Strongly Correlated Electrons
Chiral Weyl-Kondo semimetallic state through enhanced correlation in CeGaGe
Arushi, Kevin Allen, Yuan Fang et al. (+11 more)
Strongly correlated
chiral materials have been proposed to host a
chiral Weyl-Kondo semimetal (cWKSM) state, in which Kondo hybridization pins chirality-induced Kramers-Weyl point crossings, together with additional
symmetry-enforced band crossings, near the
Fermi level. Realizing this state requires a material that combines
crystal chirality, non-symmorphic
symmetry, and Kondo correlations, and currently there are no known materials that combine all these requirements. Here we report evidence for a cWKSM state in CeGaGe, a member of the RXY (R = rare earth; X = Al, Si; Y = Ga, Ge) family. Magnetization measurements confirm long-range
antiferromagnetic order below T$_N$ = 4.7 K with a complex, canted
magnetic structure. Unique to CeGaGe among the known RXY systems is a structural transition from an achiral tetragonal I4$_{1}$md structure (at high temperatures) to the
chiral tetragonal P4$_{3}$ structure (at low temperatures). The structural transition in CeGaGe allows us to highlight the role of chirality in stabilizing the Kramers cWKSM state.
Hall resistivity measurements with $H || c$ reveal an anomalous
Hall conductivity (AHC) that is constant below the Kondo temperature $T_K \approx 7$ K and drops sharply above it. This crossover tracks the onset of Kondo coherence rather than the
magnetic ordering, which occurs at T$_N$ = 4.7 K. Together with first-principles calculations for the $P4_3$ structure, this identifies the AHC as an intrinsic, Berry-
curvature-driven contribution generated by Kondo hybridization, rather than a consequence of extrinsic scattering or dynamic scalar
spin chirality. These results establish CeGaGe as a rare experimental platform in which
crystal chirality, strong electronic correlations, and non-trivial band
topology coexist, providing the first material realization of a Kondo-driven cWKSM state.
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All authors Arushi, Kevin Allen, Yuan Fang, Kuan-Sen Lin, Mounica Mahankali, Hari Bhandari, Karthik Rao, Alberto Ruiz Biestro, Christopher Lane, Jian-Xin Zhu, Sanu Mishra, Geoffroy Hautier, Qimiao Si, Emilia Morosan
General Relativity and Quantum Cosmology
Identifiability Limits of Gravitational Wave Phase Deviations: Multiclass Classification with a Multihead Neural Network
Lavinia Heisenberg and Shayan Hemmatyar
We study how well gravitational-wave phase deviations can be identified using a neural network with classification and regression heads. The classification head distinguishes general relativity (GR) from six parametrized post-Einsteinian phase families with exponents $b\in\{-7,-5,-3,-1,+1,+2\}$; the regression head predicts the logarithm of the coupling magnitude, $\log_{10}|\beta|$. The network input is a response function quantifying the sensitivity of waveform mismatch to waveform deformations. We use stationary Gaussian noise with the Advanced LIGO design spectrum for 262 sources and a measured Hanford spectrum from the third observing run (O3) for 132 sources, and also test injections into recorded Hanford strain. On the two Gaussian
datasets, the network identifies the exponent of deviations clearly above the noise with accuracies of $0.427$ and $0.329$. To interpret these results, we compare the network with an approximate classifier built from predicted waveform residuals for the six phase families and same sources. The two classifiers often confuse the same families. Examining residuals left by different phase corrections, we link these errors to similarities between the underlying deviations. On selected recorded Hanford strain, networks trained on simulated or recorded noise achieve overall classification accuracies close to those on simulated Hanford noise. Of thirteen neural-network variants tested on the Advanced LIGO design
dataset, the recurrent network has the highest mean classification accuracy for loud deviations, although all variants remain below the approximate classifier. The network nearly matches that classifier's accuracy, indicating that identification is limited by similarities between neighboring phase families rather than by the network, for known intrinsic source parameters.
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Classical Physics · Cross-listed from cs.LG
Lagrangian and Hamiltonian Neural Networks With a Dissipative System
V. Rayamajhi and J. Singal
We investigate the applicability of Lagrangian and
Hamiltonian Neural Network models to a dissipative system that has explicit time dependence in its Lagrangian,
Hamiltonian, and total energy. To do so we consider these neural network models for simulated systems of a harmonic one-dimensional, one-component oscillator with damping, as well as without damping for comparison. We find that both the Lagrangian and
Hamiltonian approaches are able to predict the empirical physical behavior of the damped oscillator systems and to effectively “learn” to varying degrees the underlying Lagrangians and
Hamiltonians, as has previously been shown to be the case with undamped oscillator systems. These investigations elucidate important properties of Lagrangian and
Hamiltonian mechanics, including properties that are not manifest when considering systems without explicit time dependence.
