Solar and Stellar Astrophysics
SN 2019vxm: A luminous and long-lived Type IIn supernova with early flash-ionisation features
Y.-Z. Cai, A. Pastorello, T. J. Moriya et al. (+38 more)
We present the photometric and spectroscopic analysis of the luminous and long-lasting Type IIn
supernova (SN) 2019vxm. The SN reaches a peak V-band absolute magnitude of MV = -20.01 +/- 0.13 mag in 35.0 days, and displays slow
evolution in both the light curves and spectra, resembling that of long-lived SNe IIn. A mid-infrared (MIR) excess is detected starting from seven months after maximum brightness, suggesting a few 10^-3
solar masses of
dust are newly formed at >= 210 days (and up to 0.01
solar masses at +4.5 yr). The spectra are dominated by a blue continuum at early stages, with narrow, symmetric Balmer lines and flash-ionisation emission lines of C III, N III, and He II. Comparing our flash-ionised spectrum with early interacting SN spectral models, we estimate a lower limit for the mass-loss rate of the progenitor of >= 0.01
solar masses per year. A weak P Cygni absorption feature is detected in the H-beta profile of the high-resolution Echelle spectrum at +19.7 d, suggesting the presence of slow-moving (60 +/- 10 km/s), unshocked circumstellar material (CSM) arising from the pre-SN wind of the progenitor. The H-alpha and H-beta profiles gradually evolve and become broader and asymmetric, showing a progressively increasing blueshift, with a clear flux deficit in the red wings of the broad velocity component after +102 days. Our observed bolometric light curve before about 100 days can be well fitted by a power-law function (L(t) = 2 x 10^44 (t/day)^-0.49 erg/s), which is very similar to SN 2010jl.
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All authors Y.-Z. Cai, A. Pastorello, T. J. Moriya, X.-F. Wang, A. Reguitti, A. V. Filippenko, L. Tomasella, K. Čotar, A. Siviero, N. Elias-Rosa, T. G. Brink, G. Valerin, S. Benetti, J.-W. Zhao, Z.-H. Peng, Z.-Y. Wang, I. Altunin, R. Baer-Way, E. Baron, V. Chander, M. Chu, A. deGraw, J. M. DerKacy, J. Isern, C. Jennings, R. Kotak, L.-P. Li, P. Marziani, M. May, P. A. Mazzali, A. Morales-Garoffolo, S. Moran, P. Ochner, I. Salmaso, L. Tartaglia, M. Turatto, H.-Y. Wu, D.-F. Xiang, S.-Y. Yan, J.-J. Zhang, W. Zheng
Lattice Field Theory
Baryon Light-Cone Distribution Amplitudes from Lattice QCD: Formalism, Renormalization, Extrapolation, and Matching
Mu-Hua Zhang, Haoyang Bai, Min-Huan Chu et al. (+11 more)
Baryon light-cone distribution amplitudes (LCDAs) are inherently multidimensional objects parametrized by two independent longitudinal momentum fractions, making their first-principles determination substantially more challenging than that of
meson LCDAs. We present a systematic large-momentum effective theory (LaMET) framework for determining
baryon leading-twist LCDAs from
lattice QCD. The framework covers the complete path from equal-time three-
quark quasi-distribution amplitudes to physical
baryon LCDAs. We formulate the leading-twist $V$, $A$, and $T$ quasi-DAs and analyze their
spin-
flavor and coordinate-space
symmetries, including antisymmetric amplitudes with vanishing local limits. We develop a hybrid renormalization prescription on the $(z_1,z_2)$ plane, introduce a newly developed large-$\lambda$ extrapolation strategy based on the asymptotic large-distance behavior of Euclidean correlators, and derive the corresponding one-loop LaMET matching relation in the hybrid renormalization scheme. As a demonstration, we apply the complete analysis pipeline to the $\Lambda$-
baryon $A$-structure quasi-DAs using seven $2+1$–
flavor lattice ensembles, and use this amplitude to examine the impact of large-distance extrapolation, perturbative matching, and extrapolation to the continuum, physical-pion-mass, and infinite-momentum limits, together with the associated systematic uncertainties. This work provides the formalism, renormalization, extrapolation, and matching infrastructure for first-principles determinations of $x$-dependent
baryon LCDAs.
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All authors Mu-Hua Zhang, Haoyang Bai, Min-Huan Chu, Jun Hua, Xiangdong Ji, Xiangyu Jiang, Jian Liang, Cai-Dian Lü, Andreas Schäfer, Wei Wang, Yi-Bo Yang, Jian-Hui Zhang, Jia-Lu Zhang, Qi-An Zhang
Quantum Physics
Blueprint for a fault-tolerant compound photon-atom quantum architecture
Geva Arwas, Doron Azoury, Daniel Azses et al. (+11 more)
Fault-tolerant
quantum computing requires architectures that simultaneously address scalability, connectivity, and error correction under realistic noise constraints. We present a compound photonic-atomic
quantum computing platform that uses cavity QED to realize near-deterministic entangling operations between flying photonic
qubits and stationary atomic
qubits.
Photons provide long-range connectivity and scalability via measurement-based
quantum computing (MBQC), while atoms supply reusable, near-deterministic resources for
photon generation and
entanglement, overcoming the inefficiency of purely photonic platforms. The core primitive is a symmetrized Duan-Kimble
photon-atom controlled-phase (CZ) gate, robust to experimental imperfections and high-fidelity. Using single $^{87}$Rb atoms coupled to optical cavities, we give protocols for state preparation, measurement,
photon generation, and entangling gates on tens-of-nanosecond timescales, and show how large-scale cluster states with effectively unrestricted connectivity and reduced overhead can be generated through atomic reuse. We analyze fault tolerance on the Raussendorf-Harrington-Goyal (RHG)
lattice with a hardware-aware noise model capturing asymmetric loss and correlated photonic-atomic errors. Logical
memory simulations yield a
photon-loss threshold near $2.6\%$ per physical gate ($\sim$15% total per trajectory). The full Clifford set – Hadamard, phase, CNOT – is implementable transversally or fold-transversally at thresholds matching the identity channel, and we propose two non-Clifford resource-state routes (code teleportation and magic state cultivation) within the foliated cluster-state architecture.
