Chaotic Dynamics · Cross-listed from cs.NE
Orbital Error Dynamics: Self-Organized Criticality, Ephemeral Parameter Resonance, and Non-Linear Biological Ontologies in Zero-Storage Neural Synthesis
Volkan Dağl{\i}, Zerrin Dağl{\i} and Dağhan Dağl{\i}
Modern deep neural networks treat parameters as static floating-point
matrices stored in physical
memory, incurring Von Neumann
memory bottlenecks and representation collapse. We formulate Orbital Error Dynamics (OED), an analytical framework wherein synaptic weights are not stored masses (O(W)), but transient topological resonances (O(1)) derived procedurally from the complex quadratic
polynomial map z_{n+1} = z_n^2 + c. We introduce the Bent Sine Wave Hypothesis, demonstrating that non-
equilibrium living systems emerge when harmonic waves curl inward through environmental drag toward the cardioid cusp (c = 1/4). We define the Observer Horizon Geometry in parameter space, identifying interior resonance shoulder loci X_upper = (0.25, +0.18) and X_lower = (0.25, -0.18) between the fixed-point basin and the true boundary at c = 0.25 +/- 0.50i. To escape non-convex stagnation without loss zeroing, we introduce a heavy-tailed Biomimetic Perturbed Jump Operator (Omega_tunneling) inspired by mammalian fertilization zinc sparks. We further couple an enteric-cranial Dual-
Brain architecture shielded by adaptive CD4+ regulatory immune gating (M_CD4), and project the 4-nucleotide genetic basis (A, T, C, G) across quadrants in C. Multi-seed empirical validation on the Two-Moons
manifold (5 seeds, 80/20 train/test split, 32x32 grid, zero test-time updates, zero label leakage) demonstrates that procedural parameterization from a 24-byte coordinate seed achieves 77.67% +/- 5.35% clean test accuracy (within an 8.00-point paired difference of an unconstrained gradient baseline at 85.67% +/- 5.35%, 95% CI: [-1.07%, 17.07%]) and 71.33% +/- 3.80% under distribution shift (N(1.2, 0.4)), alongside conceptual equivalence with an analog optical co-processor.
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Nuclear Theory
Extending multi-messenger constraints on neutron star matter through the inclusion of direct Urca cooling
M. Dio Danarianto, Guilherme Grams, Thibeau Wouters et al. (+1 more)
The properties and behavior of strongly interacting matter at extreme densities can not only be determined through terrestrial experiments or through theoretical considerations, but also astrophysical observations of
neutron stars (NSs) and binary
neutron star systems become increasingly important to obtain complementary information. In light of these findings, we perform a
Bayesian study inferring the NS equation of state (EoS) by incorporating constraints from the direct Urca (dUrca) process, thereby including information on matter composition in addition to traditionally used macroscopic observables. We implement a self-consistent treatment of $\beta$-
equilibrium and charge neutrality in the jester framework, including the calculation of the
proton fraction and the onset of nucleonic dUrca in the presence of electrons and
muons. We combine constraints from
chiral effective field theory, astrophysical measurements of NS masses, radii, and
tidal deformabilities, and observations of rapidly and slowly cooling
neutron stars. The dUrca constraint seems to be in favor of stiffer EoSs, but –at the current stage– has only a minor impact on macroscopic NS properties once we include other
nuclear and astrophysical constraints. In contrast, the dUrca information provides a constraint on the composition of canonical-mass NSs favoring a higher
proton fraction inside the
star, illustrating the complementary information carried by cooling observations. Our results demonstrate the potential of incorporating composition-sensitive observables into multimessenger inference and provide a step toward a more comprehensive treatment of dUrca constraints with microscopically motivated EoS models.
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All authors M. Dio Danarianto, Guilherme Grams, Thibeau Wouters, Tim Dietrich
Earth and Planetary Astrophysics
Deep HST/STIS Coronagraphic Imaging of the $\beta$ Pictoris Debris Disk: On the Scattered Light Component of the Cat's Tail
Arin M. Avsar, Kevin Wagner, Daniel Apai et al. (+6 more)
The $\beta$ Pictoris debris disk is a unique system where mid-infrared coronagraphic imaging with JWST/MIRI revealed a new spatially resolved substructure known as the Cat's Tail. We present deep HST/STIS coronagraphic imaging of $\beta$ Pic in scattered light, combining six epochs of observations between 2012 and 2025, in search of the scattered light component of the Cat's Tail. We detect the disk out to a projected separation of 500 au for the first time with HST/STIS, achieving SNR > 100 across much of the midplane between 50 and 200 au. We report the detection of the visible/near-infrared scattered light component of the Cat's Tail substructure. We find through injection-recovery analysis that the scattered light component of the Cat's Tail has a total flux of $0.1-0.4\%$ of the MIRI F1550C flux. Using the measured STIS-to-MIRI flux ratio, we model the Cat's Tail grain properties and find that the grains are highly porous and almost entirely composed of organic refractory material, which is in agreement with findings with JWST/MIRI. We use the organics content of
Solar System
dwarf planets and
dust in the local ISM as a proxy to estimate the size of the colliding progenitors that can produce enough organic refractory material seen in the Cat's Tail. We find that each colliding progenitor must have a mass of at least $1-3\times 10^{21}$ kg, comparable to Charon and Makemake in our Kuiper Belt. Additionally, we find a prominent warped morphology and surface brightness asymmetry in the outer
dust halo of $\beta$ Pic. We compare the observed
halo morphology and asymmetry to predicted vertical structures, which may arise from
planet–disk interactions.