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Quantum Physics
Learning Trotter Orderings for Heisenberg Hamiltonians with a Ranking Transformer
Shamminuj Aktar, Reuben Tate and Stephan Eidenbenz
Trotterization approximates
quantum time
evolution by sequentially applying
Hamiltonian terms. Because noncommuting terms introduce ordering-dependent errors, selecting an optimal term ordering is a combinatorial problem over a factorial search space. Prior approaches rely on fixed heuristics or on selection among predefined structured orderings, both of which require simulating candidates before choosing among them. For 1D and 2D Heisenberg-style
Hamiltonians, we instead learn the ordering directly with a physics-aware ranking
transformer that assigns a scalar score to each
Hamiltonian term and predicts an ordering by sorting these scores. Physical structure enters through commutator-biased
attention and an anticommutation-weighted ranking loss, and the models are trained on simulated-annealing (SA) reference orderings. We train separate models for first- and second-order Trotterization, each jointly on chains up to 14
qubits and
lattices up to 12
qubits, and evaluate them on unseen chains with 16-20
qubits and
lattices with 16 and 20
qubits. Predicted orderings are evaluated by the median gap in simulation fidelity to the SA reference. At first order, the model reaches a pooled gap below 10^-4 on chains, 0.0144 and 0.0088 on triangular
lattices, and 0.0948 and 0.0823 on rectangular
lattices at 16 and 20
qubits; at second order, the gaps are 0.0114, 0.0364 and 0.0244, and 0.1348 and 0.1239. The prediction exceeds the SA reference on 34% of first-order and 8% of second-order chain instances and can match its fidelity even when the two sequences differ because commuting terms may be rearranged without changing the Trotter
unitary. The learned models generalize to larger systems across all three geometries, performing best on chains and triangular
lattices, and produce an ordering in one forward pass without candidate enumeration, simulated annealing, or fidelity evaluation.
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Earth and Planetary Astrophysics
The First Hubble Detection of a Secondary Eclipse from a Rocky Exoplanet: the 5.4-hour planet TOI-2431 b
Sebastian Zieba, Billy Edwards, Samuel N. Quinn et al. (+18 more)
We present an HST/WFC3 G141 phase-curve observation of the ultra-short-period rocky
planet TOI-2431 b and detect its secondary eclipse in the near infrared. Combined with the TESS optical eclipse, these measurements constrain the
planet's dayside brightness temperature, reflected light contribution, albedo, and heat redistribution. We detect the eclipse in the optical and near infrared wavelengths of TESS and HST/WFC3 G141, with a
planet-to-
star flux ratio of 37+/-10 ppm and 69(+14/-13) ppm, respectively. Assuming negligible reflected light, the joint TESS+HST fit yields a brightness temperature T_b,joint=2524(+77/-84) K and a brightness temperature ratio of R_joint=T_b,joint/T_p,max=0.980(+0.032/-0.034) consistent with the zero-albedo, no-redistribution limit T_p,max=2574(+36/-35) K. The HST phase curve is consistent with zero nightside emission and no measurable hotspot offset, consistent with inefficient day-night heat distribution. Under this thermal-dominated interpretation, TOI-2431 b lies at the zero-albedo, no-redistribution limit and contrasts with previously observed lava worlds. At optical and near-infrared wavelengths, however, thermal emission is degenerate with reflected light. For a
geometric albedo of A_g=0.1, reflected light would contribute approximately 11 ppm in each bandpass, reducing the temperature to T_b,joint(A_g=0.1)=2407(+91/-102) K. Longer-wavelength observations are required to isolate the thermal component. Planned JWST/MIRI LRS observations are expected to substantially reduce this degeneracy and provide more direct constraints on heat redistribution and possible silicate-atmosphere spectral features. This marks the first secondary eclipse detection of a rocky
exoplanet using HST and establishes TOI-2431 b as a
benchmark target for studying properties of lava worlds.
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All authors Sebastian Zieba, Billy Edwards, Samuel N. Quinn, Leoni J. Janssen, Nicolas B. Cowan, Laura Kreidberg, Mercedes Lopez-Morales, Lisa Dang, Luca Malavolta, Yamila Miguel, T. Giang Nguyen, Andrew Vanderburg, Thomas G. Wilson, Mantas Zilinskas, Nicholas J. Connors, Ian J. M. Crossfield, Oliver Herbort, Adam L. Kraus, Tim Lichtenberg, Mariana Sastre, Joost P. Wardenier
Computational Physics · Cross-listed from cs.LO
Developing a Numerical Algorithm with CIVL Model Checking in the Loop
Youngjun Lee, Anshu Dubey and Jan Hückelheim
Verifying a numerical
algorithm in a large scientific simulation framework is challenging: the framework is too big to model-check, and the unit tests exercise only sampled inputs. We report a case study in which we developed a new cloud-in-
cell (CIC) deposition
algorithm for Flash-X, a large-scale multiphysics simulation framework, keeping the CIVL model checker in the development loop. Rather than verify the
algorithm within Flash-X's hefty infrastructure, we extract only the interfaces that the
algorithm needs into a small, self-contained C model, which abstracts away implementation details of the Flash-X infrastructure that are unrelated to the new
algorithm. The new
algorithm is then built and checked within this C model. The CIVL model checker enables verification of the required physical properties of the CIC deposition
algorithm using symbolic values for the particle positions. It proves two physical properties—mass conservation and the deposition location—for the continuum of admissible positions in the simulation domain. CIVL also verifies the
algorithm's
memory safety and freedom from MPI deadlocks and data race conditions over all rank distributions within specified bounds. Writing the verifying properties first and continuously checking them at each stage of the bottom-up prototyping workflow turned CIVL into a design guardrail that greatly increased confidence in the extended
algorithm. During our case study, CIVL surfaced a concurrency defect in the
algorithm that our random-seed-based tests failed to exercise. This paper shows our workflow, with the goal of helping readers understand its benefits, cost, and tradeoffs compared with testing.
