Showing 1–50 of 314 results for author: Reyes, A

Diagonalization of the Landau Hamiltonian with a Periodic Potential via a Galerkin Projection Method and Applications to Topological Band Properties

Authors: Rafael Antonio Lainez Reyes, Benjamin Stamm, Hans Peter Büchler

Abstract: In this paper, we study the numerical computation of eigenfunctions of the Landau Hamiltonian with a periodic potential. We propose a spectral method using the eigenfunctions of the Landau operator that allows us to numerically compute the band structure for potentials of different strengths, including the well-studied weak and strong potentials, and additionally systems in the intermediate regime… ▽ More In this paper, we study the numerical computation of eigenfunctions of the Landau Hamiltonian with a periodic potential. We propose a spectral method using the eigenfunctions of the Landau operator that allows us to numerically compute the band structure for potentials of different strengths, including the well-studied weak and strong potentials, and additionally systems in the intermediate regime. We then apply the method to simulations across the full range of coupling constants from weak to strong coupling and present an analysis of the band structure as a function of the potential strength. △ Less

Submitted 20 August, 2026; originally announced August 2026.

On the achromatic index of Johnson graphs $J(n,2)$

Authors: Gabriela Araujo-Pardo, Cristina Dalfó, Mónica Reyes

Abstract: In this paper, we study proper and complete edge-colorings of Johnson graphs $J(n,2)$, also called $n$-triangular graphs. They are isomorphic both to the 2-token graphs of complete graphs and to the line graphs of complete graphs. A $t$-edge-coloring of a graph $G$ is a function that assigns one color from $\{1,2,\ldots,t\}$ to each edge. Such a coloring is called proper if no two incident edges r… ▽ More In this paper, we study proper and complete edge-colorings of Johnson graphs $J(n,2)$, also called $n$-triangular graphs. They are isomorphic both to the 2-token graphs of complete graphs and to the line graphs of complete graphs. A $t$-edge-coloring of a graph $G$ is a function that assigns one color from $\{1,2,\ldots,t\}$ to each edge. Such a coloring is called proper if no two incident edges receive the same color, and complete if every pair of distinct colors appears on a pair of incident edges. The achromatic index, denoted by $α_2(G)$, is the largest integer $t$ for which $G$ admits a proper and complete $t$-edge-coloring. We establish new lower and upper bounds for $α_2(J(n,2))$, provide explicit proper and complete edge-colorings attaining the lower bounds, and determine the exact value of $α_2(J(n,2))$ for several values of $n$. △ Less

Submitted 5 August, 2026; originally announced August 2026.

Comments: 18 pages, 2 figures

MSC Class: 05C15

Morphologies of SAGAbg low-mass galaxies in Legacy Survey multi-band imaging: dependence on stellar masses, star-formation rates and low-redshift evolution

Authors: Joy Bhattacharyya, Guinevere Herron, Yasmeen Asali, Abby Mintz, Mithi A. C. de los Reyes, Yao-Yuan Mao, Annika H. G. Peter

Abstract: The optical morphologies of low-mass galaxies can be used to directly trace their assembly and constrain models of galaxy evolution. We select a sample of 6211 low-mass ($7\lesssim {\rm log}(M_{\ast}/M_{\odot})\lesssim 10$) star-forming galaxies from the SAGAbg catalog that has high-completeness at low-redshifts ($z<0.1$). We obtain their galaxy maps in the $griz$ - bands of the Legacy Surveys and… ▽ More The optical morphologies of low-mass galaxies can be used to directly trace their assembly and constrain models of galaxy evolution. We select a sample of 6211 low-mass ($7\lesssim {\rm log}(M_{\ast}/M_{\odot})\lesssim 10$) star-forming galaxies from the SAGAbg catalog that has high-completeness at low-redshifts ($z<0.1$). We obtain their galaxy maps in the $griz$ - bands of the Legacy Surveys and apply STATMORPH to calculate non-parametric morphological measures including the Gini index, $M_{20}$ measure, and CAS parameters. We study how resolution and signal-to-noise affect the morphology measures and find that the bulge strength measurements are the most reliable. The sequence in Gini$-M_{20}$ space is directly linked to the star-forming sequence of galaxies and is dominated by Sb/Sc/Ir morphologies. The $g$-band light distributions are the least concentrated among all the bands. The systematic trends of $M_{20}$ with respect to stellar mass and GALEX NUV-derived specific star formation rate (sSFR) strongly indicate that the galaxies with flatter light profiles are less massive with higher sSFR and vice-versa. We statistically infer that star-forming low-mass galaxies predominantly have disk morphologies with bulges becoming more prominent in quenched systems at higher masses (${\rm log}(M_{\ast}/M_{\odot})\gtrsim 9$). △ Less

Submitted 17 July, 2026; originally announced July 2026.

