Chemical Physics
Using large language models to probe the limits of atom-centered structural descriptors
Michelangelo Domina and Michele Ceriotti
Mapping an atomic structure to a compact set of
geometric descriptors is an essential step in any machine-learning application to atomic-scale modeling. A powerful and widely-used approach can be understood as a discretization of the histogram of pair distances, triangles, etc., that results in a hierarchy of
symmetry-invariant atom-centered descriptors. Unfortunately, the lower rungs on this hierarchy (two, three, four-neighbor clusters) were found to be incomplete, with
symmetry-unrelated pairs of structures having exactly the same descriptors. However, all the “degeneracies” reported so far are resolved by considering larger clusters of neighbors to build the descriptors. We report examples of 3D structures that are indistinguishable even if one considers clusters of up to seven neighbors, and to arbitrary order when considering a practical level of discretization of the descriptors, discovered with the assistance of large
language models. The key ingredients in their construction can be traced to results that have been known for decades in different communities: the model was able to find the references and recognize their significance for the problem at hand. We believe this experiment exposes an extremely fruitful usage pattern for AI in science: translating results between different communities and application domains, accelerating the process by which serendipitous discoveries in a field become breakthroughs in another.
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Quantum Physics
Mean-field Pulse Adaptation for the Circularization of Interacting Rydberg Atoms
Matthias Hüls, Felix Motzoi, Tommaso Calarco et al. (+1 more)
Arrays of circular Rydberg atoms provide a promising platform for
quantum simulation and computation; however, their preparation in the presence of interatomic interactions remains a major challenge. While optimal control methods have enabled the design of fast and accurate
radio-frequency pulses for the circularization of a single atom and of an atom pair, the extension to more atoms is fundamentally limited by the exponential growth of the
Hilbert space, which renders numerical simulations computationally infeasible. Here, we introduce an effective model that treats interactions within a mean-field approximation, thereby enabling the simulation of large atomic systems. Our model further enables the adaptation of pulses optimized for non-interacting atoms to interacting systems, based on the computation of a single time
evolution. For two interacting $^{87}\mathrm{Rb}$ atoms, we demonstrate that the error of our method remains below $1 \, \%$ and that our adapted pulses recover the initial performance of optimal pulses in the regime of weak to moderate interaction strengths.
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All authors Matthias Hüls, Felix Motzoi, Tommaso Calarco, Eloisa Cuestas
Mathematical Physics
Lee-Yang Zeros And Particle Fluctuations
Mohamed El Hedi Bahri, Ian Jauslin and Joel L. Lebowitz
We consider classical particles in the continuum in the grand canonical ensemble, with a stable, tempered and lower-regular pair potential and boundary conditions of uniformly bounded density. We prove that if the Lee–Yang zeros of the grand canonical partition function in the complex fugacity plane $z = e^{\beta\mu}$ remain bounded away from a real point $z_0 > 0$ for all sufficiently large volumes, then along cubes the thermodynamic limit and differentiation commute at $z_0$: every derivative of the finite-volume pressure in the chemical potential converges, uniformly in a neighborhood of $z_0$, to the corresponding derivative of the limiting pressure. The limiting values of all derivatives are independent of the boundary condition; in particular, the density and the particle-number variance per unit volume converge to $\beta^{-1}\partial_\mu p$ and $\beta^{-2}\partial^{2}_{\mu} p$, respectively. The result extends to the unbounded boundary conditions of Procacci and Yuhjtman for super-stable potentials in addition to Ruelle's tempered boundary conditions.
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Mesoscale and Nanoscale Physics
Two-magnon scattering in the framework of the Lippmann-Schwinger equation
Jorge Marquez Chavez, Ondřej Wojewoda, Yixuan Song et al. (+2 more)
Controlling
magnetic losses requires identifying the microscopic origin of extrinsic linewidth broadening. We introduce a Lippmann–Schwinger framework for two-
magnon scattering from weak defect potentials, showing that scattering is set by the overlap between the perturbation of the effective field and degenerate
spin-wave states. Applied to iron garnet films, YIG/GGG(111) and YIG/GGG(110), we identify crystallographic directions along which these perturbation are elongated. This approach provides a link between the crystallography, effective field on the sample scale and two-
magnon scattering.
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All authors Jorge Marquez Chavez, Ondřej Wojewoda, Yixuan Song, Geoffrey S. D. Beach, Caroline A. Ross
Instrumentation and Methods for Astrophysics
Dish Assembly Precision for HIRAX
Jennifer Studer, Devin Crichton, Alexandre Refregier et al. (+16 more)
The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is a
radio interferometer array that is being deployed at the South African
Radio Astronomy Observatory (SARAO) Square Kilometer Array (SKA) site in South Africa. Mapping the southern sky, its aim is to observe neutral hydrogen (HI) through intensity mapping (IM) across the
redshift range of 0.78-2.55. The observation of HI makes it possible to tomographically probe large cosmological volumes, enabling constraints on, for example, the dark energy equation of state. Systematics are a significant concern in deriving cosmological constraints from HI IM due to the presence of strong foreground signals. Instrumental effects such as dish surface deviations and feed placement errors need to be carefully controlled and monitored to preserve the sensitivity of HIRAX's redundant array configuration. These instrumental systematics cause bright foreground power to leak into the faint cosmological signal. The 6 m
parabolic dishes are made from fiberglass with an embedded aluminum mesh that acts as the reflector. The feed is held in place at the
prime focus (f/D = 0.21) by four fiberglass legs. This paper presents the dish surface and feed placement precision of the first 28 dishes, derived from photogrammetry metrology measurements taken during the dish fabrication, as well as from measurements in the field. While surface deviations are predominantly well within requirements, feed placement satisfies all accuracy criteria but fails precision limits; however, precision is expected to improve with a larger sample size. These results establish a baseline for modeling primary beam effects, ultimately enabling the characterization and mitigation of systematic errors in the HI IM signal with the full HIRAX array.