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Optics
Discrete quality-factor control in a side-coupled photonic crystal microcavity: evanescent Bloch tunnelling and the finite-cell correction
Hasan Oguz
A point-defect cavity side-coupled to a line-defect waveguide in a two-dimensional photonic
crystal of silicon rods in water is studied with plane-wave expansion and finite-difference time-domain computations. The defect-rod radius tunes the resonance continuously within the band gap, as first-order perturbation theory predicts, whereas the quality factor changes in discrete steps set by the number of
lattice rows between cavity and guide; displacing the defect rod by up to a tenth of a period changes it by less than 7 percent. Each added row multiplies the quality factor by a factor that follows, without an adjustable parameter, from the decay of the evanescent Bloch channel of the bulk
crystal that is phase-matched to the guided mode; the channel at zero wavevector along the guide predicts little more than half that factor. Two biases of a finite computational domain, leakage across the cladding and a standing wave set up by reflections at the ends of the truncated guide, lower the per-row factor and change the quality factor by up to a factor of two if left uncorrected. Scaled to 1550 nm the design gives a sensitivity of 634 nm per refractive index unit, which perturbation theory reproduces, and the linewidth agrees with that of a transmission spectrum normalized to a cavity-free reference. Absorption by water caps the quality factor near 9200 and limits the useful number of barrier rows. The guided mode lies inside the light cone, so a slab of finite height needs a different guide.
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Mesoscale and Nanoscale Physics
Nanodiamond Sensing of Stray Fields during Domain Reversal
Kin On Ho, Hamza Abudayyeh, Andrew Perez et al. (+6 more)
Quantitative measurement of nanoscale stray
magnetic fields during domain reversal is important for understanding and optimizing
magnetic memory and logic devices. Yet, achieving high spatial resolution with minimally invasive probes remains challenging. Here we demonstrate nanodiamonds (NDs) hosting an ensemble nitrogen vacancy (NV) centers as local
quantum sensors of domain-reversal stray fields in a CoFeB strip. During
magnetic-field-driven reversal, the ND sensors resolve three distinct local responses depending on their positions relative to the strip: a positive frequency jump at the edge, an unexpected negative jump just outside the strip, and a negligible change near the center. These contrasting signals are quantitatively explained by magnetostatic boundary fields from micromagnetic simulations. We further implement a fully constrained fitting procedure for optically detected
magnetic resonance spectra, enabling robust field extraction even when resonances are partially resolved. Together, these results establish NV-ND magnetometry as a simple, transferable, and quantitative approach for characterizing spatially heterogeneous
magnetic fields in thin-films and spintronic devices.
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All authors Kin On Ho, Hamza Abudayyeh, Andrew Perez, Hui-Ping Chang, Liang Juan Chang, Junwei Tong, Can Cui, Jean Anne C. Incorvia, Xiaoqin Li
Cosmology and Nongalactic Astrophysics
SLICE: Unveiling the Multi-Component Merging Core of SPT-CLJ1150-2805 Through Strong-Lensing Mass Modelling
James R. Betts, Benjamin Beauchesne, Mathilde Jauzac et al. (+16 more)
We present a new strong-
lensing and X-ray mass model of the merging
galaxy cluster SPT-CLJ1150-2805 ($z=0.383$), combining JWST NIRCam, HST, Chandra, and VLT/MUSE data to robustly decompose its collisionless and collisional components. Exploiting JWST, we expand the multiple-image catalogue with 66 new images (30 comprising 6 new systems). Our baseline model uses 118 spectroscopically confirmed images from 20 systems, achieving an image-plane root-mean-square offset of $0.56''$. An expanded model incorporating 31 additional photometric images from 8 additional systems yields a near-identical mass distribution, confirming excellent model stability. We resolve a complex multi-axis post-merger system requiring five cluster-scale dark matter
haloes, including a bimodal core with distinct
haloes coincident with each brightest cluster
galaxy. The remaining mass components are independently supported by kinematics of 291 cluster members ($\sigma_v=1960^{+84}_{-92}$ km s$^{-1}$), which reveal two new
galaxy substructures - the northernmost of which we tentatively identify as the baryonic counterpart to our fifth dark matter
halo. The cluster is an extraordinarily efficient lens, possessing an effective Einstein radius $\theta_E=42.41^{+0.05}_{-0.04}{''}$ and an enclosed mass $M(<\theta_E)=3.35^{+0.04}_{-0.03}\times10^{14}M_\odot$ for a source at $z_s=2$. For a high-
redshift source at $z_s=9$, it produces a magnification cross-section of $A(>10)\simeq0.15$ arcmin$^2$ and $A(>30)\simeq0.020$ arcmin$^2$. This global
lensing power surpasses all Hubble Frontier Fields clusters. In a regime where systematic uncertainties between mass models dominate high-
redshift magnification errors, the stability of our reconstruction sets this lens apart. This combination of extreme
lensing power and a robust mass model establishes SPT-CLJ1150-2805 as a premier
cosmic telescope for high-
redshift studies.
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All authors James R. Betts, Benjamin Beauchesne, Mathilde Jauzac, David Lagattuta, Guillaume Mahler, Jean-Paul Kneib, Gavin Leroy, Marceau Limousin, Priyamvada Natarajan, Sameeksha Saini, Keren Sharon, Stephane V. Werner, Catherine Cerny, Isaque Dutra, Dominique Eckert, Alaina Einsig, Michael D. Gladders, Gourav Khullarm, Manon Regamey
Solar and Stellar Astrophysics
Transport of Magnetic Fields by Thermohaline Convection in Crystallizing White Dwarfs
Nicolas Frazao Fernandes, J. R. Fuentes and Jim Fuller
The origins of strong
magnetic fields observed in many white
dwarfs are uncertain. Recent observations show that such fields are more common for white
dwarfs with crystallized cores. Crystallization creates a destabilizing composition gradient that drives thermohaline convection in the
star's fluid envelope, which may play an important role in
magnetic field emergence. We perform 3D magnetohydrodynamical simulations of thermohaline convection with
magnetic fields of various strengths and orientations, using the Boussinesq approximation in periodic Cartesian boxes. Our simulations suggest that thermohaline convection can generate
magnetic fields when the
magnetic Prandtl number is large (i.e., low
magnetic diffusivity), but they are likely too weak to account for those observed in
magnetic white
dwarfs. However, the simulations indicate that strong
magnetic fields can be advected outwards by the thermohaline convection without being destroyed, depending on the net
magnetic flux. Hence, crystallization-induced thermohaline mixing may transport
magnetic fields initially trapped in white
dwarf interiors to their outer layers, allowing them to be observed. However, additional simulations using more realistic geometry and
magnetic field configurations will be needed to confirm this possibility.