Comments: 24 pages, 16 figures. Submitted to ApJ

Electron stability constrains neutrino time delays

Authors: Mauricio Bustamante, José Manuel Carmona, José Luis Cortés, Ardit Gkioni, Maykoll A. Reyes

Abstract: Superluminal neutrino propagation, induced by Lorentz-invariance violation (LIV), is strongly constrained by vacuum pair emission, $ν\to ν+ e^- + e^+$, a process ordinarily forbidden, which rapidly degrades the energy of high-energy neutrinos. Consequently, observable neutrino time delays are often preferentially associated with subluminal propagation, prompting LIV interpretations of claimed time… ▽ More Superluminal neutrino propagation, induced by Lorentz-invariance violation (LIV), is strongly constrained by vacuum pair emission, $ν\to ν+ e^- + e^+$, a process ordinarily forbidden, which rapidly degrades the energy of high-energy neutrinos. Consequently, observable neutrino time delays are often preferentially associated with subluminal propagation, prompting LIV interpretations of claimed time delays between high-energy cosmic neutrinos and gamma rays. However, this expectation is at odds with the observed stability of high-energy electrons. The same Lorentz-violating correction associated with subluminal neutrino propagation opens the overlooked complementary decay channel $e^- \to e^- + ν+ \barν$, leading to electron instability. We derive constraints on LIV from recent observations of TeV--PeV astrophysical electrons. These electron stability limits rule out LIV invoked to explain delays of high-energy cosmic neutrinos. Consequently, neutrino time delays are constrained on both the superluminal and subluminal sides. Therefore, observable delays require either purely astrophysical origins, a realization of LIV that affects all particle species equally, or physics beyond the standard effective-field-theory framework. △ Less

Submitted 1 July, 2026; originally announced July 2026.

Comments: 6 pages, 2 figures, plus appendices

Detection and characterisation of binary asteroid candidates through stellar occultations

Authors: R. Lallemand, J. Desmars, B. Sicardy, Z. Liu, P. Tanga, L. Liberato, B. Carry, A. Leroy, Y. Kilic, M. Assafin, A. Siakas, L. Abe, D. Mary, R. Leiva, F. Casarramona, D. Smith, D. Antuszewicz, J. -L. Dauvergne, G. Langin, P. Henarejos, P. -L. Phan, F. Braga-Ribas, A. Castro, A. Pal, Á. Sódor , et al. (234 additional authors not shown)

Abstract: Binary asteroids provide key access to fundamental parameters of Solar System remnants and planetary formations. However, the current knowledge of binary asteroids remains strongly biased by observational limitations, and main belt binary systems are still poorly characterised since current techniques preferentially detect either widely separated binaries close and bright systems. In this context,… ▽ More Binary asteroids provide key access to fundamental parameters of Solar System remnants and planetary formations. However, the current knowledge of binary asteroids remains strongly biased by observational limitations, and main belt binary systems are still poorly characterised since current techniques preferentially detect either widely separated binaries close and bright systems. In this context, the high-precision astrometry of the Gaia mission has revealed a new population of candidate binaries exhibiting dynamical signatures consistent with unresolved companions. This work is part of the GaiaMoons program, and our aim with it was to characterise a sample of 357 potential binary asteroid targets and confirm or refute their binary nature. The properties of these candidates were derived from the high-precision photometric and astrometric observations provided by Gaia. We adopted stellar occultation as the observational method to study these targets. Between October 2023 and February 2026, we successfully carried out 165 observations for 101 targets. We subsequently analysed these events in the context of the available literature and previously reported observations. Thirty three observation led at least two positives for 24 objects that have undergone unprecedented occultation observation campaigns, with four objects showing indications of binary or contact binary features, namely 1127 Mimi, 35420 1998 AG6, 206 Hersilia, and 36882 2000 SW155. For the vast majority of these objects, the resulting dataset from all reduced observations provides unique physical and astrometric constraints, as they had never been observed through stellar occultations before. GaiaMoons illustrates how stellar occultation campaigns associated with Gaia observations generate a self-improving cycle to find new binary, thereby probing size and shape to constrain future observations. △ Less

Submitted 12 June, 2026; v1 submitted 11 June, 2026; originally announced June 2026.