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All authors Arin M. Avsar, Kevin Wagner, Daniel Apai, Isabel Rebollido, Antranik A. Sefilian, Marshall D. Perrin, Christopher C. Stark, Gabriel Weible, Andras Gaspar
Soft Condensed Matter
Large integration time-step in molecular dynamics simulation artificially enhances the strength of hydrophobic interaction
Dilipkumar N. Asthagiri
Molecular dynamics simulations are used to compute the potential of mean force (PMF) between two united-atom methane molecules at several temperatures and integration time-steps. At a fixed time-step, the contact minimum of the PMF deepens with increasing temperature, as expected for hydrophobicity driven association. Compared with a time-step of 0.5 fs, one that preserves equipartition, larger time-steps alter the PMF and make the contact minimum more favorable. Thus even relative free energy values are sensitive to time-steps that break equipartition. Using quasichemical theory, we partition the free energy of association into hydrophobic and hydrophilic contributions. The hydrophilic contribution opposes association and is insensitive to the time-step. Thus the artificial enhancement of association at larger time-steps comes entirely from the hydrophobic contribution. We explain this behavior through the temperature dependence of the internal pressure of the
liquid. The same analysis also accounts for earlier observations of the
liquid's p-V behavior under conditions that break equipartition.
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Cosmology and Nongalactic Astrophysics
The Optical Expansion Scalar in Cosmological Perturbation Theory
Alexander Oestreicher and Sofie Marie Koksbang
Within the
geometric optics approximation, the optical expansion scalar describes the local rate of change in the amplitude of a wave or the area of a light bundle propagating through the Universe. As such, it is fundamental for describing almost all the observations we make in cosmology. It was recently pointed out that this quantity can, in principle, be reconstructed from measurements of the angular diameter distance $D_A$ and the effective observed expansion rate $\mathfrak{H}$. Motivated by this possibility, we introduce the observable $\vartheta \equiv \theta/\omega_o$, where $\theta$ is Sachs' optical expansion scalar, and $\omega_o$ the observed
photon frequency. We then derive the linear perturbative expression and angular power spectrum for $\vartheta$ in a flat FLRW universe with scalar perturbations. Comparing the power spectra with those of the fluctuations in $D_A$ and with power spectra from relativistic N-body simulations reveals no immediate striking advantage of studying the fluctuations of $\vartheta$ to those of $D_A$. However, the anisotropies of $\vartheta$ do exhibit several unique qualities such as an enhanced sensitivity to the peculiar velocity and relativistic potentials. We suggest that our results may hint at $\vartheta$ being useful for developing consistency tests of cosmological observations and possibly probing departures from FLRW cosmology and modified
gravity theories. The formalism developed and presented here provides the foundation for future studies into these possibilities.
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Quantum Physics
MQSS-Selector: RL-Guided Pass Selection for an MLIR Compilation Pipeline
Andre Youssefi, Ercüment Kaya, Minh Chung et al. (+3 more)
High Performance Computing (HPC) and
Quantum Computing (QC) systems are increasingly converging towards unified High Performance Computing-
Quantum Computing (HPCQC) infrastructures, driven by a growing need to bridge classical and
quantum workflows, which affects all levels of the system stack, from the hardware to compilers and runtimes, all the way to applications. However, today's QC devices are still in the Noisy Intermediate-Scale
Quantum (NISQ) era, are error-prone and resource-limited, and therefore require specialized optimizations and
topology mappings to achieve sufficient fidelity. This places special emphasis on proper compilation and optimization within the overall
quantum software stack. Many existing stacks remain fragmented, with separate components responsible for device selection, compiler-pass optimization, and job queue scheduling. This paper proposes a unified, learning-based selector that integrates these disparate stages into a cohesive framework. Our proposed selector scheme leverages reinforcement learning and deep learning models that can be extended to simultaneously optimize multiple objectives – such as fidelity, compilation time, and scheduling latency – while dynamically adapting to
circuit characteristics and device conditions.
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All authors Andre Youssefi, Ercüment Kaya, Minh Chung, Jorge Echavarria, Laura B. Schulz, Martin Schulz
Quantum Physics
Leg-Tied Tensor Network States: Entanglement Beyond Virtual Bonds
Shuoyi Hu and Bing Gu
We introduce a class of tensor-network states in which physical legs are shared among local tensors, termed leg-tied tensor ansätze (LETTA). Physical leg ties encode long-range correlations directly, while a virtual
matrix product state (MPS) backbone retains short-range multipartite
entanglement. The linear virtual backbone allows us to develop a deterministic density
matrix renormalization group-like variational optimization
algorithm using exact contractions over the active tie-boundary sets and local minimization. We demonstrate the advantages of LETTA for the two-dimensional frustrated $J_1$–$J_2$ Heisenberg model and the three-dimensional transverse-field Ising model. Our results show that LETTA is substantially more accurate than same-bond-dimension MPS calculations and can typically reach the accuracy of much larger MPS calculations using one order of magnitude fewer variational parameters. LETTA thus opens the door for explicitly correlated tensor-network states that can encode long-range correlation beyond virtual bonds.
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High Energy Physics (Theory)
Disorder at the Cosmological Collider: Quenched Random Fields
Matheus Curado Ferreira
Cosmological-
collider signals are usually interpreted as clean probes of massive particles present during inflation. In this work, we study a massive spectator field excited by a spatially quenched random source, which may arise from a frozen realization of a light field or environmental sector whose relaxation time is long compared with the inflationary timescale. We determine which features of the
collider signal remain reliable probes of the heavy field. After Gaussian disorder averaging, the random source modifies only the statistical component of the propagator, leaving the spectral function and heavy-field poles unchanged. The particle spectrum is therefore preserved, and the logarithmic frequency of the
collider oscillations remains fixed by the heavy-field mass. What changes is how the massive modes are excited and imprinted on cosmological correlators: the temporal profile of the source controls the amplitude, phase, and envelope of the oscillations. For a power-law source, the fixed-realization problem is exactly solvable in terms of Lommel functions. Decaying sources can make the nonanalytic clock signal dominant in the squeezed limit, while spatial white noise can destructively interfere with the standard collapsed-trispectrum signal. Thus, mass measurements remain robust against this class of quenched disorder, whereas amplitude-based inferences can depend sensitively on the random environment.
