Atmospheric and Oceanic Physics
Decadal wave reconstruction in the Mediterranean Sea with graph neural networks
Federica Benassi, Lorenzo Mentaschi, Salvatore Causio et al. (+3 more)
Accurate simulation and prediction of ocean waves are essential for coastal risk management and
climate studies. Deep learning has shown promising results for wave modeling, but most approaches still operate on regular grids and on
forecasting time scales, and do not generalize to unstructured discretization or to long time horizons. Here we present WaveGraph, a model based on Graph Neural Networks (GNNs) that emulates basin-scale wave dynamics directly on unstructured meshes with high resolution along the coasts (up to 2-3 km). Trained on bias-corrected simulation data over the Mediterranean Sea, WaveGraph uses a multiscale architecture combining the unstructured model mesh with a uniform graph, allowing simultaneous representation of local coastal interactions and large-scale wave dynamics. The model reconstructs the
evolution of significant wave height, mean period, and mean direction, and is applied autoregressively for a continuous 17-year period without reinitialization or drift. Validation against buoy and satellite observations shows skill comparable to the input data set, and ablation experiments indicate that wind forcing drives most of the long-term stability while wave history improves swell-driven and basin-scale dynamics. These results show that GNNs can provide stable and efficient emulators of spectral wave models on unstructured domains, enabling decadal wave reconstructions.
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All authors Federica Benassi, Lorenzo Mentaschi, Salvatore Causio, Daniel Holmberg, Ivan Federico, Nadia Pinardi
Solar and Stellar Astrophysics
Detection and Characterization of Microlensing Events due to Isolated Black Holes towards the Magellanic Clouds in the Rubin Observations
Sedighe Sajadian and Martin Makler
Gravitational microlensing surveys potentially discover isolated black holes (IBHs) at large distances through their gravitational effects on apparent brightness and motion of collinear
stars. Here, we study detecting and characterizing IBHs within the mass range $[3,~5000]M_{\odot}$ with either
stellar or dark matter origins in the upcoming observations by Vera~C.~Rubin Observatory towards the Large and Small Magellanic Clouds (LMC and SMC). We consider four lens mass functions (MFs:~$dN/dM\propto M^{-\beta}$ for $\beta=0,~0.5,~1,~2$), and generate long-duration microlensing events due to IBHs detectable by Rubin. By assuming the fraction of IBHs's mass in total
Galactic mass as $\mathcal{F}$, Rubin potentially detects $\sim0.3,~\rm{and}~2$ microlensing events towards SMC and LMC due to IBHs if $\beta=1,~\rm{and}~\mathcal{F}=5\times10^{-3}$. These IBHs are inside our
galaxy with the probability $\gtrsim70\%$. These events have on average $\theta_{\rm{E}}\sim30-50~\rm{mas}$, so that the probabilities of resolving their
lensing-induced images through the Rubin astrometric observations are $\sim1.4,~\rm{and}~16.3\%$ towards LMC and SMC. In $\sim1,~5.2\%$ of these events their astrometric deflections are realizable. The probabilities of discerning their parallax are $\sim40,~25\%$. We evaluate relative errors with simulating synthetic data points and by assuming the true models as the best-fitted ones. We conclude for a log-uniform MF for $\lesssim0.1,~\rm{and}~0.3\%$ of photometrically detectable microlensing events towards in LMC and SMC the relative errors in the lens mass, distance and velocity are $\lesssim3\%$. We calculate the number of detectable IBHs versus by assuming their complete contribution of compact objects in
halos' darkmatter, and conclude Rubin specifies $95\%$~C.L. upper-limit on IBHs exclusion by masses $\lesssim208,~8M_{\odot}$ for $\mathcal{F}\simeq4\times10^{-3}$.
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Mesoscale and Nanoscale Physics
Raman-detected quantum dot microscopy for nanoscale electrostatic potential imaging
Jiří Doležal, Amandeep Sagwal, Rodrigo Cezar de Campos Ferreira et al. (+1 more)
Quantification of electrostatic potentials at the nanoscale is crucial for understanding the principles governing properties of materials across multiple length scales. Currently, one of the most successful approaches relies on the charging response of a molecular
quantum dot, suspended on a tip of a scanning probe microscope and measured using dynamic force spectroscopy. We investigate the possibility of an optical detection, aiming to improve the speed and reduce the complexity of this measurement scheme. We show that the integrated tip-enhanced Raman scattering intensity strongly correlates with the charge state of the
quantum dot, and use it to map the electrostatic potential of a single atom. A quantitative equivalence with the established force spectroscopy method is found. We address the underlying photophysical principle of this new method by measuring the Raman spectra as a function of excitation wavelength and the molecular
quantum dot charge. We reveal that the observed Raman intensity variations are primarily driven by transitions between resonant and non-resonant Raman scattering regimes of the molecule.
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All authors Jiří Doležal, Amandeep Sagwal, Rodrigo Cezar de Campos Ferreira, Martin Švec
Plasma Physics
Proton Radiography with Isotrajectory Optics
Dmitry Varentsov, Maksym Miski-Oglu, Zs. Major et al. (+3 more)
We consider a compact isotrajectory-optics scheme for
proton radiography. The calculation uses a 30-60 MeV
proton interval as a reference example, typical of high-energy short-pulse
laser acceleration in the TNSA regime. The idea is to use synchronized time-dependent fields such that, for one selected energy-arrival-time branch, the
proton energy changes mainly the arrival time and not the transverse image position. The reference
lattice consists of four pulsed electric quadrupoles with horizontal sign pattern + - + -, magnification Mx = My = -3.0 at a detector plane of 2.57 m, a common
Fourier plane at zF = 0.962 m, and equal outer and equal inner lens lengths. The ideal closure residual is calculated from second central moments. Fourth central moments are kept separately as a diagnostic of non-Gaussian tails. The quoted residual widths are numerical closure tests of the ideal map, not experimental resolution predictions. Real electrode fields, waveform errors, scattering, detector blur, and space charge define the next level of the problem.