On the category of semi-graded modules

Authors: Armando Reyes

Abstract: Lezama \cite{LezamaLatorre2017} introduced the notion of semi-graded ring with the aim of generalizing $\mathbb{Z}$-graded rings and several families of noncommutative rings of polynomial type non-$\mathbb{N}$-graded such as the skew Poincaré-Birkhoff-Witt extensions defined by him \cite{GallegoLezama2010}. In a series of papers, \cite{Lezama2020, Lezama2021, LezamaGomez2019, LezamaLatorre2017}, h… ▽ More Lezama \cite{LezamaLatorre2017} introduced the notion of semi-graded ring with the aim of generalizing $\mathbb{Z}$-graded rings and several families of noncommutative rings of polynomial type non-$\mathbb{N}$-graded such as the skew Poincaré-Birkhoff-Witt extensions defined by him \cite{GallegoLezama2010}. In a series of papers, \cite{Lezama2020, Lezama2021, LezamaGomez2019, LezamaLatorre2017}, he studied problems of non-commutative projective algebraic geometry generalizing the original ideas of Artin et al. \cite{Artin1992, ArtinSchelter1987, ArtinTateVandenBergh2007, ArtinTateVandenBergh1991, ArtinZhang1994} on $\mathbb{N}$-graded rings, in the categorical context of the category $\mathsf{SGR}-R$ of left semi-graded modules over a semi-graded ring $R$. In this note we prove that $\mathsf{SGR}-R$ possesses a canonical set of free generators via shifted twists, which endows the category with a {\em Grothendieck structure} and guarantees the existence of enough injective and projective objects. This categorical robustness allows us to formulate a semi-graded analogue of Baer's criterion for injectivity and to establish a first approach to the dual theory of projective resolutions using shifted twists. △ Less

Submitted 25 May, 2026; originally announced May 2026.

Comments: 14 pages

MSC Class: 14A22; 16S38; 16S80; 16U20; 16W60

First-principles finite-size correction schemes for point defects of Cu$_3$N

Authors: Abdul M. Reyes, Sebastian E. Reyes-Lillo, Eduardo Menéndez-Proupin

Abstract: Point defects play a key role in determining semiconductor properties, such as electrical conductivity and photoluminescence, and often enable functional behavior. Accurate first-principles supercell simulations of point defects require reliable finite-size corrections. In this study, we combine PBE+U structural relaxations with HSE hybrid-functional calculations to determine defect formation ener… ▽ More Point defects play a key role in determining semiconductor properties, such as electrical conductivity and photoluminescence, and often enable functional behavior. Accurate first-principles supercell simulations of point defects require reliable finite-size corrections. In this study, we combine PBE+U structural relaxations with HSE hybrid-functional calculations to determine defect formation energies and thermodynamic transition levels of Cu$_3$N. Finite-size trends are quantified using $Γ$-point calculations in supercells containing 256, 864, and 2048 atoms. We assess and extend the Makov-Payne and Lany-Zunger correction schemes by introducing additional $1/L^n$ terms, together with core-level potential alignment and defect-specific scaling models. Using Cu$_3$N as a case study, we show that charged vacancies with strongly localized defect states are accurately described by the Makov-Payne-type scaling ($1/L + 1/L^{3}$), whereas interstitial defects with shallow or weakly localized electronic character are better captured by a hydrogenic impurity model that accounts for defect-band dispersion. Residual trends for neutral or weakly localized defects are described by higher-order polynomial fits in $1/L^{3}$ and $1/L^{4}$. Hybrid-functional energetics corrected using PBE+U-based finite-size trends confirm the intrinsic $p$-type character of Cu$_3$N under the conditions considered and demonstrate that no single finite-size correction can be transferred across all defect types. △ Less

Submitted 24 May, 2026; originally announced May 2026.

Comments: 13 pages, 10 figures

$V/σ$ Trends with Mass for Dwarf Galaxies from the Marvelous Massive Dwarfs Suite

Authors: Dilys Ruan, Alyson M. Brooks, Leonardo A. Barba, Mithi A. C. de los Reyes, Akaxia Cruz, Robel Geda, Annika H. G. Peter, Benjamin W. Keller, Thomas Quinn, James W. Wadsley

Abstract: Galaxy formation scenarios can be interpreted through galaxy morphology and the level of rotational versus pressure support, quantified through the ratio of a galaxy's rotation speed to its velocity dispersion: $V/σ$. Observational studies of dwarf galaxies find that $V/σ$ does not strongly depend on environment, and may weakly depend on galaxy mass, which could shift our understanding of how dwar… ▽ More Galaxy formation scenarios can be interpreted through galaxy morphology and the level of rotational versus pressure support, quantified through the ratio of a galaxy's rotation speed to its velocity dispersion: $V/σ$. Observational studies of dwarf galaxies find that $V/σ$ does not strongly depend on environment, and may weakly depend on galaxy mass, which could shift our understanding of how dwarf galaxies form. We utilize the Marvelous Massive Dwarfs suite to examine whether $V/σ$ depends on mass in simulations, and understand how this varies for different baryonic components of the galaxy: HI gas, young stars ($<$ 1 Gyr) and old stars ($>$ 1 Gyr). We use a simulation sample of 67 isolated dwarf galaxies with M$_\star=10^6-10^9$ M$_\odot$ and produce line-of-sight maps for rotation speed and dispersion for different viewing angles of each galaxy. We find that $V/σ$ increases with mass, and that HI gas and young stars are more rotation-supported ($V/σ\approx 1-13$) while old stars are more dispersion-supported ($V/σ\approx 0.2-5$). This result is consistent with the scenario where young stars are born from dynamically cold gas in the interstellar medium and undergo dynamical heating over time. We quantify the effects of spatial resolution in observational determinations of $V/σ$ and find that existing observations using old stars may underestimate the intrinsic $V/σ$. We find a correlation between $V/σ_\mathrm{HI,global}$ and HI line profile shape that is qualitatively similar to previous simulation results, but we find higher $V/σ_\mathrm{HI,global}$ compared to prior work which found values $\lesssim 2$ for most galaxies in this mass range. Our results motivate future work to examine $V/σ$ and dwarf galaxy formation with different kinematic tracers of the galaxy. △ Less