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All authors Geva Arwas, Doron Azoury, Daniel Azses, Orel Bechler, Dana Ben Porath, Barak Dayan, David Dentelski, Yaron Jarach, Nadav Kandel, Aviad Landau, Yair Margalit, Alexander Poddubny, Michael Slutsky, Konstantin Yavilberg
Disordered Systems and Neural Networks · Cross-listed from cs.LG
Scalar Representations of Neural Network Training Dynamics
Pedro Jiménez-González, Miguel C. Soriano and Lucas Lacasa
Training in artificial neural networks can be viewed as a trajectory evolving through a high-dimensional loss landscape. However, the large number of trainable parameters makes the direct analysis of these dynamics challenging. In this work, we treat such training trajectories as temporal networks and apply recently proposed strategies for the scalar
embedding of temporal networks. We investigate whether such a scalar
embedding provides a meaningful low-dimensional representation of neural network training dynamics. Using a multilayer perceptron trained on the MNIST classification task, we show that the
embedding preserves the main dynamical features observed in the original parameter space, including the emergence of sensitivity to initial conditions for specific learning rate regimes and an accurate reconstruction of the network's maximum Lyapunov exponent. We then use the embedded scalar trajectory to define a characteristic time, analogous to a Lyapunov time, after which the exponential separation between initially close embedded trajectories saturates. This characteristic time captures the typical decorrelation time between initially close network trajectories in the original high-dimensional system. Finally, we investigate the statistical organization of asymptotic training states through a spacing observable defined in the embedded space. We find that the distributions of rescaled asymptotic spacings collapse onto a common form across initial conditions and are compatible with a skew lognormal distribution. Altogether, our results suggest that scalar low-dimensional
embeddings provide a useful framework for studying and visualizing the dynamical properties of neural network optimization trajectories.
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Earth and Planetary Astrophysics
The impact of numerical derivatives on radial velocity extraction
A. M. Silva and K. Al Moulla
The radial velocity (RV) method is a widely used technique to infer planetary masses and orbital parameters. One of the most widely used methods to compute RVs is based on the
alignment of a high-SNR, data driven,
stellar model with individual observations, commonly referred to as template matching. Typically, the
alignment is performed through a $\chi^2$ minimization, but some approaches rely on the derivative of the
stellar template to do so, which is often the case in line-by-line methods. In this paper we aim to explore the limitation of derivative-based methods for RV extraction in the case of using low-SNR
stellar models. We use simulated Gaussian profiles to investigate the effect of computing a numerical derivative of the
stellar template, in comparison with the usage of an analytical profile. The impact on RV and associated uncertainty is then analyzed as a function of the signal-to-noise ratio (SNR) of the line. Then, using real observations we compare the residuals between a derivative-based RV extraction and a classical template matching implementation, as function of the SNR of the
stellar template. We find that on simulated Gaussian profiles the usage of the numerical approach leads to a RV residual at the level of the meter per second, at a per-pixel SNR regime of 100. An increase of the SNR leads to a decrease of this impact, falling under the current noise-floor of state-of-the-art spectrographs at SNR>1000 for a single spectral line. The inclusion of multiple spectral lines in the simulations lead to an overall decrease of the contamination, across all SNR regimes. The application to a real
dataset presents a decrease of the RV impact with the increase of the template's SNR, albeit still presenting a 12.5 cm/s difference when including 78 observations in the
stellar template.
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High Energy Physics (Theory)
Positivity properties of observables in planar maximally supersymmetric Yang-Mills theory
Maximilian Haensch
We study positivity properties of exact observables in planar N=4 super Yang-Mills as functions of the 't Hooft coupling. Motivated by analogous results in
quantum mechanics, we ask whether such observables admit a once-subtracted dispersion representation in the coupling over a positive spectral measure. Our main result is that this property, also known as the Stieltjes property, holds for a broad class of exact observables. We prove it analytically, through integral representations, for the octagon anomalous dimension, the logarithm of the circular Wilson loop, the Bremsstrahlung function, and anomalous dimensions in the BMN limit, and we provide numerical evidence for the cusp and tilted cusp anomalous dimensions. We also identify quantities for which the Stieltjes property does not hold, and study the weaker positivity property of complete monotonicity. The Stieltjes property yields two powerful consequences: it lets us turn perturbative input into rigorous non-perturbative bounds, and bootstrap perturbative coefficients. We also show how the strong-coupling expansion and its non-perturbative corrections can be recovered from the once-subtracted dispersion representation via a Mellin-Barnes representation and outline a method to estimate the strong-coupling expansion from weak-coupling data.
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Materials Science
Hidden Defect Chemistry in Ion-Irradiated MoS$_2$ Field-Effect Transistors Revealed by Photocurrent Loss
L. Daniel, D. Sutarma, L. Klieve et al. (+7 more)
Defect engineering in monolayer MoS$_2$ is a promising route to tune field-effect transistors (FETs), but the electronic response of defects in processed devices can be masked by contacts, substrate effects, adsorbates, and chemical passivation. Here, we irradiate MoS$_2$ FETs with low-energy 40~eV Ar$^+$ ions to preferentially create sulfur vacancies (V$_S$) in the channel while minimizing substrate damage. We compare dark and illuminated electrical characterization with surface analysis and first-principles calculations. Dark transfer characteristics show an apparent robustness against irradiation up to moderate fluences, with pronounced degradation only at the highest fluence. Under 532~nm illumination, however, the photocurrent and light-induced photodoping decrease systematically with increasing ion fluence, revealing irradiation-induced changes that are hidden in standard dark measurements. Atomic force microscopy and X-ray photoelectron spectroscopy show substantial carbon-containing residues on processed devices even after extended cleaning. We propose that such residues may provide a reservoir for hydrocarbon-mediated passivation of sulfur vacancies. Density-functional-theory calculations provide a microscopic model consistent with this scenario: unsaturated V$_S$ introduce in-gap states, H-C$_S$ configurations suppress these states, and carbon substitution without hydrogen leaves defect states in the band gap. Our results highlight carbon-containing surface contamination as a key factor in interpreting defect engineering experiments on MoS$_2$ and related TMDC devices.