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General Relativity and Quantum Cosmology
A Cartan-geometrical perspective on torsion and non-metricity
Damianos Iosifidis, Tomi Koivisto, Wit Krośnicki et al. (+1 more)
Élie Cartan established that the metric and intrinsic
curvature of a $D$ dimensional embedded
manifold $M$ could be determined by tracing the response of another surface $N$ of the same dimensionality, as it is rolled without slipping and twisting on $M$. In the context of spacetime geometry, this construction underpins the MacDowell-Mansouri formulation of General Relativity. We consider extensions of this framework that correspond to rolling of a shape with twisting and with shape
evolution; it is shown that these naturally describe torsion and non-metricity respectively. Cartan-
geometric formulations of teleparallel
gravity and symmetric teleparallelism are discussed in addition to further manifestations of non-metricity in first-order formulations of
gravity.
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All authors Damianos Iosifidis, Tomi Koivisto, Wit Krośnicki, Tom Zlosnik
Materials Science
Ultrafast Electron Microscopy: A Quantitative Platform for Nonequilibrium Materials Research
David J. Flannigan and Swarit Ahmed Shadman
Macroscopic materials function is determined not merely by
equilibrium structure, but by how carriers,
phonons, fields, defects, interfaces, and collective order dynamically evolve after perturbation. Ultrafast electron microscopy (UEM) uniquely bridges this gap, coupling femtosecond-to-nanosecond timing with real-space, reciprocal-space, and energy-resolved contrast. Here, we review how these integrated capabilities now quantitatively map energy flow and conversion in electronic materials, decode electronic-structural coupling in
quantum and correlated systems, and isolate the localized propagation of carriers, polaritons, strain, and
phonons across optoelectronic and nanomechanical architectures. We emphasize the predictive design rules now emerging from direct metrology of carrier-
lattice coupling, momentum-resolved
phonon thermalization, defect-controlled phase transformations, and authentic operando switching. We critically assess UEM's ongoing maturation from a qualitative, proof-of-concept experiment into a rigorous, quantitative materials platform. This paradigm shift is actively driven by integrated
multimodal detection, advanced energy-resolved spectroscopy, high-repetition-rate sources, multidimensional (4D and 5D) acquisition, and physically constrained forward modeling. Ultimately, the central opportunity lies in establishing a complete, causal link from initial excitation to localized energy flow, transient structure, and macroscopic device function. By prioritizing quantitative reproducibility and robust mechanistic interpretation, UEM is positioned to engineer materials in functional states that
equilibrium thermodynamics simply cannot describe.
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Quantum Physics
Design Principles for Ultra-High-Rate Quantum Codes
Jong Yeon Lee, Koki Okada, Nishad Maskara et al. (+2 more)
Reducing the
qubit overhead of
quantum error correction is a central challenge for scalable fault-tolerant
quantum computing. Recent ultra-high-rate
quantum codes offer a promising route toward this goal, with some constructions requiring as few as two physical data
qubits per logical
qubit. However, systematic principles for navigating the tradeoffs among encoding rate, distance, check weight, and blocklength remain lacking. Here, we develop and analyze principles for exploring this design space, and use them to design compact code constructions with improved performance. We develop code templates based on a pair-partition construction and a halving transformation that further reduces blocklength. Motivated by ensemble analysis of the degree distributions, we identify column weight as a key design parameter: increasing the column weight enables larger distances at compact blocklengths, at the cost of heavier checks. We find that at physical error rates of 0.1%, the benefits of increased distance often outweigh the penalty associated with heavier checks. Applying this framework, we identify numerous compact codes with favorable parameters, including [[90,21,11]], [[140,31,15]], and [[200,43,20]] non-CSS codes with check weight 10. Moreover, we develop
symmetry-informed strategies for identifying low-weight logical bases. These results provide systematic strategies for designing ultra-high-rate
quantum codes and navigating their Pareto frontier.
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All authors Jong Yeon Lee, Koki Okada, Nishad Maskara, Kenta Kasai, Hengyun Zhou
Quantum Physics
Beyond Bond Gauge: Exact Tensor-Network Tangent Spaces at Weighted Graph States
Song Cheng
For normal PEPS, the fundamental
theorem settles at the finite level whether virtual-bond gauge exhausts a tensor network's representation freedom. We ask the first-order question at a fixed representation, from both sides of the differential: which tensor variations leave the state unchanged without being bond gauges, and which physical directions can no variation reach? We answer both exactly for weighted graph state (WGS) tensor networks with equal physical and bond dimension $q\ge2$, which include the graph-state resources of measurement-based
quantum computation. Dividing a single-tensor variation by the nonvanishing amplitude turns it into an arbitrary function on the closed neighborhood of its vertex. Overlapping neighborhoods give the complete kernel. Its non-bond part is generated on periodic regular-polygon tilings by triangles, chordless squares, and edge-sharing diamonds. Under stated period conditions, generic gauge completeness on all thirty-nine families studied identifies this nullity as a WGS rank drop: for thirty-three families at every $q\ge2$, and for six at $q=2$. Supports outside every neighborhood give the missing directions: at
qubit graph states on the eleven Archimedean tilings every nearest-neighbor $XX$ and $YY$ direction is missing, including on honeycomb, where the non-bond kernel is empty. On large honeycomb and square
tori, small nonzero coherent $XX$ errors leave the bond-two PEPS set on the same graph. Removing redundant parameters and supplying missing directions are therefore distinct operations.
