Applied Physics
Oscillator-Based Processing Unit for Formant Recognition
Tamás Rudner-Halász, Wolfgang Porod and Gyorgy Csaba
Oscillatory neural networks have been successfully applied to a number of computing problems, such as associative
memories and computationally hard optimization tasks. In this paper, we show how to use oscillators to process time-dependent waveforms with minimal or no preprocessing. Since preprocessing and first-layer processing are often the most power-hungry steps in neural networks, our findings may open new doors to simple and power-efficient edge-AI devices.
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Soft Condensed Matter · Cross-listed from cs.LG
What Should a Large Language Model See? Physical Invariants as a Data Representation for PDE Discovery
Fan Yang and Matt Thomson
Understanding how molecular interactions govern macroscopic behaviour is a central challenge in molecular sciences. However, conventional theory building cannot keep pace with the vast
datasets modern experimentation routinely produces. Large
language models offer a promising route to automating theory construction, but a spatiotemporal field cannot be directly placed in a
prompt. Existing models generally learn about the data only through a score measuring how well each proposal fits it. Here we introduce data interpretation, a stage that measures the field into the quantities a theorist would consult and supplies them to the model as a direct input. On a
benchmark of simulated fields, interpretation nearly triples the accuracy of recovered equations relative to showing the raw data, at negligible computational cost and without any training. By allowing a
language model to read field data as a theorist does, data interpretation offers a practical route to automated field theory construction that can coevolve with experimentation.
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High Energy Physics (Theory)
Chaos in Yang-Mills
Barel Skuratovsky
We study the dynamics of pure-gauge SU(N) through the time
evolution of a spatial Wilson loop. We compute its out-of-time-order correlator at weak 't Hooft coupling and large N, and propose a framework for the strong-coupling description. We find that operators in pure-gauge Yang-Mills grow only when the group is non-abelian and d>2, and
conjecture that pure gauge theories are chaotic only when non-abelian at d>2. Even at weak coupling the correlator's exponent inherits the IR sensitivity of the
gluon self-energy imaginary part, which rests on the non-perturbative
magnetic scale. We then explore the possibility that the loop's own size supplies that scale, since the loop operator is blind to any momenta softer than 1/2R. With the cutoff imposed that way the exponent changes sign at a critical diameter: smaller loops scramble, larger ones do not, and the scrambling time diverges at the crossing. The transition follows from that cutoff. Further investigation, in particular a first-principles treatment of the thermal decay width, is required to establish whether it is physical.
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Instrumentation and Methods for Astrophysics
Spatially Scanned STIS Spectra of the Exoplanet Host Star 55 Cnc
D. E. Welty, J. D. Lothringer, D. K. Sing et al. (+3 more)
We discuss the analysis of two sets of optical/near-IR spectra of the
exoplanet host
star 55 Cnc, obtained with the Space
Telescope Imaging Spectrograph (STIS) and grating G750L in spatial scanning mode, in order to assess the performance of that relatively new observing mode for studies of transiting
exoplanets. Standard pipeline reductions of the CCD spectral images were augmented by custom procedures for removing both
cosmic rays and the strong fringing seen at wavelengths longer than 7000 A. Both total ("white-light") fluxes and the fluxes for narrower wavelength intervals were extracted from the processed spectral images. Apart from slight ($\sim$400 ppm) orbit-to-orbit offsets between the relative fluxes in each set, the patterns exhibited by the flux values within each orbit are very similar. The systematic differences in the fluxes are somewhat smaller than those seen in STIS spectra of 55 Cnc obtained in "stare mode", where the CCD is deliberately saturated at a fixed pointing. A parameterized detrending method similar to those commonly used to remove instrumental effects from time series observations of
exoplanet host
stars was then applied to the extracted fluxes. For the total fluxes, the scatter about the detrending models is $\sim$30-40 ppm – comparable to the best precision previously obtained for time series photometry with HST – but is somewhat larger for narrower wavelength bins. The depth of the transit of the super-Earth 55 Cnc e ($\sim$450 ppm for the total flux) is consistent with previous values. Both the scan-mode and the stare-mode observations of 55 Cnc e appear to indicate an unexpected (and variable?) increase in the transit radius Rp/Rs between 0.55 and 1.0 $\mu$m. While these data are somewhat limited, they do suggest that spatial scanning with the STIS CCD can provide high-quality optical/near-IR spectra of the brighter
exoplanet hosts. (edited)
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All authors D. E. Welty, J. D. Lothringer, D. K. Sing, A. M. Jones, A. Riley, C. R. Proffitt
High Energy Physics (Theory)
Exact All-Level Positivity of the Bosonic Veneziano Amplitude
Qi Chen and Yuan Yin
Tree-level partial-wave unitarity of the open bosonic Veneziano amplitude follows indirectly from the no-ghost
theorem, but a direct proof from the beta function has been missing at the critical dimension. We prove nonnegativity at every mass level and
spin throughout the sharp range 3 < D <= 26, using a Bessel recurrence that reduces the infinite sign problem to a manifestly positive bulk and a finite exact boundary.
