Applied Physics
The Swiss Roll Metamaterial Revisited
Zachary Fritts and Anthony Grbic
In this work, we analytically model the Swiss roll metamaterial medium, showing that each unit
cell can be thought of as a flux-coupled waveguide terminated in coupled inductors. The equivalent
circuit model of the metamaterial accurately predicts its response, including its higher order resonances, even when made of a lossy, finite-thickness conductor. A closed-form solution for the response of this
circuit model is then derived by solving a
matrix equation of arbitrarily large dimensions. Along the way, we provide a general method for modeling the effective permeability of uniaxial, anisotropic metamaterials formed from axially invariant conducting inclusions.
Read the full abstract ▾
Quantum Physics · Cross-listed from math.CT
Possibilistic collapse and extremality of simplicial distributions
Aziz Kharoof and Cihan Okay
Consistent families of locally defined probability distributions that do not admit a joint global distribution are known as contextual, with primary examples arising in
quantum theory. In this paper, we study such families of distributions using the theory of simplicial distributions, and further develop the theory for possibilistic distributions defined over the Boolean semiring. We characterize possibilistic collapses of simplicial distributions geometrically using bundle scenarios. Using this characterization together with a new connectivity condition on the total space of a bundle scenario, we provide a criterion for detecting extremal simplicial distributions. In parallel, we develop an analogous theory for presheaves on simplicial complexes, describe possibilistic collapses of empirical models on them using event scenarios together with a categorical extremality condition, and relate the two frameworks via a comparison result. We provide examples of contextual simplicial distributions that arise from our criteria on scenarios of interest in
quantum foundations, such as Bell scenarios and boundaries of standard simplices, the latter connecting to Vorob'ev's classical
theorem on acyclic complexes.
Read the full abstract ▾
Optics
Avoiding a line-of-sight obstacle via deep sub-Rayleigh shadow-projection utilizing space-time wave packets
Layton A. Hall, Bryan L. Turo and Ayman F. Abouraddy
A challenge in optics, which is shared by other sources of radiation, is to direct a coherent beam to impinge on a target behind an obstacle intervening in the line-of-sight (LoS). While self-accelerating or bending beams can help avoid an LoS obstacle, the beam does not reach the LoS target downstream beyond the obstacle. If one instead avoids the obstacle by projecting a transverse null or shadow onto the axial plane at which it is located, an associated axial shadow is cast that extends over the effective Rayleigh length, which reduces the utility of this approach. Unless either the wavelength or the transverse shadow width is changed, this Rayleigh length can only be reduced by modifying the structure of the illumination beam. Here we show that space-time wave packets (STWPs), in which each spatial frequency is tightly associated with a single wavelength, when used as an illumination beam, can dramatically reduce the axial extent of the cast shadow. Indeed, by utilizing STWPs we produce deep sub-Rayleigh-length shadows, in some cases with a more than two orders-of-magnitude reduction below the conventional Rayleigh length. For example, a 5-mm-wide transverse shadow in a Gaussian beam at a wavelength of $\sim1$~$\mu$m has a Rayleigh length of $\sim25$~m, whereas the same shadow projected by an STWP extends only $\sim0.15$~m. We demonstrate this sub-Rayleigh-length reduction in the axially cast shadow accompanying transverse nulls whose widths extend over a broad span of widths from 80~$\mu$m to 48~mm – almost three orders-of-magnitude. These results may lead to advances in safe radiation therapy, non-LoS optical and wireless communications, selective stand-off detection, three-dimensional photolithography, and
laser ablation and micro-machining.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Anisotropic magnetoresistance of two-dimensional Rashba systems with in-plane Zeeman field and point-like disorder
Igor Gornyi and Alexander Khaetskii
We study the dc conductivity of a two-dimensional Rashba system with an in-plane Zeeman field and delta-correlated scalar disorder. We show that, although the field deforms the two helicity
Fermi contours and rotates the
spin texture, it does not produce anisotropic magnetoresistance in the leading quasiclassical conductivity. The result follows from a
geometric identity for the total area occupied by the two helicity sheets. A density Ward identity fixes the
spin-vector part of the Born self-energy to the derivative of the total particle density with respect to the field. This derivative vanishes, because the total area enclosed by the two Rashba-Zeeman sheets is independent of the in-plane field. The Born self-energy is therefore scalar and field independent, and the quasiparticle lifetime stays isotropic. The same occupied-area identity controls transport: the leading
impurity ladder reduces the current vertex to the
parabolic velocity, and the diagonal intraband Kubo conductivity collapses onto the two-sheet occupied area and is field independent as well. Thus, point-like nonmagnetic
impurities produce neither angular anisotropy nor field-magnitude dependence in the leading diagonal two-sheet quasiclassical conductivity. Any residual AMR from delta-correlated disorder must originate from corrections outside this sector.
Read the full abstract ▾
Computational Physics
CodeJeNN: A simple C++ neural network generator for physics applications
Jay Arcities, Pavel Popov, Eric J Ching et al. (+2 more)
Machine learning has shown promise for physics applications, but integrating Python-based libraries into high-performance C++ solvers can create performance bottlenecks. We present CodeJeNN, which addresses this gap by auto-generating self-contained C++ code from trained Keras models for inference. This eliminates external dependencies through inlined functions, allowing seamless integration into existing frameworks. We describe the Keras-to-C++ workflow, supported architectures, and limitations. CodeJeNN is demonstrated through inference
benchmarks against Keras (eager and optimized) and a computational fluid dynamics (CFD) simulation of a hydrogen-air mixing layer in which viscosity is modeled using a neural network, showing that the generated models integrate directly into a solver while remaining efficient and accurate.