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All authors L. Daniel, D. Sutarma, L. Klieve, O. Kharsah, U. Hagemann, O. Altenhoff, S. Sleziona, L. Breuer, P. Kratzer, M. Schleberger
Applied Physics
Decision-support strategies for photovoltaic self-consumption under declining electricity prices and limited remuneration of surplus generation
Ana B. Cristóbal, Daniel Sierra, Laura Palomino et al. (+2 more)
The success of distributed photovoltaics may be undermining its own future. As
solar penetration increases, electricity prices decline during periods of peak generation, reducing the value of surplus photovoltaic production. This raises a critical question: can citizen-led energy systems remain economically viable in electricity
markets dominated by renewable generation? Rather than exploring technically optimal but institutionally unrealistic solutions, we examine the options available under current regulatory and
market conditions. Using high-resolution consumption data from a rural community sharing a PV facility among 24 users, we identify pathways for long-term sustainability. The study makes two contributions. First, it shows that effective internal coordination can mobilize participation and investment as successfully as external subsidies. Second, it compares static, dynamic, and hybrid energy-sharing models, with and without storage, providing a flexible framework that balances efficiency,
fairness, and governance. Results show that collective self-consumption reduces required PV capacity, lowers investment costs, and increases annual savings compared with individually operated systems. Alternative allocation schemes further improve benefit distribution and local electricity use, although gains depend on trade-offs between efficiency,
fairness, and governance complexity. Under current electricity prices and remuneration schemes, battery storage provides limited additional economic value and becomes attractive only under specific
market conditions. Overall, the long-term viability of citizen-led photovoltaic initiatives depends less on technological sophistication than on collective coordination and adaptive governance.
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All authors Ana B. Cristóbal, Daniel Sierra, Laura Palomino, Luis Miguel Carrasco, Luis Narvarte
Quantum Physics
Learning the structure of open quantum systems
Laura Lewis, Ewin Tang and John Wright
We design an
algorithm for learning the coefficients of an $n$-
qubit constant-local Lindbladian to $\varepsilon$ error with $O(g d^2 \log(n) / \varepsilon^2)$ total
evolution time, where $g$ is the single-site energy and $d$ is the (approximate) degree of the interaction graph. Though Lindbladians present new challenges not present in the special case of
Hamiltonians, our
algorithm achieves the suite of desiderata attained by state-of-the-art
Hamiltonian learning
algorithms: (1) it uses non-adaptive, ancilla-free randomized Pauli measurement
circuits with a time resolution of only $\Theta(1/g)$; (2) it works without knowledge of the structure of the unknown Lindbladian; (3) it depends on a smooth form of degree, thereby supporting the learning of quasi-local and power-law Lindbladians. Moreover, we prove a lower bound showing that our
algorithm is optimal in each parameter up to logarithmic factors. Our
algorithm is a simple iterative method, where the objective function consists of
Fourier coefficients of the Lindbladian restricted to few-site regions. Its analysis identifies the difficulty unique to open systems, which we call "confusing" terms. For settings where the "confusion" is limited, the performance of the
algorithm improves. We demonstrate this for the case of structure learning of
Hamiltonians from access to real-time
evolution, where we obtain a new
algorithm that is significantly simpler than previous work. In addition, using the same iterative method, we design the first efficient
algorithm for structure learning
Hamiltonians from high-temperature Gibbs states.
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Mathematical Physics
Generalized Hermite Polynomials and Spectral Degeneracies of a Singular Sextic Oscillator
Davide Guzzetti and Dmitrii Rachenkov
We study a quasi-exactly solvable singular sextic oscillator and its algebraic spectrum. For a distinguished range of parameters, we prove that the discriminant of the characteristic
polynomial of the
matrix determining the algebraic spectrum admits a natural factorization into three factors. One of these factors is the square of a generalized Hermite
polynomial $H_{m,n}$, whose zeros are poles of a rational solution of the fourth Painlevé equation. Hence, the spectral degeneracies (level crossing points) corresponding to a component of the discriminant locus are in exact correspondence with the zeros of generalized Hermite
polynomials, providing an exact Painlevé IV analogue of the Shapiro–Tater asymptotic correspondence originally conjectured for the quartic oscillator and Painlevé II. We also characterize the values of the parameters for which the sextic oscillator admits simultaneously two quasi-
polynomial eigenfunctions with opposite exponential behaviour at infinity, and show that this phenomenon is also governed by generalized Hermite
polynomials. Our result also yields a new determinantal representation of $H_{m,n}$ as the resultant of the characteristic
polynomials of two complementary blocks of the
matrix determining the algebraic spectrum.
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High Energy Physics (Phenomenology)
Solution of Canonical Differential Equations for Integrals on Arbitrary Geometries
Michał Czakon and Lorenzo Tancredi
A highly successful approach to computing multi-loop scattering amplitudes is to reduce the Feynman integrals that arise to a smaller set of master integrals using integration-by-parts identities. These dimensionally-regulated master integrals can often be determined by solving a system of first-order partial differential equations with respect to masses and external invariants. The application of this method to large classes of problems became much more streamlined thanks to the introduction of $\epsilon$-factorized canonical forms. There is increasing evidence that a canonical form can always be achieved, although the required transformation may involve transcendental functions related to the periods of geometrical objects such as
elliptic curves or Calabi-Yau
manifolds. Until now, obtaining numerical values for the master integrals in such cases has been difficult in practice, also due to the lack of closed-form expressions for the transcendental functions involved. We show that this obstruction is only apparent. Since the original master integrals satisfy linear differential equations with rational coefficients, any functions appearing in the transformation to a canonical basis satisfy, by construction, rational differential equations as well. By solving these auxiliary equations, the numerical evaluation of the canonical system reduces to solving an enlarged rational system. We implement this strategy in a C++ package and apply it to the two-loop master integrals that enter di-jet and $\gamma$+jet hadro-production via a heavy-
quark loop.