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Exactly Solvable and Integrable Systems
Superintegrability of discrete-time rational Ruijsenaars-Schneider model and deformed polynomial symmetry algebras
Pavel Drozdov
We explicitly construct the additional integrals of motion, ensuring maximal superintegrability of the discrete-time rational Ruijsenaars-Schneider model. Using them, we investigate the algebraic aspects of superintegrability in both continuous- and discrete-time settings. In particular, we determine the complete structures of the
polynomial symmetry algebras associated with both the rational Ruijsenaars-Schneider model and its discretization. We demonstrate that discretization leads to a nontrivial deformation of the continuous
symmetry algebra with respect to the discretization parameter, thereby extending recent analogous results from the rational Calogero-Moser system to its relativistic generalization.
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Optics
Angular-Channel Capacity and Nonlocal Wavefront Engineering for Phased-Array–Lens Systems
Mohammad Soltani and George V. Eleftheriades
Wide-angle beam steering with high directivity is fundamentally limited by diffraction, restricting the scan performance of phased-array systems. Here, we establish the bounds governing beam steering with high directivity in phased-array–lens systems and show that nonlocal dielectric metalenses can operate close to these limits. Unlike conventional metalenses that suppress mutual coupling, our approach exploits nonlocal electromagnetic interactions to laterally redistribute energy and expand the spatial width of phase coherence across the aperture. This enables efficient wavefront engineering for uniformly excited planar phased arrays using conventional linear progressive phasing. We further reveal the roles of diffraction and evanescent waves in determining the maximum coherent-aperture expansion and directivity enhancement. The resulting angular-channel bounds identify two distinct operating regimes for passive linear phased-array–lens systems: scan-resolution enhancement and directivity enhancement with preserved scan range. Guided by these limits, we derive geometry-independent design equations and develop an adjoint-based inverse-design framework for passive linear metalenses, enabling planar and cylindrical implementations that operate close to the fundamental limits. We experimentally validate a compact cylindrical metalens that preserves the $50^\circ$ scan range and scan resolution of a phased array with a $3.5\lambda_0$-wide aperture while providing a $2.5$–$3.5\,\mathrm{dB}$ increase in peak directivity. These results establish nonlocal dielectric metalenses as a practical platform for diffraction-limited wavefront engineering in phased arrays.
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High Energy Astrophysical Phenomena
A Helical Trajectory Interpretation of a Multi-wavelength Event in a Blazar S5 0716+714
Zhihao Ouyang, Jingyu Wu, Hubing Xiao et al. (+9 more)
Relativistic jets in blazars exhibit strong variability across multiple timescales, but the connection between temporal variability and the
evolution of jet structures remains poorly understood. In this work, we investigate the $\gamma$-ray variability of the BL Lac object S5 0716+714 from July 2014 to June 2015 and explore its possible connection with the parsec-scale jet
evolution. We identify an escalating periodic oscillation (EPO) in the $\gamma$-ray light curve, characterized by a sequence of successive flux enhancements with progressively increasing temporal separations. Combining
Fermi-LAT data with contemporaneous 43 GHz Very Long Baseline Array (VLBA) observations, we find a temporal association between the EPO and the downstream propagation of a superluminal
knot. A helical trajectory model simultaneously fitting the $\gamma$-ray variability and the two-dimensional VLBA component positions reproduces the observed flux modulation and component motion. These results suggest that
geometric Doppler modulation caused by the changing viewing angle of a moving jet component provides a possible explanation for the observed EPO. This work provides a framework of connecting blazar variability to the
knot evolution of relativistic jets.
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All authors Zhihao Ouyang, Jingyu Wu, Hubing Xiao, Zhijian Luo, Zhu Chen, Shaohua Zhang, Liang Chen, Jianzhen Chen, Marina Manganaro, Luis C. Ho, Junhui Fan, Chenggang Shu
Solar and Stellar Astrophysics
DKIST unveils MHD-predicted sub-50 km photospheric vortices
S. Vargas Dominguez, O. A. Calvo Rebellon, J. S. Castellanos Duran et al. (+4 more)
Solar vortices are rotating
plasma structures that play a key role in the transport of energy and
magnetic helicity from the photosphere to the chromosphere and corona. While numerical simulations predict the existence of small-scale photospheric
vortices with diameters of $50$–$100$ km, no direct observational evidence has been reported to date, primarily because of the limited spatial resolution of previous instrumentation. Here, we analyze high-resolution observations obtained with the 4-meter Daniel K. Inouye
Solar Telescope (DKIST) at 416 nm, with a spatial resolution of 12.3 km. Using
Fourier local correlation tracking and the swirling strength criterion ($\lambda_{\rm ci}$), we identify 201
vortex detections across a sequence of 143 reconstructed frames, spanning approximately 3.2 minutes, within a field of view of $4.92 \times 4.13$ Mm. The observations cover a photospheric plage region containing pore-like
magnetic concentrations. The detected
vortices have a median equivalent diameter of 38.6 km and a mean diameter of $39.5 \pm 3.3$ km. Virtually all detections are smaller than 50 km and therefore fall within the subgranular regime predicted by magnetohydrodynamic simulations but never previously observed. The median swirling period, $\tau_{\rm ci}=37.3$ s, satisfies the $\tau_{\rm ci}<100$ s criterion established by MURaM simulations. No statistically significant preference is found for prograde rotation (53.7%) over retrograde rotation (46.3%), consistent with the negligible influence of the Coriolis force at subgranular scales. These results demonstrate the unique capability of DKIST to resolve the population of photospheric convective
vortices predicted by state-of-the-art magnetoconvection simulations, opening a new observational window into small-scale
solar convective dynamics.