Read the full abstract ▾
All authors Jay Arcities, Pavel Popov, Eric J Ching, Kamal Viswanath, Ryan F Johnson
Fluid Dynamics
Two-way coupling in active suspensions suppresses particle accumulation and induces non-monotonic flow stabilization
Miyi Wu, Ziyue Yu and Lei Fang
We experimentally study the two-way coupling between a swarm of centimetre-scale active swimmers (Artemia salina) and an electromagnetically driven quasi-two-dimensional cellular flow. The swimmer loading $N$ and the background forcing $E$ are varied independently across 85 conditions, and the coupled dynamics are characterized through Lagrangian diagnostics built on the attracting Lagrangian coherent structures (LCS) of the flow. In the dilute limit, swimmers accumulate onto the attracting LCS most strongly when their speed is comparable to the flow speed, recovering the mobility-selective accumulation predicted by one-way-coupled simulations at the fixed aspect ratio of A. salina. As the loading increases, this accumulation is progressively suppressed, a collective effect inaccessible to single-swimmer models. The back-action of the swarm on the flow is itself bidirectional and regime-dependent: at low forcing the swarm disorders the attracting-LCS web and scatters the topological critical points of the cellular pattern, whereas at high forcing it reorganizes and reinforces the skeleton. The temporal stability of the skeleton is correspondingly non-monotonic in both $N$ and $E$, with the conditions of maximal stability migrating systematically through the $(N,E)$ plane. This reinforcement of coherent structures has no counterpart in prior simulations, which reported a predominantly disruptive back-action. Resolving both directions of the coupling shows how collective activity can either erode or reinforce the transport skeleton of a structured flow.
Read the full abstract ▾
Astrophysics of Galaxies
Small-scale dynamo saturation across magnetic Prandtl numbers using the EDQNM closure
Muhammed Irshad, Kandaswamy Subramanian and Pallavi Bhat
Small-scale dynamos (SSDs) are believed to be the primary source of
magnetic fields in all turbulent astrophysical systems, especially those with weak rotation such as elliptical
galaxies and
galaxy clusters. The initial kinematic phase of these dynamos is relatively well understood. Here we demonstrate analytically and numerically that, in an appropriate limit, the eddy-damped quasi-normal Markovian (EDQNM) closure for incompressible magnetohydrodynamic
turbulence is strictly equivalent to the earlier models of kinematic dynamos. Moreover, it allows the extension of the kinematic dynamo framework to multi-scale turbulent flows and into the nonlinear regime. The EDQNM closure also enables us to explore a wide parameter range which is inaccessible to direct numerical simulations of the SSD. Using nonhelical EDQNM simulations, we identify several asymptotic regimes of nonlinear dynamo action when the system is highly turbulent with fluid Reynolds number $Re \gtrsim 10^6$ for
magnetic Prandtl number $Pm > 1$ and
magnetic Reynolds number $Rm \gtrsim 10^6$ for $Pm < 1$: 1) the kinematic growth rate approaches a value independent of $Pm$, 2) the saturated
magnetic to kinetic energy ratio similarly converges to $\simeq 0.55$ across $Pm$, while the ratio of
magnetic to kinetic integral wavenumbers asymptotes to $\simeq 3$. For all $Pm$, we further find strong feedback between
magnetic field and velocity field largely via Alfvénisation leading to a saturated kinetic and
magnetic spectra with almost the same inertial range with a slope of $-3/2$. These findings could provide guidance for future global simulations and for modeling the nonlinear regime of astrophysical systems living in these extreme limits.
Read the full abstract ▾
Fluid Dynamics · Cross-listed from math.AP
On the sharpness of bounds on the rate of growth of Lebesgue norms of the velocity in Navier-Stokes flows
Fabian Bleitner and Bartosz Protas
In this paper we consider solutions $\boldsymbol{u}$ of the three-dimensional Navier-Stokes system and investigate sharpness of the a priori bound \begin{align*} \frac{d}{dt}\|\boldsymbol{u}\|_q^q \leq C\|\boldsymbol{u}\|_q^{q\frac{q-1}{q-3}}, \qquad q > 3. \end{align*} This bound is closely related to the Ladyzhenskaya-Prodi-Serrin conditions characterizing classical solutions of the Navier-Stokes system. Velocity fields maximizing the rate of growth $(d/dt)\|\boldsymbol{u}\|_q^q$ under certain constraints are found as solutions of a suitable optimization problem which is solved numerically using a Riemannian conjugate gradient approach. The results obtained for different $q$ and increasing values of $\|\boldsymbol{u}\|_q$ indicate that the bound is indeed sharp, up to a numerical prefactor, and therefore cannot be fundamentally improved. Additionally, the results also suggest that the rate of growth $(d/dt)\|\boldsymbol{u}\|_q^q$ diverges as $q\to 3$.
Read the full abstract ▾
Mathematical Physics
Transition-Set Morphometry for Inter-Scale Contacts in Digital Sandstones
O. M. Kiselev
This paper introduces a transition-set morphometry for quantifying inter-scale contacts in digital sandstones. Pore volume, a medial pore-throat subsystem, and fracture porosity are treated as distinct
geometric subsystems. Their finite-neighborhood contacts are represented by transition sets such as $T_{VL}$, $T_{VF}$, and, when a residual skeleton is resolved, $T_{LF}$. The method measures the density, finite-scale dimension, and weighted contact measures of these sets. A
matrix-mode test was performed on 21 digital sandstone samples from the Imperial College micro-CT collection and Digital Porous Media Portal
dataset DRP-317. Permeability, expressed as $\log_{10}K$, served as an external response for assessing how much structural information the descriptors carry. The transition dimension $d_{VL}$ alone produced little independent predictive gain, whereas contact measures combining transition-set density with local pore radius were more informative. The adaptive measure $\widehat C_{VL}^{(d+1)}=\mu_{VL}(\overline D_{VL}/D_*)^{d_{VL}+1}$ increased leave-one-out $R^2$ from 0.752 to 0.881 in the combined sample and from 0.287 to 0.807 within DRP-317. Fractured
datasets DRP-5, DRP-31, and DRP-285 were then used to test the transfer of the same transition-set construction to fracture-related contacts. The results support transition sets as reproducible morphometric descriptors of inter-scale contact.