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Plasma Physics
Joint Amplitude-Phase Optimization of Broadband Lasers Raises Absolute Two-Plasmon-Decay Thresholds Above Coherence-Time Predictions
A. S. Joglekar, R. K. Follett, D. H. Froula et al. (+1 more)
Broadband
lasers suppress the absolute two-plasmon-decay instability that preheats inertial-fusion targets. The usual scaling relates this suppression to the drive's coherence time, a power-spectrum statistic insensitive to spectral phase. By gradient descent through a differentiable enveloped wave solver, we show that at fixed power spectrum phase optimization raises the threshold from the random-phase median of $2.8\,I_\mathrm{mono}$ to $4.1\,I_\mathrm{mono}$, but produces a transform-limited (TL) pulse train with peak-to-average ratio $R=32$. Joint amplitude–phase optimization reaches $5.6\,I_\mathrm{mono}$ at $R=3.6$, above the best tested TL line-count result of $4.5\,I_\mathrm{mono}$ at $R=16$; relaxing the peak constraint raises the joint threshold to $6.4\,I_\mathrm{mono}$. An exact growth-rate budget evaluated inside the simulation separates the two mechanisms. TL suppresses coupling mainly by concentrating the pump field into short bursts, thereby lowering its time-averaged magnitude at fixed average intensity. The joint optima retain near-random values of this amplitude measure while suppressing both the available coupling and the fraction realized through pump–daughter
alignment. The advantage of joint optimization persists from $1\%$ to $4\%$ bandwidth and from OMEGA-scale to ignition-scale conditions.
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All authors A. S. Joglekar, R. K. Follett, D. H. Froula, J. P. Palastro
Quantum Physics
Quantum error mitigation from information dynamics
Philippe Suchsland, Thomas Schuster, Manuel S. Rudolph et al. (+3 more)
Overcoming experimental errors is a central challenge in
quantum science. This challenge is particularly acute in large and complex
quantum circuits, where
quantum information spreads into exponentially many paths, foiling any direct attempt to understand errors' impact. In this work, we present a novel approach to understanding and mitigating experimental errors, based on a surprisingly compact representation of a
quantum circuit's information dynamics, the reactivity function. The shape of a
circuit's reactivity function governs its noise response, and its amenability to different error mitigation methods. From this viewpoint, we introduce two complementary such methods. The first, Pauli-path zero-noise extrapolation, fits a parameterized model to a
circuit's reactivity function and uses it to accurately extrapolate to zero noise. The second, tunable error cancellation, filters a
circuit's reactivity function to cancel noise on all information up to a threshold locality. Crucially, both methods feature a tuning parameter that allows one to systematically improve their accuracy until convergence. Across three
circuit families from published experiments, our methods overcome conventional zero-noise extrapolation biases as large as 30%; at $\sim$$10^{-2}$ root-mean-square error, they reduce sampling cost relative to probabilistic error cancellation by up to a factor of $10^3$.
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All authors Philippe Suchsland, Thomas Schuster, Manuel S. Rudolph, Nicholas Noll, Thomas E. O'Brien, Zlatko K. Minev
Physics Education
Artificial Neural Network Assisted Modelling of Tangent Galvanometer Measurements for the Determination of Horizontal Component of Earth's Magnetic Field
Saralasrita Mohanty, Sudakshina Prusty, Anshuman Pal et al. (+1 more)
The Tangent Galvanometer (TG) is a standard undergraduate laboratory experiment for estimating the horizontal component of Earth's
magnetic field (BH) by measuring the angle of deflection of a
magnetic needle corresponding to the current flowing through a circular coil. In this study, an artificial neural network (ANN) is used as a complementary data-driven model to predict the value of BH. A
dataset comprising 225 observations obtained using 50-turn and 500-turn coils was used for developing the ANN model. After quality control, 223 observations were retained and divided into training (70%), validation (15%), and testing (15%) subsets. The model was optimized using a feed-forward neural network with Tanh activation. Three different models (Models A, B, and C) with different input variables were compared for optimum performance. Model C used five input variables: current, deflection angle, tan(theta),
magnetic field produced by the coil, and number of turns. The addition of tan(theta) produced a substantial improvement in prediction performance, which was further improved by including the
magnetic field produced by the coil. Model C gave the best test performance, with R2 = 0.99053, RMSE = 0.54076 microT, and MAE = 0.32940 microT. The experimental and ANN-predicted values of BH were also compared with an adopted local geomagnetic reference value of 39.0 microT. The mean experimental and ANN-predicted values were 37.38898 microT and 37.32161 microT, respectively. The results demonstrate the usefulness of ANN as a complementary tool for analyzing experimental variability and nonlinear relationships in an undergraduate physics laboratory experiment.