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Instrumentation and Methods for Astrophysics
Deep Learning-Based Coarse Alignment and Cophasing of a Distributed-Aperture Telescope. Application to the Small ExoLife Finder (SELF)
N. Arteaga-Marrero, J. Iborra-Luis, A. Padrón-Brito et al. (+1 more)
The ExoLife Finder (ELF), a 35–50-meter-class Fizeau interferometric
telescope, was designed to detect biosignatures on
exoplanets through direct imaging. The Small ExoLife Finder (SELF), a 3.5-meter prototype, serves as a testbed for the innovative technologies required for such a facility. A key challenge is the precise cophasing of its distributed aperture, where the optical path differences between subapertures must remain below a small fraction of the operating wavelength. This work investigates convolutional neural networks (CNNs) to estimate
alignment errors directly from focal-plane images, enabling fast, data-driven coarse
alignment to the few-micrometer level. A supervised regression framework was developed using a custom CNN to model the nonlinear mapping between subaperture misalignments and focal-plane intensity distributions. Training and validation
datasets were generated from high-fidelity optical simulations of the simplified SELF system. Gaussian-noise augmentation was used to assess robustness, and several established CNN architectures were evaluated for comparison. The proposed approach reconstructed piston and tilt misalignments across all mirror pairs, demonstrating that focal-plane interference patterns can be exploited for
alignment estimation. The custom CNN provided a favorable balance between estimation performance, robustness, and computational efficiency, with millisecond-scale inference times. A trade-off between performance and noise robustness was identified, with noise augmentation improving reconstruction at low signal-to-noise ratios but reduced performance under near noise-free conditions. These results demonstrate the feasibility of data-driven focal-plane wavefront sensing for distributed-aperture
telescopes and provide a basis for autonomous, computationally efficient cophasing strategies for future high-resolution interferometric systems.
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All authors N. Arteaga-Marrero, J. Iborra-Luis, A. Padrón-Brito, J. Kuhn
Solar and Stellar Astrophysics
ABYSS. IV. Identifying signatures of stellar youth in APOGEE spectra
Valentina Bonilla Villalobos, Marina Kounkel, Joseph Mullen et al. (+9 more)
We develop a convolutional neural network classifier that performs spectroscopic identification of
stellar youth (<40 Myr) in APOGEE spectra. This classifier is sensitive to several youth-related features, including rotational broadening, which is common in younger
stars, and to several discrete lines that appear to be indicative of a very spotted photosphere. The model is successful at identifying youth across a wide range of
stars, achieving its strongest performance at discriminating young M and K
dwarfs, while maintaining useful discriminatory power for hotter
stars as well. This work enables more robust separation of pre-main-sequence
stars from more evolved sources in the field even when they have comparable Teff and log(g), providing a reliable means to substantially reduce contamination in photometrically selected YSO candidates. In addition to constructing a classifier for APOGEE spectra, we also perform classification of young
stars in optical BOSS spectra.
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All authors Valentina Bonilla Villalobos, Marina Kounkel, Joseph Mullen, Eleonora Zari, Alexandre Roman-Lopes, Keivan Stassun, Ricardo López-Valdivia, Jinyoung S. Kim, Mojgan Aghakhanloo, Facundo Pérez Paolino, Jonathan C. Tan, Jesús Hernández
Fluid Dynamics
First-principles perturbative theory of anomalous scaling in a stochastic shell model of turbulence
Alexei A. Mailybaev
Deriving anomalous scaling exponents from the equations of motion remains a central problem in the statistical theory of
turbulence. Here we obtain a first-principles perturbative solution for a nonlinear
stochastic dyadic shell model. The model preserves the conservative cascade structure and exact scaling
symmetry of the deterministic dynamics, while
stochastic transfer fluctuations provide a perturbative setting in which the leading-order rescaled dynamics is Gaussian. Using the statistically restored hidden scaling
symmetry of the inertial-range equations, we determine the stationary statistics of the rescaled variables. We then formulate anomalous scaling as a Perron–Frobenius
eigenvalue problem for the multiplier statistics. The resulting perturbative expansion yields explicit analytical expressions for the scaling exponents of structure functions of arbitrary order in the weak-noise regime. Direct numerical simulations provide an independent verification of the theoretical predictions. The results demonstrate that the hidden-
symmetry perturbation framework extends from linear random models to a genuinely nonlinear cascade system.
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Quantum Physics
Optical centrifuge as a probe of strong dissipative coupling between a molecular rotor and superfluid helium
Ian MacPhail-Bartley, Sören E. Mahr, Cameron E. Peters et al. (+7 more)
A macroscopic manifestation of superfluidity is that objects moving through
liquid helium experience negligible friction below the Landau critical velocity. How this frictionless motion breaks down at the nanoscale remains an open question. Molecules embedded in helium nanodroplets represent a well-controlled system for studying this breakdown, yet none has reached the regime of strong dissipative coupling, when energy transfer from the molecule to the superfluid dominates the observed dynamics. Molecular rotation, induced by short
laser pulses, offer a suitable probe to reach rotational energies in the range of the roton gap, where superfluid helium supports a large number of elementary excitations. However, the solvation shell around a rotating molecule caps the energy reachable by a free rotor after impulsive excitation well below the roton excitation energy. Here we show that continuous driving with an ultraslow optical centrifuge overcomes this limitation: the strong field dresses the molecule into pendular states whose energies fall within the spectrum of the collective excitations of the superfluid, placing the system in the strong-dissipation regime. The resulting rapid thermalization locks the molecule to the rotating field until the rotation-induced level splittings overtake the thermalization rate, beyond which the molecular
alignment is progressively lost. Our approach offers a direct measurement of the molecule-bath coupling in a
quantum fluid.