Read the full abstract ▾
Quantum Physics
Encoding matroids into quantum states
Nathan Ferreira, Alison A. Silva, Giuliano G. La Guardia et al. (+1 more)
Efficient representations of multipartite
quantum states play a fundamental role in
quantum information theory, providing both conceptual insight and practical tools for characterizing
entanglement. Motivated by the axiomatic framework for graph states [Phys. Rev. A 85, 062313 (2012)] and its subsequent extension to hypergraph states [Phys. Rev. A 87, 022311 (2013)], we introduce an axiomatic construction of matroid states, a new family of multipartite
quantum states associated with matroids. Our constructions are based on a set of axioms analogous to those that define graph and hypergraph states, yielding a consistent
quantum representation of arbitrary matroids. Two ways of constructing matroid states are proposed: the first is defined in terms of
circuits, and the second in terms of independent sets. In both approaches, we establish the existence of universal global operators that satisfy desirable properties such as locality,
symmetry, commutativity, and are associated with the combinatorial structure of matroids. Furthermore, we establish a hierarchy connecting graph, matroid, and hypergraph states within a unified framework. Additionally, we show how to obtain an arbitrary graph state by applying suitable families of matroid states, whose corresponding operators are the generators of the stabilizer subgroup of the graph state. These results identify matroid theory as a natural combinatorial
language for the efficient description of multipartite
quantum states and open new perspectives for the investigation of
quantum entanglement and related combinatorial structures.
Read the full abstract ▾
All authors Nathan Ferreira, Alison A. Silva, Giuliano G. La Guardia, Fabiano M. Andrade
Chemical Physics
A self-adaptive tube restraint for free-energy calculations along path collective variables
Radu A. Talmazan, Cheng Giuseppe Chen, Chenyu Tang et al. (+1 more)
Path collective variables (PCVs) reduce a high-dimensional transition to a progress coordinate, s, and an orthogonal distance, z. Computing the free energy along s often requires restraining z, so that sampling embraces a tube centered on the reference path. However, a conventional fixed half-harmonic wall demands an a priori tube width that is both system dependent and s-dependent. Too tight a tube biases the path-projected free energy. Conversely, too loose a tube induces numerical instability and inter-channel leakage. We present an adaptive tube restraint the half-width of which evolves on the fly to track a fixed contour {\Delta}F* of the orthogonal free energy F(z|s), widening automatically in flat basins and narrowing at pinched saddles, with minimalist user intervention. We prove that, for a locally harmonic perpendicular well, a contour-following tube captures an s-independent fraction of the orthogonal partition function, so that in the hard-wall limit, its bias cancels out. In stark contrast, the bias of a fixed-width tube varies with s and distorts the free-energy landscape. We probe the
algorithm on several model potentials, on N-Acetyl-N'-methylalanylamide isomerization, on the folding of the mini-
protein chignolin, and on the folding-upon-binding of the ribose-binding
protein. The method is implemented in the open-source Colvars library, and is, therefore, usable within popular MD engines, such as NAMD, LAMMPS, GROMACS, and Tinker-HP.
Read the full abstract ▾
All authors Radu A. Talmazan, Cheng Giuseppe Chen, Chenyu Tang, Christophe Chipot
Optics
Ultrafast All-Optical Polarization Control in a Plasmonic Metasurface by Selective Hot-Electron Heating of Orthogonal Gold Nanorods
Nikolaos Matthaiakakis, Lea Teste and George Kakarantzas
Metamaterials tailor light's degrees of freedom through static designs, but sub-picosecond, all-optical control without sacrificing signal throughput remains challenging. Here, a metasurface is presented whose unit
cell contains two independent, orthogonal and spectrally detuned Au nanorod resonators. A femtosecond pump polarized along either nanorod selectively heats its electrons, modulating one polarization channel while the other serves as an essentially unperturbed phase reference, turning a static wave retarder into an ultrafast, all-optically reconfigurable one. The transient response is computed by coupling a Three-Temperature Model, benchmarked against published experiments, with Finite-Difference Time-Domain simulations. Hot electrons damp and red-shift the pumped resonance, modulating the amplitude ratio and phase retardation of the two channels. In transmission at normal incidence and sub-mJ cm$^{-2}$ fluence, a 45$^\circ$ probe undergoes changes of $\approx$10$^\circ$ in ellipticity and $\approx$15$^\circ$ in optical rotation within $\approx$100 fs (relaxation time $\approx$4 ps), while its transmittance ($\approx$0.4) changes by at most $\approx$0.05. A second, delayed pump along the other nanorod raises these changes to $\approx$15$^\circ$ and $\approx$22$^\circ$ and, for a suitably polarized probe, cancels the intensity change of the first within $\approx$60 fs while the polarization stays changed. Selective all-optical control of independent resonators offers a practical route to transmissive ultrafast polarization control.
Read the full abstract ▾
Fluid Dynamics
Semi-analytical model for the rising sheet generated by droplet-pair impact
Shushan Hu, Liwu Fan and Nan Hu
When two low-Ohnesorge-number drops impact a dry substrate simultaneously, their spreading lamellae collide and lift a free-standing vertical sheet. The sheet grows by inertial feeding from the spreading drops and is pulled back by capillary retraction at its rim. We develop a semi-analytical model for this rising sheet by extending the single-drop impact description of~\citet{Gordillo2019} to the two-drop geometry. The thin-film flow in the sheet is coupled at its base to the colliding lamellae and at its apex to a capillary-retarded rim. The sheet interior is then solved along ballistic characteristics in two stages: a lamella-fed stage, for which the velocity and thickness fields can be obtained in closed form, and a post-lamella stage, for which the inlet conditions are taken from simulations. The resulting framework gives the three-dimensional velocity and thickness fields and therefore the full sheet shape. On the centreline, the apex height and local thickness are obtained explicitly, showing that the different Weber-number exponents reported in the literature arise from a crossover rather than from a single universal scaling law. At sufficiently large Weber number, the apex pinches off. A linear Rayleigh–Plateau analysis, using the time-dependent jet diameter and deceleration predicted by the model, then bounds the maximum attainable height and closes the description of the pinch-off regime.