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All authors Dmitry Varentsov, Maksym Miski-Oglu, Zs. Major, Paul Neumayer, Martin Schanz, John Schmidt
Quantum Physics
Optimal bounds on the classical value of the repeated CHSH game
Andris Ambainis
We show that the maximum winning probability in the repeated CHSH game for classical strategies is at most $\left(\frac{1+\sqrt{5}}{4}\right)^n$. Together with a matching lower bound by Barak et al. (FOCS'2008), this determines the asymptotic value of the repeated CHSH game exactly. We also show that, if an XOR game has a gap between classical and
quantum values, there is also a gap between the asymptotic values for the repeated game.
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Quantum Physics
Captured weight and boundary leakage bound the error of sample-based spectral functions
Nicolás Bonilla Vargas
Rayleigh-Ritz on a subspace from sample-based
quantum diagonalization yields the spectral function of a probe state; we ask what bounds its error. The captured Born weight w does not do so alone: an analytic counterexample forces any bound indexed on it to its trivial value. On Hubbard rings at broadening $\eta=0.18t$, the probe's whole support (w=1) still has relative error 0.35–0.43: Rayleigh-Ritz displaces the poles a subspace keeps. The error is bounded instead by the missed weight and the
Hamiltonian coupling across the subspace boundary. Given the exact ground state, we prove for any orthogonal projector that the relative $L_1$ error lies between 1-w and $\min\{1+w,(1+\sqrt{w})(\sqrt{1-w}+\Lambda(\eta)/\eta)\}$, with $\Lambda$, that coupling at resolution $\eta$, computed from the Ritz pairs and the retained probe. We test it on L-site rings with classical Born draws of an exactly time-evolved probe, or their infinite-shot ranking; our device runs are execution records only. On the ranked subspaces the bound is vacuous at every operating fraction of the resource scan, at all five sizes up to a 10306296-determinant sector: its leakage branch exceeds the trivial bound 1+w by factors 1.66–8.61. It is informative only well above those fractions, where it is calibrated: at L=6–12 it first beats the trivial bound at a true error of (1.2–7.3)$\times10^{-3}$, though an unproven fit in 1-w is tighter on 11 of 14 splits. For the Born-ranked $A(k,\omega)$ at 85% of its sector, the bound is 350–900 times the true error. In the determinant basis, zero leakage at full weight needs every
symmetry-allowed determinant: the probe's measured Krylov support at L=6–14. Plane-wave orbitals reduce a momentum probe's support to one block, 1/L of an exponentially growing sector. At full weight a second-order certificate follows; below it, where every operating fraction lies, one is open.
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Mesoscale and Nanoscale Physics
Stability and optoelectronic properties of oligothiophene molecules confined in boron-nitride nanotubes : A many-body theoretical approach
Xavier Blase, Mauricio Rodriguez-Mayorga and Ivan Duchemin
We investigate the structural and optoelectronic properties of oligothiophene (nT) molecules encapsulated in boron-nitride (BN) nanotubes using density functional theory, many-body GW and Bethe-Salpeter equation approaches. We show that the binding energy is maximized for tube diameters of approximately 10 Å, decreasing gradually for larger diameters. The nT molecules can slide along the tube with a corrugation potential smaller than room temperature thermal energy, promoting their head-to-tail aggregation. Regarding the electronic properties, we find that hybridization with the tube electronic states has a much smaller effect than that of screening, which can close the nT photoemission gap by as much as an eV. A simple model for the polarization of the BN tube demonstrates how these polarization effects decrease with increasing nT molecule length and BN tube diameter. Compared to the gas phase optical properties, structural relaxation, hybridization, and screening can
redshift the absorption onset by up to 250 meV for isolated intercalated nTs. Additionally, the study of a head-to-tail sexithiophene dimer reveals an
exciton-
exciton interaction that splits the absorption onset into a lowest bright
exciton, separated by approximately 75 meV from a dark peak. This suggests possible collective effects upon the formation of nT chains inside BN tubes. Our results confirm and clarify experimental data, mitigating the conclusion that insulating BN tubes just act as a protecting environment for encapsulated molecules.
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Chemical Physics
ChemReporter: A Framework for Curating and Exporting Large-Scale Chemical Datasets for MLIP Training
Marie Bluntzer, Jules Tilly and Christoph Brunken
Training set quality and diversity are key determinants of the reliability of machine learning interatomic potentials (MLIPs), yet using massive
datasets in full is often impractical and redundant, making intelligent data selection essential. A major bottleneck, however, is the lack of infrastructure for uniformly accessing, curating, and subsampling heterogeneous large-scale chemical
datasets, which differ widely in structure, metadata, and file format. We address this gap with ChemReporter, a modular, method-agnostic framework that converts arbitrary molecular and materials
datasets into a unified, queryable representation and exports the results directly into MLIP-ready training data. ChemReporter operates in three decoupled stages: processing, which parses raw
datasets into a partitioned Apache Parquet repository enriched with structural, physical, and chemical metadata; querying, which filters and samples this repository via a CLI or Python API using arbitrary selection criteria, from simple physical constraints to custom, user-defined strategies; and exporting, which streams the selected subset into an HDF5 file ready for direct use in modern MLIP training frameworks. Throughout this process, every exported data point remains traceable to its original source entry, and
dataset exports can be reliably reproduced given the same configuration and query database version. Because data is stored in a queryable, disk-backed format, ChemReporter can process
datasets far larger than available
memory, allowing it to scale to billion-structure
datasets on standard compute infrastructure. ChemReporter is available on GitHub and PyPI under the Apache License 2.0.