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All authors Ian MacPhail-Bartley, Sören E. Mahr, Cameron E. Peters, Baptiste Coquinot, Volker Karle, Giacomo Bighin, Ragheed Alhyder, Mikhail Lemeshko, Henrik Stapelfeldt, Valery Milner
Geophysics · Cross-listed from math.NA
ROMNet: a hybrid reduced order modeling and machine learning approach to waveform inversion
Liliana Borcea, Alexander Mamonov, Kui Ren et al. (+2 more)
Waveform inversion seeks to estimate the wave speed of a heterogeneous, inaccessible medium, from time-resolved measurements of the waves at user controlled sensors. We consider this inverse problem for acoustic waves and an active array of source/receiver sensors that emit probing signals and measure the generated pressure waves. The forward map, from the wave speed to the measurements, is nonlinear and oscillatory. The oscillations cause cycle skipping, the main impediment to using the standard, nonlinear least-squares data fitting formulation, known as full waveform inversion (FWI). A recently introduced alternative waveform inversion approach computes from the measurements an algebraic surrogate of the wave operator, a reduced order model (ROM)
matrix, which is then used to estimate the wave speed. The mapping from the measurements to the ROM is nonlinear, but well understood. It is computed efficiently, in a non-iterative manner. The nonlinear mapping from the ROM to the wave speed is less understood, and its approximation involves time-consuming optimization. Our goal in this paper is to use a neural network to map the ROM
matrix to a nearby one, that has a simpler and explicit dependence on the wave speed. This simplifies and reduces the computational cost of the ROM-based waveform inversion. We introduce the methodology, called ROMNet, and test it with numerical simulations, using two training data sets: The first set consists of random media with variations of the wave speed modeled by a superposition of Gaussians with random amplitudes and standard deviations. The second is the publicly available GeoFWI
dataset introduced for benchmarking FWI using deep learning. We compare the performance of ROMNet with the direct ROM-based inversion and with two representative deep learning approaches to FWI: “
Fourier-DeepONet" and “InversionNet".
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All authors Liliana Borcea, Alexander Mamonov, Kui Ren, Haizhao Yang, Chugang Yi
General Relativity and Quantum Cosmology
21-cm Brightness Temperature in a Unified-Dark-Sector Horndeski Theory
Bertha Cuadros-Melgar, Thanasis Karakasis, Eleftherios Papantonopoulos et al. (+1 more)
We investigate the impact of scalar-tensor theories on the 21cm brightness temperature. We consider a specific model in Horndeski scalar-tensor theory in which dark matter and dark energy in the framework of shift-symmetric generalized Galileon theories was described and an effective unified
cosmic fluid was obtained. We calculate the Hubble parameter of the model and we plot the curve of the
evolution of the 21-cm temperature in a specific range of the
redshift parameter $z$ and compare it to the curve corresponding to $\Lambda$CDM paradigm.
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All authors Bertha Cuadros-Melgar, Thanasis Karakasis, Eleftherios Papantonopoulos, Maria Petronikolou
Materials Science
Tuning Dirac-Rashba and Double Dirac Cone Surface States of Topological Crystalline Insulator Pb$_{1-x}$Sn$_{x}$Se by Transition Metal Adsorbate
Bartłomiej Turowski, Wojciech Brzezicki, Ondřej Caha et al. (+9 more)
The electronic structure of topological
insulator/
magnetic metal (TI/MM) interfaces is of great importance for understanding of exotic
spin-dependent phenomena and realization of advanced
spin-orbitronic devices. Here, we employ a model system of submonolayer transition metal (TM) deposited on the surface of a topological crystalline
insulator (TCI) of Pb$_{1-x}$Sn$_{x}$Se to systematically map out the modification of the surface electronic structure by angle-resolved photoemission spectroscopy (ARPES) as a function of coverage. For the polar (111) Pb$_{1-x}$Sn$_{x}$Se surface, we observe the coexistence of the Dirac topological surface states (TSS) and Rashba-split surface states (RSS) induced by the combined effects of inversion-
symmetry breaking, surface band bending and orbital angular momentum effects. In particular, we demonstrate very large Rashba splittings can be obtained and the Rashba parameter (${\alpha}_R$) can be tuned over a remarkably wide range from 0 to 3.5 eV ${\cdot}$ $\mathring{\mathrm{A}}$, depending on the type and coverage of the TM adatoms. Model-
Hamiltonian calculations corroborate the experimental findings and reveal that this coexistence results from the filling of the TSS by the surface doping caused by the TM. In contrast, for the nonpolar (001) surface exhibiting a double Dirac cone topological surface state, the inversion
symmetry is preserved and hence no Rashba-split surface states emerge. Instead, surface charge imbalance induces dephasing of the wave functions of the double Dirac cones that diminishes the momentum-space separation between them. These findings shed light on novel phenomena occurring at the topological
insulator / transition metal interface, offering a versatile platform for future spintronic and
quantum devices.
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All authors Bartłomiej Turowski, Wojciech Brzezicki, Ondřej Caha, Rafał Rudniewski, Natalia Olszowska, Jacek Kołodziej, Marta Aleszkiewicz, Tomasz Wojciechowski, Tomasz Wojtowicz, Timo Hyart, Gunther Springholz, Valentine V. Volobuev
Chemical Physics
An embedding method with constant potential boundary conditions
Lisa Hetzel, Martin Head-Gordon and Christopher J. Stein
We present a self-consistent field framework for finite embedded
quantum-chemical clusters with constant potential boundary conditions. The coupling is realized through an energy-independent self-energy commonly employed in
quantum-transport calculations within the wide-band approximation. Starting from the corresponding non-
equilibrium Green's function formalism, we derive an analytic expression for the one-particle density
matrix update that can be incorporated into conventional Hartree–Fock and density functional theory. The resulting non-Hermitian self-consistent field equations are solved using adapted Pulay-type mixing schemes. Applications to a quasi-periodic hydrogen ring demonstrate that a finite fragment coupled through an optimized self-energy accurately reproduces the polarization response of the extended system, while calculations on a lithium cluster capture metallic charge transfer and fractional occupations under open-boundary conditions. The proposed framework establishes practical grand-canonical boundary conditions for finite
quantum-chemical clusters and lays the methodological foundation for
quantum embedding methods for electrochemical systems.