Read the full abstract ▾
Atomic Physics
Helium Ground State Treated in Classical Physics with Classical Zero-Point Radiation
Timothy H. Boyer
The ground state of the helium atom is considered within classical electrodynamics which includes classical electromagnetic zero-point radiation. Approximate energy balance between energy loss through emitted radiation and energy gain from classical zero-point radiation is found when the two electrons are treated as charges located on opposite ends of a diameter of a common circular orbit around the
nucleus. The classical result gives approximately the same value as that given by the
quantum calculation, but is a different value.
Read the full abstract ▾
Solar and Stellar Astrophysics
Unveiling the properties of pulsating low-mass helium-core white dwarfs through TESS asteroseismology I. First results
Leila M. Calcaferro, Nikoo Hosseininezhad, Murat Uzundag et al. (+4 more)
Recent space-based photometry, particularly from TESS, has opened new possibilities for probing the internal structure of low-mass (LM) helium (He)-core white
dwarfs (WDs). We present a homogeneous asteroseismological analysis of six pulsating LM WD
stars, based on new and updated TESS photometry. We processed short- and ultra-short-cadence TESS observations of TIC 290904838 (J1112), TIC 156064657, TIC 33717565, TIC 344130696, TIC 72637474, and TIC 188087204, and analyzed the resulting pulsation spectra. We then carried out a detailed asteroseismological analysis using fully evolutionary models of LM He-core WDs that allow for varying hydrogen (H)-envelope thicknesses. We also estimated spectroscopic/photometric
stellar masses when atmospheric parameters are available. We report the first TESS-based frequencies for J1112 and provide revised or expanded frequency solutions for the remaining targets. The asteroseismological analysis yields relatively well-constrained solutions for three
stars, a representative but more tentative solution for one target, and constrained ranges for the remaining two. The inferred solutions span a broad range of H-envelope thicknesses, although some of the asteroseismological inferences remain tentative because of the limited number of observed periods available for the analysis. For most objects, the derived spectroscopic/photometric
stellar masses are broadly compatible with the asteroseismological values. This is the first homogeneous TESS-based asteroseismological study of a small sample of pulsating LM WDs. Our results suggest that LM WDs can harbor H envelopes with a range of thicknesses, from canonical (thick) to very thin, as in average-mass H-rich pulsating WDs. They also provide a useful reference point for future studies of larger samples, which will hopefully benefit from richer mode sets and improved mode identification.
Read the full abstract ▾
All authors Leila M. Calcaferro, Nikoo Hosseininezhad, Murat Uzundag, Alejandro H. Córsico, Keaton J. Bell, Leandro G. Althaus, J.J. Hermes
Strongly Correlated Electrons
Correlation-Induced Topological Reconstruction in a Periodically Driven Kagome Mott Insulator
Rahul Ghosh, Subhajyoti Pal and Ganesh C Paul
We study the interplay between electronic correlations and circularly polarized periodic driving in the Hubbard model on a Kagome
lattice. Using Brillouin-Wigner perturbation theory, we derive an effective Floquet
Hamiltonian in which the drive renormalizes the bare hopping and generates
chiral nearest- and next-nearest-neighbor terms, producing repeated topological transitions and a flat band whose position is continuously tunable across the spectrum. Within slave-rotor mean-field theory, we show that the resulting Mott transition is strongly non-monotonic in the drive amplitude, yielding repeated metal-
insulator transitions, and that the spinon excitations inside the Mott phase acquire a band
topology distinct from that of the non-interacting Floquet bands. This correlation-driven topological reconstruction produces emergent flat-band spinon
insulators inaccessible to either driving or interactions alone. Our results establish periodically driven Kagome systems as a platform for engineering correlated topological flat-band physics out of
equilibrium, with proposed realizations in ultracold atomic
lattices.
Read the full abstract ▾
Biological Physics
Electric Field Propagation with Spinal Cord Stimulation
Olivier Bernard, Réjean Fontaine, Oussama Eddaoui et al. (+3 more)
Spinal cord stimulation is routinely used for the treatment of chronic pain, and is increasingly being investigated for the restoration of movement after paralysis. However, most of our current knowledge on epidural spinal cord stimulation relies on empirical approaches and semi-hybrid models. Hence, optimizing this therapy requires a better theoretical understanding of how stimulation affects the target neural structures. Using the physical properties of tissues combined with an electromagnetic, dielectric, and metallic description of them, we derived the electric field transmission coefficient through a given number of layers of tissue in the spinal cord. We then used this model to calculate the transmission of electric field energy in target neural tissues such as grey or white matter for different pulse width. Simulations suggest that the propagation through the tissues of the spinal cord of an epidurally applied electric field has a complex relationship with the field pulse width. In addition the electric field energy is absorbed at the junction between dura matter and cerebrospinal fluid, and within the cerebrospinal fluid as induced current. These currents hit the different bodies floating within the cerebrospinal fluid, and/or dorsal horn in a very localized region of the spinal cord. The proposed models allow theoretical calculation of the transmission factor for different numbers of layers of tissue within the spinal canal, and for different electric field pulse widths. This eases the prediction of the expected energy reaching each layer of the spinal cord for different tissues, parameters, and electrode configurations, simplifying the optimization of spinal cord stimulation treatment.