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All authors Jennifer Studer, Devin Crichton, Alexandre Refregier, Keshav Bechoo, H. Cynthia Chiang, Chandrachud B. V. Dash, Sindhu Gaddam, Aditya Krishna Karigiri Madhusudhan, Martin Kunz, Kavilan Moodley, Warren Naidoo, Tasmiya Papiah, Isibabale Qhoboshiyane, Liantsoa F. Randrianjanahary, Benjamin R. B. Saliwanchik, Ajith Sampath, Corrie Ungerer, Thierry Viant, Anthony Walters
Materials Science
Ferroelectric switchable altermagnetic-like compensated ferrimagnets with charge ordering
Xinyu Yang and Shuai Dong
Unconventional collinear magnets with almost zero magnetization but prominent nonrelativistic
spin-splitting, such as altermagnets, can inherit the advantages of both ferromagnets and antiferromagnets. By incorporating more degrees of freedom such as ferroelectricity and charge ordering, these unconventional magnets can be even more interesting and functionalized. With this design principle, the Fe$_3$O$_5$ monolayer is predicted to exhibit a hybrid
spin-splitting mechanism, with the superposition of the altermagnetic-like $k$-path alternating splitting and ferrimagnet-like Zeeman splitting. Benefiting from the hidden magnetoelectricity based on the
spin-charge coupling, such
spin-splitting can be fully switched by an electric field. Its conductivity is highly
spin-polarized, with a polarization ratio above $99\%$, comparable to half-metals but with zero magnetization.
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Solar and Stellar Astrophysics
Constraints from parallaxes and average period spacings in the asteroseismic study of 8 DAVs
Agnès Kim and Keaton J. Bell
With space missions such as Kepler, TESS, and
Gaia, we have a wealth of data on pulsating white
dwarfs that can be leveraged in white
dwarf asteroseismology. We address the question of the proportion of white
dwarfs with thin hydrogen layers versus those with thick hydrogen layers. We also provide a mass-radius relation for carbon-oxygen core, hydrogen atmosphere white
dwarfs. Such a relationship can be used in conjunction with magnitudes and distance measurements to constrain the mass and effective temperature of the white
dwarfs. We select eight hydrogen atmosphere, pulsating white
dwarfs (DAVs), for their rich pulsation spectra. From such pulsation spectra, we can derive an asymptotic period spacing, which in turn allows us to determine the thickness of the hydrogen and helium envelope of the models, without having to perform period by period fitting. We find that the majority of the white
dwarfs have thicker hydrogen layers and determine an upper limit of Mr = 1 - 10 to the -2.2 for the location of the base of the helium layer, in accordance with
stellar evolution models. We confirm a finding from earlier studies that used a mass-radius relation and
Gaia data to determine the effective temperatures of white
dwarfs. The
Gaia data systematically points to white
dwarfs of lower effective temperature than indicated by the spectroscopy. Our results also support the hypothesis that white
dwarfs with thicker hydrogen layers are more common than those with thinner layers.
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Plasma Physics
Measurement of multiple mechanical properties from multi-dimensional signals in nanosecond laser ablation via PINN
Ying Zhou, Jian Wu, Ziyuan Song et al. (+6 more)
Accurate evaluation of mechanical properties in steels under ageing or service conditions remains a major challenge. We propose a thermo-mechanical coupling framework for nanosecond
laser ablation based on energy conservation, which is embedded into a physics-informed neural network (PINN) to enable simultaneous inversion of multiple mechanical properties. A thermo-mechanical coupling coefficient is defined to uniformly describe the dynamic allocation of input
laser energy among thermal
diffusion, mechanical work and
plasma shielding across different deformation stages under
laser irradiation. Furthermore, hard-to-measure physical characteristics in the coupled equation are replaced with experimentally accessible features obtained through the simultaneous acquisition of spectroscopic, shockwave and surface-wave signals. Using 210 experimental
datasets, the framework simultaneously recovers Young's modulus, yield strength, ultimate tensile strength and micro-Vickers hardness with high accuracy (R2=0.9927, 0.9912, 0.9916 and 0.9959 respectively), significantly outperforming the baseline method (ultrasonic velocity regression for E, R2=0.0012). Comparisons with linear normalization and unconstrained neural networks demonstrate that PINN achieves near-unity accuracy through the
embedding of conservation-law constraints. Partial dependency analysis further uncovers the nonlinear coupling laws between input features and mechanical properties. The proposed paradigm, integrating conservation laws, measurable features and physics-informed learning, offers a universal approach for non-contact, high-precision and physically consistent multi-to-multi inversion of multiple material properties under nanosecond
laser ablation conditions.