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Mesoscale and Nanoscale Physics
Field-controlled breaking and restoration of parity-time symmetry in Josephson interference
Yi-Chen Tsai, Yung-Yeh Chang, Tao-Yi Hsu et al. (+6 more)
Symmetry plays a fundamental role in determining the phases and physical properties of
quantum matter. Controlling
symmetry in mesoscopic superconducting devices provides a route to reconfigure their phase-coherent transport. Here we demonstrate
symmetry-selective Josephson interferometry in lateral NbTi/PtTe$_{\text{2}}$/NbTi junctions by controlling the relative orientations of the current and
magnetic field. From the supercurrent interference patterns, we construct a field-current
symmetry map that identifies configurations exhibiting or violating the device-level parity ($\mathcal{P}$), time-reversal ($\mathcal{T}$) and their combined $\mathcal{PT}$
symmetry. In the absence of an in-plane field, the junction exhibits a symmetric Fraunhofer pattern. An in-plane field parallel to the current produces a pronounced side-lobe asymmetry, whereas reversing both the current and the complete
magnetic-field configuration restores a generalized $\mathcal{T}$ relation. Remarkably, orienting the in-plane field perpendicular to the current restores the $\mathcal{PT}$-symmetric Fraunhofer response even at substantial field strengths. A microscopic model attributes this behavior to the interplay between disorder-induced potential variations and flux dipoles generated by in-plane-field Meissner focusing near the superconducting electrodes. Our results establish a reconfigurable Josephson interferometer in which the field-current geometry selects the
symmetry operation being probed and switches the device between
symmetry-broken and
symmetry-restored interference states.
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All authors Yi-Chen Tsai, Yung-Yeh Chang, Tao-Yi Hsu, Thomas Kuo, Chia-Nung Kuo, Chin-Shan Lue, Kuei-Lin Chiu, Chen-Hsuan Hsu, Chung-Ting Ke
Materials Science
Tuning electronic properties and Schottky contact in graphene-based van der Waals heterostructures by electric gating and interlayer coupling
Poonam Sharma, Archana Sharma and Alok Shukla
Van der Waals
heterostructures (vdW HTSs) incorporating
graphene (GE) have been an active area of research, both theoretical and experimental, due to their potential to yield devices with a wide variety of applications. In this paper, first-principles calculations are employed to investigate C$_{6}$N$_{6}$/GE, hg-C$_{3}$N$_{4}$/GE, and C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$ 2D vdW HTSs. A systematic analysis of structural and thermodynamic stability, electronic, mechanical, and optical properties of
semiconductor/metal and
semiconductor/
semiconductor interfaces is performed. Both
semiconductor/metal HTSs form $n$-type Schottky contacts, which can be converted into $p$-type Schottky or Ohmic contacts by tuning the external perpendicular electric field and the interlayer coupling. In the
semiconductor/
semiconductor C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$ HTS, the valence and conduction band edges originate from distinct layers, resulting in a type-II band
alignment that promotes efficient electron-hole (e-h) separation. Furthermore, the band
alignment can be effectively tuned between type-I and type-II by applying an external electric field and varying the interlayer distance. From the optical absorption spectra of the HTSs, we concluded that the C$_{6}$N$_{6}$/GE and hg-C$_{3}$N$_{4}$/GE exhibit an optical response across a wide frequency range, whereas the C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$ HTS shows prominent activity primarily in the ultraviolet region. Using the $G_{0}W_{0}$+BSE approach, the
exciton binding energies are also calculated for the gapped systems, namely C$_{6}$N$_{6}$, hg-C$_{3}$N$_{4}$ monolayers, and their HTS (C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$), yielding values of 1.01 eV, 1.14 eV, and 1.18 eV, respectively, highlighting strong e-h interactions. Moreover, the band-edge analysis of C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$ HTS further favors pronounced interlayer e-h coupling.
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High Energy Physics (Phenomenology)
Cosmological Signatures of the Conformal and Non-Conformal Next-to-Minimal Two-Higgs-Doublet Model
Filip Gustavsson, Roman Pasechnik and Johan Rathsman
We investigate cosmological signatures of the next-to-minimal two-
Higgs-doublet model (N2HDM) in both the classically scale-invariant, or conformal, realization and in the corresponding non-conformal theory. Using a one-loop finite-temperature effective potential,
collider and flavour constraints implemented through ScannerS, HiggsBounds and HiggsSignals, and a modified on-shell counterterm prescription for the conformal model, we identify parameter regions with a first-order electroweak phase transition and potentially observable
stochastic gravitational waves. We find that both conformal and non-conformal scenarios can produce sound-wave signals in the sensitivity range of future space-based interferometers, including LISA, while the electroweak transitions complete promptly ($T_n\simeq T_p$), with pronounced supercooling below the critical temperature confined to the strongest transitions. The two scenarios nevertheless populate different regions of the scalar mass spectrum when the gravitational-wave signal is observable, suggesting that a future
stochastic background measurement combined with
collider information on the additional
Higgs states could discriminate between the two realizations. We further study partonic
Higgs-pair production, in the heavy-top approximation, and find that large deviations in the SM-like di-
Higgs rate tend to occur away from the regions with the strongest gravitational-wave signals, while enhanced BSM
Higgs-pair rates are mainly associated with the conformal model. The analysis highlights a complementary interplay between electroweak cosmology, scalar spectroscopy and
Higgs self-interaction probes in extended
Higgs sectors.