Read the full abstract ▾
All authors Olivier Bernard, Réjean Fontaine, Oussama Eddaoui, Jonathan Harnie, Alain Frigon, Christian Iorio-Morin
Space Physics
Evolution and Impact of Switchbacks Throughout the Heliosphere
Alfred Mallet, Chen Shi, Anna Tenerani et al. (+23 more)
Magnetic switchbacks are large-amplitude fluctuations in the interplanetary
magnetic field, and appear frequently in the near-Sun
solar wind explored recently by Parker
Solar Probe: these new observations have prompted many new studies into their properties and origins. Here, we first review what is known about how switchbacks evolve as they travel away from the Sun: both in terms of their expansion-driven growth and their decay due to various processes like
turbulence, reconnection, dispersion, parametric instability, and interaction with interplanetary shocks. We then review the current state of knowledge on how switchbacks impact the physics of the
solar wind as a whole: in terms of the turbulent cascade, acceleration and heating of the wind, modification of the open
solar flux and scattering of energetic particles. Finally, we suggest future studies to further our understanding of switchback
evolution and impacts on the heliosphere.
Read the full abstract ▾
All authors Alfred Mallet, Chen Shi, Anna Tenerani, Oleksiy Agapitov, Mojtaba Akhavan-Tafti, Samuel Badman, Nina Bizien, Trevor Bowen, Mihir I. Desai, J.F. Drake, Timothy Horbury, Andrea Larosa, Maria S. Madjarska, Francesco Malara, Lorenzo Matteini, Mathew Owens, Victor Réville, Nikos Sioulas, Shirsh Lata Soni, Jonathan Squire, Gabriel Ho Hin Suen, Marc Swisdak, Marco Velli, Jaye Verniero, Nicholas Watkins, Luca Sorriso-Valvo
Cosmology and Nongalactic Astrophysics
S-PLUS Clusters And Large-scale Environments (SCALE): II. PZWav versus redMaPPer identification of eRosita groups
L. Doubrawa, A. Finoguenov, E. S. Cypriano et al. (+10 more)
We present the construction and characterization of a multi-wavelength catalog of
galaxy groups and clusters by matching optical detections from the Southern Photometric Local Universe Survey (S-PLUS) with extended X-ray emission from the first eROSITA all-sky survey data release (eRASS1). We employ a probabilistic matching framework, based on the modified Hausdorff distance, to associate
galaxy systems identified by the PZWav cluster finder and characterized by the AME membership
estimator with X-ray surface brightness contours. This method explicitly accounts for the photometric
redshift probability distribution of
galaxies and allows us to explore the critical trade-off between catalog completeness and purity. We investigate how the matched sample changes with different optical selection depths, defined by absolute magnitude cuts of $M_r$ < -18.5, -19, -19.5, and -20 sampling
redshifts within 0.08 < z < 0.25, and across purity levels of 80%, 90%, and 95%. We find that fainter optical cuts enhance the recovery of low-mass, low-luminosity groups, while brighter cuts favor more massive clusters and increase the effective survey volume at higher
redshifts. Stricter purity requirements reduce contamination but systematically lower completeness, particularly for low-luminosity systems. The derived X-ray luminosity functions agree well with previous determinations, and the logN-logS distributions confirm the high recovery rate of luminous clusters. Comparisons with the redMaPPer cluster catalog validate our approach, showing consistent trends and significant overlap, while our method offers improved completeness at the group scale. This work demonstrates a robust, flexible methodology for creating reliable multi-wavelength cluster catalogs, essential for cosmological studies and investigations of
galaxy evolution in dense environments.
Read the full abstract ▾
All authors L. Doubrawa, A. Finoguenov, E. S. Cypriano, C. Mendes de Oliveira, E. V. Lima, L. Nakazono, G. Souza, J. Comparat, A. Gonzalez, R. Demarco, A. Kanaan, T. Ribeiro, W. Schoenell
Cosmology and Nongalactic Astrophysics
S-PLUS Clusters And Large-scale Environments (SCALE): I. A catalog of known clusters and groups in DR5 and a pilot study of Abell 4038
C. Mendes de Oliveira, N. M. Cardoso, P. A. A. Lopes et al. (+26 more)
Within the framework of the Southern Photometric Local Universe Survey (S-PLUS), we introduce ${\bf S}$-PLUS ${\bf C}$lusters ${\bf A}$nd ${\bf L}$arge-scale ${\bf E}$nvironments (SCALE), a project dedicated to the study of
galaxy clusters, groups, and their environments using 12-band photometry of S-PLUS combined with spectroscopic and photometric data from the literature. In this first paper, we present a catalog of 83 previously known systems in the
redshift range $0.008 \leq z_{\rm spec} \leq 0.1$, for which we derive $R_{200}$, $M_{200}$, and velocity dispersions. Spectroscopic members are selected and matched with S-PLUS photometric
redshifts (photo-$z$s). We find very good agreement between literature spectroscopic
redshifts (spec-$z$s) and S-PLUS photometric
redshifts (photo-$z$s), demonstrating the potential of the latter for cluster and group membership determination. As a proof of concept, we obtain photometric memberships for Abell 4038 using the Reliable Photometric Membership technique. A two- and three-dimensional analysis of the region within $10 h^{-1}$ Mpc ($10\times R_{200}$) from the center of Abell 4038 reveals about a dozen substructures including two additional clusters within $1.3\times R_{200}$ (Abell 4038B and Abell 4049). A color-luminosity segregation analysis shows that more luminous (less luminous)
galaxies are redder (bluer), as expected. Low-concentration
galaxies ($C \leq 2.5$) exhibit a weaker color-luminosity dependence, compared to higher-concentration ones, indicating mass-dependent evolutionary pathways that challenge a simple morphology-color dichotomy, with low-luminosity
galaxies presenting bluer colors largely independent of concentration. The SCALE catalog provides a valuable basis for future studies of large-scale structures and their connection to
galaxy evolution.