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All authors S. Vargas Dominguez, O. A. Calvo Rebellon, J. S. Castellanos Duran, M. van Noort, F. Wöger, D. A. Rodriguez Torres, C. G. Bernal
Materials Science
From Processing to Functionality: Engineering Accessible Material States in Cu-Embedded SiO$_x$ Memristive Devices
Tobias Gergs, Rouven Lamprecht, Sahitya Yarragolla et al. (+5 more)
Resistive switching in
oxide-based devices is widely governed by
stochastic defect processes, yet a predictive link between fabrication conditions and functional behavior remains elusive. Here, we establish a multiscale framework connecting
plasma-defined deposition conditions to macroscopic device functionality in sputtered SiO$_x$/Cu/SiO$_x$-based systems. By combining large-scale statistical analysis of more than 50,000 experimentally characterized devices with physics-based
plasma and atomistic simulations, we show that device behavior does not emerge from deterministic process-to-performance mappings, but from a probabilistic cascade spanning defect formation, defect-state
evolution, and functional-regime emergence. Data-driven clustering reveals a continuous functional state space composed of operational switching types, while inverse modeling identifies the reconstructed oxygen-vacancy density as an effective latent descriptor capturing the combined influence of structural disorder and defect
topology. This latent descriptor is strongly coupled to both Cu redistribution and electrical response, linking otherwise hidden material properties to observable device characteristics. Furthermore, macroscopic switching behavior is argued to arise from ensemble integration across spatially heterogeneous subdomains, providing a physical explanation for the pronounced variability of large-area devices. These findings shift the perspective from deterministic defect engineering toward probabilistic defect-state design and establish a physically grounded framework for understanding and controlling functional variability in such
oxide-based systems, such as memristive or resistive-switching devices.
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All authors Tobias Gergs, Rouven Lamprecht, Sahitya Yarragolla, Ole Gronenberg, Luca Vialetto, Hermann Kohlstedt, Thomas Mussenbrock, Jan Trieschmann
Optics
Ultrabroadband Optical Pulses with Quadratic Spectral Phase Part I: Temporal Form
George A. Hine
A time-domain representation for ultrabroadband optical pulses that includes chirp, stretching, and absolute phase is presented. This is accomplished by holomorphic
Fourier transform of a class of spectra that include spectral phase up to second order, resulting in derivatives of the Faddeeva function $w(\zeta)$. Relating the real part of this pulse to physical quantities, its shape is investigated. The derivative order $\eta$ is shown to dictate relative spectral bandwidth. The absolute phase determines the mixing of more localized (Gaussian decay) and less localized (algebraic decay) components of $w(\zeta)$. Second order spectral phase accounts for linear dispersion and is shown to cause a sheering of the Wigner-Ville distribution of the pulse, akin to the linear chirp that would be seen in the quasi-monochromatic case. Along with $\eta$ it determines the pulse length and number of oscillations. A correspondence with the slowly varying envelope approximation is derived for large order $\eta$, although the algebraic decay persists.
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Optics
Inverse design of large-scale freeform meta-optics by breaking the memory wall of full-wave simulation
Hyoseok Park and Yeonsang Park
Gradient-based design of large optical surfaces hits a
memory wall: a stored-history time-domain adjoint needs $24N_t$ bytes per
cell for $N_t$ steps, and every field update is bound by
memory bandwidth. Here we present a validated framework that removes this wall and makes globally optimized freeform meta-optics practical. Its finite-difference time-domain adjoint reconstructs interior fields backwards from two recorded planes, so volume
memory no longer grows with $N_t$, and fused kernels raise
memory-bandwidth use on an H200 GPU from 6.4% to a remarkable 56% of peak. Overlapping tiles, coupled by angular-spectrum propagation and distributed over GPUs, keep tile
memory independent of the aperture. Within hours on one GPU node, we optimize, against one global objective, every density variable of single-layer metasurfaces 100 to 200 $\mu$m across, and design a nine-wavelength lens, a color hologram and a polarization-switched hologram. Confirmed by an independent solver within 1.6%, they substantially outperform meta-atom designs, reaching 1.64, 1.65 and 1.24 times their objectives.
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Earth and Planetary Astrophysics
The GAPS programme at TNG LXXIX. New mass constraints for the infant planets in the V1298 Tau system through a long-term radial velocity monitoring with HARPS-N
M. Damasso, P. Leonardi, L. Borsato et al. (+26 more)
We aim to constrain the dynamical masses of the four confirmed transiting
planets orbiting the infant ($20\pm10$ Myr)
star V1298,Tau (orbital periods $P_b\sim$24.1 d, $P_c\sim$8.2 d, $P_d\sim$12.4 d, and $P_e\sim$48.7 d), through a new analysis of a homogeneous radial velocity
dataset. This system is a key
benchmark for testing formation and early-stage evolutionary models of
planets. We analysed more than 380 high-resolution spectra collected with the HARPS-N spectrograph over a time span of 4.5,yr. To account for dominant
stellar activity and transit-timing-derived
planet-
planet interactions, we analysed radial velocities extracted using two different approaches, and combined N-body simulations with multi-dimensional Gaussian process regression. We tested a set of spectroscopic and photometric activity diagnostics to mitigate the variability due to the
stellar magnetic activity in the radial velocity time series. The mass determinations are sensitive to the choice of the radial velocity extraction method and activity diagnostics. For some specific models, we measured masses with a significance of 3.5–4$\sigma$ for
planets b ($0.52^{+0.12}{-0.14}$, $0.65^{+0.21}{-0.18}$, $0.67\pm0.16$, and $0.78^{+0.19}{-0.20}$ $M_{\rm Jup}$) and e (0.40$^{+0.14}{-0.13}$, 0.66$^{+0.17}{-0.18}$, and $0.71\pm0.20$ $M_{\rm Jup}$). These values are compatible with masses of
giant planets, and are notably higher than those recently derived from transit timing variations alone, which indicate that these are low-density “super-puffy”
planets. Injection-and-recovery simulations moderately support this conclusion for
planet b. For
planets c and d, we primarily provide updated mass upper limits. Our analysis represents an exploratory study to address the complex issue of mass measurement in a multi-planetary system characterised by high levels of
stellar activity.