Submitted 7 May, 2026; originally announced May 2026.

Comments: 26 pages, 12 figures, submitted to ApJ

Combinatorial aspects of normal ordering of 3-dimensional skew polynomial rings

Authors: Andrés Rubiano, Armando Reyes

Abstract: In this paper, we discuss combinatorial aspects of normal ordering of 3-dimensional skew polynomial rings defined and classified by Bell and Smith \cite{BellSmith1990}. With some help of the Mathematical software \texttt{SageMath}, we are able to reduce the length of computation of PBW forms and normal orderings appearing in commutation rules of these algebras. In this paper, we discuss combinatorial aspects of normal ordering of 3-dimensional skew polynomial rings defined and classified by Bell and Smith \cite{BellSmith1990}. With some help of the Mathematical software \texttt{SageMath}, we are able to reduce the length of computation of PBW forms and normal orderings appearing in commutation rules of these algebras. △ Less

Submitted 14 May, 2026; v1 submitted 4 May, 2026; originally announced May 2026.

Comments: 61 pages

MSC Class: 05A05; 05A10; 05A15; 05A19; 11B73; 11B75; 13N15; 16S15; 16S32; 16S36; 16S38; 16T30

Development of Anisotropic Magnetized Viscosity for Magnetized Liner Inertial Fusion Simulations in FLASH

Authors: Ashwyn Sam, Fernando Garcia-Rubio, Scott Davidson, C. Leland Ellison, Jason Hamilton, Raymond Lau, Nathan Meezan, Adam Reyes, Paul Schmit, Alexander Velikovich

Abstract: Magnetized liner inertial fusion (MagLIF) operates in a regime where anisotropic transport phenomena fundamentally influence implosion dynamics. In strongly magnetized plasmas, the viscous stress tensor becomes highly anisotropic, yet no prior work has incorporated or examined magnetized viscosity effects in MagLIF configurations. We present the first implementation of the full Braginskii magnetiz… ▽ More Magnetized liner inertial fusion (MagLIF) operates in a regime where anisotropic transport phenomena fundamentally influence implosion dynamics. In strongly magnetized plasmas, the viscous stress tensor becomes highly anisotropic, yet no prior work has incorporated or examined magnetized viscosity effects in MagLIF configurations. We present the first implementation of the full Braginskii magnetized viscosity tensor for arbitrary magnetic field orientations in the Pacific Fusion branch of FLASH. The implementation is verified through analytical comparisons, direct verification against Braginskii's original formulation, Method of Manufactured Solutions, and against analytical shock solutions. Application to MagLIF-relevant configurations reveals that magnetized viscosity damps vortical structures, converts kinetic energy in those vortical structures into thermal energy, and mitigates the Rayleigh-Taylor instabilities. Simulations with seeded perturbations demonstrate yield preservation when magnetized viscosity is included. These results establish magnetized viscosity as a non-negligible physical mechanism in MagLIF plasmas and provide a validated capability for predictive modeling of magnetized high-energy-density plasmas. △ Less

Submitted 22 April, 2026; originally announced April 2026.

CRITERIA: A network decomposition and elementary flux mode translation-based tool for computing equilibria of biochemical systems