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Solar and Stellar Astrophysics
Machine Learning in Application to Automatic Noise Processing of Solar Spectrograms
I. I. Yakovkin, A. O. Bartenev and N. V. Petrova
In this paper, a machine learning approach for processing
solar spectral data were developed. Its performance was demonstrated using the example of the limb
solar flare on July 17th, 1981. The results indicated that machine learning can be effectively utilized to transform between differently digitized spectra, fill gaps in unique experimental data, and undertake spectrum cleaning. Specifically, convolutional neural networks were devised to transform between reflective and transmissive scans of a
solar flare spectrogram. This can be a convenient technique for treating the spectrograms of unique
solar events, most notably increasing the proportion of observational spectra that can be further analyzed. Namely, in subsequent research, we will be able to confidently incorporate data such as that captured on the edges of spectrograms, which was previously deemed insufficiently reliable due to limitations of available processing techniques. This will consequently increase the number of spectral lines studied for certain observed events, which is paramount for constructing physical models, as the spectral peculiarities are expected to manifest consistently across different spectral lines. The developed approach also notably facilitates the detection and removal of
impurities in the spectrograms. Previously, each distinct feature in the spectra was manually scrutinized to check its integrity in order to be excluded if identified as an
impurity, such as a scratch or a
dust particle. By employing the suggested protocol for treating the spectrogram, which includes scanning the spectrogram using multiple distinct techniques and then leveraging machine learning for comparison, the process of excluding
impurities can now be automated. Furthermore, the spectrum areas affected by such exclusions can be restored, enabling further analysis.
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Plasma Physics
Assessing the Projector Augmented-Wave Method for Stopping Power Calculations
Bryn Lloyd, Dirk O. Gericke, Gilles Rodway-Gant et al. (+1 more)
The stopping power of charged particles is investigated using time-dependent density functional theory (TDDFT). Such simulations are made possible by recent advances in computational resources and numerical implementations of this first-principles method. In practice, DFT simulations widely employ the projector augmented-wave (PAW) method to approximate all-electron behaviour, but the implications of the PAW approximation for non-adiabatic stopping simulations remain insufficiently explored. Here, the suitability of the PAW method for stopping power simulations is evaluated. A workflow for generating and selecting PAW
datasets tailored to these simulations is developed, enabling systematic optimisation of augmentation radii and projector constructions. The approach is applied to
proton stopping in FCC aluminium, demonstrating how
dataset design influences stopping predictions, and enabling an investigation of
crystal channelling effects on charged-particle transport.
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All authors Bryn Lloyd, Dirk O. Gericke, Gilles Rodway-Gant, Gianluca Gregori
Mesoscale and Nanoscale Physics
A magnonic-optoelectronic reservoir for physical reservoir computing
Alexey B. Ustinov, Ivan Y. Tatsenko, Andrei A. Nikitin et al. (+1 more)
Physical reservoir computing is a promising approach for fast and energy efficient computer
vision, natural
language processing, and general pattern recognition. This work presents a physical reservoir based on magnonic-optoelectronic oscillator (MOEO). This approach allowed us to realize short-term
memory and nonlinearity as separate system components. The device`s optical path uses a fiber-optic delay line as a short-term-
memory element. The microwave path is responsible for nonlinear mapping of input data to a higher-dimensional space. The strong four-wave nonlinearity of
spin waves propagating in an yttrium-iron garnet (YIG) ferrite film enables the process. The reservoir performance is evaluated by completing task-independent tests known as short-term
memory (STM) and parity-check (PC) tasks. In addition, a numerical model of the MOEO based reservoir is developed. Results of the numerical simulation of the reservoir performance are in good agreement with the experimental data.
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All authors Alexey B. Ustinov, Ivan Y. Tatsenko, Andrei A. Nikitin, Mikhail P. Kostylev
General Relativity and Quantum Cosmology
Limiting cases of second-order moments of relativistic stars and their universality
Koutarou Kyutoku
Extending the work presented in a workshop “From
Quarks to
Neutron Stars: Insights from kHz gravitational waves”, we discuss some limiting cases of the moment of inertia,
tidal deformability, and
spin-induced quadrupole moment for relativistic
stars. First, conjecturing that a hierarchy of the length scale is the key to proposed universality among these second-order moments, we revisit the relation for incompressible relativistic
stars (known as Schwarzschild's interior solution) as a candidate of the possible stiff limit. Second, we present the limiting form for the weak-field limit. In particular, we demonstrate how relativistic computations of
tidal deformation are related to the traditional Newtonian counterpart, which might not have been presented explicitly in the literature.
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High Energy Physics (Theory)
Quantum Stability of the Fuzzy Sphere Black Hole Horizon
Chong-Sun Chu
We establish the perturbative stability of the fuzzy-sphere black-hole horizon in the large-$N$
matrix quantum mechanics of \cite{Chu:2024qil}. Large-$N$ counting shows that the leading
quantum correction to the fluctuation spectrum is the planar bosonic one-loop contribution, while higher-loop bosonic effects and the leading fermionic one-loop contribution are parametrically suppressed. The classical spectrum contains a tachyonic $(1,2)$ mode and a marginal $(2,3)$ mode; we show that both acquire positive
quantum curvature and are stabilized. For the general spectrum, we find that a factorization structure of the Hessian controls the leading
quantum curvature and renders it non-negative.
Quantum effects dominate the stabilization of generic low-angular-momentum modes, whereas classical
curvature dominates at high angular momentum. The two effects become comparable in the crossover regime $L \sim \sqrt{N}$, where both must be retained. Under smoothness and non-saturation assumptions supported by finite-$N$ numerical tests, positivity of the
quantum fluctuation spectrum is thus established for sufficiently large but finite $N$. This local
curvature stability is compatible with non-perturbative monopole tunneling. Intriguingly, the same $L\sim\sqrt{N}$ mesoscopic angular momentum range also dominates the tunneling process, suggesting a distinguished IR–UV crossover regime in the
quantum dynamics of the black-hole horizon.