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All authors Saralasrita Mohanty, Sudakshina Prusty, Anshuman Pal, Pradipta Kumar Mishra
High Energy Physics (Theory)
General Relativity with Finite Boundaries
Chawakorn Maneerat
In this thesis, we consider general relativity on a
manifold with a timelike boundary of finite size, across all signs of the cosmological constant $\Lambda$. We impose conformal boundary conditions, whereby the conformal class of the induced metric and the trace of the extrinsic
curvature $K$ are fixed at the boundary. In Lorentzian signature, we analyse the linearised Einstein equations about Minkowski, de Sitter (dS), and anti-de Sitter (AdS) space for a variety of boundaries, employing the Kodama-Ishibashi formalism adapted to
manifolds with a boundary. In Euclidean signature, we study the thermodynamics of black hole and cosmological horizons enclosed by the boundary, computing the leading semiclassical approximation of the gravitational path integral, for which the boundary data define a conformal canonical ensemble of fixed conformal temperature and $K$.
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Fluid Dynamics
Reversibility and Multiplicity in Liquid-Vapor Phase Change
Luiz Eduardo Czelusniak, Alexander J. Wagner and Luben Cabezas Gómez
Using diffuse-interface theory, we uncover unexpected phase-change phenomena that are absent from widely used models of evaporation and condensation. In the inviscid limit, the same adjacent thermodynamic states admit stationary evaporation and condensation with equal and opposite mass fluxes, even when the vapor pressure lies below saturation. Viscosity breaks this reversibility but gives rise to multiple stationary condensation rates for the same vapor state.
Lattice Boltzmann simulations dynamically recover these states, showing that these phenomena are dynamically realized by the diffuse-interface equations rather than arising solely as mathematical solutions of the reduced interfacial relations. Our results reveal previously unexplored behavior in a well-established theory of
liquid–vapor interfaces.
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Astrophysics of Galaxies
Dynamical Evolution of The Open Clusters Collinder 110 and NGC 2477
Zahra Al, Yüksel Karataş and Forough Rajaei
Using
Gaia DR3 photometric and astrometric data, we identified the likely members of the open clusters Collinder 110 and NGC 2477, and derived their astrophysical and dynamical parameters. We obtained reddening values of $E(B-V) = 0.43 \pm 0.05$ and $0.33 \pm 0.04$, and ages of $1.82 \pm 0.10$ Gyr and $1.05 \pm 0.10$ Gyr for Collinder 110 and NGC 2477, respectively. Within the uncertainties, the distances derived from the color-magnitude diagrams ($2.09 \pm 0.06$ and $1.38 \pm 0.04$ kpc) are consistent with those obtained from
Gaia DR3 parallaxes ($2.08 \pm 0.31$ and $1.45 \pm 0.11$ kpc). Both clusters exhibit large core and limiting radii. The core radius ($R_c$) of Collinder 110 does not follow the expected decreasing trend with increasing evolutionary parameter ($\log\tau_2$). In addition to losing part of its low-mass
stellar content, its relatively large $R_c$ may reflect
primordial conditions and/or the presence of a possible
stellar-mass black hole. The relatively large $R_c/R_h$ ratios, together with their advanced dynamical
evolution ($\log\tau_2 = 1.24$ and $1.34$), indicate that significant two-body relaxation and mass segregation have occurred within their central regions. The small values of $R_h/R_j$ ($0.32$ and $0.16$) suggest that low-mass
stars have dynamically redistributed within the comparatively large Jacobi radii under the combined influence of internal and external processes. However, their large $R_t/R_j$ ratios ($1.60$ and $1.23$) imply that both clusters are tidally affected and have likely lost part of their low-mass
stellar populations to the
Galactic field. Despite these effects, their locations in the third
Galactic quadrant, where
giant molecular clouds are relatively scarce, may explain their survival to their present ages of $1.82$ and $1.05$ Gyr, respectively.
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Earth and Planetary Astrophysics
JWST Reveals the Kuiper Belt-like Compositions of the Uranian Rings and Small Moons
Matthew Belyakov, M. Ryleigh Davis, Zachariah Milby et al. (+2 more)
We present the JWST NIRSpec 1–5 micron spectra of the Uranian rings and four ringmoons: Puck, Perdita, Portia, and Juliet. We find that the compositions of the rings and moons strongly resemble water-type Kuiper belt objects, showing deep 3.0 micron O–H and water ice features as well as the CO$_2$ band at 4.27 micron. The volatiles show a radial trend of decreasing volatile abundance at closer radial distance to the
planet, consistent with recent estimates of the densities of the innermost moons. Given the observed compositional signatures, we suggest two ways to reconcile the history of the small inner moons with that of the regular ones. The first is that the Uranus-tilting collision produced a disk from an impactor formed out of material similar to that which comprises water-rich Kuiper belt objects, and the ringmoons are small undifferentiated remnants of that process. Alternatively, the rings and ringmoons postdate the formation of the regular moons, and formed from the later
tidal disruption of a several hundred kilometer sized undifferentiated water-type Kuiper belt object.
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All authors Matthew Belyakov, M. Ryleigh Davis, Zachariah Milby, Ian Wong, Michael E. Brown
Superconductivity
Quantum Geometric Origin of Yu-Shiba-Rusinov States
Rui-Xing Zhang
In this work, we revisit the classic Yu-Shiba-Rusinov (YSR) problem of
magnetic impurities in $s$-wave
superconductors and uncover a
quantum geometric origin of the YSR bound-state structure. The key
geometric quantity is the momentum-space average of Bloch band projector over low-energy electrons, whose
matrix rank, positive
eigenvalues, and corresponding eigenvectors directly control the number, energies, and
symmetry representations of the YSR states, respectively. As a result, a
superconductor with nontrivial normal-state
quantum geometry can host more bound states than its trivial counterpart, even if they share the same electronic dispersion. We apply our theory to monolayer $1H$-NbSe$_2$ and find that the
geometric texture of its single superconducting band enforces three
symmetry-distinct YSR channels for a
magnetic point
impurity at Nb or Se sites. Our work opens a route to probing normal-state wavefunction geometry through local YSR spectroscopy.