Authors: Exequiel Jun V. Villejo, Aurelio A. de los Reyes V, Bryan S. Hernandez

Abstract: Understanding how biochemical systems settle into stable states, such as how protein concentrations reach equilibrium, is central to explaining cellular behavior and designing synthetic biological circuits. However, existing analytical tools for computing these equilibria, such as COMPILES, are limited by computational bottlenecks and can only be applied to a restricted class of reaction networks.… ▽ More Understanding how biochemical systems settle into stable states, such as how protein concentrations reach equilibrium, is central to explaining cellular behavior and designing synthetic biological circuits. However, existing analytical tools for computing these equilibria, such as COMPILES, are limited by computational bottlenecks and can only be applied to a restricted class of reaction networks. In this work, we introduce CRITERIA (Computing paRametrized posITive EquilibRIA), a new computational framework that makes equilibrium analysis more efficient and broadly applicable. CRITERIA uses a graph-based approach built on elementary flux modes to streamline key steps in the computation. It also changes how the problem is solved by combining subnetworks into a single system before computing equilibria, which avoids complicated symbolic calculations required in previous methods. We demonstrate the usefulness of CRITERIA by studying biologically important systems, including the EnvZ-OmpR signaling pathway and a synthetic CRISPRi circuit. Our approach enables faster and more scalable analysis, allowing researchers to better understand how complex biochemical networks behave over time. △ Less

Submitted 22 April, 2026; originally announced April 2026.

Noncommutative differential geometry of ambiskew polynomial rings

Authors: Andrés Rubiano, Armando Reyes

Abstract: We determine sufficient criteria for the differential smoothness of ambiskew polynomial rings defined and studied by D. A. Jordan in several papers \cite{FishJordan2019, Jordan1993b, Jordan2000, JordanWells2013}. We determine sufficient criteria for the differential smoothness of ambiskew polynomial rings defined and studied by D. A. Jordan in several papers \cite{FishJordan2019, Jordan1993b, Jordan2000, JordanWells2013}. △ Less

Submitted 14 April, 2026; originally announced April 2026.

Comments: 28 pages

MSC Class: 16E45; 16S30; 16S32; 16S36; 16S38; 58B34

On supertoken graphs

Authors: Mónica A. Reyes, Cristina Dalfó, Miquel Àngel Fiol

Abstract: We generalize the concept of token graphs to obtain supertoken graphs. In the latter case, there can be more than one token in a vertex. We formally define supertoken graphs and establish their basic properties. Moreover, we provide some bounds and exact values on the independence number, clique number, and chromatic number of these graphs. Finally, we construct a new infinite family of graphs, wh… ▽ More We generalize the concept of token graphs to obtain supertoken graphs. In the latter case, there can be more than one token in a vertex. We formally define supertoken graphs and establish their basic properties. Moreover, we provide some bounds and exact values on the independence number, clique number, and chromatic number of these graphs. Finally, we construct a new infinite family of graphs, which we call the $p$-augmented 2-token graphs of cycles, and study their properties, including the spectral radius or largest adjacency eigenvalue. △ Less

Submitted 7 April, 2026; originally announced April 2026.

On the smoothness of 3-dimensional skew polynomial rings

Authors: Andrés Rubiano, Armando Reyes

Abstract: This paper is part of a series of papers in which we have investigated the differential smoothness of families of noncommutative algebras. Here, we consider this topic for the family 3-dimensional skew polynomial rings characterized by Bell and Smith \cite{BellSmith1990}. This paper is part of a series of papers in which we have investigated the differential smoothness of families of noncommutative algebras. Here, we consider this topic for the family 3-dimensional skew polynomial rings characterized by Bell and Smith \cite{BellSmith1990}. △ Less

Submitted 11 March, 2026; originally announced March 2026.

Comments: 19 pages

MSC Class: 16E45; 16S30; 16S32; 16S36; 16S38; 16S99; 16T05; 58B34

It's a matter of time: Empirical Constraints on Supernova Yields and Delay Times from Dwarf Spheroidal Galaxies

Authors: Mairéad E. Heiger, Alexander P. Ji, Joshua S. Speagle, Ting S. Li, Alessandro Savino, Nathan R. Sandford, Evan N. Kirby, Mithi A. C. de los Reyes, Joshua D. Simon

Abstract: The chemical abundances of a stellar population encode information about nucleosynthesis and its astrophysical sites, but this information is confounded by the specific star formation history of the host galaxy. As a result, placing empirical constraints on supernova yields and timing using abundances has been very challenging. We introduce a galactic chemical evolution model DLEIY that uses an ob… ▽ More The chemical abundances of a stellar population encode information about nucleosynthesis and its astrophysical sites, but this information is confounded by the specific star formation history of the host galaxy. As a result, placing empirical constraints on supernova yields and timing using abundances has been very challenging. We introduce a galactic chemical evolution model DLEIY that uses an observed star formation history and metallicity distribution to reduce these confounding factors. Using a joint statistical model of the dwarf spheroidal galaxies Sculptor and Fornax, simultaneous constraints on population-averaged yields and galactic outflows are achieved with DLEIY, without fixing the absolute scale of nucleosynthetic yields. The Fe yield from core collapse supernovae is consistent with existing theoretical yield models, while the measured Mg yield is a factor of 2-4 higher, corroborating previous suggestions that yield models may under-predict [Mg/Fe]. We also find that the rate of Type Ia supernovae is enhanced by about a factor of 5 relative to field galaxies, and the delay-time distribution goes as $\sim t^{-2}$, a much steeper relationship than that measured from supernova surveys ($\sim t^{-1.1}$). These findings may suggest a metallicity dependence of the Type Ia rate and delay-time distribution. △ Less

Submitted 25 February, 2026; originally announced February 2026.