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Pattern Formation and Solitons
Traveling and Dispersive Shock Waves in a Two-Dimensional Fermi-Pasta-Ulam-Tsingou Lattice
Christopher Chong, Panayotis G. Kevrekidis, Gino Biondini et al. (+1 more)
In the present work we analyze traveling and dispersive shock waves of a two-dimensional
Fermi-Pasta-Ulam-Tsingou
lattice. In the first part of the paper, using variational techniques we prove the existence of both periodic and solitary traveling waves for convex potentials. In the case of unimodal profiles we are able to remove the assumption of convexity. The variational formulation also provides a natural
algorithm for the numerical computation of traveling waves, which we use to explore both solitary and periodic traveling waves. The numerical computations are compared with analytical approximations based on the derivation of the KdV equation for quasi-one-dimensional propagation. In the second part of the paper, we focus on dispersive shock waves (DSWs), which are expanding modulated waves that connect states of different amplitude. In particular, we focus on line DSWs, which are constant along one direction and propagate in the direction orthogonal to which it is constant. Such solutions form when subject to quasi-one-dimensional jump initial data. We find that while the shape of the DSW depends on the direction of travel, properties such as the speed and amplitude do not. The systematic numerical study of the line~DSWs is then compared to those predicted by the KdV equation along the line of propagation. Key characteristics of the DSWs, such as the speeds of the trailing and leading edges, are investigated for various jump heights, yielding good agreement between simulation and KdV approximation in the limit of vanishing jump height. Finally, we apply the DSW fitting method to study the trailing and leading edge characteristics of the DSW, finding even better agreement to the numerics when compared to the KdV prediction. The KdV prediction and DSW fitting predictions agree in the limit of small jump height.
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All authors Christopher Chong, Panayotis G. Kevrekidis, Gino Biondini, Wolfgang Reichel
Disordered Systems and Neural Networks · Cross-listed from cs.SI
Detector-Output Instability near the Kesten-Stigum Boundary: Separating Hard Readout, Relaxation, and Fixed-Point Dispersion
Faruk Alpay and Baris Basaran
Community-detection
algorithms usually return a single partition, even when independent initializations or small data perturbations yield several plausible outputs. We probe this output distribution through three paired observables: hard-partition variation of information (VI), a residual-gated fixed-point VI, and a cutoff-free Jensen-Shannon distance between belief-propagation (BP) marginal fields. For the symmetric sparse
stochastic block model, linearizing BP around the uninformative fixed point gives the Kesten-Stigum onset at $\mathrm{snr}=(c_{\rm in}-c_{\rm out})/(q\sqrt{c})=1$. The hard VI maximum is instead a finite-size, readout-dependent detector curve on the detectable side, typically $\mathrm{snr}^\star \simeq 1.05\text{-}1.10$; moving the polarization cutoff from 0.001 to 0.1 shifts it across 1.047-1.128. The nontrivial-readout activation obeys $\mathrm{snr}_{50}(\tau)-1 = 0.0086 + 0.522\,\tau$ ($R^2=0.996$). Long-budget residual gating separates readout and critical slowing from fixed-point dispersion: at $\mathrm{snr}=1.05$ and 1.10 the hard VI is 1.49 and 1.58 bits but the gated subsets have zero VI, whereas from 1.15 to 1.30 nearly all runs pass the gate and retain VI 1.31 down to 1.24 bits. A high-replication audit through $N=100000$ disfavors a zero-asymptote power law and finds a small plateau $\mathrm{snr}^\star-1 \simeq 0.024$ (graph-bootstrap 90% interval [0.0227, 0.0316]). On real networks, a label-free Bethe-Hessian modularity margin with a Chung-Lu null gate is run on political blogs and six SNAP graphs: the measurement stays label-free, while heterogeneous networks can retain null-significant structure even after strong edge subsampling. The result is a detector-output decomposition near the Kesten-Stigum boundary, reporting hard readout, relaxation dynamics, and fixed-point-field dispersion separately.
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High Energy Physics (Theory)
A note on the holographic consistency of DGKT-type vacua with $h^{2,1}=0$
Filippo Revello and Farah Verbeure
Recent works have pointed out the existence of a
holographic constraint on (extremal) three-point functions of scalar
moduli in scale-separated AdS
vacua. Moreover, it has been shown that this constraint is satisfied in the DGKT scenario in massive type IIA for the original $\mathbb{T}^6/(\mathbb{Z}_3 \times \mathbb{Z}_3)$ orbifold, as a result of a series of unexpected cancellations. We extend the analysis to more elaborate scenarios, involving geometries with less
symmetry and more complicated triple-intersection numbers. Surprisingly, the cancellations persist in all examples with $h^{2,1}=0$, leading us to speculate this conclusion might hold more generally.
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Materials Science
Bayesian model comparison of type-I and type-II ultrafast demagnetization dynamics
Hiroki Wadati and Tetsuro Ueno
Ultrafast demagnetization dynamics are often phenomenologically classified into type-I and type-II responses according to their temporal
evolution following femtosecond
laser excitation. However, finite experimental temporal resolution and noise can substantially obscure the intrinsic dynamics and complicate this classification. In this work, we investigate the distinguishability of type-I and type-II demagnetization dynamics using Gaussian-convolved phenomenological models and
Bayesian information criterion-based statistical model comparison. Synthetic
datasets with varying temporal resolution and noise levels are first analyzed to evaluate the conditions under which the two classes can be reliably discriminated. We show that convolution with the instrumental response function significantly reduces the observable differences between the intrinsic responses, thereby producing broad regimes in which model discrimination becomes statistically inconclusive. The applicability of the framework is further demonstrated through analysis of representative experimental ultrafast demagnetization data from NiCo2O4 thin films. These results suggest that the apparent classification of ultrafast demagnetization dynamics can be highly sensitive to experimental resolution, noise level, and analysis methodology.