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Quantum Physics · Cross-listed from cs.CV
Facial classification Using Hybrid Quantum Machine Learning
Roshan Babu Bandlapalli, Srinivas V Katakam, Jitendra Chougala et al. (+2 more)
Hybrid
quantum methods have received limited study for resource-constrained facial biometrics. We present a hybrid
quantum-classical facial recognition pipeline designed to run on standard computing hardware. Images undergo gamma correction, contrast enhancement, and principal component analysis before their features are encoded into an eight-
qubit variational
quantum classifier. Classical image matching then performs recognition. In experiments with 50,000 images, comprising 25,000 faces from CelebA and 25,000 non-face images from CIFAR-10, the method outperformed the reported CPU-trained FaceNet baseline in accuracy and training efficiency. The pipeline was also evaluated on GPU and
quantum hardware. In an attendance monitoring deployment at Mahindra University in collaboration with Lloyds Technology Centre, CPU inference took 0.2 to 0.5 seconds per person, and the system remained robust to the use of spectacles. These findings support the feasibility of deploying hybrid
quantum methods for facial recognition on existing CPU hardware.
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All authors Roshan Babu Bandlapalli, Srinivas V Katakam, Jitendra Chougala, Ravi Kumar Kappagantu, Jayasri Dontabhaktuni
Quantum Physics
Gate Synthesis in Dephasing-Limited Nitrogen-Vacancy Ensembles
Ankita Chakravarty, Arnaud Carignan-Dugas, Eva Dupont-Ferrier et al. (+1 more)
Ensemble nitrogen-vacancy (NV) centers are widely used for
quantum sensing and magnetometry, where performance depends on the accurate implementation of microwave pulse sequences. In these systems, inhomogeneous broadening and short coherence times limit reliable multi-pulse control, while hardware imperfections and off-resonant excitation distort implemented rotations, making direct calibration of arbitrary gates tedious. To address this, we implement a control framework with a ZXZXZ gate decomposition which uses fixed-angle, phase-parameterized pulses, enabling universal single-
qubit control from a single calibrated $ \pi/2$ primitive ($X_{\pi/2}$) along with virtual Z operations. We compare a standard pulse with a composite pulse designed for high-power operation in a regime where the Rabi frequency is comparable to the hyperfine splitting, leading to non-uniform
evolution across hyperfine levels. Using pre-determined combinations of $\pi/2$ pulse sequences, we observe that standard pulses rapidly deviate from ideal behavior under repeated application, while the composite pulse suppresses this error accumulation by more than 70$\%$ for longer sequences despite its longer duration. In contrast, randomized benchmarking yields similar decay factors for both implementations, highlighting its limited sensitivity to coherent control errors. These results establish a practical route to robust control in short-coherence ensemble systems and emphasize the importance of pulse-level characterization.
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All authors Ankita Chakravarty, Arnaud Carignan-Dugas, Eva Dupont-Ferrier, Yves Bérubé-Lauzière
Quantum Physics
Quantum Encoding Agents: A Natural Language Interface for Data Embedding Strategy Selection in Quantum Machine Learning
Ana Paula Appel
Selecting a data encoding is a central and poorly tooled decision in
quantum machine learning. The feature map fixes the geometry of the
Hilbert space, the expressibility of
quantum kernels, and whether the
circuit can run on near-term hardware. This paper presents
Quantum Encoding
Agents, an open-source system that turns encoding selection into a natural-
language interaction. Given a
dataset and an optional task description, it profiles the data, applies a hardware-aware policy using the gate-error threshold p* approximately 10^{-3}, returns a copyable Qiskit
circuit with a justification in Portuguese or English, and scores the
quantum kernel by Kernel-Target
Alignment (KTA). When a numerical
matrix is available, it estimates the correlation fractal dimension D_2 and selects original columns with FD-ASE, using q* = max(2, ceil(D_2)) as a
qubit budget so that angle and IQP maps are not proposed at a width where the fidelity kernel has collapsed. The service implements seven encoding families: amplitude, angle, dense angle, IQP, basis, data re-uploading, and custom feature map. On
benchmark datasets, KTA separates these encodings under realistic NISQ constraints.
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Materials Science
Jahn-Teller Distortion-Driven Lattice Parameter Tunability in Coherent High-Entropy Oxide Thin Films
Dhiya Srikanth, Joseph Petruska, Matthew Furst et al. (+3 more)
Here, we isolate how Cu concentration and Jahn-Teller distortions control the out-of-plane
lattice parameter of pseudomorphic MgCoNiCuZnO-derived high-
entropy oxide films on MgO. We prepare nine compositions spanning 0-20% Cu, verify target composition and phase by X-ray fluorescence and diffraction, and grow films by pulsed
laser deposition across multiple substrate temperatures. At 500 {\deg}C, the
lattice parameter increases nearly linearly with Cu content; at 300{\deg}C, it decreases nonlinearly, producing a 2.6% difference between temperature regimes for equimolar MgCoNiCuZnO at our growth conditions. We attribute this change in
lattice parameter to temperature-dependent coupling between Cu-driven Jahn-Teller distortions and Co valence change. While prior work identifies Co valence as the primary driver of the MgCoNiCuZnO
lattice response with temperature; our results establish Cu Jahn-Teller distortion as an equally important structural control parameter.