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Quantum Physics
No Free Compression in Quantum Relaxations for Optimization
Stuart Hadfield
Qubit-efficient
quantum relaxations compress classical decision variables into expectation values on substantially fewer
qubits. We ask what resource tradeoffs this compression entails for
quantum optimization. For the complete quadratic-Majorana encoding of $m=\Theta(n^2)$ binary variables on~$n$
qubits, we define the universal margin as the smallest correlator magnitude that can be guaranteed with prescribed signs for every target sign (bit) assignment. We show that it is exactly $\Delta_{\rm Maj}(n)=\tan\!\left(\frac{\pi}{4n}\right)=\Theta(1/n)$, whereas uniformly random sign assignments retain $\Theta(1/\sqrt n)$ target-specific margins. Arbitrary density operators and mixed fermionic Gaussian states generate the same quadratic-Majorana covariance body, so non-Gaussian state resources cannot enlarge this two-point relaxation. More generally, standard
quantum random access code bounds provide general information-theoretic baselines. For any fixed family of $m$ designated binary observables on~$n$
qubits, the universal margin is at most $\sqrt{(2\ln2\,n/m)}$, and random access decoding from $N$ copies with constant success probability above $1/2$ requires $nN=\Omega(m)$. For a fixed Pauli correlation encoding required to work uniformly over all targets, maintaining a fixed nonzero decoded magnitude under smooth sign decoding therefore requires a rescaling parameter that grows as the available margin shrinks. Thus, while providing substantial
qubit savings, compression can shift cost into restricted expectation value geometry, smaller expectation value magnitudes, or more demanding information recovery rather than eliminate it.
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Fluid Dynamics
Wing-Rotor Aerodynamic Interactions in Small UAVs During Hover and Cruise
Dev Pradeepkumar Nayak, Seungmin Choi and Muhammad Saif Ullah Khalid
A compact vertical take-off and landing aircraft requires the same tilt-rotor configuration to perform two fundamentally different aerodynamic tasks: sustain hover and deliver efficient cruise. This work investigates the underlying wing-rotor interactions in both operating regimes using a validated unsteady Reynolds-averaged Navier-Stokes equations-based computational framework. For cruise, the advance ratio governs the balance between thrust production, propulsive efficiency, and wake coherence. Lower advance ratios produce a tightly wound slipstream that undergoes strong
vortex interactions, leapfrogging, and early wake bifurcation. At higher advance ratios, the slipstream retains a narrower and more coherent jet-like structure, improving propulsive efficiency while reducing both thrust of the propellor and lift of the wing. The flow impingement at the wing is characterized through the approaching, interaction, and convection phases, revealing the combined influence of
vortex stretching, wake bifurcation, blockage, image-induced velocity, and streamwise momentum convection on the downstream wake. In hover, the propeller's rotational speed governs the overall aerodynamic performance more strongly than the wing's placement. Although the position of the wing with respect to the propellor modifies the local wake interactions and flow impingement on its leading edge, its influence on the integrated thrust coefficient and figure of merit remains limited. We also explain the
vortex and wake dynamics around the propellor and the wing responsible for governing these aerodynamic performance.
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Lattice Field Theory
Anomalous behavior of Wilson fermions in the presence of monopoles
Manuel Cortina, Rajamani Narayanan and Ray Romero
Three dimensional compact U(1) gauge theory supports a finite density of monopoles at a fixed
lattice gauge coupling. After showing evidence for the expected dependence on the
lattice coupling of the density of monopoles, we study the low lying spectrum of a two
flavors of two-component Wilson
fermions as a function of the bare Wilson mass. The Wilson-Dirac operator that realizes the two
flavors are hermitian conjugate of each other to restore parity invariance and the commutativity of the two operators expected in the typical continuum limit is not the case in the presence of monopoles for all values of the
lattice gauge coupling. This results in an anomalous behavior where we see clear evidence for the presence of very small
eigenvalues for a wide range of a particular sign of the bare Wilson mass. These eigenmodes are typically in one-to-one correspondence with the number of monopoles as defined by the gauge field and the spectrum associated with these modes are separated by a gap from the bulk in the asymptotic regime of the
lattice gauge coupling. The
eigenvalues come in pairs around zero and the
eigenvalues of one sign couple to the monopoles while the modes of the opposite sign couple to the anti-monopole implying
flavor symmetry breaking.