Comments: 26 pages, 13 figures, 4 tables. Submitted to ApJ

Superluminal constraints from ultra-high-energy neutrino events

Authors: J. M. Carmona, J. L. Cortés, M. A. Reyes

Abstract: The $220^{+570}_{-100}\,$PeV neutrino detected by KM3NeT marks the beginning of ultra-high-energy neutrino astronomy and provides a powerful probe of Lorentz Invariance Violation (LIV). In superluminal scenarios, neutrinos can decay through vacuum $e^-e^+$ pair emission or neutrino splitting. Previous analyses of the KM3-230213A event relied on simplified survival-probability estimates and, in som… ▽ More The $220^{+570}_{-100}\,$PeV neutrino detected by KM3NeT marks the beginning of ultra-high-energy neutrino astronomy and provides a powerful probe of Lorentz Invariance Violation (LIV). In superluminal scenarios, neutrinos can decay through vacuum $e^-e^+$ pair emission or neutrino splitting. Previous analyses of the KM3-230213A event relied on simplified survival-probability estimates and, in some cases, used inaccurate decay-width expressions or neglected redshift and threshold effects. In this work we present a unified and self-consistent framework that corrects these issues and applies to both the energy-independent ($n=0$) and quadratic ($n=2$) superluminal cases. We collect and recast the decay-width and threshold expressions, clarify their flavor dependence, and include a consistent treatment of cosmological propagation. We also assess the impact of cascade regeneration and show that cascade effects are negligible for the purpose of setting LIV bounds. The survival-probability approximation adopted in previous works is therefore justified, while our framework provides a coherent basis for future analyses of superluminal neutrino constraints, which should consistently include possible time-delay signatures. △ Less

Submitted 11 March, 2026; v1 submitted 9 December, 2025; originally announced December 2025.

Comments: 12 pages, 4 figures

Journal ref: JCAP 03 (2026) 023

Resource Estimation of CGGI and CKKS scheme workloads on FracTLcore Computing Fabric

Authors: Denis Ovichinnikov, Hemant Kavadia, Satya Keerti Chand Kudupudi, Ilya Rempel, Vineet Chadha, Marty Franz, Paul Master, Craig Gentry, Darlene Kindler, Alberto Reyes, Muthu Annamalai

Abstract: Cornami Mx2 accelerates of Fully Homomorphic Encryption (FHE) applications, enabled by breakthrough work [1], which are otherwise compute limited. Our processor architecture is based on the systolic array of cores with in-memory compute capability and a network on chip (NoC) processor architecture called the "FracTLcore compute fabric processor" (Mx2). Here, we describe the work to estimate proces… ▽ More Cornami Mx2 accelerates of Fully Homomorphic Encryption (FHE) applications, enabled by breakthrough work [1], which are otherwise compute limited. Our processor architecture is based on the systolic array of cores with in-memory compute capability and a network on chip (NoC) processor architecture called the "FracTLcore compute fabric processor" (Mx2). Here, we describe the work to estimate processor resources to compute workload in CGGI (TFHE-rs) or CKKS scheme during construction of our compiler backend for this architecture [2]. These processors are available for running applications in both the TFHE-rs Boolean scheme and CKKS scheme FHE applications. △ Less

Submitted 15 October, 2025; originally announced October 2025.

Comments: 5 tables, 2 figures, conference style

The SAGA Survey. VI. The Size-Mass Relation for Low-Mass Galaxies Across Environments

Authors: Yasmeen Asali, Marla Geha, Erin Kado-Fong, Yao-Yuan Mao, Risa H. Wechsler, Mithi A. C. de los Reyes, Imad Pasha, Nitya Kallivayalil, Ethan O. Nadler, Erik J. Tollerud, Yunchong Wang, Benjamin Weiner, John F. Wu