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Mesoscale and Nanoscale Physics
Tunable Fano Resonance and Frequency Locking in a Graphene-SiNx Hybrid Nanomechanical Resonator
Ateesh K. Rathi, Javed A. Mondal, Rajan Singh et al. (+3 more)
Fano resonances, arising from the interference between discrete and continuum states, are observed across a wide range of
quantum and classical systems. Here, we report the experimental observation of Fano resonances in a
graphene SiNx hybrid nanomechanical system modeled as coupled oscillators. The broad, low quality factor
graphene mode plays the role of the continuum, while the dense comb of sharp, high quality factor SiNx modes provides the discrete states. The inter-mode detuning is tunable via a DC gate voltage, enabling dynamic control of the Fano resonance: we demonstrate gate controlled switching of both the sign and the magnitude of the Fano asymmetry parameter $q$, in quantitative agreement with a coupled oscillator theory that predicts $q=-\cot\phi$, with $\phi$ the phase of the continuum response. At strong drive, the
graphene mode enters the Duffing regime and its jump-down frequency locks to successive SiNx modes, producing a staircase of drive insensitive frequency plateaus; a weak seeding tone deterministically switches the resonator between adjacent locked states. The dense SiNx mode thus acts, in the linear regime, as the discrete states of a tunable Fano interferometer and, in the nonlinear regime, as a frequency ruler that stabilizes and quantizes the
graphene oscillation. This platform offers a controllable mechanical realization of Fano interference and opens new avenues for high resolution hybrid resonant sensors and stable nanomechanical frequency references.
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All authors Ateesh K. Rathi, Javed A. Mondal, Rajan Singh, Ryan J.T. Nicholl, Kirill I. Bolotin, Saikat Ghosh
Nuclear Theory
Scalable nuclear shell model calculations on noisy quantum computers
Durgesh Pandey, Ankit Kumar Das and P. Arumugam
The exact diagonalization of the
nuclear shell model scales exponentially, leading to severe
memory bottlenecks in classical high-performance computing (HPC). While hybrid
quantum algorithms like the Variational
Quantum Eigensolver (VQE) aim to overcome these limits, their deep
quantum circuits and iterative feedback loops are susceptible to substantial noise inherent in the current Noisy Intermediate-Scale
Quantum (NISQ) hardware. This noise renders several
algorithms, such as the VQE, impractical for large-scale calculations despite sophisticated noise-mitigation techniques. As a pragmatic approach tolerant to these issues, we apply the Sample-based
Quantum Diagonalization (SQD) framework to
nuclear shell models for the first time. Using $^{38}\text{Ar}$ as a
benchmark to confirm the numerical accuracy, we extend SQD to $^{32}\text{Mg}$, solving a
nuclear shell-model
Hamiltonian whose underlying
Hilbert space cannot be directly diagonalized using conventional classical methods in a given HPC system. We present a systematic comparison of SQD with standard variational
quantum schemes and exact classical solvers. By leveraging NISQ hardware connected via the cloud to classical HPC clusters, the SQD-based scheme could outperform conventional supercomputers in
memory scaling and total execution time, enabling more rigorous large-scale shell model calculations.
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High Energy Physics (Theory)
Quantum-Corrected Black Holes in Higher Dimensions: From Gravitational Collapse to Remnants, WGC-Like Behavior and Accretion Signatures
Saeed Noori Gashti, Umair Anwar, Abdul Jawad et al. (+4 more)
We study the gravitational collapse of a homogeneous
dust sphere in higher-dimensional spacetime, with the loop
quantum gravity correction entered through a modified Friedmann equation. Its most striking feature is an endpoint: at a finite horizon radius the temperature vanishes and evaporation stops, leaving a remnant. Reading \(\alpha\) as an effective charge, we find behavior reminiscent of the Weak
Gravity Conjecture (WGC), although no \(U(1)\) gauge field is present in the model. Solving the degeneracy conditions with the untruncated metric function, rather than with a mass expansion that is not uniform near the endpoint, we obtain closed-form expressions for the remnant radius and mass in \(D=4,5,6,7\). The unscaled ratio \(\alpha/M_{\text{remnant}}^2\) is constant only in four dimensions and grows as \(\alpha^{4-D}\) elsewhere, but it carries dimension \(L^{8-2D}\), so that growth is an artifact of the units. The dimensionless combination \(\tilde{\mathcal{R}} = (\alpha/M^2) r_0^{2D-8}\) settles instead on a finite \(\alpha\)-independent number in every dimension, decreasing from \(27/64\) in four dimensions to \(13824/(15625\pi^4)\) in seven. We also deform the
quantum parameter, \(\alpha \to \alpha + \varepsilon\), and evaluate \(-T(\partial S/\partial \varepsilon)_M\) in the remnant limit. Because \((\partial M/\partial r)_\alpha\) vanishes there, the fixed-
entropy derivative reduces exactly to a fixed-radius one, and the resulting combination \(\mathcal{U}\) is finite in each dimension but depends on \(\varepsilon\) except for \(D=5\). What is invariant is the product \(\mathcal{R}\,\mathcal{U}\,M_{\text{remnant}} = (D-3)/2\), which we verify numerically. Lastly, we study Bondi
accretion onto the
quantum-corrected black hole and obtain the Eddington luminosity for each dimension.
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All authors Saeed Noori Gashti, Umair Anwar, Abdul Jawad, Behnam Pourhassan, İzzet Sakall{\i}, Sanjar Shaymatov, Aram Bahroz Brzo
Materials Science
Javier Sivianes, Enrique Boquete-Someso, Daniel Hernangómez-Pérez et al. (+1 more)
The optical response of
magnetic materials is conventionally classified through
magnetic space groups (MSGs), where
spin and
lattice are locked by the relativistic
spin-orbit interaction. However, most optical observables are governed primarily by nonrelativistic physics, and thus a purely MSG-based description can overlook important insights. Here we systematically show that
spin-space groups (SSGs), which operate at the nonrelativistic level, provide a broader and more predictive framework for analyzing a variety of optical responses of magnets. Focusing on linear optical absorption, we derive the transformation rules imposed by SSGs and show that they generate effective real-space point groups, which can enforce relations among charge response coefficients that are absent from conventional MSG analysis. We illustrate the basic principle in a Lieb-
lattice altermagnet model with tunable
spin-orbit coupling, where SSG predictions on the linear dichroism remain remarkably accurate even when relativistic band splittings become sizable. We further establish the predictive power of this framework through first-principles calculations on two altermagnetic candidates: the actinide UCr2Si2C, where the optical absorption remains nearly isotropic despite its strong
spin-orbit coupling and the pronounced anisotropy apparent from
magnetic symmetries, and the transition-metal fluoride RbMnF4, where birefringence is confined to a single plane by
symmetries emerging exclusively from SSGs. Finally, we extend the concept to the
spin Hall response of the coplanar noncollinear antiferromagnet ScMnO3, where SSGs explain the hierarchy of calculated
spin Hall coefficients, demonstrating their direct relevance to spintronics as well.