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Statistical Mechanics
Thermalization packets and optimal ice cubes
Israel Klich and Marija Vucelja
Relaxation toward
equilibrium is usually accelerated by modifying the environment or by cooling a system further from
equilibrium. Here we introduce a distinct strategy: thermalization packets, auxiliary systems prepared in advance and later coupled to a target system to accelerate its relaxation toward a prescribed thermal state. Thus, thermalization packets trade preparation effort for reduced waiting time. When the objective is cooling, we colloquially refer to such packets as ice cubes. Unlike ordinary coolants, thermalization packets are characterized not only by their temperature or heat capacity, but also by their microscopic preparation. We define perfect and optimal packets by their ability to suppress the slowest relaxation mode of the coupled dynamics: perfect packets eliminate it entirely, while optimal packets minimize its amplitude. We show that, under generic conditions, perfect packets exist among thermal preparations near
equilibrium. Surprisingly, for asymptotic relaxation, the optimum among thermal preparations is generally not the coldest packet: cooling the packet beyond the slow-mode-cancelling optimum restores a nonzero slow mode and can therefore slow relaxation, yielding a packet analog of the Mpemba effect. We demonstrate the concept in exactly solvable Metropolis dynamics, a minimal two-
qubit model, and a boundary-coupled interacting Ising-
spin system. We also extend the framework to packets optimized for finite readout times. Finally, we show that the perfect-packet contour can connect the trivial bath-
equilibrium point to a nontrivial strong Mpemba or strong inverse-Mpemba point.
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Accelerator Physics
Enhancing 10 TeV $\gamma\gamma$-collider luminosity through scattering-laser wavelength selection in the presence of prolific electron-positron pair production
S. S. Bulanov, T. Barklow, C. Benedetti et al. (+8 more)
A $\gamma\gamma$-
collider capable of reaching the 10 TeV parton-center-of-momentum (pCM) frontier of particle physics may enable the study of phenomena beyond the Standard Model. Based on compact linear wakefield accelerator technology, such a
collider could be realized by Compton scattering multi-TeV
lepton beams off moderate-intensity
laser pulses close to the
collider interaction point, producing the required $\gamma$-
photons. It is shown that, for a wide range of scattering-
laser wavelengths, $\gamma\gamma$-collisions at the interaction point can meet the luminosity requirements for novel particle physics studies, even in the presence of the prolific electron-positron pair production that accompanies the interaction of the scattering
laser with the multi-TeV
lepton beam. Notably, this pair production imposes a natural limit on the maximum achievable
photon luminosity. Accounting for this limit and for the angular divergence of the Compton
photons yields an enhanced $\gamma\gamma$-
collider luminosity for 250 nm and 1.25 nm scattering
lasers. Moreover, the secondary pairs can themselves be exploited in physics studies, since their luminosity is high enough to produce heavy particles at rates needed for discoveries well beyond the reach of existing
colliders.
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All authors S. S. Bulanov, T. Barklow, C. Benedetti, A. Formenti, S. Gessner, R. Lehe, A. Rastogi, S. Pagan Griso, C. B. Schroeder, A. Schwartzman, J. Osterhoff
Quantum Physics
Generalized Efficient Quantum Circuit Implementation of Discrete-Time Quantum Walks on Cayley Graphs
Seoyoon Kang
We present a generalized and efficient
quantum circuit framework for implementing discrete-time
quantum walks (DTQWs) on Cayley graphs of arbitrary dimension. Building on the Boundary QFT scheme of Razzoli et al., we introduce a systematic multi-stage decomposition of the shift operator for 1D Cayley graphs across three classes of generating sets: inverse-closed without involutions, inverse-closed with an involution, and non-inverse-closed. The decomposition hierarchically factorizes the QFT-diagonalized shift operator into structured block components, progressively reducing the control degree of the required rotation gates and replacing high-degree multi-
qubit controlled operations with collections of lower-degree equivalents. We extend this construction to $d$-dimensional
torus graphs and provide explicit
circuit implementations for an 8-Cayley graph and a $\mathbb{Z}_{16} \times \mathbb{Z}_8$
torus graph as concrete illustrations. Gate complexity analysis using the linear CNOT scaling of Rosa et al. demonstrates that the decomposed implementation achieves a substantial reduction in upper-bound CNOT cost relative to the naive implementation within the regime $k \leq 64$ for inverse-closed graphs and $k \leq 16$ for non-inverse-closed graphs, where $k$ denotes the degree of the generating set. Benchmarking further reveals that this efficiency gain is largely insensitive to the system size $N$, identifying $k$ as the dominant resource parameter for the shift operator. These results provide a scalable and hardware-conscious pathway toward practical DTQW implementations on near-term
quantum devices.
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Instrumentation and Methods for Astrophysics
Capra: Scalable HEALPix-Native Intensity Reconstruction for High-Resolution IMAP Analyses
Nikola Bukowiecka, Daniel B. Reisenfeld and Maciej Bzowski
We present Capra, a HEALPix-native pipeline for reconstructing all-sky energetic neutral atom (ENA) intensity maps from the NASA Interstellar Boundary Explorer (IBEX) and Interstellar Mapping and Acceleration (IMAP) missions' event-counting data. Capra produces two products: (1) a baseline boresight-assigned map, and (2) an optional smoothed map on the HEALPix grid. This produces smooth, physically interpretable maps with consistent resolution changes and reference-frame transformations. The smoothed Capra maps recover the large-scale ENA morphology while reducing sampling-driven mottling and strip-like artifacts. Relative comparison with the Theseus reconstruction shows broadly consistent large-scale structure, with the discrepancies reflecting differences in reconstruction methods, rather than major morphological discrepancies. We verify invariance (preservation) of count numbers, rates, and intensities across tessellations under coordinate transformations, and demonstrate numerical convergence up to HEALPix resolution Nside = 64 for a representative
dataset. We show that thread-based parallelism performance exhibits approximately linear strong scaling, with bounded
memory usage, enabling efficient high-resolution reconstruction and making Capra well-suited for high-resolution IMAP reconstruction.
