically, we establish a sixth order polynomial model that relates film thickness to the characteristic X ray yield. The model can both predict the X ray yield of graphite films at arbitrary thicknesses and infer the film thickness from a corresponding characteristic X ray yield. We validate the model by comparing its predicted X ray yields for graphite films with those obtained from Monte Carlo simulations. Additionally, we experimentally validated the reliability and feasibility of the proposed method for extracting graphite film thickness via X ray photon yield characterization. Our results provide a non destructive approach for determining the thickness of van der Waals thin films.

Growing environmental and energy-related challenges have intensified the search for technologies capable of improving energy recovery and resource efficiency. Bioinspired photonic structures offer promising opportunities for the development of efficient infrared absorbers by exploiting optical mechanisms found in natural systems. In this work, we present a bioinspired approach for the design and optimization of a broadband mid-infrared absorber based on the highly absorbing wing scales of the Troides magellanus Magellan birdwing butterfly. The characteristic geometry of the biological structure is rescaled and adapted to shift its optical response from the visible to the infrared spectral range. Numerical simulations are used to investigate the influence of the main geometrical parameters on the spectral absorptance and to identify an optimized configuration. The optimized structure achieves an absorption enhancement of 391% compared with a flat steel reference. The improved optical response is attributed to the optimized high-aspect-ratio geometry, which enhances multiple scattering and light trapping, thereby increasing the effective light-matter interaction area. These results demonstrate the potential of bioinspired geometric scaling as an effective strategy for engineering efficient infrared absorbers and tailoring their spectral response for thermal radiation management and infrared photonic applications.

Scientific progress emerges from a longitudinal ecosystem in which researchers, institutions, funding agencies, collaboration networks, and the scientific literature co-evolve. As AI becomes increasingly involved throughout the scientific research cycle, understanding these interconnected and evolving processes becomes increasingly important. We introduce SciUtopia, a persistent, closed-loop LLM-agent simulation framework for studying academic research ecosystems. SciUtopia models interconnected scientific processes such as research-direction choice, collaboration, submission, peer review, resubmission, citation, funding, and researcher attrition, while maintaining evolving states across simulated years. Its configurable institutional mechanisms and information channels provide a controlled testbed for matched counterfactual experiments and targeted interventions. Across 61 simulation worlds, SciUtopia simulates over 40,000 researchers from 8,000 institutions, producing around 400,000 publication decisions and 1.2 million LLM-generated peer reviews. Using these longitudinal simulations, we find that rejection-driven resubmission substantially amplifies reviewer burden beyond population growth alone, cautious exploration balances citation impact with career success and long-term topic diversity, and resource inequality can emerge even without detectable cumulative advantage from narrowly winning early funding. Code is available at https://github.com/Ahren09/ScienceUtopia.

This paper introduces the foundational principles underlying hardware engineering models and argues that abstraction is their defining characteristic. Because abstraction necessarily omits detail and constrains what engineers can build, models are inherently incomplete in specific respects - or, as George Box famously observed, "All models are wrong, but some are useful". At the same time, abstraction is essential for simplification, which is key to managing complexity. More abstract models also tend to simulate faster because fewer details must be considered. This paper subsequently examines a range of abstraction methods in digital design - sometimes referred to as design disciplines - including lumped models, value-discrete models, and time-discrete models. Together with constraints that define the validity of the abstraction and design guidelines, these abstraction methods establish design disciplines. This paper further relates these forms of abstraction to pre-clustered design elements such as transistors, gates, registers, and transfer functions. These pre-clustered elements define abstraction levels, such as the gate level, and are presented as a key enabler of increased design productivity.

Long-range electronic correlation can be represented in terms of coupled fluctuations of atomic charges and higher multipoles, motivating a density-response description beyond local dipolar polarization, particularly in low-dimensional, conducting, and small-gap systems where collective electronic fluctuations become important. We extend the frequency-dependent polarizable force field ACKS2$ω$ to electronic-structure references containing exact exchange by deriving both the static and additional frequency-dependent exchange contributions, with particular attention to HFsrPBE, which combines long-range Hartree--Fock exchange with short-range PBE exchange and correlation. Numerical validation of ACKS2$ω$ using dipole polarizabilities and $C_6$ dispersion coefficients for the 27 molecules of the TS27 set, with HF, PBE, B3LYP, and HFsrPBE as the underlying electronic-structure references, shows that including the exchange contributions and enriching the response basis improve agreement with the corresponding orbital-space linear-response calculations, although finite-response-basis errors remain molecule dependent. Long-range correlation energies evaluated through the adiabatic-connection fluctuation-dissipation theorem using the ACKS2$ω$ parameters reproduce the corresponding HFsrPBE orbital-space results for small test molecules when the response basis is made complete within the chosen orbital basis, while a local multipole decomposition resolves the finite-basis energies into monopole--monopole, mixed, dipole--dipole, and remaining higher-multipole contributions, providing a route to evaluating long-range correlation energies in terms of charge fluctuations within atom-condensed models.