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All authors Ying Zhou, Jian Wu, Ziyuan Song, Jinghui Li, Xinyu Guo, Hao Sun, Yuhua Hang, Cuixiang Pei, Xingwen Li
Mesoscale and Nanoscale Physics
Depth-Resolved Lattice Distortions in a Silicon-Germanium Qubit Host
Jonathan C. Marcks, E. S. Joseph, J. Reily et al. (+6 more)
Semiconductor qubits, promising for
quantum computation, inherit properties from their host
lattice.
Quantum dot
spins, occupying the local lowest energy states in the conduction band, necessarily couple to structural disorder and interfaces. While silicon-based systems promise low noise alongside industrially compatible manufacturing, the growth of SiGe—a leading platform—unavoidably introduces
lattice dislocations, inhomogeneous strain, and crosshatch patterns, expected to cause fluctuations between devices,
qubit failure, and subsequently higher operational overhead. Through X-ray nano-structural mapping of an Intel Si/SiGe chip, we reveal, with 30$~$nm lateral and 200$~$nm functional depth resolution, how extended
lattice defects introduced during growth propagate through the
heterostructure, creating permanently distorted
lattice planes and strain. We correlate these at the $\approx1~\mu$m scale of a
quantum dot device and calculate the impact on
qubit energy spectra. We observe crosshatch fine structure and find that substrate miscut and growth correlate with the final crosshatch pattern.
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All authors Jonathan C. Marcks, E. S. Joseph, J. Reily, Talise Oh, Abigail Postlewaite, Tao Zhou, M. A. Eriksson, Mark Friesen, Martin V. Holt
Nuclear Theory
Gamow shell model description of the hypernuclei
Alan Cruz Dassie, Emiko Hiyama, Nicolas Michel et al. (+1 more)
Hypernuclear physics studies
baryon interactions and the structure of exotic atomic
nuclei, where strangeness plays a key role in dense matter. High-resolution $\gamma$-ray spectroscopy (e.g., Hyperball at BNL/KEK) and upcoming facilities (J-PARC, JLab) have provided precise data on $p$-shell hypernuclei, constraining $YN$ potentials. We applied the Gamow shell model to $p$-shell hypernuclei to systematically investigate the role of the $\Lambda N$ interaction and its components, and how it affects the mean field of nucleons. The Gamow shell model extends the standard shell model by replacing the harmonic oscillator basis with the Berggren ensemble, treating bound, resonant, and continuum states on equal footing. The effective
Hamiltonian includes Woods-Saxon core potentials and two-body interactions (central,
spin-orbit, tensor) optimized to experimental data. Our calculations reproduce and predict binding energies, excitation spectra, and densities for hypernuclei from ${}^{5}_{\Lambda}\mathrm{He}$ to ${}^{16}_{\Lambda}\mathrm{O}$ using the same $\Lambda N$ interaction. The tensor force significantly impacts excited-state splittings in bound systems, while its effect is suppressed in unbound cases due to the continuum coupling. The Gamow shell model provides a unified framework for hypernuclei, capturing the interplay between bound, resonant, and continuum states. This work lays the foundation for extending the model to heavier and multi-strange systems.
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All authors Alan Cruz Dassie, Emiko Hiyama, Nicolas Michel, Marek Płoszajczak
Nuclear Theory
Spectroscopic basis for short-range three-nucleon forces
Josep Solà Cava, Arseniy A. Filin, Sven Heihoff et al. (+2 more)
We introduce a spectroscopic basis for the subleading contact three-nucleon forces, which allows one to classify these interactions according to the total angular momentum and parity
quantum numbers in a transparent way. Using this new basis, we explore the sensitivity of nucleon-deuteron observables to the three-nucleon short-range interactions. The low dimensionality of the variable-parameter space in the spectroscopic basis allows us to build a simple nucleon-deuteron scattering emulator using radial basis function interpolation. We perform exploratory fits of the subleading contact three-nucleon interactions and demonstrate that 9 of 13 low-energy constants can be reliably determined from elastic nucleon-deuteron scattering data.
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All authors Josep Solà Cava, Arseniy A. Filin, Sven Heihoff, Henri Paul Huesmann, Evgeny Epelbaum
Quantum Physics
Two-photon interference from as-grown InAsP/InP quantum dots under detuned excitation
Maja Wasiluk, Anna Musiał, Paweł Mrowiński et al. (+3 more)
In this study, we investigate as-grown InAsP/InP
quantum dots emitting in the third telecommunication window under detuned quasi-resonant excitation. A large excitation-emission detuning of 32 meV enables efficient suppression of scattered
laser light while retaining several advantages of near-resonant excitation. The single-
photon nature of the emission is confirmed by a Hanbury Brown and Twiss experiment, yielding a raw second-order autocorrelation value of $g_{\mathrm{raw}}^{(2)}(0)=0.076(6)$. Hong-Ou-Mandel measurement is used to determine the degree of indistinguishability of single
photons and reveal as measured visibilities of $V=0.094(4)$ and $V=0.106(5)$ for excitation pulse separations of 13.1 ns and 5.3 ns, respectively. These results demonstrate the potential of as-grown InAsP/InP
quantum dots grown via molecular beam epitaxy under not experimentally demanding detuned excitation for generating indistinguishable telecom single
photons. Further improvements are to be achieved through Purcell enhancement in optical cavities.