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Computational Physics · Cross-listed from math.OC
Local-Minima-Preserving Continuous Relaxation of Ising Problems
Debraj Banerjee, Santanu Mahapatra and Kunal N. Chaudhury
The generalized Ising problem captures a broad spectrum of hard combinatorial problems, including MAX-CUT, Number Partitioning (NPP), and Maximum Independent Set. In this work, we consider the notion of one-flip local minima for this problem. We construct a
polynomial relaxation and prove the landscape equivalence
theorem: there exists a one-to-one correspondence between the local minima of the relaxation and the one-flip minima of the original Ising problem. This guarantee reduces the Ising problem to finding the local minima of a smooth function, allowing us to leverage gradient-based optimizers such as ADAM. We demonstrate that our method is scalable and it achieves strong performance across challenging
benchmarks, including
spin-glass models, MAX-CUT, and NPP.
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Chemical Physics
Size Effects in the Strong-Field Ionization and Dissociation Dynamics of (H$_2$O)$_n$ (n=1-4)
Chen Jiang, Cody L. Cavington and Kalman Varga
The size-dependent strong-field ionization and dissociation dynamics of (H$_2$O)$_n$ (n=1-4) are investigated using real-time time-dependent density functional theory (RT-TDDFT) coupled to Ehrenfest molecular dynamics under a common few-cycle near-infrared
laser pulse. It is found that the net ionization per monomer varies only weakly on cluster size, whereas the protonic and oxygen response is changed much more strongly once the cluster size grows beyond the dimer. In particular, H-ejection activity is observed to rise sharply from the dimer to the trimer/tetramer regime, while stable H-transfer is essentially absent in the dimer under the present criterion but becomes substantial in the trimer and is further amplified in the tetramer. Through timing analyses, it is shown that the dimer exhibits a weak and temporally broad response, whereas the larger clusters display a much stronger early-time protonic response concentrated within and immediately after the
laser pulse window. By endpoint oxygen statistics, a systematic increase in dissociation propensity with cluster size is likewise shown. For a clean subset of direct two-body dimer breakup trajectories, the asymptotic kinetic energy release is estimated to be 4.47 $\pm$ 1.03 eV, in reasonably good agreement with the experimental value for the unprotonated two-body Coulomb-explosion channel. Overall, it is shown by the results that increasing water-cluster size primarily reshapes the strong-field response through
proton-mediated and
topology-level
nuclear dynamics rather than through a large change in net ionization alone.
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Quantum Physics
Phase-Altered Interleaved Randomized Benchmarking for Compiled Non-Clifford Gates
Simona K. Grigorova, Nikolay V. Vitanov and Boyan T. Torosov
Interleaved randomized benchmarking (IRB) provides a scalable estimate of a gate's error rate, but its standard guarantees require the interleaved gate to be Clifford~\cite{Magesan2012Interleaved,magesan2012characterizing}. In superconducting processors, many non-Clifford phase gates in compiled
circuits are implemented virtually as software-defined frame updates rather than as additional control pulses~\cite{mckay2017efficient}. This raises the question of whether inserting or removing such virtual phases measurably changes IRB error estimates. We introduce phase-altered interleaved randomized benchmarking (PA-IRB), a paired-IRB diagnostic protocol comparing phase-stripped and phase-dressed Clifford interleaving gates derived from the same compiled implementation. PA-IRB reports $\Delta r=r_d-r_s$ with combined uncertainty to test whether virtual phase gates affect the extracted IRB decay beyond statistical error. As a case study, we apply PA-IRB to a compiled Toffoli gate executed on IBM superconducting processors, where the constituent $T/T^\dagger$ gates are implemented as virtual $Z$ rotations. Across tested calibration runs, $\Delta r$ is consistent with zero within uncertainty, indicating that virtual phase addition or removal does not measurably alter the IRB-derived error estimate under the employed compilation and execution stack. More generally, PA-IRB provides a lightweight, abstraction-aware diagnostic for benchmarking workflows involving software-defined phase operations. The same paired comparison can also be used to place operational bounds on the contribution of non-Clifford components to the compiled gate error, even when those components are physically executed rather than implemented virtually.
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Nuclear Theory
Construction of Nuclear Covariant Energy Density Functional from A Physics-Guaranteed Neural Network Approach
W. F. Li, Z. M. Niu, H. Z. Liang et al. (+2 more)
Density functional theory is a practical approach for solving
quantum many-body problems with available computational resources. The complexity of the
nuclear force makes constructing an accurate
nuclear energy density functional much more challenging. The feasibility of constructing a
nuclear covariant energy density functional with deep neural networks is demonstrated. This physics-guaranteed neural network approach achieves high accuracy in predicting
nuclear energy density and exhibits significantly better extrapolation abilities than traditional machine learning methods for binding energies. When combined with the existing covariant density functional, the neural network approach improves the binding energy accuracy from $644$ keV to $86$ keV in the known region and also effectively captures the microscopic shell effect. Furthermore, its extrapolation performance is also significantly enhanced, achieving an accuracy of approximately $5$ MeV even when extrapolating up to $30$ steps. This work paves the way for the construction of accurate
nuclear energy density functionals through machine learning.