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All authors Javier Sivianes, Enrique Boquete-Someso, Daniel Hernangómez-Pérez, Julen Ibañez-Azpiroz
Chemical Physics
Extracting a nitrile-centered, ether-assisted motif hierarchy for lithium-battery electrolyte design from billion-scale molecular space
Yifeng Xia, Guanghui Wang, Sining Wang et al. (+4 more)
Designing electrolyte molecules for lithium batteries requires balancing electronic stability with appropriate Li+ solvation, yet the structural basis remains unclear across chemically diverse molecules. High-throughput screening expands the searchable space, but ranked candidates alone do not reveal recurring motifs or their applicability limits. We searched nearly one billion GDB13 structures using electronic–solvation descriptors without explicit functional-group preferences or scaffold constraints. Across descriptor weights, high-ranking populations separated into a nitrile-dominant regime and a coexistence regime containing substantial fractions of both nitrile- and ether-containing molecules. These regimes together define a nitrile-centered, ether-assisted motif hierarchy: nitrile remains favored across broad weight ranges, whereas ether becomes prominent under stronger electrostatic and polarity constraints. Encoding this hierarchy in a generative model expands the candidate space beyond GDB13 and yields high-scoring fluorinated structures without an explicit fluorination reward. Explicit-solvent molecular dynamics simulations show weak, exchangeable coordination of representative candidates without displacing ethylene carbonate from the dominant first solvation shell around Li+; effects on ion association and transport depend on molecular structure and concentration. These results establish a quantitative, interpretable and physically bounded motif hierarchy that systematizes established nitrile and ether chemistry for lithium-battery electrolyte design.
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All authors Yifeng Xia, Guanghui Wang, Sining Wang, Wenting Chen, Zheng Cheng, Jinzhe Zeng, Qiangqiang Gu
Quantum Physics
Optimizing Subspace Expansion in Quantum Chemistry through Operator Selection and Reference State Choice
Konstantin Lamp, Alejandro D. Somoza, Elias Walter et al. (+4 more)
The Virtual
Quantum Subspace Expansion (VQSE) extends the Variational
Quantum Eigensolver (VQE) by leveraging additional measurements on the reference state to capture the influence of excluded virtual orbitals. This makes VQSE attractive for chemical applications where accurate energy differences along potential energy surfaces are crucial for modeling reaction rates and kinetics. In this work, we analyze VQSE performance on H$_2$ dissociation including references that use Hartree–Fock molecular orbitals with broken
spin symmetry. We identify two mechanisms which affect accuracy: overlap of the reference state with the exact full configuration interaction (FCI) wavefunction and operator pool expressivity. We show these mechanisms are strongly co-dependent. When operators are restricted to act only from the active to the virtual space, results become highly sensitive to the reference, and enlarging the active space does not guarantee improved accuracy. In this case, prioritizing reference overlap over energy minimization is therefore essential. Adding single excitations and number operators within the active space recovers the accuracy of MR-CISD (multi-reference configuration interaction singles and doubles) regardless of the reference. In our noisy hardware experiments, we achieve chemical accuracy by adding additional operators and using strict regularization. These findings motivate careful co-design of reference fidelity, pool expressivity, and hardware constraints for practical VQSE deployment.
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All authors Konstantin Lamp, Alejandro D. Somoza, Elias Walter, Marina Walt, Michael Marthaler, Maria Fernanda Juarez, Birger Horstmann
Quantum Physics
Negative quasiprobability trajectories for Bell-diagonal states under local decoherence
Qing Yu, Kun Zhang, Yang-Yang Chen et al. (+1 more)
The fluctuation
theorem (FT) relates microscopic trajectory distributions to macroscopic averages. Using quasiprobability trajectories, this framework has recently been extended to
quantum information dynamics. Despite sharing the form of conventional thermodynamic FTs, information FTs involve quasiprobabilities whose negativity and statistical properties remain poorly understood. In this work, we analytically determine the properties of negative distributions for two-
qubit Bell-diagonal states evolving under local dephasing, depolarizing, and amplitude-damping channels, under the fixed local computational basis. We show that the occurrence of negative quasiprobabilities is not determined by the
entanglement or Bell nonlocality of the initial state. For these channels, a diagonal-interference decomposition identifies a nonnegative reference contribution and yields channel-dependent interference bounds. More importantly, we prove that quasiprobability distributions containing negative weights can violate Horváth's necessary and sufficient criterion for the Jensen-Steffensen inequality to hold for every continuous convex function, even though the specific exponential Jensen-like relation enforced by the FT and the
quantum data-processing inequality remains valid. This trajectory-level contrast with classical
stochastic descriptions reveals a distinctive feature of
quantum information dynamics that is invisible when only the corresponding average-level information inequalities are considered.