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All authors Maja Wasiluk, Anna Musiał, Paweł Mrowiński, Johann Peter Reithmaier, Mohamed Benyoucef, Wojciech Rudno-Rudziński
Instrumentation and Methods for Astrophysics
Characterization and on-sky testing of photonic, AWG-based astronomical spectrographs
Jeronimo Calderon-Gomez, Frantz Martinache, Nick Cvetojevic et al. (+14 more)
Astrophotonics is a field that intends to meet the needs of next-generation instruments at a small footprint, low cost, and high stability, compared to bulk-optics-based alternatives. Much development effort is driven by the stringent requirements of direct detection and characterization of
exoplanets. Our team works in characterizing Arrayed-Waveguide Grating (AWG) chips for photonics-based, high-resolution, near infrared spectro-interferometry. AWG spectrographs allow to test the feasibility of photonic spectro-interferometers for
exoplanet characterization, another step towards fully photonic instruments for astronomy. We present the current status of our AWG characterization and a preliminary on-sky qualification campaign at the PAPYRUS AO system. We present the CoLiBRIS-AWG spectrograph prototype built for on-sky testing, and preliminary results using our high-resolution (H band, R~18000) AWG for observations of Arcturus (alpha Boötes) and Betelgeuse (alpha Orionis). This work contributes to assessing the capabilities of photonic spectroscopy for the development of future compact instruments.
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All authors Jeronimo Calderon-Gomez, Frantz Martinache, Nick Cvetojevic, Marc-Antoine Martinod, Vincent Foriel, Nemanja Jovanovic, Pradip Gatkine, Gregory Sercel, Alexis Carlotti, Marc Ferlet, Matteo Pasinetti, Angelie Alagao, Arnaud Striffling, Guillermo Martin, David Mary, Roxanne Ligi, Sylvie Robbe-Dubois
Geophysics · Cross-listed from math.NA
A Spectral-Domain Pseudo-Inverse Construction Method for Unitary Diagonalizable Linear Inverse Problems
Shengchang Chen
Linear inverse problems are prevalent in geophysics, signal processing, image restoration, and medical imaging. Mathematically, they can be formulated as $Gm = d$. When $G$ is ill-conditioned or singular, the problem becomes ill-posed and requires regularization methods or generalized inverse methods for a stable solution. However, both types of methods encounter significant computational difficulties for large-scale linear inverse problems. In this paper, we establish a spectral-domain pseudo-inverse construction method for a class of linear inverse problems that can be diagonalized by
unitary matrices. The core idea is to construct a stable pseudo-inverse operator directly in the transform domain, starting from the
unitary diagonalization structure of the
matrix. We first provide the analytic Singular Value Decomposition (SVD) of this class of
matrices, clarifying the correspondence between spectral decomposition and SVD. On this basis, we define spectral-domain regularization filtering factors, construct a stable spectral-domain pseudo-inverse operator, and prove its bounded stability as well as its consistency in converging to the Moore–Penrose generalized inverse. This construction is numerically equivalent to zeroth-order Tikhonov regularization and converges to the Moore–Penrose generalized inverse as $\alpha \to 0^+$, but its methodological path differs from both. This paper reveals that the stable generalized inverse of a class of structured
matrices can be directly constructed from their spectral decomposition, providing an efficient solution method for large-scale structured inverse problems. The
Fourier transform case is a special instance of this method when the
unitary matrix is taken as the discrete
Fourier transform
matrix.
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Optics
Spiking Photonic Neurons Based on Two-Section InP Quantum-Well Lasers Integrated on Silicon
Menelaos Skontranis, Benoit Charbonnier, Olivier Girard et al. (+2 more)
In this work we experimentally investigate the spiking dynamics of two-section InP
quantum-well
lasers monolithically integrated on silicon. By appropriately tuning the electrical bias conditions, we realize multiple neuronal-like operating regimes, such as integrate-and-fire and resonate-and-fire, highlighting the device's versatility as a high-speed photonic
neuron. A systematic investigation of
laser design parameters, including cavity length and gain/saturable absorber ratio, elucidates their impact on spiking-related properties (such as pulse repetition frequency) and traces the operational parameter space that unlocks stable spiking. Finally, these findings pave the way toward scalable neuromorphic photonic integrated
circuits, where low-loss silicon synapses coexist with versatile
laser neurons.