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All authors W. F. Li, Z. M. Niu, H. Z. Liang, Y. F. Niu, B. H. Sun
High Energy Astrophysical Phenomena
Enabling population studies on wind-driven Galactic binary systems
B. Marcote, P. Benaglia, V. Bosch-Ramon et al. (+8 more)
Galactic binaries driven by
stellar wind shocks, such as colliding wind binaries (CWBs) and gamma-ray binaries (gBs), harbor one of the most efficient particle acceleration engines known in the Universe. Despite their potential, these sources remain relatively unexplored, particularly in the domains of low
radio frequencies and very high resolution. As a result, we lack comprehensive population studies and well-characterized individual systems. Only a few of these binaries, such as the iconic gB PSR B1259$-$63 or the massive CWB WR 140, have been studied in enough detail to probe their wind dynamics and shock physics. Current observations lack the sensitivity to detect weak non-thermal synchrotron emission from low-energy particle populations and the angular resolution to resolve shock structures on sub-au scales. The Square Kilometre Array Observatory (SKAO) will mark a significant improvement in both sensitivity and resolution with its SKA-low and SKA-mid
telescopes, solving these challenges. This will enable systematic studies of the winds and shock interactions in these binary systems. Additionally, SKA-VLBI will facilitate the observation of changes in shock geometry at different orbital phases, linking particle acceleration processes to the binary's orbital characteristics and
stellar wind properties. SKAO will pave the way for comprehensive population studies of these energetic binary systems.
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All authors B. Marcote, P. Benaglia, V. Bosch-Ramon, M. De Becker, S. del Palacio, P. Atri, J. Moldón, J. M. Paredes, M. Ribó, G. E. Romero, A. Tej
Quantum Physics
All-optical switching of continuous-variable entanglement in an absorption-suppressed plasmonic nanodimer
Elif Ozturk, Mehmet Gunay, Ramazan Sahin et al. (+1 more)
A subwavelength
quantum-photonic
circuit element should simultaneously generate nonclassical light, suppress plasmonic loss, and remain dynamically tunable. We show that an orthogonal plasmonic nanorod dimer can satisfy all three requirements. A phase-locked control polarization induces plasmonic refractive-index enhancement, driving the probe response toward a near-zero-extinction regime while simultaneously tuning the local second-harmonic parametric interaction. The resulting nonlinear plasmonic source operates in an absorption-suppressed regime and enables all-optical control of
quantum correlations. We demonstrate switchable logarithmic negativity and single-mode nonclassicality, establishing a route toward actively tunable
quantum-plasmonic
circuit elements operating well below the diffraction limit.
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All authors Elif Ozturk, Mehmet Gunay, Ramazan Sahin, Mehmet Emre Tasgin
Astrophysics of Galaxies
The SKA-VLBI Perspective on Radio-Quiet AGN
Francesca Panessa, Tao An, James Petley et al. (+21 more)
The
accretion-ejection mechanism in Active
Galactic Nuclei (AGN) remains a central open problem in astrophysics, tied to the role of AGN feedback in
galaxy formation and
evolution.
Radio-quiet AGN dominate the observed AGN population. Lacking luminous jets, their
radio emission traces a rich set of processes spanning the host
galaxy kpc scales down to the vicinity of the supermassive black hole:
star formation, AGN-driven winds and shocks, free-free emission from photo-ionized gas, low-power jets, and coronal activity close to the inner
accretion disk. The Square Kilometre Array (SKA) will probe these processes across a wide frequency range with unprecedented sensitivity, wide-field survey capability, and, critically, high-resolution VLBI imaging. Flux, spectral, and polarization monitoring will constrain dynamics and environmental coupling, while mapping
nuclear regions on sub-pc to kpc scales will disentangle compact cores from host emission, resolving the diversity of
radio activity across
accretion regimes and jet powers from the local Universe to the
cosmic dawn. At the full AA4 deployment, the SKA-MID phased into global VLBI arrays will deliver sub-milliarcsecond imaging and $\mu$Jy sensitivity over 0.35–15\,GHz, enabling the first population-level census of
radio-quiet AGN
nuclei. Earlier AA$\ast$ operations will support pilot studies of the brightest nearby systems.
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All authors Francesca Panessa, Tao An, James Petley, Ailing Wang, Ranieri Diego Baldi, Ehud Behar, Emmanuel Bempong-Manful, Gabriele Bruni, Ning Chang, Sina Chen, Lang Cui, Filippo D'Ammando, Marcello Giroletti, Magdalena Kunert-Bajraszewska, Sibasish Laha, Ari Laor, Ian McHardy, Eileen Meyer, Monica Orienti, Miguel Pérez-Torres, Isabella Prandoni, Claudio Ricci, David R. A. Williams-Baldwin, Zsolt Paragi
Solar and Stellar Astrophysics
The role of mass transfer efficiency in stability criteria: Implementation in SEVN and a test on blue stragglers and binary compact objects
M. Echeveste, G. J. Escobar, G. Iorio et al. (+12 more)
Context: The stability of mass transfer through Roche-lobe overflow plays a key role in shaping the outcome of binary interactions. However, the criterion for mass transfer stability remains one of the main open questions in the theory of binary
evolution. Aims: We develop a mass transfer stability prescription that accounts for mass and angular momentum loss, and implement it in the population synthesis code SEVN. We assess its impact relative to the standard formalism used in SEVN, using blue stragglers and binary compact objects as illustrative cases. Methods: We derive an expression for the response of the Roche-lobe radius to mass loss in the general case where the mass and angular momentum of the system are not conserved. On the basis of this formulation, we construct a new mass transfer stability criterion that modifies the standard approach only through the Roche-lobe response term. Results: Population synthesis simulations with SEVN show that the new criterion allows stable mass transfer in binaries with higher donor-to-accretor mass ratios, leading to an overall increase in the predicted number of blue stragglers and promoting their formation in wider orbits. This contributes to reconciling the differences between theory and observations. For binary compact objects, the impact of the new stability criterion varies across system types, with the strongest effects occurring in binaries containing at least one
neutron star. In particular, for low mass transfer efficiency, the new criterion enhances the contribution of channels involving stable mass transfer and leads to a larger number of systems, including gravitational wave progenitors. Conclusion: The inclusion of a new, simple, yet more consistent prescription for mass transfer stability has proven that refining this criterion can significantly improve our understanding of the formation channels of specific
stellar populations.