Read the full abstract ▾
All authors C. Mendes de Oliveira, N. M. Cardoso, P. A. A. Lopes, A. L. B. Ribeiro, D. E. Olave-Rojas, A. Krabbe, L. Sodré Jr., R. Demarco, A. V. Smith Castelli, R. Cid Fernandes, F. R. Herpich, S. Torres-Flores, E. R. Carrasco, E. V. R. Lima, G. Oliveira Schwarz, A. P. Costa, L. Doubrawa, G. P. Montaguth, C. Lima-Dias, E. S. Cypriano, M. S. Carvalho, C. Lobo, M. Fonseca-Faria, L. Nakazono, A. R. Lopes, F. Almeida-Fernandes, A. Kanaan, T. Ribeiro, W. Schoenell
Mathematical Physics
Van Vleck spectra of high-order Heun operators:\ finite-band universality and exterior asymptotics
Boris Shapiro
We study high-order analogues of the classical Heun operator of Fuchs index one, \[ \dq=\sum_{i=1}^k Q_i(z)\frac{d^i}{dz^i}, \qquad \deg Q_i\le i+1, \qquad \deg Q_k=k+1. \] For a fixed degree $n$ we consider the linear Van Vleck
polynomials $V$ for which $\dq+V$ has a
polynomial solution of degree $n$, and we form the spectral
polynomial $Sp_n$ whose zeros are the zeros of these Van Vleck
polynomials. The main result is a finite-band determinant representation and the resulting universality
theorem: after normalization, all fixed power sums of the zeros of $Sp_n$ have limits given by explicit constant-term formulae depending only on the leading coefficient $Q_k$. The lower coefficients of $\dq$ enter only lower order correction terms. Combining this with the localization
theorem for Van Vleck roots, we strengthen the usual germ-at-infinity conclusion to locally uniform convergence of the normalized Cauchy transforms and logarithmic potentials on the whole exterior of the convex hull of the zeros of $Q_k$. We also prove a determinacy criterion: if the spectral roots are asymptotically confined to a compact set with empty interior and connected complement, then the finite-band moments determine the actual weak limit. In particular, when the zeros of $Q_k$ are collinear the root-counting measures of $Sp_n$ converge weakly to a probability measure supported on the corresponding segment; this limit is independent of all lower coefficients of $\dq$. Finally, we prove holonomicity of the exterior Cauchy transform and derive Picard–Fuchs equations for the WKB periods, with an explicit third-order equation in the first non-classical case $k=3$. The paper ends with a precise mother-body
conjecture for the genuinely complex case, clearly separated from the unconditional results.
Read the full abstract ▾
Quantum Physics
Parametrized-circuit-free quantum regression with variance regularization
Yerassyl Balkybek, Andrey Kardashin, Vladimir V. Palyulin et al. (+1 more)
Quantum regression tasks for predicting properties of
quantum states are commonly addressed using variational
quantum algorithms. While variational
quantum circuits are highly expressive and allow to achieve reasonable accuracy, training these
circuits may demand a considerable amount of time and resources. In this work, we propose an approach of constructing problem-specific
quantum regression models with encoding relevant
symmetries and regularizing the variance. The proposed method is based on finding the coefficients of the linear combination of suitably chosen observables. Although it requires the knowledge of the
symmetries of the problem in question, the method does not involve parameterized
quantum circuits, and the training is done efficiently once the observables are measured. We demonstrate this method on two examples: Prediction of the transverse field strength in the Ising model, and quantification of
entanglement in bipartite
qubit systems. Our approach is accurate and less resource-intensive than conventional variational methods.
Read the full abstract ▾
All authors Yerassyl Balkybek, Andrey Kardashin, Vladimir V. Palyulin, Konstantin Antipin
Mathematical Physics · Cross-listed from math.DS
Variational integrators using forced discrete Hamiltonian systems
M. I. Caruso, J. Fernandez, C. I. Tori et al. (+1 more)
We study discrete
Hamiltonian systems defined on cotangent bundles that are subjected to external forces, whose trajectories are determined by a discrete variational principle. We analyze the
evolution of the canonical
symplectic structure and, when a Lie group of
symmetries is present, the corresponding
evolution of the associated momenta. Given a continuous forced
Hamiltonian system, we construct an exact discrete analogue whose order-$r$ approximations yield trajectories that approximate the continuous ones with accuracy of at least order $r$. We also give two methods to build approximate discrete systems. Combining these, we obtain a variational integrator: first approximate the exact discrete system and then solve the resulting algebraic equations of motion.
Read the full abstract ▾
All authors M. I. Caruso, J. Fernandez, C. I. Tori, M. Zuccalli
Geophysics · Cross-listed from cs.CV
Property-Constrained 3D Porous Media Reconstruction from 2D Images via Conditional Generative Adversarial Networks
Ali Sadeghkhani, Brandon Bennett and Arash Rabbani
This study presents a conditional Generative
Adversarial Network (cGAN) framework for generating 3D porous media volumes with controlled porosity, trained exclusively on 2D thin section images. The key innovation lies in combining property-conditioned generation with 2D-to-3D reconstruction, eliminating the need for expensive 3D training data while maintaining control over petrophysical properties. The framework employs a hybrid architecture with a 3D generator and 2D discriminator, where multi-axis slice extraction enables learning 3D-consistent structures from 2D training data. Porosity labels are extracted using an Enhanced U-Net
segmentation model. The methodology was demonstrated on two carbonate samples with different lithologies: dolomite-anhydrite and pure dolomite. Results show that the framework successfully generates realistic 3D volumes capturing lithological features such as anhydrite inclusions and fine crystalline textures. Porosity control achieved an $R^2$ of 0.93, with mean absolute errors of 0.019 and 0.010 for the heterogeneous and homogeneous samples, respectively.