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All authors Menelaos Skontranis, Benoit Charbonnier, Olivier Girard, Adonis Bogris, Charis Mesaritakis
Cosmology and Nongalactic Astrophysics
An efficient one-loop EFTofLSS framework for Vainshtein-screened Horndeski gravity
Stan Verhoeve, Dani de Boe, Gen Ye et al. (+1 more)
We present an extension of PyBird for one-loop large-scale structure analyses of modified
gravity models. We implement support for quasi-static, Vainshtein-screened luminal Horndeski models (in EFTofDE and covariant formalisms) and nDGP, and replace the Green's function approach with a direct ODE method for computing the exact time-dependent functions entering the perturbation kernels. The new implementation improves computational efficiency while maintaining numerical consistency with the standard approach, and we validate the resulting one-loop matter power spectrum against $N$-body simulations for the $\alpha_i\propto\Omega_{\rm DE}$ parametrization. We apply this framework to constrain the $\alpha_i \propto a^3$ and $\alpha_i \propto \Omega_{\rm DE}$ parametrizations using Planck CMB, BOSS full-shape, and DESI DR2 BAO data, finding that full-shape information significantly tightens the constraints. We further showcase the pipeline for the cubic Galileon and nDGP models, demonstrating its applicability beyond the phenomenological amplitude parametrizations to covariant modified-
gravity theories. Finally, we assess the impact of the Einstein–de Sitter approximation and find that exact time dependence can be retained at modest computational cost, which may become relevant for future large-scale structure surveys.
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All authors Stan Verhoeve, Dani de Boe, Gen Ye, Alessandra Silvestri
Mesoscale and Nanoscale Physics
Majorana current induced by charge current in Kitaev magnet/graphene bilayers
Takehito Yokoyama
We investigate Majorana current induced by charge current in Kitaev magnets coupled with
graphene through the mechanism by which Majorana
fermions in the Kitaev magnet are dragged by electrons in
graphene. We calculate Majorana current density based on the perturbation with respect to a Kondo type Majorana-electron coupling and obtain an analytical expression of the Majorana current induced by charge current, indicative of electronic control of charge-neutral Majorana
fermions. We also discuss Majorana heat current induced by charge current and give estimations of their magnitudes.
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Soft Condensed Matter
Instability-induced bistable shape-morphing kirigami structures
Xiaoyuan Ying and Marcelo A. Dias
Deployable shape-morphing structures that transform from flat sheets into stable three-dimensional configurations are highly desirable for applications ranging from soft robotics and biomedical devices to adaptive architecture and aerospace systems. Existing kirigami-based morphing systems primarily rely on isotropic deployment, compliant soft materials, or external constraints to maintain deployed shapes, which limits
geometric programmability, structural integrity, and applicability in rigid-material systems. Here, we present an inverse design framework for anisotropic bistable kirigami structures that enables programmable shape morphing through controlled
geometric frustration and instability-induced deployment. The framework combines a semi-analytical mechanical model with geometry to establish a direct connection between
geometric transformation and the underlying energy landscape. We show that instability-induced shape morphing leads to tunable bistability and directional deployment in anisotropic kirigami structures. The results are validated through finite element simulations and experiments, demonstrating stable deployed configurations and programmable anisotropic morphing. The proposed framework further provides a general design strategy that can be integrated with various active actuation systems, enabling broader engineering applications.
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Lattice Field Theory
Static Quark-Antiquark Interactions in Rotating SU(3) Gluodynamics
Heng-Tong Ding, Olaf Kaczmarek, Ran Luo et al. (+1 more)
We study static
quark–antiquark interactions in rotating SU(3) gluodynamics using quenched
lattice simulations at imaginary angular velocity. At zero temperature, we extract the static potential from Wilson loops for
quark–antiquark pairs aligned with the rotation axis, for transverse pairs with one source on the rotation axis, and for symmetric transverse pairs across the rotation axis. Within the present accuracy, no significant rotation dependence or anisotropy is observed in the zero-temperature potential. At finite temperature, imaginary rotation suppresses the color-averaged free energies obtained from Polyakov-loop correlators in both longitudinal and transverse geometries. Axial-diagonal comparisons are used to identify a bulk region where open-boundary artifacts are reduced. In this region, the large-distance longitudinal free-energy shift is well described by $\Delta F_z(R_{xy})=A R_{xy}^2+B$. The transverse channels exhibit the same qualitative suppression, while their distance dependence additionally reflects the radial arrangement of the static sources and is compatible with a radial single-source free-energy shift in the bulk region. For the finite-temperature observables studied above $T_c$, the response weakens as the temperature is increased. These results provide
lattice evidence for a position- and geometry-dependent response of bare static-source free energies to imaginary rotation in a gluonic medium.
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All authors Heng-Tong Ding, Olaf Kaczmarek, Ran Luo, Hai-Tao Shu
Mesoscale and Nanoscale Physics
Symmetry-Selective Strain Control of Anisotropic Magnetic Response in a Silicon FinFET Double Quantum Dot
Yuze Lu, Xiaoyan Liu and Fei Liu
Strain naturally develops in three-dimensional
quantum-dot structures such as silicon FinFETs during fabrication and cooling. Such strain becomes especially important in a double
quantum dot, because the two dots can experience different local strain and therefore acquire different
magnetic responses. To understand how this dot-to-dot strain difference affects coupled hole
spins, we theoretically study the local \(g\) tensors of a silicon FinFET double
quantum dot by combining a three-dimensional Poisson–Schrödinger calculation based on a six-band \(k\!\cdot\!p\) model with configuration interaction. We find that the effect of strain depends on both its tensor component and its spatial
symmetry. For the diagonal components \(\epsilon_{yy}\) and \(\epsilon_{zz}\), strain mainly changes the principal \(g\) values, with only a small opening of the maximum-response axes. In contrast, the shear component \(\epsilon_{yz}\) can also change the orientation of the local
magnetic response. When the strain profile preserves the transverse mirror
symmetry, the shear-induced rotation is strongly suppressed. Breaking this local constraint permits a pronounced off-diagonal response and rotates the principal
magnetic axes. The same component- and
symmetry-selected trends appear in a Zeeman-only calculation, showing that the valence-band Zeeman coupling is sufficient to generate them, while the full
Hamiltonian determines their quantitative expression. Together, these results show how the tensor component and spatial
symmetry of strain can be used to control both the magnitude and orientation of the
magnetic response in coupled hole-
spin qubits.