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All authors M. Damasso, P. Leonardi, L. Borsato, S. Benatti, A. Suárez Mascareño, A. Bonfanti, C. Di Maio, M. Mallorquín, L. Fossati, F. Marzari, D. Nardiello, S. Desidera, L. Naponiello, A. Sozzetti, G. Andreuzzi, M. Basilicata, A. Bignamini, A. S. Bonomo, M. Brogi, P. Giacobbe, G. Guilluy, A. F. Lanza, M. Lodi, L. Malavolta, L. Mancini, S. Messina, G. Micela, V. Nascimbeni, T. Zingales
Soft Condensed Matter
Orientational Ordering of Janus Particle Arrays as Classical Compass Spin Systems
Zhijie Fan, Myeonggon Park, Marija Vucelja et al. (+1 more)
Janus-particle arrays provide a soft-matter platform in which particle orientations act as classical
spins with anisotropic, bond-dependent interactions. Motivated by recent experiments on triangular arrays of metallodielectric Janus particles exhibiting sixfold orientational order and directly observable
vortices and antivortices, we study effective models beyond the isotropic XY description. A classical $120^\circ$ compass model captures the minimal bond-directional interaction, while an effective Kern–Frenkel model incorporates the geometry of the Janus surface interaction more directly. Monte Carlo simulations show that both models exhibit a low-temperature sixfold ordered phase, a high-temperature disordered phase, and an intermediate quasi-long-range-ordered regime consistent with two Berezinskii–Kosterlitz–Thouless transitions. In both cases, the sixfold order arises through thermal order-by-disorder from a continuously degenerate
ferromagnetic manifold. We further show that higher-order extensions of the $120^\circ$ interaction can alter the orientational selection: a quadratic term reverses the fluctuation-induced sixfold anisotropy, while a cubic term lifts the degeneracy energetically and selects the
lattice-aligned directions that coincide with those observed experimentally. These results connect the microscopic anisotropy of Janus-particle interactions to emergent XY-like
vortex physics and illustrate how distinct microscopic mechanisms can produce similar sixfold orientational order.
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All authors Zhijie Fan, Myeonggon Park, Marija Vucelja, Gia-Wei Chern
General Relativity and Quantum Cosmology
Stability and Formation of Solitonic Boson Stars
Gareth Arturo Marks
We extend a previous study of the radial stability of solitonic
boson stars by nonlinearly evolving them under aspherical perturbations, and by studying their formation from the collapse of scalar clouds. We focus in particular on models previously identified as radially stable, despite having positive binding energy, which ordinarily suggests that dispersion of all scalar matter is energetically preferred. A mode analysis of our 3+1 evolutions produces no evidence for the presence of a non-radial instability in any radially stable model, including those with positive binding energy. However, we do find evidence that such models do not generically form via gravitational cooling. We also find that it is possible to form another kind of compact object, which undergoes long-lasting radial oscillations and hence cannot be described as a stationary
boson star. These objects may be characterized, we suggest, by energetically favoured multi-oscillating solutions to the Einstein-Klein-Gordon equations, present in certain regions of the parameter space.
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General Relativity and Quantum Cosmology
Hawking radiation and graybody factor of slightly deformed Schwarzschild black holes
Asier Alonso-Bardaji, David Brizuela and Marc Schneider
We analyze the radiative properties of a general class of static and spherically symmetric black holes described by three independent shape functions, that encompass a broad family of regular and
quantum-corrected geometries. We consider a minimally coupled massless scalar field, and derive the Hawking temperature and graybody factor for the different geometries. While the Hawking temperature is determined by the near-horizon geometry, the graybody factor depends on the scattering properties of the entire exterior spacetime, and therefore exhibits a richer dependence on the deformation parameters, frequency, and angular mode. Then we particularize to geometries that describe slight deformations of the Schwarzschild black hole, and obtain analytic expressions for the leading corrections to the graybody factor. Finally, we apply our results to several specific well-known black-hole models, including Reissner-Nordström, Bardeen, Hayward, Simpson-Visser, as well as geometries inspired by loop
quantum gravity. In general, the deformations lead to colder horizons than Schwarzschild, and their effect on the graybody factor is frequency-dependent: the transmission of low-frequency modes is suppressed, whereas it is enhanced for high-frequency modes. This behavior is found for all but one of the geometries considered, which exhibits just the opposite trend. The analyzed modifications to the Hawking spectrum may therefore have relevant observational consequences, potentially providing signatures of deviations from the Schwarzschild geometry.