Abstract: We investigate how Milky Way-like environments influence the sizes and structural properties of low-mass galaxies by comparing satellites of Milky Way analogs from the Satellites Around Galactic Analogs (SAGA) Survey with two control samples: an environmentally agnostic population from the SAGA background (SAGAbg) sample and isolated galaxies from the SDSS NASA-Sloan Atlas. All sizes and structura… ▽ More We investigate how Milky Way-like environments influence the sizes and structural properties of low-mass galaxies by comparing satellites of Milky Way analogs from the Satellites Around Galactic Analogs (SAGA) Survey with two control samples: an environmentally agnostic population from the SAGA background (SAGAbg) sample and isolated galaxies from the SDSS NASA-Sloan Atlas. All sizes and structural parameters are measured uniformly using pysersic to ensure consistency across samples. We find the half-light sizes of SAGA satellites are systematically larger than those of isolated galaxies, with the magnitude of the offset ranging from 0.05 to 0.12 dex (10-24%) depending on the comparison sample and completeness cuts. This corresponds to physical size differences between 85-200 pc at 10^7.5 solar masses and 220-960 pc at 10^10 solar masses. This offset persists among star-forming galaxies, suggesting that environment can influence the structure of low-mass galaxies even before it impacts quenching. The intrinsic scatter in the size-mass relation is lower for SAGA satellites than isolated galaxies, and the Sérsic index distributions of satellites and isolated galaxies are similar. In comparison to star-forming satellites, quenched SAGA satellites have a slightly shallower size-mass relation and rounder morphologies at low-mass, suggesting that quenching is accompanied by structural transformation and that the processes responsible differ between low- and high-mass satellites. Our results show that environmental processes can imprint measurable structural differences on satellites in Milky Way-mass halos. △ Less

Submitted 29 September, 2025; originally announced September 2025.

Comments: 30 pages, 14 figures, 2 tables

SAGAbg III: Environmental Stellar Mass Functions, Self-Quenching, and the Stellar-to-Halo Mass Relation in the Dwarf Galaxy Regime

Authors: Erin Kado-Fong, Yao-Yuan Mao, Yasmeen Asali, Marla Geha, Risa H. Wechsler, Mithi A. C. de los Reyes, Yunchong Wang, Ethan O. Nadler, Nitya Kallivayalil, Erik J. Tollerud, Benjamin Weiner

Abstract: Recent efforts have extended our view of the number and properties of satellite galaxies beyond the Local Group firmly down to $\rm M_\star\sim 10^6 M_\odot$. A similarly complete view of the field dwarf population has lagged behind. Using the background galaxies sample from the Satellites Around Galactic Analogs (SAGA) Survey at $z<0.05$, we take inventory of the dwarf population down to… ▽ More Recent efforts have extended our view of the number and properties of satellite galaxies beyond the Local Group firmly down to $\rm M_\star\sim 10^6 M_\odot$. A similarly complete view of the field dwarf population has lagged behind. Using the background galaxies sample from the Satellites Around Galactic Analogs (SAGA) Survey at $z<0.05$, we take inventory of the dwarf population down to $\rm M_\star \sim 5\times10^6 M_\odot$ using three metrics: the stellar mass function (SMF) as function of environment, the stellar-to-halo mass relation (SHMR) of dwarf galaxies inferred via abundance matching, and the quenched fraction of highly isolated dwarfs. We find that the low-mass SMF shape shows minimal environmental dependence, with the field dwarf SMF described by a low-mass power-law index of $α_1=-1.44\pm0.09$ down to $\rm M_\star \sim 5\times10^6 M_\odot$, and that the quenched fraction of isolated dwarfs drops monotonically to $f_{q} \sim 10^{-3}$ at $\rm M_\star \sim \rm 10^{8.5} M_\odot$. Though slightly steeper than estimates from \HI{} kinematic measures, our inferred SHMR agrees with literature measurements of satellite systems, consistent with minimal environmental dependence of the SHMR in the probed mass range. Finally, although most contemporary cosmological simulations against which we compare accurately predict the \sagalocal{} SHMR, we find that big-box cosmological simulations largely over-predict isolated galaxy quenched fractions via a turnaround in $f_q(\rm M_\star)$ at $\rm 10^8\lesssim M_\star/M_\odot\lesssim 10^9$, underscoring the complexities in disentangling the drivers of galaxy formation and the need for systematic multidimensional observations of the dwarf population across environments. △ Less

Submitted 2 October, 2025; v1 submitted 24 September, 2025; originally announced September 2025.

Comments: 34 pages, 12 figures, 6 pages; submitted to ApJ

Measurement of ion acceleration and diffusion in a laser-driven magnetized plasma

Authors: J. T. Y. Chu, J. W. D. Halliday, C. Heaton, K. Moczulski, A. Blazevic, D. Schumacher, M. Metternich, H. Nazary, C. D. Arrowsmith, A. R. Bell, K. A. Beyer, A. F. A. Bott, T. Campbell, E. Hansen, D. Q. Lamb, F. Miniati, P. Neumayer, C. A. J. Palmer, B. Reville, A. Reyes, S. Sarkar, A. Scopatz, C. Spindloe, C. B. Stuart, H. Wen , et al. (3 additional authors not shown)