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All authors Dhiya Srikanth, Joseph Petruska, Matthew Furst, Kaylin Lamaute, Jon-Paul Maria, Saeed S. I. Almishal
Materials Science
The Young-E(3) Tensor Product Decomposition for Rotation and Permutation Equivariant Cluster Expansions
James M. Goff and Aidan P. Thompson
A generalization of fixed-
lattice cluster expansions (CE) and atomic cluster expansions (ACE) is presented that expresses both rotation and permutation
symmetries. By performing Schur–Weyl decomposition in Young subgroup-stabilized carriers, followed by joint coupling of rotation and permutation representations, arbitrary $S_N\times SO(3)$ tensor product carriers are generated. This allows us to resolve complete, orthonormal joint rotation and permutation-adapted bases for arbitrary tensor product ranks and arbitrary angular and radial tensor product content. We show that this very general Young–E(3) (YE3T) tensor product basis contains the ACE basis as a subset, corresponding to the special case where permutation
symmetry character is restricted to the fully symmetric carrier. Rather than constructing an overcomplete rotation and permutation-invariant basis and reducing it a posteriori, Barthelemy et al. recently demonstrated scaling benefits by not constructing an overcomplete basis. YE3T directly produces a complete orthonormal basis without an overcomplete step and rigorously extends to permutation characters beyond permutation-symmetric features. The YE3T decomposition yields new joint irreducible rotation- and permutation-equivariant basis sets that surpass existing rotation-adapted expansions in both speed and accuracy, defining a new Pareto front for machine-learned interatomic potentials. We show that the tunability of the permutation
symmetry character makes the basis useful for both atomistic and electronic-structure simulations.
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Solar and Stellar Astrophysics
Spectroscopic Signatures of Nonuniform Lateral Expansion of a Coronal Mass Ejection in the Low Corona with ADITYA-L1/VELC
Saurabh Tripathi, Tanmoy Samanta and Jayant Joshi
Coronal mass ejections (CMEs) undergo rapid
evolution in the low corona ($<2R_\odot$), yet their three-dimensional kinematics remain poorly constrained. We present a spectroscopic and imaging analysis of a CME observed on 2024 August 5 using the Visible Emission Line Coronagraph (VELC) on board ADITYA-L1 and Atmospheric Imaging Assembly (AIA)/
Solar Dynamics Observator (SDO). The VELC Fe XIV 5303 Å spectra captured the erupting CME as it crossed the western slit. Space-time maps from single-Gaussian fits reveal coronal dimming and enhanced Doppler velocities during the eruption. Detailed spectral analysis reveals strongly Doppler-shifted secondary components associated with the CME front. These components appear as two spatially separated emission branches on opposite sides of the rest wavelength, producing a distinct bifurcated spectral morphology superposed on the nearly stationary reduced-intensity coronal emission. Double-Gaussian fitting yields line-of-sight (LOS)
plasma velocities of up to 218 km/s, likely a lower limit as the secondary component reaches the edge of spectral window. AIA 211 Å observations measure a projected radial speed of 1135 km/s, larger than the plane-of-sky (POS) lateral speed of 692 km/s along the slit. To interpret the observed CME
evolution and spectral structure, we developed a simplified three-dimensional
geometric-kinematic model of an expanding axially tilted CME shell. Synthetic spectra from the model show that an inclined CME undergoing asymmetric lateral expansion can produce a bifurcated spectral morphology similar to that observed, with velocity components projected in the radial, POS-lateral, and LOS-lateral directions. Our results demonstrate that combining spectroscopy and EUV imaging constrains different components of CME kinematics during early
evolution.
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Accelerator Physics
Incorporating Heightened Scrutiny into a Large HEP Software Project
Philippe Canal, Chris Green, Kyle Knoepfel et al. (+5 more)
In 2023, DUNE began re-evaluating the requirements of its data-processing framework, which led to commissioning a new design that would better fit
neutrino physics than the existing reconstruction frameworks designed for
collider physics. Due to the radical changes expected, significant multi-institutional effort has been directed toward the creation of the Phlex framework. In addition, the tight timelines in which to implement such a framework have invited scrutiny from various parties, including DUNE itself, the host laboratory Fermilab, and the US Department of Energy. After briefly discussing the unique needs of
neutrino physics, we will recount how the Phlex development team has approached the design and development of a framework in the context of this heightened scrutiny. This process began with a systems-engineering approach to formally manage the requirements DUNE has of its framework. What followed was, for the first time in the HEP community, a review of the framework's conceptual design by a panel of external framework experts before developers proceeded to the implementation. The implementation efforts have led to a series of prototypes that are being used to provide rapid feedback from Phlex users to framework developers. We will discuss how each of these steps has resulted in a strong design that has the backing of the DUNE experiment, Fermilab, and the US Department of Energy.
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All authors Philippe Canal, Chris Green, Kyle Knoepfel, Wim Lavrijsen, Adam Lyon, Marc Paterno, Saba Sehrish, Beojan Stanislaus
Quantum Physics
Scattering amplitudes from quantum hardware a la RESOs
Raul A Briceno, Ivan M Burbano, Anthony N Ciavarella et al. (+3 more)
We report the first
quantum-hardware implementation of Real-time
Estimators for Scattering Observables (RESOs). The physical model is a one-dimensional
lattice theory of non-relativistic
spin-1/2
fermions with a single contact interaction. The
lattice sizes studied are up to $N_x=54$
lattice sites and up to $20$ time steps. Spacetime correlation functions were computed on IBM's
quantum computers, using $109$
qubits with $10,806$ CZ gates applied, reaching a two-
qubit gate depth of $246$. We demonstrate how to study bound states and extract scattering amplitudes from these correlation functions.