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Strongly Correlated Electrons
The Effects of Inter-Valley Coupling of Dirac Fermions near Four Dimensions
S. Thiagarajan and F. Krüger
We analyze the criticality of an Ising Gross-Neveu-Yukawa (GNY) theory of $N_\psi$ Dirac
fermion valleys with intra- and inter-valley interactions, using a renormalization-group analysis in $4-\epsilon$ space-time dimensions to one-loop order. The conventional GNY fixed point of decoupled valleys is unstable against inter-valley fluctuations which are naturally present if the
symmetry breaking is driven by short-ranged interactions. At the new fixed point, the critical exponents differ from the conventional GNY universality. Most importantly, Lorentz invariance is broken due to interference effects resulting from the relative rotation between valley coordinate frames. In the limit of large $N_\psi$ the critical fixed point with finite inter-valley coupling remains stable but Lorentz invariance is asymptotically restored.
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Medical Physics
Evaluation of the Exradin A30 Parallel Plate Ion Chamber as a Reference Dosimeter in Ultra-High Dose Rate (UHDR) Electron Beams
Mervat Alharbi, Kevin Liu, Brian Hooten et al. (+8 more)
Reliable reference dosimetry for ultra-high dose-rate (UHDR) beams (>40 Gy/s) is challenging because conventional ionization chambers (ICs) exhibit saturation from ion recombination. The Exradin A30 IC uses an ultra-thin 0.3-mm electrode spacing to improve charge-collection efficiency (CCE). This study evaluated the commercial A30 as a reference dosimeter for UHDR electron beams by characterizing leakage current, CCE, polarity correction (Ppol), and beam-quality correction factors (kQ). Measurements were performed with a 9-MeV IntraOp Mobetron from the accelerator head, achieving up to 9 Gy per pulse (DPP) and an instantaneous dose rate of 2.25 MGy/s. Data were acquired in grounded water-equivalent plastic, distilled water, and saline water. DPP was varied by changing SSD at a fixed 4-{\mu}s pulse width, while pulse repetition frequency (PRF) ranged from 5 to 90 Hz. CCE was determined using EBT-XD film under matched UHDR and conventional dose and energy conditions. CCE and Ppol were also evaluated as functions of DPP and PRF in distilled and saline water. Values of kQ were calculated using Monte Carlo simulations and measured in TrueBeam electron beams. Leakage current was <2 fA. Both CCE and Ppol decreased with increasing DPP; however, CCE remained 90-99% across all three phantoms, while Ppol decreased from 0.990 to 0.981 in
liquid and solid water. Neither CCE nor Ppol depended on PRF over 5-90 Hz. Measured and calculated kQ values agreed within 0.8% at all energies except 9 MeV, where they differed by 2%. The A30 exhibited 5% recombination at DPP up to 5 Gy in distilled and saline water. Its response in solid phantoms was affected by charge buildup, which was mitigated by grounding. With appropriate CCE corrections and grounded solid phantoms, the commercial A30 is suitable for reference dosimetry in UHDR electron beams.
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All authors Mervat Alharbi, Kevin Liu, Brian Hooten, Shannon Holmes, Stefanno Alarcon-Nunez, Jeffrey Radtke, Larry DeWerd, Sam Beddar, Wesley Culberson, Emil Schueler, Ahtesham Khan
Medical Physics
Clustering of anterior corneal surface shapes in normal adults
Hala Bouazizi, Isabelle Brunette and Jean Meunier
In the present study, we investigated a large
dataset of normal adult corneal topographies in an exploratory attempt to identify the natural groupings of their 3D shapes, with the practical clinical aim of categorizing the shape of a future generation of biosynthetic corneal implants. Because of the wide range of shapes among normal corneas, we needed to identify a limited number of normal corneal shape categories to guide the conception of different implants to match the patient's own corneal shape category. At this stage of our research, we focused on the anterior surface, which exhibits greater variation in a normal population and is responsible for most of the refractive power of the eye. The corneal surface 3D data used were the anterior elevation maps taken from corneal topographies. Clustering corneal topography elevation maps was performed to reveal the normal corneal shape categories. To facilitate groupings, corneal data had their dimensionality reduced by Zernike
polynomial modeling. The resulting clusters were evaluated using different clustering scores, representations and statistical cluster comparisons. While several hard and soft linear and nonlinear clustering methods were tested in this way, k-means proved to be sufficient for this task. The best number of clusters was three and they were primarily differentiated according to corneal
curvature (Zernike defocus coefficient). These clusters were related to established clinical parameters, confirming that the
algorithm extracted relevant information based solely on the normal 3D shape of corneas.
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Optics
First-Principles Prediction of Nonlinear Optical Response in TiO$_2$ for High-Power Dielectric Mirror Applications
Koya Shimaoka, Yusuke Kondo, Kazunori Shibata et al. (+1 more)
Dielectric multilayer mirrors are essential components in optical experiments using high-power
lasers, where titanium dioxide (TiO$_2$) is widely employed as a high-refractive-index dielectric material. In this study, we investigate the nonlinear optical response of TiO$_2$ under intense ultrashort
laser pulses using real-time first-principles electron-dynamics simulations based on time-dependent density functional theory (TDDFT). We reveal intensity-dependent absorption driven by multiphoton excitation and optically excited free carriers, and simulate the resulting electron-light coupled dynamics in TiO$_2$ nanofilms using a multiscale Maxwell-TDDFT framework. Direct evaluation of the reflected and transmitted fields shows reduced reflectance at high intensities ($I \sim 10^{13}$ W/cm$^2$), demonstrating a pronounced nonlinear optical response. Furthermore, the optical response properties are compared among various stable and metastable crystalline phases of TiO$_2$-rutile, anatase, brookite, TiO$_2$-II, and TiO$_2$-B-as well as an amorphous supercell model. These results provide microscopic insight into intensity-dependent optical degradation in TiO$_2$-based dielectric optical components exposed to intense femtosecond
laser fields.