Read the full abstract ▾
Earth and Planetary Astrophysics
Multistage Rocket Optimization, Geophysics, and the Spacefaring Envelope of Habitable Super-Earths
Sanjoy M. Som
Habitability is typically defined by whether a
planet can support life, rather than whether it can support a technological civilization capable of escaping its
gravity well. We introduce spacefaring capability as a technological axis of habitability, defined by the ability to place a 1000 kg payload on an escape trajectory using chemical propulsion. We develop a coupled geophysical–atmospheric–astronautical model that maps this “spacefaring envelope” as a function of planetary mass and surface pressure. Building on Hippke (2018) and Gonzalez (2020), we optimize multistage chemical rockets by minimizing the reliability-weighted expected launch mass while determining the optimal stage count, first-stage engine number, and mission reliability. Assuming F-1-class first-stage engines, the model reproduces the Saturn V gross lift-off mass to within $\sim\!30\%$ and the F-1 turbopump power to within $\sim\!18\%$. Over $0.1$–$10$~bar, atmospheric pressure changes the required launch mass by up to $\sim\!35\%$ on $0.5\,M_\oplus$
planets, where drag contributes substantially to the ascent $\Delta v$, but by only a few percent for $M_\oplus \gtrsim 4$.
Gravity, rather than atmospheric drag, therefore sets the primary limit on chemical escape from super-Earths. Imposing a post-optimization limit of $\sim\!100$ F-1-class first-stage engines renders escape of the
benchmark payload impractical above $\sim\!11.5\,M_\oplus$. This engine-counting constraint independently corroborates the $\sim\!10\,M_\oplus$ limit derived by Hippke (2018) from an engine-independent fuel-ratio argument. These results provide a physically motivated framework for assessing whether rocky
exoplanets are capable of supporting technological civilizations that can escape their planetary
gravity wells.
Read the full abstract ▾
Optics
Nonlinear Self-Action across Temporal Regimes in Resonant Dielectric Metasurfaces
Alfonso Nardi, Sonia Freddi, Michael Scalora et al. (+8 more)
Quasi-bound states in the continuum (qBICs) enable exceptional field confinement, strongly reducing the pump intensity threshold for nonlinear light-matter interaction in dielectric metasurfaces. As a result, nonlinear self-action effects, often elusive in bulk nonlinear media, emerge at moderate excitation intensities. Here, nonlinear self-action in resonantly enhanced third-harmonic (TH) generation from a dielectric metasurface supporting a qBIC resonance is investigated across distinct temporal excitation regimes. These regimes establish different coupling conditions between the excitation and the resonant mode, causing the same nonlinear self-action to emerge through complementary intensity-dependent signatures. Under spectrally narrow picosecond excitation, resonance-enhanced TH generation shows pronounced deviations from cubic scaling at high intensities. In contrast, broadband femtosecond excitation transiently drives the resonance, encoding the nonlinear response in the spectral reshaping and broadening of the TH signal. Simulations reproduce both regimes: continuous-wave modeling captures picosecond power scaling and the role of higher-order nonlinear susceptibilities, while time-domain simulations resolve femtosecond dynamics. These results clarify how pulse duration, bandwidth, and resonant coupling determine the observable signatures of nonlinear self-action in resonant dielectric metasurfaces, linking field confinement to conversion efficiency, power-law scaling, and ultrafast spectral dynamics.
Read the full abstract ▾
All authors Alfonso Nardi, Sonia Freddi, Michael Scalora, Agostino Di Francescantonio, Johann Osmond, Sofia Martins, Attilio Zilli, Marco Finazzi, Michele Celebrano, Monica Bollani, Maria Antonietta Vincenti
Earth and Planetary Astrophysics
The Longest-period Young Transiting Exoplanets. A Duo of Puffy Giants inside a Debris Disk
Carlos del Burgo, Alejandro Suárez Mascareño, Ana Heras Pastor et al. (+35 more)
We identify two large-radius
planets around the F-type
star HD 114082 as the longest-period young transiting
exoplanets known. From the first transit, detected by NASA's Transiting
Exoplanet Survey Satellite (TESS), and a second dip, spotted by the Next-Generation Transit Survey (NGTS), we predicted mid-transit times for HD 114082 b (
planet b). We pinpoint its orbit (period Pb= 225.5504$\pm$0.0004 days) from a third transit captured with the ESA's CHaracterising
ExOplanet Satellite and the upgraded Antarctic Search for Transiting
ExoPlanets telescope (ASTEP+), alongside orbit-discriminating observations. Another dimming partly covered by ASTEP+ completes the four-transit series. We support with dynamical evidence the planetary nature of a deeper transit detected with TESS and NGTS, identifying
planet c. Additionally, we reexamine the debris disk, fitting its excess emission with two
dust components. Fundamental
stellar parameters are inferred from
stellar evolution models, while a joint modeling of photometric and radial-velocity time series yields the planetary parameters, with masses further constrained using an N-body code. For
planet b, the semimajor axis a$_b$= 0.791$\pm$0.008 au, eccentricity eb$\approx$ 0, inclination ib= 89.791$\pm$0.014 degrees, radius Rb= 1.046$\pm$0.014 R$_J$, and 95 % confidence upper limit on its mass M$_{95\%,b}$= 1.6 M$_J$. For
planet c, a$_c$= 0.99$^{+0.03}_{-0.04}$ au, ec$\approx$ 0, i$_c$= 89.701$\pm$0.011 degrees, R$_c$= 1.36$\pm$0.03 R$_J$, and M$_{95\%,c}$= 2.0 M$_J$ (0.24 M$_J$ if adding transit timing variation constrains). They seem to be moderate-to-low-mass
giants in nearly resonant, coplanar, circular orbits that formed in situ, or beyond the snowline, and migrated inwards, shaping the disk.