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Strongly Correlated Electrons
The electric field gradient tensor as a symmetry-adapted order parameter in Landau theory
L. Scalise and A. W. Carbonari
Quadrupolar hyperfine spectroscopies, including
Nuclear Quadrupole Resonance (NQR),
Nuclear Magnetic Resonance (NMR), Time-Differential Perturbed Angular Correlations (TDPAC), and Mössbauer spectroscopy, have long used the electric field gradient (EFG) at a
nuclear site as an empirical proxy for order parameters in structural and electronic phase transitions, yet the EFG has never been systematically incorporated into Landau theory. Here we provide that framework. The EFG is an exactly traceless, symmetric rank-2 tensor defined at a crystallographic site. Decomposing it under the site-
symmetry group and inducing over the Wyckoff orbit determines its irreducible representation content in the parent space group. Whenever the representation of a zone-center transition is present,
symmetry requires the corresponding EFG combination to vanish above the transition and grow linearly with the order parameter below it, inheriting its critical exponent, sign, and domain structure.
Symmetry-orthogonal channels are quadratic, recovering the classic empirical relations. This yields a falsifiable classification of primary, secondary, and forbidden EFG responses. The framework is validated against five decades of quadrupolar experiments, reproducing critical exponents, first-order discontinuities, and a null result, and by first-principles calculations satisfying the predicted parity and zero
theorems. All-electron calculations for $\alpha$-quartz confirm the orbit-selection rule: only the EFG combination transforming as the soft-mode irreducible representation varies linearly with distortion amplitude, while the orthogonal combination remains suppressed by two orders of magnitude. A proposed study of the $^{75}$As site across the nematic transition in BaFe$_2$As$_2$ provides five falsifiable predictions, including a previously unstated null result.
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Cosmology and Nongalactic Astrophysics
J-PAS & FLAMINGO: Cosmic voids and void galaxies in the gravitational landscape of photometric surveys
J.A. Mansour, B. McCarthy, L. J. Liivamägi et al. (+34 more)
Photometric surveys offer a powerful way to map the large-scale structure of the Universe, but their
redshift errors complicate the identification of
cosmic voids, challenging studies of their environmental effect on
galaxy properties. We present an approach to robustly identify dynamically relevant voids and void
galaxies in
galaxy mocks of the Javalambre Physics of the Accelerating Universe Astrophysical Survey (J-PAS), testing whether known trends in void
galaxy properties survive photometric
redshift errors. Using FLAMINGO mocks at z = 0.3 and mi < 20, we compare a FLAMINGO-based ideal (FBI) mock to a FLAMINGO-based JP mock with J-PAS-like
redshift errors. We mitigate
redshift errors using a quasi-gravitational potential field in the two
galaxy mocks. We apply a watershed
algorithm to the thresholded quasi-potential field to identify dynamically dominant voids, and define massive void
galaxies alongside a comparison sample in high-density regions. Photometric errors lead to a slightly lower void abundance and a marginal shift toward larger, less spherical voids, but overall size and ellipticity distributions agree well between mocks. Their main impact is contamination of void interiors in the JP density profiles by
galaxies scattered from high-density regions. We recover a reasonable number of FBI sample voids in the JP sample, with excellent size and shape agreement, occupying ~63% of the thresholded quasi-potential volume. In both mocks, void
galaxies show lower
stellar masses, bluer colours, and enhanced
star formation relative to equal-mass
galaxies in high-density regions. These results suggest a quasi-potential can mitigate
redshift errors at the level expected for J-PAS, enabling identification of reliable, dynamically dominant voids that are less sensitive to small-scale noise. The massive void
galaxy population shows the expected trends relative to high-density environments.
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All authors J.A. Mansour, B. McCarthy, L. J. Liivamägi, A. Tamm, R. van de Weygaert, J. Laur, E. Tempel, M. Einasto, P. Heinämäki, J. Schaye, M. Schaller, R. Abramo, A. Hernán-Caballero, V. Marra, J. Alcaniz, N. Benitez, S. Bonoli, S. Carneiro, J. Cenarro, D. Cristóbal-Hornillos, S. Daflon, R. Dupke, A. Ederoclite, Rosa M. González Delgado, C. Hernández-Monteagudo, J. Liu, C. López-Sanjuan, A. Marín-Franch, C. M. de Oliveira, M. Moles, F. Roig, L. Sodré Jr, K. Taylor, J. Varela, H. Vázquez Ramió, J. Vilchez, J. Zaragoza-Cardiel
High Energy Physics (Theory)
Extended Phase Space Thermodynamics and Joule-Thomson Expansion of Regular AdS Black Holes in a String Cloud
Y. Elaima, A. Daassou, H. Lekbich et al. (+1 more)
We investigate the extended phase space thermodynamics of a static, spherically symmetric regular black hole immersed in a string cloud background. By identifying the negative cosmological constant as a thermodynamic pressure, our analysis indicates that the
quantum-inspired regularizing core and the string cloud density significantly affect the thermal stability of the black hole. We specifically illustrate a stringent scale invariance linked to the regularizing core, while the dimensionless string cloud parameter substantially alters the universal Van der Waals critical compressibility ratio. The significant
geometric inconsistencies result in computed critical exponents that align with those of mean-field theory. We specify the Joule-Thomson expansion to define the isenthalpic heating and cooling regimes, so providing a comprehensive thermodynamic characterization of this non-singular spacetime.