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All authors Koya Shimaoka, Yusuke Kondo, Kazunori Shibata, Mitsuharu Uemoto
Soft Condensed Matter
Micromechanical statistical model links induced nematic order to mechanical response in fiber networks
Ehud Haimov, Yoni Koren, Ayelet Lesman et al. (+2 more)
Contractile
cells and external loads reorganize the fibrous extracellular
matrix, aligning and compacting fibers over distances far exceeding a
cell's size, strongly affecting bioprocesses such as wound healing, angiogenesis and tumor invasion. We develop a continuum micromechanical theory that links, at every material point, the load-induced orientational order to the mechanical response that the reoriented network then exhibits. The network is described statistically, by the probability density of fiber orientations, and deforms affinely, so that a single-fiber stress-strain law is carried into the network stress, with the deformation set self-consistently by mechanical
equilibrium. Critical to realistic biological relevant conditions, this theory allows both geometrical and material nonlinearities. Applied to a two-dimensional network under uniaxial stretch, the theory collapses onto a single anisotropy parameter that governs the orientation distribution, the nematic order, the Poisson ratio, and the densification of fibers. Our theory reveals that induced order and densification are highly positively correlated, and in the case of uniaxial stretch they collapse onto a nearly universal curve, independent of the single-fiber stiffness behavior. For a contracting
cell, we find that buckling controls how far nematic orientational order and densification propagate. We find an algebraic decay of deformations with distance and solve for the dependence of the power-law exponent on the buckled-reduced stiffness of a single fiber. We validate our theory by comparison with non-affine discrete fiber-network simulations.
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All authors Ehud Haimov, Yoni Koren, Ayelet Lesman, Jonathan Selinger, Yair Shokef
Mesoscale and Nanoscale Physics
Carrier-Resolved Attosecond Valley Polarimetry of Monolayer MoS$_2$
Navdeep Rana, Lun Yue and Mette B. Gaarde
In recent years, all-optical writing and switching of valley polarization in two-dimensional
semiconductors has been demonstrated on femtosecond timescales. Reading this polarization out on the same timescale, carrier by carrier, has so far remained out of reach. Employing
semiconductor Bloch equation simulations of monolayer MoS$_2$, we show that attosecond transient absorption closes this gap by turning the Mo $4p$ semicore edge into a quantitative valley polarimeter. We find that pump-enabled core-to-valence absorption probes the holes while core-to-conduction bleaching probes the electrons, so that a single spectrum identifies each carrier by its photoabsorption energy. The hole channel, Pauli-blocked in
equilibrium, emerges background-free. Its circular dichroism reverses sign with the pump helicity, and its normalized magnitude is proportional to the valley polarization. Finally, we show that scanning the probe delay clocks the few-femtosecond write in real time. Thus, attosecond core-level dichroism is a carrier-sensitive, quantitative probe of the creation and
evolution of valley polarization.
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High Energy Physics (Phenomenology)
Orbital angular momentum at small $x$ in the large $N_c\&N_f$ limit
G. Zardo Becker, Yuri V. Kovchegov, Ming Li et al. (+2 more)
We extend the small-$x$ analysis of the
quark and
gluon orbital angular momentum (OAM) distributions in the
proton from the large-$N_c$ limit considered in our earlier works to the large-$N_c\&N_f$ limit, in which the numbers of
quark colors $N_c$ and
flavors $N_f$ are large with their ratio held fixed. Working in the double-logarithmic approximation (DLA), summing powers of $\alpha_s \ln^2(1/x)$ with $\alpha_s$ the strong coupling and $x$ the
proton's momentum fraction carried by a parton, we correct the small-$x$ operator expression for the
quark OAM distribution suggested earlier in \cite{Kovchegov:2024wjs} and relate both the
quark and
gluon OAM distributions to the impact-parameter moments of the polarized dipole amplitudes. We derive the large-$N_c\&N_f$
evolution equations for these moment amplitudes in the DLA; these include a new equation for the moment amplitude governing the
quark OAM. We then solve these
evolution equations numerically together with the helicity
evolution for $N_f = 2,3,4,5,6$ and $N_c =3$. We find that, similar to the large-$N_c$ case, the OAM distributions share a common small-$x$ intercept with the helicity distributions, $L_{q+\bar{q}}(x,Q^2) \sim L_G(x,Q^2) \sim \Delta \Sigma (x,Q^2) \sim \Delta G(x,Q^2) \sim \left(\frac{1}{x} \right)^{\alpha_h}$ with the intercept $\alpha_h \approx {3.48 \sqrt{\alpha_s N_c/2\pi}}$ for $N_f = N_c = 3$ (cf.~\cite{Borden:2025ehe}): this result, along with $\alpha_h$ for other values of $N_f \neq 0$ that we studied, is smaller than the intercept of $3.66\sqrt{\alpha_s N_c/2\pi}$ found in the large-$N_c$ limit. We also compute the ratios of the OAM distributions to the helicity parton distribution functions as $x\to 0$, obtaining $L_{q+\bar{q}}(x,Q^2)/\Delta\Sigma(x,Q^2) = -1$ and $L_G(x,Q^2)/\Delta G(x,Q^2) = -2$ at $Q^2=10\, \mathrm{GeV}^2$, with both ratios being independent of $N_f$.