We present CAFES, a correlation-aware agentic framework for electronic-structure simulations of strongly correlated systems. CAFES addresses two challenges: the fragmented software landscape for many-body calculations and the difficulty of selecting appropriate methods across diverse correlation regimes. It combines correlation diagnostics, adaptive method selection, and large language model (LLM) assistance for molecular, crystalline, and model-Hamiltonian systems. A study-task architecture separates study-level planning from task-level execution, while a curated scientific knowledge layer provides reusable guidance for method selection, workflow design, and result interpretation. We demonstrate CAFES through three research-level studies: calculating the low-lying electronic states of lutein using DMRG-CASSCF, probing phase competition in the extended honeycomb Hubbard model using DMET, and generating a quantum-chemical dataset with CCSD labels. These calculations demonstrate the potential of agentic workflows for strongly correlated electronic-structure problems, a regime that has received limited attention in existing agentic computational frameworks.

Machine-learned interatomic potentials are commonly fitted by weighted-sum scalarization, which combines energy and force errors in a single loss. A nominal weight, however, identifies a potential only relative to the complete fitting protocol. We therefore treat energy--force balancing as a protocol-dependent problem of physical model selection. For fixed-basis atomic cluster expansion models of molten LiCl, liquid H$_2$O, and Si, the resulting scalarization paths contain dominated states at extreme weights. Their nondominated subsets depend on the solver, and the out-of-distribution Si path is nonmonotone. We replace direct weight selection by minimizing the regularized energy objective subject to an upper bound on the normalized force loss. Projected dual ascent adjusts the Lagrange multiplier from the force-constraint residual. A frozen-multiplier limited-memory quasi-Newton refinement then returns the final model. Across the three systems, the constrained procedure reaches the solver-matched low-error region and gives measured speedups of $6.7$--$8.9$ over completed scalarization scans under the stated timing convention. Physical-property calculations show that first-shell geometry is comparatively insensitive to the selected balance, whereas transport and solid-state observables vary more strongly. These results identify the fitted model--protocol pair as the relevant object of energy--force model selection and support force-constrained fitting as an explicit selection rule.

Uncovering new phenomena in nature requires experiments. For centuries, their design has been exclusively a human endeavor. Today, a new paradigm is emerging in which artificial intelligence and computational methods can design experiments themselves. Realizing this form of automated scientific discovery requires simulators that are sufficiently expressive to represent the diverse physical processes and couplings from which new experiments can be constructed. In this direction, we introduce \textsc{esQueranto}, a differentiable software that brings photon-number quantum optics and structured-light propagation into a common description, allowing the spatial evolution of light to directly influence non-classical quantum states and their interference. \textsc{esQueranto} is implemented in JAX, providing automatic differentiation and hardware-accelerated evaluation for optimization and automated search. We demonstrate the framework across a broad range of quantum-optical applications that exercise complementary aspects of its physical description. By combining quantum and structured-light physics within a single differentiable simulator, \textsc{esQueranto} takes an important step towards the dream of a foundational simulator in physics.

The Straight-Through Estimator (STE) is a widely used heuristic for Quantization-Aware Training (QAT), but its surrogate gradients can exhibit substantial mismatch with the underlying quantized objective, leading to noisy updates and parameter oscillations, particularly in ultra-low-bit regimes. We propose the Quantization-Aware Minimal-Norm Optimizer (Q-MINO), a temporal bundle method that combines gradient consensus, state-drift regularization, and an alignment constraint to construct stabilized, minimum-norm update directions from recent optimization states. Q-MINO solves the resulting constrained subproblem using a warm-started Frank--Wolfe procedure with a feasible fallback initialization. Theoretically, via a stochastic Lyapunov Kurdyka--Łojasiewicz (KL) framework, we show that Q-MINO achieves asymptotic neighborhood convergence. Moreover, we detail numerical experiments with Q-MINO at various quantizations.

Network topology describes connections between neurons, whereas synaptic placement specifies how those connections are arranged within individual cells. How these levels of organization correspond remains incompletely understood. Here we show that connectivity between presynaptic neurons is reflected in relative input placement within Drosophila descending neurons (DNs). Across thousands of one-way DN connections in the independently reconstructed MaleCNS and FlyWire brains, inputs from sources also contacting the partner DN lay on average 9.4 and 8.0 μm nearer that partner's inputs along the receiver's neurites than other non-DN inputs. The same ordering held when source-input positions were fixed and partners with and without recorded source input were compared after standardizing reference-set size. In BANC and MaleCNS, shared input and measured spatial overlap provided complementary predictive information about DN interconnection. Two interconnected DNs sharing an ascending source differed in their identified cord outputs. Together, these findings link a three-neuron topological relationship to relative input placement, revealing a correspondence between network connectivity and the internal spatial organization of a receiving neuron.

Design of a 3nm base logic die for 2048-bit HBM4 stacks integrating real-time per-channel timing calibration, on-die thermal/voltage telemetry, and high-coverage BIST engine with <1.2% area overhead.

Finite-element thermomechanical modeling and experimental validation of CTE-matched glass core substrates under solder reflow cycles (up to 260℃), demonstrating a 65% warpage reduction over organic package substrates.