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All authors Y. Elaima, A. Daassou, H. Lekbich, F. Oubbad
Solar and Stellar Astrophysics
Evolutionary variations of superficial iron and calcium abundance in main sequence A stars
Yu.A. Fadeyev and R.M. Bayazitov
Main sequence
stellar evolution models were computed together with solution of the equations of atomic
diffusion for 16 elements from hydrogen to nickel. The grid of evolutionary tracks comprises the models with
stellar masses ranged from 1.4 to $2.5M_\odot$ computed for initial helium and metal abundances $Y=0.28$ and $Z=0.02$, respectively. The calculations were done for the mass loss rates $10^{-15}M_\odot/\textrm{yr}\le\dot M\le 10^{-12}M_\odot/\textrm{yr}$ as well as for $\dot M=0$. The high superficial abundance of iron in Am
stars is shown to be due to the radiative acceleration acting on the atoms of iron. The significantly smaller absorption coefficient of calcium is responsible for its gravitational settling and accumulation above its opacity maximum at $T\sim 10^6\:\textrm{K}$. Recover of the superficial calcium abundance is due to plunge of the outer convection zone bottom to layers with its excessive abundance. A significant role in the evolutionary variations of superficial abundances of chemical elements belongs to the intermediate convection zone arising for the first $\lesssim 300$ Myr due to accumulation of the atoms of iron and nickel in the layers with temperature $T\sim 2\times 10^5\:\textrm{K}$. In
stars with mass $M\le 1.9M_\odot$ both the outer and intermediate convection zones merge due to evolutionary descend of the bottom of the outer convection zone so that overabundant iron and nickel are transported to the outer layers by convection. The merging of the convective zones is responsible for considerable variations of superficial abundances of calcium and iron with duration ranging from a quarter to a half of the main–sequence lifetime depending on the
stellar mass. Therefore, Am
stars as well as slowly rotating nonmagnetic A main–sequence
stars have the common origin, whereas appearance of their chemical anomalies depend of the
stellar mass and age.
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Quantum Physics
Sparse Quantum Voxel Encoding for Readout-Efficient Molecular Geometry Reconstruction on NISQ Devices
Eros De Simone, Giuseppe Bifulco, Lorenza Di Mauro et al. (+2 more)
We propose a sparse computational-basis encoding of voxelized molecular geometries that converts molecular reconstruction from full-state
tomography into support recovery by computational-basis sampling. To realize the encoding scheme, the molecular space is discretized into a 3D grid, and each atom's position and chemical species is mapped to a single computational basis state. This discretization introduces spatial quantization at the voxel-resolution scale. The molecule is then encoded as an equal superposition over this sparse set of occupied states, where we assume that a suitable state preparation method exists. In contrast to full state
tomography, which requires on the order of $\mathcal{O}(3^n \times 10^{2\text{--}3})$ measurement shots, where $n$ is the number of
qubits, our proposed encoding scheme reduces to a coupon-collector sampling problem in the computational basis. Complete recovery of an $A$-atom molecule requires $\mathcal{O}(A\log A)$ shots on noise-free hardware. On noisy hardware, the required number of shots increases. We demonstrate the method on the 156-
qubit IBM Kingston device using 8-
qubit circuits to reconstruct the discretized geometry of a 10-atom ethylamine molecule with high mean reconstruction recall using only $\mathcal{O}(10^2)$ shots despite substantial hardware noise. These results demonstrate that our proposed encoding scheme is a practical, readout-efficient representation for molecular geometries on near-term devices.
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All authors Eros De Simone, Giuseppe Bifulco, Lorenza Di Mauro, Antonio Policicchio, Raoul Heese
Statistical Mechanics
Boundary-Driven Anisotropic Coarsening in Conserved Phase Separation
Emilio N.M. Cirillo, Nicklas Jävergård, Adrian Muntean et al. (+1 more)
Universal scaling in phase separation is typically assumed to be isotropic in systems with conserved dynamics. Here we show that boundary forcing alone can break this dynamical scaling
symmetry, leading to anisotropic coarsening, with different effective global growth laws observed parallel and perpendicular to the boundary. We consider a ternary mixture with two conserved components and a passive species undergoing surface evaporation, which provides a simple setting to investigate this effect. In this case, evaporation leads to a progressive mass loss and to the formation of macroscopic concentration gradients, which, in turn, drive anisotropic coarsening, with different effective growth laws observed parallel and perpendicular to the boundary. At the same time, bulk regions appear to retain the standard Model B scaling, suggesting that the observed anisotropy is mainly induced by boundary fluxes rather than by changes in the intrinsic dynamics. Our results indicate that boundary conditions can play an important role in breaking scaling
symmetry and may offer a way to influence coarsening behavior in nonequilibrium phase separation.