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All authors G. Zardo Becker, Yuri V. Kovchegov, Ming Li, Brandon Manley, Andrey Tarasov
Instrumentation and Methods for Astrophysics
TESSExtractor: A web-based interactive tool for light-curve visualisation and period estimation using TESS full-frame images
Javier Serna, Jesús Hernández, Sean P. Matt et al. (+23 more)
We present a user-friendly web application that allows users to extract, visualise, and interact with TESS light-curves (LCs) from full-frame images. The service works for any
star identified in the TIC database or using
stellar coordinates. TESSExtractor performs photometry using a circular aperture centred on the object of interest, with a sky annulus for background subtraction. The application also uses cotrending basis vectors provided by TESS to correct photometry for possible systematic effects. The Lomb-Scargle Periodogram is used to obtain periods from the LC. The TESSExtractor's website offers an intuitive interface for scientific and educational purposes and is publicly available at https://www.tessextractor.app. This tool simplifies the analysis of TESS LCs and provides valuable insight for researchers seeking to extract and analyse TESS data for a variety of scientific goals (e.g.,
stellar rotation, activity, transient detection, asteroseismology, or simply detection of planetary transits or
stellar companions, among others). TESS provides insights into our understanding of time-domain astrophysics, and TESSExtractor provides an accessible and intuitive web interface for scientific exploitation of TESS data. We demonstrate that TESSExtractor produces LCs of sufficient quality for both quantitative and morphological time-domain studies.
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All authors Javier Serna, Jesús Hernández, Sean P. Matt, Giovanni Pinzón, Astaroth Elizabethson, Jorge Martínez-Palomera, Carlos G. Román-Zúñiga, Sergio Sánchez-Sanjuán, Jaime Morice, Thanawuth Thanathibodee, Margarita Pereyra, Mauricio Tapia, Alejandro García-Varela, Juan F. Cabrera-García, Marcelo Jaque Arancibia, María Gracia Batista, Ricardo López-Valdivia, Raúl Michel, Ezequiel Manzo-Martínez, Keivan G. Stassun, Cesar Briceño, Sydney Robertson, Tanay Ayiliath, David Fernández, Fabián Ahumada, Alejandro Alfonso
Chemical Physics
Exploring electron transport in carbon wire systems using a wave function-based multiconfigurational non-equilibrium Green's function approach
Pranesh Raghavendran, Gabriela E. Campbell, Erik P. Hoy et al. (+1 more)
One-dimensional carbon wire materials are an interesting class of materials which have potentially useful applications in sub-nanoscale junction technology due to their unique
quantum transport properties. In this work, we apply a non-
equilibrium Green's function approach based on multiconfiguration pair-density functional theory (NEGF-MCPDFT). NEGF-MCPDFT is a wave-function-based non-periodic framework to study electron transport in systems exhibiting strong correlation. The advantage of this approach is multiconfigurational wave functions are used which offer enhanced abilities to describe strong electron correlation beyond single-determinant approaches. MC-PDFT necessitates the use of an active space, and a key step in such calculations is the determination of which orbitals to include. In application of this theory to carbon wire junctions of various lengths, we find that NEGF-MCPDFT is capable of reproducing trends from recent experimental results, and we use our findings to further the development of best practices in active space design for transport calculations of this type.
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All authors Pranesh Raghavendran, Gabriela E. Campbell, Erik P. Hoy, Andrew M. Sand
Instrumentation and Methods for Astrophysics
CCAT: The Prime-Cam Instrument for the Fred Young Submillimeter Telescope – Overview and Status
Eve M. Vavagiakis, Yuhan Wang, Lawrence T. Lin et al. (+32 more)
Prime-Cam is a first-generation science instrument for the CCAT Observatory's six-meter aperture Fred Young Submillimeter
Telescope (FYST), under construction at an elevation of 5600 m on Cerro Chajnantor in Chile's Atacama Desert.
Prime-Cam will deliver over ten times greater mapping speed at submillimeter wavelengths than current facilities for unprecedented broadband and spectroscopic measurements in windows between 1.4 – 0.3 mm (220 – 850 GHz). When fully populated,
Prime-Cam will field over 100,000 kinetic inductance detectors across seven independently optimized instrument modules. With
Prime-Cam, the CCAT Collaboration will address a suite of science goals, from Big Bang cosmology, to
galaxy evolution and
star formation over
cosmic time.
Prime-Cam is scheduled for integration in FYST in late 2026, followed by a year of early science observations with the 280 and 350 GHz instrument modules. We discuss the design and in-lab testing of the 1.8-m diameter
Prime-Cam receiver and 280 GHz instrument module, and give an update on deployment status and early science plans.
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All authors Eve M. Vavagiakis, Yuhan Wang, Lawrence T. Lin, Manuel Aravena, Jason E. Austermann, Frank Bertoldi, James Burgoyne, Victoria Butler, Scott Chapman, Steve K. Choi, Dongwoo Chung, Abigail Crites, Ankur Dev, Cody J. Duell, Michel Fich, Laura Fissel, Rodrigo G. Freundt, Eliza Gazda, Anthony I. Huber, Doug Johnstone, Ben Keller, Paul Malachuk, Alicia Middleton, Jenna Moore, Michael D. Niemack, Thomas Nikola, Yoko Okada, Darshan A. Patel, Tilak M. Patel, Dominik A. Riechers, Douglas Scott, Gordon J. Stacey, Benjamin J. Vaughan, Samantha Walker, Ruixuan Xie