Read the full abstract ▾
All authors Carlos del Burgo, Alejandro Suárez Mascareño, Ana Heras Pastor, Jonathan P. Marshall, Peter J. Wheatley, Edward M. Bryant, Samuel Gill, Jorge Fernández Fernández, David R. Anderson, Matthew P. Battley, Edward Gillen, Solène Ulmer-Moll, James McCormac, Monika Lendl, Ioannis Apergis, Faith Hawthorn, James S. Jenkins, Maximiliano Moyano, Louise D. Nielsen, Alexis M. S. Smith, Suman Saha, Stéphane Udry, Jose I. Vines, Richard G. West, Daniel Bayliss, Hugh P. Osborn, Tristan Guillot, Amaury H. M. J. Triaud, Olga Suarez, Matteo Beltrame, Abdelkrim Agabi, Isabella Pagano, Matthew J. Hooton, Matthew R. Burleigh, Lyu Abe, Philippe Bendjoya, Georgina Dransfield, Djamel Mékarnia
Earth and Planetary Astrophysics
On the Eccentricity Distribution and Tidal Evolution of Transiting Brown Dwarfs
Thiago Ferreira and Malena Rice
Brown
dwarfs on short-period orbits populate an intermediate regime between hot Jupiters and tight
stellar binaries, lying at the intersection of possible evolutionary avenues. Their orbital eccentricities retain the dynamical imprint of both their formation pathways and any subsequent
tidal evolution, providing a diagnostic for whether such objects formed in situ at small separations or were driven inward from higher-eccentricity orbits shaped by
tidal dissipation. Using a hierarchical
Bayesian framework, we characterise the orbital eccentricity distribution of transiting brown
dwarfs. Short-period brown
dwarfs ($P < 16$ days) are well represented by a Beta distribution with $\alpha < 1$ and $\beta > 1$, indicating a population concentrated at low eccentricities, whereas longer-period brown
dwarfs ($P \geq 16$ days) display $\alpha,~\beta > 1$ and therefore occupy a more dynamically excited regime. This difference in eccentricity distributions likely reflects corresponding differences in the populations' eccentricity-damping timescales: close-in systems may evolve toward circular orbits on relatively short timescales, whilst wider companions experience negligible
tidal processing over their lifetimes. Assuming that the full set of transiting brown
dwarfs stems from a single
primordial eccentricity distribution, {we constrain the typical brown
dwarf tidal quality factor to $\mathcal{Q}_{\rm BD} = 10^{8.1\pm1.0}$ when neglecting the influence of tides raised on the host
star, or $\mathcal{Q}_{\rm BD} = 10^{7.1\pm0.3}$ and $\mathcal{Q}_{\star} = 10^{6.0\pm0.1}$ when they are included.
Read the full abstract ▾
Earth and Planetary Astrophysics
Detection and identification of asteroids with the 4-m ILMT
Sara Filali, Bhavya Ailawadhi, Talat Akhunov et al. (+11 more)
The International
Liquid Mirror
Telescope (ILMT) covers a 22.3' wide strip of sky in declination ({\delta}), centred at {\delta} = +29{\deg} 21' 41.4” and right ascension ({\alpha}) in the range 0 h <= {\alpha} < 24 h. Having a short focal length (f /D ~ 2.4) and a large diameter (4 m), makes the ILMT an excellent asteroid hunter. The ILMT began its 4th cycle in October 2024, running through May 2025. The astrometric accuracy has been improved to 0.1” , and the PyLMT - a detection and classification pipeline -, has been fine-tuned using data from previous cycles. The current detection rate is tens of transients detected each night with high accuracy in classification and identification. We present statistical results for the asteroids detected during ILMT's Cycles 1-4. We first evaluate the astrometric performance of the detections across different ecliptic latitude ranges. We then describe the positions, apparent motions, and V magnitudes predicted by the Minor
Planet Center (MPC) for the asteroids observed in the SDSS g', r', and i' bands. Finally, we assess the ILMT's potential for detecting near-Earth objects (NEOs), potentially hazardous asteroids (PHAs), and comets.
Read the full abstract ▾
All authors Sara Filali, Bhavya Ailawadhi, Talat Akhunov, Monalisa Dubey, Naveen Dukiya, Paul Hickson6, Priyanshi Kumari, Gokul Singh Mehra, Kuntal Misra, Vibhore Negi, Anna Pospieszalska-surdej, Kumar Pranshu, Jean Surdej, Sarvesh Kumar Yadav
Quantum Physics
Quench Spectroscopy of Magnetic Excitations on a Superconducting Quantum Processor
D. A. Millar, G. W. Pennington, N. T. M. Siow et al. (+5 more)
The elementary excitation spectrum of a many-body
quantum system encodes many key properties, including phenomena as diverse as transport, thermalisation and ground state structure. Excitation spectra of strongly correlated systems are typically encoded in dynamical structure factors, which are demanding to measure experimentally and challenging to compute classically. Here we use quench spectroscopy on a superconducting
quantum processor to extract excitation spectra of
spin chains of $L=101$
spins. By tailoring the combination of quench protocol and observable, we selectively access distinct excitation sectors across several phases of the
spin-$1/2$ XXZ chain, resolving free
magnons, multi-
magnon bound states, and two-spinon continua. Notably, we demonstrate that the protocol does not rely on ground state preparation: in the classically challenging gapless regime, we extract spectra directly from the quench dynamics of easily prepared product states, a procedure that is natural and straightforward on
quantum hardware. Our work establishes quench spectroscopy as a fast and flexible probe of many-body excitation spectra on digital
quantum hardware, introduces a novel quench protocol that does not require costly state preparation routines, and provides a scalable route towards regimes where classical simulation may become intractable.
Read the full abstract ▾
All authors D. A. Millar, G. W. Pennington, N. T. M. Siow, S. Brandhofer, J. Crain, F. H. L. Essler, A. G. Green, S. J. Thomson