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All authors M. Echeveste, G. J. Escobar, G. Iorio, E. Pancino, M. Mapelli, D. Alvarez Garay, A. Avdeeva, E. Leitinger, S. Nedhath, S. Rani, E. Reggiani, N. Sanna, S. Saracino, L. Steinbauer, A. Turchi
Quantum Physics
Thermometry with multilevel transmon probes
Antonio Mandarino, Matteo G. A. Paris and Claudia Benedetti
Superconducting transmon systems are promising platforms for nanoscale thermometry due to their high sensitivity to environmental fluctuations. Their intrinsic anharmonicity, which is essential for
qubit operations, gives rise to a non-equidistant energy spectrum that significantly affects the thermal populations and, consequently, the thermometric sensitivity. In this work, we investigate the ultimate
quantum limits of temperature estimation with a transmon beyond the two-level approximation. We compare the thermometric performance of three complementary models: the
qubit, a harmonic oscillator and a weakly anharmonic Duffing oscillator, evaluating their corresponding
quantum Fisher information (QFI) as a function of the temperature. We show that the multilevel anharmonic structure of the transmon affects its thermometric precision. Indeed, including higher excited states enhances the maximum amount of information that can be extracted about the system temperature, compared to a
qubit probe. Furthermore, we address a fundamental limitation of the standard quartic truncation, which yields a potential that is unbounded from below and supports only spurious metastable states. By introducing bounded anharmonic models, namely a confined quartic potential and a sextic correction term, we assess the robustness of the thermometric precision beyond the Duffing regime. Our results provide practical guidelines for transmon-based nanoscale thermometry and clarify the role of the anharmonic multilevel spectrum in
quantum temperature estimation.
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Solar and Stellar Astrophysics
Spatially Coherent and Intermittent Alfvénic Fluctuations in Solar Polar Spicules
Edris Tajfirouze, Christopher H. K. Chen, Richard J. Morton et al. (+1 more)
Alfvénic fluctuations are considered a key mechanism for transporting energy from the lower
solar atmosphere into the corona, with spicules acting as dynamic conduits for this transfer. We investigate transverse and Doppler velocity fluctuations in quiet-Sun polar spicules observed in the Si IV 1394\,Å\ line by the Interface Region Imaging Spectrograph.
Fourier analysis in time and space is used to characterize power across frequency and spatial scales. The temporal power spectra show broadband fluctuations with enhanced power in the 3–7~mHz range and a peak near 4–6~mHz. Spatial
Fourier analysis of Doppler velocities reveals a perpendicular power spectrum scaling as $\sim k_{\perp}^{-1.43}$, slightly shallower than the canonical $-5/3$ and $-3/2$ slopes of strong MHD
turbulence, but consistent with reflection-driven
turbulence simulations. Velocity increment PDFs show non-Gaussian behavior, with kurtosis increasing toward smaller scales, consistent with intermittency. Spatial coherence analysis using cross-correlation and spectral diagnostics indicates an outer scale of a few hundred to about a thousand kilometres, with cross-correlation yielding smaller values. These results provide observational evidence that polar spicules host multiscale Alfvénic fluctuations consistent with a developing turbulent cascade and intermittency, suggesting a role in energy transport into the
solar corona.
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All authors Edris Tajfirouze, Christopher H. K. Chen, Richard J. Morton, Peter R. Young
Optics
Exact Helicity-Orbital Coupled Dynamics in Chiral Media: An Optical Dirac Framework for Photonic Rabi Oscillations
Xuhui Cheng and Longlong Feng
We demonstrate that light propagation in reciprocal
chiral photonic media admits a unified description in terms of an emergent Dirac structure in helicity space. Starting from Maxwell's equations, we reformulate the electromagnetic field as a four-component spinor governed by an effective non-Hermitian optical Dirac equation. In this representation, the magnetoelectric response of the
chiral medium appears as a helicity-dependent background that modifies the spectrum and eigenmodes, while the breaking of the
spin-degenerate condition generates the intrinsic
spin-orbit coupling between helicity and orbital degrees of freedom. After projection onto the positive-frequency sector, the theory reduces to an exact two-level helicity-orbital model. This model is found to have an analytical solution and describes coherent Rabi-like oscillations between
spin-orbit-coupled vector modes. Chirality controls the helicity splitting and detuning, whereas the electromagnetic mismatch of the medium determines the coupling strength responsible for oscillatory
spin-orbit conversion. The resulting dynamics is constrained by exact conservation of the total angular momentum, leading to reversible conversion between
spin and orbital angular momentum with well-defined selection rules. Our work establishes an optical Dirac framework for structured light in
chiral media, and provides experimentally accessible predictions for chirality-controlled oscillations, polarization dynamics, and orbital angular momentum conversion in structured optical fields.
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Instrumentation and Methods for Astrophysics
Streak detection in the VST/OmegaCAM archive using deep learning
Elisabeth Rachith, Stephan Hellmich, Vincent Fiszbin et al. (+3 more)
Ground-based astronomical surveys inadvertently capture streaks from satellites and space debris crossing their fields of view. These incidental observations from wide-field instruments such as OmegaCAM on the VST offer valuable opportunities to characterise resident space objects without the need for dedicated observing time. We developed an automated deep-learning pipeline to detect and classify streaks in the OmegaCAM archive, enabling large-scale analyses of space object populations and their impact on astronomical data. The pipeline combines an adapted Hough transform lookup-based convolutional neural network (HT-LCNN) for initial streak detection on raw images with a VGG6-based CNN classifier to reject false positives. We augmented a manually annotated
dataset of 384 000 patches from archive images with physically simulated streaks. Following a detection, we applied astrometric calibration and cross-matched the results with the space-track catalogue. We find the detector achieves F1-scores of 0.966 (validation) and 0.958 (test) on the augmented
dataset, detecting > 95% of artificial streaks with a signal-to-noise ratio of S/N > 4. On real 2023 data, the precision drops to 0.783 due to image variability, but the classifier boosts it to 0.990, while retaining 97% of true positives and rejecting > 96% of false positives. Applied to one year of VST observations (1 246 048 OmegaCAM CCD frames), the pipeline identified 25 335 streaks, including more than 20% uncorrelated with catalogue entries; finally, 16.9% of images revealed some level of contamination. The pipeline demonstrates robust performance on real archival data and successfully uncovers faint uncatalogued objects, highlighting the potential of survey archives for debris monitoring.