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All authors Qing Yu, Kun Zhang, Yang-Yang Chen, Xiao-Hui Wang
Superconductivity
Koki Shimura, Shuntaro Sumita and Yusuke Kato
We study the dynamical
spin response of UTe$_2$ by using a mixed-dimensional periodic Anderson model. Within the BCS-RPA formalism, we examine how the $f$-orbital character of the quasiparticles affects
magnetic excitations in both the normal and superconducting (SC) states. In the normal state, finite mixing between localized $f$ electrons and conduction electrons produces a hybridization gap and enhances the
spin response at $\mathbf{Q}_{\mathrm{Y}} = (0,\pi,0)$, indicating that the
magnetic excitation originates from particle–hole scattering across the hybridization gap. In the SC state, we compare four odd-parity irreducible representations, $A_u$, $B_{1u}$, $B_{2u}$, and $B_{3u}$, for the
spin-triplet order parameter. We find that, for the component of the
spin susceptibility parallel to the $\mathbf{d}$ vector, a pronounced superconductivity-induced
spin resonance appears at $\mathbf{Q}_{\mathrm{Y}}$ only in the $B_{2u}$ state. This behavior arises because the $B_{2u}$ order parameter remains finite and changes its sign between the relevant $f$-electron-dominated
Fermi-surface regions connected by $\mathbf{Q}_\mathrm{Y}$ near $k_z=\pi$. The sign-change criterion is applicable to multiband
superconductors in three-dimensional heavy-
fermion systems, in the presence of (i) low-dimensional portions of the
Fermi surface connected by a nesting vector, (ii) the dominance of the $f$-electron character, and (iii) the finite amplitude of SC gap on the portions.
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Materials Science
Effect of Magnetic Vacancies on the Spontaneous Spin-Reorientation Transition in HoFe$_{1-x}$Al$_x$O$_3$ Single Crystals
S. A. Skorobogatov, V. A. Babkina, M. S. Pavlovskii et al. (+5 more)
In this work, we report the first growth of single
crystals of the substitution series HoFe$_{1-x}$Al$_x$O$_3$ with aluminium concentrations up to $x=0.2$ and investigate the
evolution of their spontaneous
spin-reorientation transition (SRT). Among rare-earth orthoferrites, HoFeO$_3$ exhibits a distinctive sequence of
magnetic phases ($\Gamma_4$-$\Gamma_{24}$-$\Gamma_{12}$-$\Gamma_2$). This complex sequence arises from the competition between the $K_{ac}$ and $K_{ab}$ anisotropies associated with the Ho$^{3+}$ ions and the effective
magnetic field produced by the weak
ferromagnetic moment of the canted Fe$^{3+}$ sublattice. Introducing
magnetic vacancies perturbs the
antiferromagnetic compensation of the Fe$^{3+}$ subsystem in the $ab$ plane and generates an additional effective
magnetic field acting on the Ho$^{3+}$ ions. This field alters the balance between the $K_{ac}$ and $K_{ab}$ anisotropies within the SRT temperature range and thereby broadens the stability range of the $\Gamma_{12}$ phase in the
magnetic phase diagram.
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All authors S. A. Skorobogatov, V. A. Babkina, M. S. Pavlovskii, M. I. Kolkov, S. V. Semenov, I. N. Khoroshiy, S. E. Nikitin, K. A. Shaykhutdinov
Astrophysics of Galaxies
RIOJA. Environmental Effects on Stellar Populations and Ionized Gas in a Protocluster at $z=7.88$
Wataru Osone, Takuya Hashimoto, Javier Álvarez-Márquez et al. (+23 more)
Protoclusters in the epoch of reionization provide key laboratories for investigating how environment shapes early
galaxy formation and
evolution, and may also have contributed to
cosmic reionization. We analyze 23 member
galaxies of A2744-z7p9OD, a protocluster at $z=7.88$, using JWST/NIRCam and NIRSpec to investigate their
stellar population properties, rest-frame UV sizes, and ionized-gas properties. We also quantify the internal structure of A2744-z7p9OD using the projected distance to the most massive
galaxy ($D_{\rm YD4}$), and to the nearest neighbor ($D_{\rm nei}$), as global and local environmental indicators, respectively.
Stellar mass, SFR on a 100 Myr timescale,
dust attenuation, and
galaxy size show significant correlations ($p<0.05$) with $D_{\rm YD4}$, but not with $D_{\rm nei}$, suggesting that these properties are primarily linked to the global protocluster structure. The member
galaxies also show a large
galaxy-to-
galaxy variation in R23 ($=\log{(([\mathrm{O}\text{\textsc{iii}}]\lambda\lambda4960,5008\rm{\AA}+[\mathrm{O}\text{\textsc{ii}}]\lambda\lambda3727,3730\rm{\AA})/\rm{H}\beta)}$), implying inhomogeneous chemical enrichment in the protocluster environment. O32 ($=\log{([\mathrm{O}\text{\textsc{iii}}]\lambda5008\rm{\AA}/[\mathrm{O}\text{\textsc{ii}}]\lambda\lambda3727,3730\rm{\AA})}$) correlates with $D_{\rm YD4}$, indicating that the core region is characterized by low-ionization gas. Together with the non-detection of Ly$\alpha$ emission, the possible neutral-gas reservoir traced by ALMA [Cii]~$158\mu$m emission, and evidence for high-column-density neutral hydrogen in the core, this suggests a neutral-gas-rich protocluster core where the current escape of ionizing
photons may be suppressed, even in a overdense environment during the EoR.
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All authors Wataru Osone, Takuya Hashimoto, Javier Álvarez-Márquez, Luis Colina, Akio K. Inoue, Ken Mawatari, Yuma Sugahara, Carmen Blanco-Prieto, Takeshi Hashigaya, Takahiro Morishita, Massimo Stiavelli, Santiago Arribas, Tom J. L. C. Bakx, Daniel Ceverino, Alejandro Crespo Gómez, Yoshinobu Fudamoto, Masato Hagimoto, Asahi Hamada, Rui Marques-Chaves, Yurina Nakazato, Hideki Umehata, Hidenobu Yajima, Hiroshi Matsuo, Naoki Yoshida, Yi W. Ren, Yoichi Tamura
Physics and Society
Exploring Initial CO2 Transport Topologies for Germany's Carbon Management
Toni Seibold, Luna Lütz and Tom Brown
Germany's
climate target requires carbon capture and sequestration for residual emissions from hard-to-abate sectors such as cement production and waste incineration. Planning this infrastructure is challenging because capture investments and CO2 transport networks are strongly interdependent. Existing energy system models capture system-wide interactions but provide limited insight into robust transport
topologies, while detailed infrastructure studies usually neglect feedbacks with the wider energy system. This study combines graph-theoretic
topology generation with a large-scale sector-coupled energy system model to evaluate alternative CO2 transport networks for Germany in 2035. We generate and evaluate 60 candidate
topologies that differ in network length, sink accessibility and source prioritization. The deployment of a domestic CO2 transport network reduces German consumer costs by around 22 bnEUR/a relative to a scenario without CO2 pipelines. The resulting network is primarily used by industrial point sources, including process emissions, cement production and biomass-based carbon dioxide removal, while contributions from backup power generation remain comparatively small. Transport corridors are repeatedly selected and utilized in north-western Germany, reflecting the concentration of industrial CO2 sources and access to international sequestration routes. Early access to Dutch sink infrastructure provides particularly high system value. Compared to 1500 km, as little as 500 km of CO2 pipeline infrastructure captures most of the economic benefit when North Rhine-Westphalia is connected to the Netherlands, while also limiting long-term transport infrastructure lock-in. These findings suggest that the availability of CO2 transport infrastructure is more important than the exact
topology once major industrial source regions and sink access points are connected.