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All authors Emilio N.M. Cirillo, Nicklas Jävergård, Adrian Muntean, Stela Andrea Muntean
High Energy Physics (Theory)
Quantum Fisher information of the Klein–Gordon and Dirac vacua
Preslav Asenov and Alessio Serafini
The
quantum Fisher information (QFI) of the
vacuum of three
quantum field theories is evaluated with respect to the mass parameter of each theory. All field theories are considered on a $(d+1)$-dimensional Euclidean spacetime. We consider the Klein-Gordon field and the free Dirac field. For the free KG case, we find a $m^{d-2}$ dependence of the QFI, and thus no dependence for $d=2$, in agreement with the
holographic duality characterizing the theory. The
vacuum QFI with respect to the free Dirac field mass is shown to be UV-divergent for $d=2$ and $d=3$, mass-dependent for $d=1$, and zero for $d=0$.
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Geophysics
How to quantify earthquake predictability? Advances in earthquake forecasting and predictability limits
Jiancang Zhuang and Didier Sornette
Earthquakes resist deterministic prediction, yet their occurrence is not fully random. This paper develops a unified information-theoretic framework to quantify predictability. By reviewing Shannon
entropy and the Kullback-Leibler divergence, we formalize predictability as the
entropy gap between complete randomness and the true data-generating process and clarify how this absolute notion relates to the relative skill gains used in prospective model evaluation. Within the point-process setting, we derive
entropy rates for the Poisson process and for ETAS and identify the intrinsic predictability rate as an information gain functional of the conditional intensity. Using this lens, we summarize what is currently established about earthquake predictability in time, space, and magnitude: temporal and spatial predictability are dominated by clustering and heterogeneous background rates, while magnitude predictability requires separating marginal magnitude statistics (e.g., Gutenberg-Richter and tapered laws) from genuine inter-event dependence encoded by the multivariate magnitude distribution. Finally, we show how incorporating high-dimensional pre-event observations can increase predictability through mutual information, thereby reframing
forecasting progress as the extraction of structured dependence between available information and future seismicity. This perspective provides a coherent basis for assessing predictability limits, comparing models, and identifying where additional information and physics that are most likely to yield substantive
forecasting improvements.
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Plasma Physics
Low-Temperature Co-Fired Ceramics for a Sustainable Planar Plasma Jet with Homogeneous Plasma in Large Treatment Areas for Biomedical Applications
Ivan Gomez Ho, Hua-Lin Chen, Cheng-Han Tsai et al. (+2 more)
This study presents a portable planar argon-based
plasma jet designed for large-area biomedical applications, with an emphasis on uniform discharge, stability, and safety. The device incorporates interchangeable rear and side inlet gas adapters with restriction plates and channels to equalize gas flow, while electrodes are encapsulated in low-temperature co-fired ceramics to reduce degradation and arcing during repeated operation. Flow simulations were conducted for multiple channel configurations to ensure laminar gas distribution and uniform
plasma generation. Device performance and safety were evaluated using the kinPen MED as a reference standard. Electrical characteristics, optical emission, discharge uniformity, temperature, gas velocity, ozone generation, UV irradiance, and leakage current were systematically measured. The
plasma exhibited stable voltage, current, and power after an initial warm-up period. Temperatures stabilized within minutes, with the rear-inlet configuration demonstrating lower operating temperatures due to higher outlet gas velocity. Ozone levels remained below established safety limits, while UV exposure constrained allowable treatment times. Leakage current decreased with increasing distance and approached safety thresholds at short separations. These results demonstrate that the proposed planar
plasma jet provides stable, uniform
plasma delivery while meeting key safety requirements, supporting its potential for clinical and biomedical use.
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All authors Ivan Gomez Ho, Hua-Lin Chen, Cheng-Han Tsai, Jong-Shinn Wu, Yun-Chien Cheng
Nuclear Theory
Critical net-proton number fluctuations with hydrodynamics
Rui-zhe Zhao, Shi Yin, Shanjin Wu et al. (+3 more)
We compute the net-
proton number fluctuations and their ratios $C_2/C_1$, $C_3/C_2$ and $C_4/C_2$ on the hydrodynamic freeze-out hypersurface of particlization at nine collision energies, $\sqrt{s_{\mathrm{NN}}}=7.7-200$ GeV, based on the fluctuations obtained from the functional renormalization group (fRG) approach, where both the regular and the critical fluctuations arising from the critical end point (CEP) are included. The transverse momentum and rapidity acceptance windows as same as the experimental measurements, the isospin randomization for the
proton number fluctuations, and the global
baryon conservation effect are implemented in the calculations. The results are also compared with the baseline results without critical fluctuations. It is found that for the low-order cumulants, e.g., $C_2/C_1$ the difference between the critical and non-critical results is small, while the difference increases with the increasing order of cumulants in the region of low collision energy. A non-monotonic dependence on the collision energy is observed in $C_4/C_2$ with critical fluctuations, which is absent in the results without critical fluctuations.
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All authors Rui-zhe Zhao, Shi Yin, Shanjin Wu, Lipei Du, Xiaofeng Luo, Wei-jie Fu