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Applied Physics
Topological-Insulator Heterophase Gate Stacks for Transistor Electrostatics
Minuk Song, Jiwan Kim, MD Gius Uddin et al. (+25 more)
Conventional gate-stack scaling reduces dielectric thickness and increases permittivity while largely treating the position and electronic character of the gate-side screening boundary as fixed. Here we show that this boundary can be engineered by converting the surface of the topological
insulator Bi\textsubscript{2}Se\textsubscript{3} into insulating high-$\kappa$ BiF\textsubscript{3}. Position-resolved calculations reveal a gap-opened immediate amorphous-BiF\textsubscript{3}/crystalline-Bi\textsubscript{2}Se\textsubscript{3} interface and a reconstructed gap-closed Bi\textsubscript{2}Se\textsubscript{3}-derived state in the adjacent subinterface layer, accompanied by a localized interfacial dipole. Capacitor measurements independently resolve a finite series response consistent with electronic compressibility at this boundary; this response lowers the nominal stack capacitance. Despite this capacitance penalty, MoS\textsubscript{2} transistors with closely matched BiF\textsubscript{3} thicknesses and a common BiF\textsubscript{3}/MoS\textsubscript{2} channel-side material interface exhibit near-thermionic-limit switching, negligible hysteresis and substantially weaker subthreshold drain-bias dependence than BiF\textsubscript{3}-only controls. These results identify the position and electronic character of the gate-side screening boundary as additional design variables for transistor electrostatics beyond nominal dielectric capacitance.
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All authors Minuk Song, Jiwan Kim, MD Gius Uddin, Wonseok Kim, Jihun Park, Han Uk Lee, Dong Won Jeon, Dohyung Lee, Lide Yao, Jouko Lahtinen, Gyunghyun Jang, Soohyun Min, Yonas Tsegaye Megra, Xiaoqi Cui, Seungwoo Choi, Yunyun Dai, Sang Hoon Chae, Keun Su Kim, Dong-Ho Kang, Hyeon-Jin Shin, Wooseok Song, Seth Ariel Tongay, Chul-Ho Lee, Manish Chhowalla, Sung Beom Cho, Zhipei Sun, Kibog Park, Hoon Hahn Yoon
General Relativity and Quantum Cosmology
Gravitational spin Hall effect in the Reissner-Nordström black holes: evolution equations and charge effects
Zhan Liu and Jia-Hui Huang
We study the spinoptics equations for test electromagnetic wave in the Reissner-Nordström spacetime. The explicit and hidden
symmetries of this background allow the complex null tetrad parallel-propagated along the null geodesic to be constructed explicitly. From this tetrad we obtain the
evolution equations for the deviation of the ray from the null geodesic and for the tilting angle of its orbital plane. In these equations the charge term enters with a sign opposite to the mass term. Numerical integration confirms that the gravitational
spin Hall effect becomes weaker with increasing charge: at a fixed impact parameter away from the critical value, the magnitude of the dimensionless tilting angle decreases with $Q$. As the turning point approaches the
photon sphere, its magnitude grows firstly, and then exhibits an oscillatory behavior. Since the physical tilting angle is proportional to the reduced wavelength, it remains small whenever the spinoptics approximation is applicable. A divergence occurs only when the ray travels on the
photon sphere.
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Instrumentation and Detectors
Impact of the position effects in the energy calibration of the BULLKID detector
Matteo Folcarelli, Matteo Cappelli, Giorgio Del Castello et al. (+6 more)
BULLKID is a cryogenic solid-state detector based on an array of silicon dice equipped with Kinetic Inductance Detectors (KIDs) for low-mass dark matter searches and coherent elastic
neutrino-
nucleus scattering. Energy calibration can be performed using optical LED
photon bursts, which are absorbed within the first few hundred nanometers of the substrate. An energy calibration using a $^{241}$Am gamma-ray source revealed a $<10\%$ discrepancy with the LED calibration. A recent study by Matava and Williams suggested that
phonon statistics and
phonon collection varying with the interaction position could explain such a discrepancy. This work evaluates the impact of these effects on the calibration of the BULLKID detector, demonstrating they both have a negligible effect. We clarify the results obtained during the $^{241}$Am calibration regarding the origin of the observed discrepancy.
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All authors Matteo Folcarelli, Matteo Cappelli, Giorgio Del Castello, Camilla Bonomo, Angelo Cruciani, Daniele Delicato, Leonardo Pesce, Davide Quaranta, Marco Vignati
Astrophysics of Galaxies
The JWST and ALMA view of local dwarf Pox 186: Evidence of stripped binaries driving a hard radiation field and little cold molecular gas resulting in high star-formation efficiency
Nimisha Kumari, Renske Smit, Claus Leitherer et al. (+5 more)
We present a JWST mid-infrared (MIR) view of Pox 186, one of the best local analogs of reionization-era
galaxies based on its extreme properties in the ultraviolet, optical, and far-infrared (FIR). We extracted a high signal-to-noise spectrum of Pox 186 from the spatially resolved MIR data taken with the Medium Resolution Spectrometer (MRS) on the MIR Instrument (MIRI), and compared its MIR properties with those of the other
dwarf galaxies in the Herschel
Dwarf Galaxy Survey. We probe the radiation hardness of Pox 186 using the so-called softness diagram, based on the MIR line ratios [NeIII]/[NeII] and [SIV]/[SIII], which suggest that Pox 186 hosts ionization sources with a hard radiation field. We probe the dominant ionization source in Pox 186 using diagnostic diagrams based on MIR line ratios. Our photoionization models provide evidence that stripped binary
stars are the main cause of the extreme MIR line ratios. Similarly, a young starburst is needed to reproduce the MIR
dust continuum. We probe the warm and cold molecular gas content using the MIR H$_2$ rotational lines (S(1)-S(7)) from JWST, and the archival sub-mm CO(2-1) line from ALMA, which indicate a high
star-formation efficiency (SFE; $>$ 15 $\times$ 10$^{-9}$ yr$^{-1}$) and low gas depletion time comparable to that of the reionization-era
galaxies. This analysis strongly suggests that
star formation rather than active
galactic nuclei drives the hard radiation field observed in Pox 186, and cautions against relying solely on the UV diagnostics to establish the nature of high-z
galaxies.