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General Relativity and Quantum Cosmology
Charge-Induced Pole Cancellation and Horizon Transitions in Scale-Dependent Gravitational Collapse
Ghulam Muhammad, Syed Zaheer Abbas and Muhammad Sajjad
We construct a charged Oppenheimer-Snyder-like collapse model in scale-dependent
gravity by matching a spatially flat FLRW interior to a charged scale-dependent exterior across a timelike thin shell. The electric charge is confined to the
stellar surface, preserving interior homogeneity and isotropy. The exterior geometry is supported by a phenomenological Bianchi-consistent effective source, while the shell dynamics follow from the Israel-Maxwell junction conditions. A barotropic surface equation of state closes the shell system, with a charged-
dust shell as the minimal realization. For a negative scale-dependent parameter, $\tilde{\omega}<0$, the exterior contains a finite-radius boundary $x_s$ defined by $D(x_s)=0$. Charge separates the solutions into three regimes. For $0\le q^2<x_s$, the lapse develops a negative pole at a
curvature singularity, the physical exterior contains one outer horizon, and a representative monotonic collapse crosses this horizon before reaching $x_s$; no future-directed locally outgoing radial null branch emerges from the singular boundary. At $q^2=x_s$, simultaneous zeros of the numerator and denominator cancel the
curvature pole, although the prescribed running coupling remains singular. For $q^2>x_s$, the
curvature singularity persists with a positive pole and locally outgoing radial null branches exist. Depending on the physical extremality condition $x_e>x_s$, the exterior may contain two simple horizons, one degenerate horizon, or no horizon. These results show that charge qualitatively changes the singular and horizon structure of scale-dependent collapse and provide model-level evidence for horizon shielding in the negative-pole regime.
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Computational Physics
Unlocking Multi-Component Bulk-Materials Molecular Dynamics with a Small-Footprint Machine Learning Interatomic Potential
Yucheng Ouyang, Xin Chen, Ying Liu et al. (+8 more)
Bulk materials, as opposed to nanomaterials, require molecular dynamics (MD) simulations on a large spatial scale (~10^9 atoms or more) to adequately capture their atomic-scale physical properties. Previously, the introduction of machine-learning interatomic potentials (MLIPs) has extended MD to this scale, but even single-component bulk systems require tens of thousands of GPUs on high-end supercomputers. However, multi-component bulk MD simulations remain barely achievable, as the HBM footprint of existing MLIPs - already substantial for single-component systems - grows explosively in multi-component scenarios. This paper proposes an MLIP with a small HBM footprint - less than 3% that of existing MLIPs - unlocking multi-component bulk MD using only hundreds of GPUs. This is achieved by first identifying feature vectors and intermediate tensors as the two primary contributors to HBM footprints in existing MLIPs. To address these two sources, the dimensionality of the feature vectors has been reduced by introducing physical and chemical knowledge, and intermediate tensors have been eliminated by aggressively fusing all kernels into a single mega-kernel. In evaluation, the proposed MLIP has used 144 NVIDIA A100 GPUs to perform MD simulations on a 6-component bulk system with 1.14x10^9 atoms, while previously such MD simulation spatial scale has been restricted to unary systems and typically achieved on high-end supercomputers equipped with tens of thousands of GPUs.
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All authors Yucheng Ouyang, Xin Chen, Ying Liu, Lifang Wang, Xingyu Gao, Xiawei Du, Jianierken Habudelihan, Haifeng Song, Huimin Cui, Xiaobing Feng, Jingling Xue
Classical Physics
Modeling Newtonian noise of acoustic origin in the Virgo gravitational wave detector
Lionel Maurin, François Gautier, Maël Brun et al. (+9 more)
Since the first gravitational-wave (GW) detection of September 14th 2015 and with hundreds of gravitational-wave sources identified by the LIGO-Virgo-KAGRA network, GW have produced many important results in astrophysics and fundamental physics. Along with planned new data takings, current detectors will be upgraded and new project, such as Einstein
Telescope and
Cosmic Explorer, are under study. Among noises limiting low frequency sensitivity, vibro-acoustic noises are particularly important. In this work, we focus on the
gravity gradient noise (also called Newtonian noise) of acoustic origin, which refers to the small fluctuations in the
gravity field resulting from the acoustic pressure field present in the experimental areas of the detector. The induced noise is quantified in an original way, using a detailed nu- merical acoustic model of the experimental room, when the pressure field is excited by the air conditioning system. The method is used for Virgo, but it can be easily extended for future detectors and used to guide the design of caverns and experimental areas.
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All authors Lionel Maurin, François Gautier, Maël Brun, Soizic Terrien, Matteo Barsuglia, Donatella Fiorucci, Irene Fiori, Maria Tringali, Roberto Passaquieti, Federico Paoletti, Mariusz Suchenek, Tomasz Bulik