Fabrication and high-frequency signal integrity characterization of an ultra-large glass substrate interposer with 20:1 aspect ratio TGVs, exhibiting 40% lower insertion loss at 112 Gbps compared to silicon interposers.

Real-time radical and ion energy distribution tracking using multi-wavelength OES during deep silicon and dielectric trench etching, enabling 0.1nm depth precision endpoint detection in 300mm automated production lines.

A novel atomic-layer etching (ALE) based selective SiGe cavity formation and low-k SiOCN internal spacer process for 2nm nanosheets, reducing gate-to-drain capacitance (Cgd) by 22% and improving ring-oscillator speed by 14%.

Development of ultra-thin, free-standing multi-walled carbon nanotube pellicle membranes exhibiting 92.8% single-pass EUV transmittance and withstanding continuous thermal radiation loads exceeding 600W scanner source powers.

Demonstration of 0.8um pitch copper-to-copper direct hybrid bonding using chemical-mechanical planarization (CMP) optimized with 2nm dishing control and surface-activated bonding under low temperature (<180℃).

This paper proposes a 4F2 3D DRAM architecture utilizing vertical channel transistors (VCT) with high-k metal gate and ultra-high aspect ratio (>70:1) ZrO2/Al2O3/ZrO2 (ZAZ) dielectric capacitors.

A 1Tb TLC 3D NAND flash memory with over 400 word-line layers fabricated via two-stack etching and word-line replacement, supporting a 3.6 GB/s toggle DDR 6.0 interface and sub-35us random read latency.

Full-field aerial image simulation and scanner aberration characterization under 0.55 NA illumination, analyzing pupil transmission asymmetry and demonstrating stochastic nano-bridging defect suppression via tailored dipole sources.

A hardware acceleration pipeline for 100B+ parameter generative model serving utilizing adaptive FP4 tensor systolic arrays with hardware-managed microscaling formats, achieving a 3.4x throughput leap.

We demonstrate a 0.0175 um2 high-density 6T-SRAM macro fabricated in a 2nm GAA nanosheet process with internal spacer engineering, achieving robust sub-0.5V Vmin operation with assisted read/write circuitry.

Epitaxial synthesis of a 3nm-thick Mn-doped spinel shell on single-crystal LiNi0.92Co0.04Mn0.04O2 prevents microcracking and oxygen release during 4.45V cycling, retaining 89% capacity after 1,000 10-minute fast-charge cycles.

We evaluate backside power distribution with buried tungsten rails and 500nm-deep nano-TSVs on 300mm wafers, demonstrating a 28% reduction in IR drop and 16% speedup in critical timing paths.

A 32Gb DDR5 SDRAM fabricated in 1c nm CMOS process with quadruple-patterning EUV layers, featuring a 4-phase digital-controlled delay loop (DCDL) achieving 9.6 Gbps/pin I/O performance at 1.1V VDD.

This work presents a fully integrated monolithic CFET stacking n-FET over p-FET with self-aligned middle dielectric isolation, achieving a 50% standard cell footprint reduction over 2nm GAA nanosheets while preserving symmetric subthreshold swings of 65 mV/dec.

We demonstrate a co-packaged 6.4 Tbps optical engine directly attached to a 100mm x 100mm substrate, delivering 1.8 pJ/bit energy efficiency and sub-nanosecond round-trip serialization latency.

We demonstrate anamorphic magnification imaging using 0.55 NA High-NA EUV scanners, achieving sub-16nm pitch line/space patterning with critical dimension uniformity <0.8nm and 3x reduction in stochastic defectivity.

Quantum dot nanorod color-conversion layers integrated onto blue GaN micro-LED arrays achieve 98% Rec.2020 color gamut and 10x longer operational lifetime through conformal ALD Al2O3 moisture encapsulation.

Integration of sub-1nm equivalent oxide thickness (EOT) crystalline HfO2 dielectrics on synthetic bilayer MoS2 channels using low-damage plasma-enhanced ALD, demonstrating on/off current ratios >10^8 and subthreshold swing of 68 mV/dec.

High-density inductively coupled fluorocarbon plasma etching operated at wafer stage temperatures of -80℃, achieving vertical profile etching of 120:1 HARC oxide-nitride stacks with zero bowing defectivity.

A 16-high HBM4 memory subsystem implemented with sub-micron pitch direct copper-to-copper hybrid bonding on a 3nm finfet base logic die, achieving 2.0 TB/s sustained bandwidth with 35% lower thermal resistance than microbump bonding.

We present a direct-patterned RGB tandem OLEDoS display fabricated on a 28nm high-voltage CMOS backplane, reaching 4,000 pixels per inch and peak luminance of 15,000 nits without color filter optical attenuation.

Design and empirical thermal-electrical characterization of an integrated 72-GPU rack cluster operating at 130kW total power, utilizing dielectric fluorochemical two-phase immersion cooling with PUE of 1.025 and 3.2 Tbps CPO optical links.

We demonstrate an all-solid-state pouch cell (ASSB) with Li6PS5Cl electrolyte and atomic-layer engineered LiF-rich interphases operating at 500 Wh/kg and surviving over 1,200 cycles at 3C charge rate without short circuits.