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All authors Nimisha Kumari, Renske Smit, Claus Leitherer, J. Álvarez-Márquez, Katherine Ormerod, Joris Witstok, Suzanne Madden, Matthew Hayes
Mesoscale and Nanoscale Physics
Real-axis least-squares bath discretization for real-time transport in quantum-dot Josephson junctions
Ruixin Zhou, Bing Dong and Yiyan Wang
Efficient real-time methods are essential for resolving transient coherence and nonlinear transport in driven superconducting nanostructures. Such simulations remain challenging because finite representations of the BCS continuum generate recurrences, while the damping used to suppress them smears gap-edge structure and artificially shortens coherent lifetimes; finite-broadening regularization of the gap-edge singularity likewise imposes a lifetime-resolution floor. Here we extend the driven Liouville–von Neumann approach to superconducting reservoirs—a noninteracting
quantum dot with Bogoliubov–de Gennes leads—building an explicit-
Hamiltonian framework that hosts a family of bath discretizations (uniform and Gaussian baselines and a new real-axis least-squares recipe, with mode energies, spectral weights, and mode-resolved dampings optimized jointly under gap-aware constraints)—making the broadening an independently calibrated numerical parameter whose leading long-time effect extrapolates controllably along the joint ($\gamma\to0$, $N_b\to\infty$) refinement path while cutting computational cost by over an order of magnitude versus the high-resolution DLvN reference. The compressed baths recover established current-phase relations, multiple-Andreev-reflection structure, quasiparticle-trapping oscillations, and integer and fractional Shapiro locking; the lifetime analysis yields the parameter-free leading-order relation $\kappa\simeq w_{\mathrm{bath}}\gamma_{\mathrm{eff}}$ and resolves damping-induced decay rates below the resolution scale of a previous finite-broadening calculation. As an explicit
Hamiltonian reservoir representation, the framework generalizes naturally to multiterminal normal–superconducting geometries and offers a route toward interacting
impurity solvers, while finite-gap strong-drive locking amplitudes mark its present quantitative boundary.
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Cosmology and Nongalactic Astrophysics
Two-rung ladder: $H_0$ from Tip of the Red Giant Branch and geometric anchors alone
Richard Stiskalek, Harry Desmond and Guilhem Lavaux
We infer the Hubble constant $H_0$ from the ~400 Extragalactic Distance Database hosts with a tip of the red
giant branch (TRGB) distance, calibrated on the
geometric anchors of the Large Magellanic Cloud and NGC 4258. We forward-model the tip magnitudes and host
redshifts including magnitude-limited selection, sky exposure, and density-dependent
galaxy bias, conditioning on each of the 80 Manticore-Local realisations of the local density and peculiar-velocity fields in turn. As most hosts lie at $cz_{\rm CMB} \lesssim 1000$ km/s, where peculiar velocities are important, the inference is limited by the variance of these fields rather than by the TRGB calibration. For a fixed realisation, the
redshift likelihood and density smoothing each move $H_0$ by less than 1 km/s/Mpc and a velocity monopole by $5.4 \pm 3.4$ km/s/Mpc, whereas the field-to-field scatter in $H_0$ is 5.2 km/s/Mpc. Weighting the posteriors from each realisation equally gives $H_0 = 68.4 \pm 5.9$ km/s/Mpc, while weighting each by its
Bayesian evidence gives $72.3 \pm 2.6$ km/s/Mpc. The latter value is set by a single particularly high-evidence realisation, making it sensitive to the finite sampling of the reconstruction posterior. This ladder therefore cannot yet arbitrate the Hubble tension. Extending the TRGB data beyond the present ~1000 km/s, together with improved reconstructions of the local Universe, would reduce the field-to-field scatter well below the 5.2 km/s/Mpc we find here.
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General Relativity and Quantum Cosmology
Analytic detector responses and entanglement in constant-curvature spacetimes
Dyuman Bhattacharya, Jiayue Yang, Ming Zhang et al. (+1 more)
We derive analytic response functions for Unruh–DeWitt detectors coupled to real, massless, conformally coupled scalar fields, to distinguish the effects of the field spectrum and global geometry from those of the interaction protocol. For Gaussian-switched static pairs in Minkowski, anti-de Sitter, and de Sitter spacetimes, we obtain the leading-order excitation probabilities and two-detector coherences in spacetime dimension $\mathcal D=d+1\ge3$. Time-ordered coherence requires distinct spatial worldlines; the local response and single-excitation coherence also admit coincidence. For equal-
redshift pairs, Gaussian switching separates the gap dependence of the time-ordered coherence. In de Sitter space, KMS detailed balance fixes the gap that maximizes the ratio of nonlocal coherence to local excitation, giving a single-gap test for the existence of leading-order
entanglement and restricting any entangling gaps to one bounded interval. When
entanglement is present, the concurrence itself peaks at a smaller positive gap. In the three-dimensional BTZ black hole, an integrated Legendre series gives the sharply switched response of a radially infalling detector. A uniform image-sum estimate establishes logarithmic growth near the singularity and determines its coefficient from the covering-AdS response. A sufficiently smooth monotone onset removes the finite-time onset glitches but leaves a positive logarithmic coefficient; the accumulated leading-order response remains finite. Independent numerical calculations test the analytic expressions, their convergence properties, and these physical distinctions.
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All authors Dyuman Bhattacharya, Jiayue Yang, Ming Zhang, Robert B. Mann