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All authors Elisabeth Rachith, Stephan Hellmich, Vincent Fiszbin, Belén Yu Irureta-Goyena, Andrew Price, Jean-Paul Kneib
Mathematical Physics · Cross-listed from math.AP
Long-range scattering
Avy Soffer, Gavin Stewart and Xiaoxu Wu
We study the scattering problem for a long range potential, which is time dependent. We prove the existence and completeness of the scattering wave operators, and find some properties of the weakly localized, non-scattering part of the solution. The method we use follows recent methods introduced and applied to short range systems.
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Quantum Physics
Quantum Lazy Sampling and Path Recording for Any Group
Ben Foxman, Alex Lombardi, Fermi Ma et al. (+2 more)
A central challenge in
quantum algorithms and cryptography is
reasoning about
algorithms with oracle access to a random group element (e.g. a random function, permutation, or
unitary). Can we efficiently simulate such
algorithms? Can we determine what they know after t queries? A classical tool for this is lazy sampling: the oracle does not commit to the full group element upfront, but rather samples partial information about it on the fly. We study a
quantum analog of lazy sampling: compressed oracles (or recording oracles). These are
quantum data structures that allow on-the-fly simulation for
quantum queries, originally introduced by Zhandry (CRYPTO '19) for random functions, and generalized to
unitaries by Ma-Huang (STOC '25) and permutations by Carolan (STOC '26), and used to great effect in security proofs and lower bounds due to their interpretability. We define and analyze a general-purpose and interpretable path-recording oracle, derived from first principles, that perfectly simulates random elements of any closed subgroup of $U(N)$. Our oracle stores, in superposition, t input-output pairs, with updates described in terms of the commutant of the group's tensor power representation. This transparently records the information the
algorithm has learned. Our oracle builds on recent work of Grinko-Yoshida (QIP '26), who gave a different general-purpose compressed oracle without clear interpretability. One interesting application of our path-recording is allowing direct comparisons between compressed oracles of different groups, giving a new technique for proving pseudorandomness results. For example, comparing $S_N$ and $U(N)$ yields what is arguably the simplest construction to date of pseudorandom
unitaries: the product PC of a pseudorandom permutation and a random Clifford, improving on the prior PFC construction (Metger-Poremba-Sinha-Yuen, FOCS '24; Ma-Huang, STOC '25).
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All authors Ben Foxman, Alex Lombardi, Fermi Ma, Barak Nehoran, John Wright
Earth and Planetary Astrophysics
Multi-year Ground-Based Survey Photometry of Active Comet 103P/Hartley 2 and Centaur (2060) Chiron: A Tale of Two Comets in the Pre-LSST Era
Joseph Murtagh, Megan E. Schwamb, Michael S. P. Kelley et al. (+22 more)
Comets and Centaurs trace the
evolution of trans-Neptunian objects (TNOs) into the inner
solar system. Their activity reflects the interplay between volatile sublimation,
dust dynamics, and ring scattering. Yet the long-term behavior of individual objects is less constrained. To probe this evolutionary transition, we use wide-field survey photometry from the Asteroid Terrestrial-impact Last Alert System, Zwicky Transient Facility, and Las Cumbres Observatory observations of the Jupiter-family comet (JFC) 103P/Hartley 2 during its 2023/24 apparition, and the Centaur (2060) Chiron across 2020-2025, including its 2021 outburst. For 103P, heliocentric activity slopes are asymmetric about perihelion, with a steep inbound index ($n_{r,\rm pre}=-3.48\pm0.08$) and flatter outbound value ($n_{r,\rm post}=-1.16\pm0.04$), consistent with enhanced relative
dust contribution post-perihelion. Reduced brightness versus prior apparitions matches reported secular fading trends.
Dust mass-loss rates are $\sim4$-16 kg s$^{-1}$ for assumed grain properties. Colors exhibit a blueward trend near perihelion, consistent with enhanced gas contamination of the $g$-band, with possible phase-dependent scattering. A periodogram recovers a $\sim18.7$ hr activity-linked period near perihelion. For Chiron, subtracting a quiescent baseline reveals exponential decay from the 2021 outburst on a $\sim1.4$ yr timescale. Seasonal phase curves flatten from $\beta_o=0.150\pm0.034$ mag deg$^{-1}$ in 2021 to $\lesssim0.09$ mag deg$^{-1}$ by 2023-2025, converging with quiescent behavior. Broad-band colors remain unchanged at ATLAS ($c-o$)=0.22$\pm$0.09 mag. This extended activity suggests a new epoch of persistent, low-level activity and/or evolving ring-scattering. These objects bracket the TNO-to-JFC evolutionary sequence, with 103P near the volatile-depleted end, and Chiron still volatile-rich and capable of episodic activity.
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All authors Joseph Murtagh, Megan E. Schwamb, Michael S. P. Kelley, Matthew M. Knight, Thomas Lehmann, Giannantonio Milani, A. Fraser Gillan, Alan Fitzsimmons, Ryan R. Lyttle, Matthew M. Dobson, Carrie E. Holt, Tim Lister, Joseph P. Chatelain, Sarah Greenstreet, Quanzhi Ye, Henry H. Hsieh, Denis Bodewits, Tracy X. Chen, Richard G. Dekany, Matthew J. Graham, Steven L. Groom, George Helou, Mansi M. Kasliwal, Ashish A. Mahabal, Reed Riddle