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All authors Raul A Briceno, Ivan M Burbano, Anthony N Ciavarella, Ermal Rrapaj, Thomas R Richardson, Andre Walker-Loud
Materials Science
Knowledge-Driven XRD Phase Identification via Multi-View Retrieval and Explanation
Doaa Mohamed and Markus Stricker
X-ray diffraction (XRD) is a experimental technique for determining the phase composition and structure of crystalline materials. However, interpreting XRD patterns is challenging, particularly in high-throughput materials discovery, where many novel materials may need to be characterized and no reference patterns are available. Consequently, machine learning is increasingly used to accelerate and automate the analysis while reducing errors associated with human interpretation. We propose a multi-decision framework for XRD phase analysis that integrates representation learning, similarity-based
retrieval, and explainable decision support within a unified reference database. A convolutional autoencoder learns compact latent representations of XRD patterns that preserve structural similarity while remaining robust to variations arising from experimental noise and measurement conditions. By integrating multiple decision pathways within a shared latent space, the framework moves beyond single-label prediction toward ranked and interpretable phase analysis that mirrors expert practice. During inference, complementary decision mechanisms are applied, including latent-space classification and
retrieval, explanation-guided similarity using Integrated Gradients, and composition-based similarity search. These mechanisms generate ranked candidate phase lists that are aggregated into a final prediction with an associated confidence score. Experiments on synthetic
datasets demonstrate strong predictive performance, achieving 98.85\,% accuracy for
crystal system classification and 95.82\,% accuracy for space group prediction on the test set, while maintaining robustness under realistic perturbations. The framework supports reliable, analyst-friendly identification of
crystal phases and structures in high-throughput and exploratory materials discovery settings.
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Solar and Stellar Astrophysics
Negative and Positive Cascade Rates of Slow Alfvénic Turbulence in Switchback and Non-switchback Intervals: Wind Observations
Sofiane Bourouaine
We estimate the turbulent cascade rate in imbalanced Alfvénic
turbulence in the slow
solar wind using a Politano–Pouquet-based approach that does not require an isotropic assumption. We analyze selected 8-hour intervals provided by Wind spacecraft. These intervals are characterized by near-homogeneity, weak velocity shear, and imbalanced Alfvénic fluctuations, and are classified as switchback or non-switchback depending on the angular spread of the
magnetic field relative to the mean field. Switchback intervals are identified by large
magnetic-field rotations, whereas non-switchback intervals exhibit only small angular deviations. Our results show that non-switchback intervals exhibit a positive total cascade rate and power spectra consistent with a $-3/2$ scaling, indicative of a forward energy cascade. In contrast, switchback intervals are characterized by a negative total cascade rate (inverse cascade), and by steeper power spectra with a spectral index of approximately $-1.6$. This indicates that large
magnetic-field rotations can substantially modify the scale-to-scale energy transfer in Alfvénic slow
solar wind. The results suggest that switchbacks may be associated with additional physical processes, such as local instabilities, or reconnection-related structures, that alter the direction and magnitude of the turbulent cascade. These findings may help explain previous reports of negative cascade rates in imbalanced Alfvénic
solar-wind
turbulence.
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High Energy Physics (Theory)
Transient Coherence and Multiscale Spectral Structure after a Mass Quench in a 1+1-Dimensional Scalar Field
Gabriel Abellán and Nelson Bolívar
A mass quench generates anomalous pair correlations that are absent from the final particle occupations. For a free real scalar field in $1+1$ dimensions, we define a bilocal observable by smearing the statistical Keldysh correlator with a Morlet kernel on the finite post-quench relative-time interval. Its excess over the dephased correlator gives a dimensionless relative coherence weight. At fixed momentum, this weight is exactly independent of the initial temperature for Gaussian thermal states evolved with the same free
Hamiltonian: the common thermal amplitude cancels between numerator and denominator. The cancellation is not a purity criterion and is not exclusive to wavelets. We derive the finite-window response and show that the anomalous signal depends essentially on the observation window; an admissible zero-mean wavelet annihilates the relative-time-constant anomalous term on the full line. We compare this response with the signed finite-time Wigner spectrum and derive a distinct Gaussian-extension positivity bound. Exact smooth-quench occupations provide an independent dynamical reference. Finally, we formulate a renormalized Hartree extension and delimit the oscillatory and nonoscillatory regimes of a scalar mode on a fixed two-dimensional de Sitter background.
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High Energy Astrophysical Phenomena
Not all spins of black-hole binaries formed in clusters are isotropic and not all spins of black-hole binaries formed in isolation are aligned
Sofia Dossena, Davide Gerosa and Tristan Bruel
Spin directions are promising observables for distinguishing between the formation channels of merging
stellar-mass binary black holes with gravitational-wave observations. In this work, we challenge the standard expectation that binaries formed via dynamical interactions in
stellar clusters have isotropically distributed
spins and that binaries formed in isolation have
spins aligned with the orbital angular momentum. For dynamically formed binaries, we account for observational findings suggesting that the
spins of
stars in clusters may exhibit a preferred degree of
alignment and construct a simple geometrical description of the resulting black-hole
spin directions. This results in an analytical joint distribution for the polar angles of first-generation black-hole binaries, whose key feature is a correlation between the two
spin-orbit tilts. We show that, under reasonable assumptions and independently of the initial
spin configuration,
spins are fully randomized after a single black-hole merger, implying that binaries formed through hierarchical mergers have isotropically distributed
spin orientations. For isolated binaries, we introduce a simple model for
spin evolution as a function of the natal kick imparted during the first
supernova explosion, while accounting for
tidal interactions and mass-ratio reversal. The resulting distribution is also fully analytic. We investigate the impact of relativistic
spin precession, as well as that of the finite escape speed of clusters, on our geometrically derived distributions. Our results provide a simple analytical framework for modeling the
spin directions of merging black holes in gravitational-wave population fits.
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