Abstract: Here we present results from an experiment performed at the GSI Helmholtz Centre for Heavy Ion Research. A mono-energetic beam of chromium ions with initial energies of $\sim 450$ MeV was fired through a magnetized interaction region formed by the collision of two counter-propagating laser-ablated plasma jets. While laser interferometry revealed the absence of strong fluid-scale turbulence, accele… ▽ More Here we present results from an experiment performed at the GSI Helmholtz Centre for Heavy Ion Research. A mono-energetic beam of chromium ions with initial energies of $\sim 450$ MeV was fired through a magnetized interaction region formed by the collision of two counter-propagating laser-ablated plasma jets. While laser interferometry revealed the absence of strong fluid-scale turbulence, acceleration and diffusion of the beam ions was driven by wave-particle interactions. A possible mechanism is particle acceleration by electrostatic, short scale length kinetic turbulence, such as the lower-hybrid drift instability. △ Less

Submitted 28 February, 2026; v1 submitted 9 September, 2025; originally announced September 2025.

$^{51}$V NMR evidence for interlayer-modulated charge order and a first-order low-temperature transition in CsV$_3$Sb$_5$

Authors: Xiaoling Wang, Arneil P. Reyes, Hrishit Banerjee, Andrea N. Capa Salinas, Stephen Wilson, Brenden R. Ortiz

Abstract: Charge order in the kagome superconductor CsV$_3$Sb$_5$ exhibits a complex three-dimensional organization and intermediate-temperature anomalies whose bulk character has remained unsettled. We use orientation-dependent $^{51}$V NMR as a site-selective probe to determine the stacking of the charge density wave (CDW) state and its thermal evolution. Below $T_{\mathrm{CDW}}\!\approx\!94$~K, the field… ▽ More Charge order in the kagome superconductor CsV$_3$Sb$_5$ exhibits a complex three-dimensional organization and intermediate-temperature anomalies whose bulk character has remained unsettled. We use orientation-dependent $^{51}$V NMR as a site-selective probe to determine the stacking of the charge density wave (CDW) state and its thermal evolution. Below $T_{\mathrm{CDW}}\!\approx\!94$~K, the field-linear splitting of the $^{51}$V central transition together with the anisotropy of the Knight-shift tensor identify an interlayer-modulated $3\mathbf{q}$ CDW whose local environments are consistent with a four-layer $2\times2\times4$ stacking with mixed trihexagonal/Star-of-David distortions, in agreement with synchrotron x-ray determinations. For comparison, RbV$_3$Sb$_5$ serves as a reference exhibiting a uniform trihexagonal $2\times2\times2$ stacking, allowing us to isolate features unique to the $2\times2\times4$ state in CsV$_3$Sb$_5$. With $\mathbf{H}_0\!\parallel\!c$, the $^{51}$V quadrupolar satellites through the intermediate temperature scale near $T_{\mathrm{CO}}\!\approx\!65$ K reorganize into two well-resolved electric-field-gradient manifolds that coexist over a finite interval; their relative spectral weights interchange on cooling while the total integrated satellite intensity remains conserved and $ν_Q$ within each manifold is nearly temperature independent. The coexistence without critical broadening, together with conserved intensity, provides bulk evidence consistent with a first-order charge-order transition near $T_{\mathrm{CO}}$. Our measurements do not resolve whether this lower-temperature transition corresponds to a distinct in-plane order or a reorganization of the $3\mathbf{q}$ state; rather, they delimit this window and provide bulk, site-resolved constraints that connect prior reported anomalies to a thermodynamic first-order transition. △ Less

Submitted 4 September, 2025; originally announced September 2025.

Comments: 7 pages, 4 figures

On SAGBI bases theory of skew Poincaré-Birkhoff-Witt extensions

Authors: Yésica Suárez, Armando Reyes

Abstract: In this paper we present a first approach toward a \texttt{SAGBI} bases theory of skew Poincaré-Birkhoff-Witt extensions, and investigate the problem of polynomial composition for \texttt{SAGBI} bases of subalgebras of these extensions. In this paper we present a first approach toward a \texttt{SAGBI} bases theory of skew Poincaré-Birkhoff-Witt extensions, and investigate the problem of polynomial composition for \texttt{SAGBI} bases of subalgebras of these extensions. △ Less

Submitted 14 August, 2025; originally announced August 2025.

Comments: 26 pages

MSC Class: 13P10; 08A30; 16Z05; 16S36; 16S38

Gemini 2.5: Pushing the Frontier with Advanced Reasoning, Multimodality, Long Context, and Next Generation Agentic Capabilities

Authors: Gheorghe Comanici, Eric Bieber, Mike Schaekermann, Ice Pasupat, Noveen Sachdeva, Inderjit Dhillon, Marcel Blistein, Ori Ram, Dan Zhang, Evan Rosen, Luke Marris, Sam Petulla, Colin Gaffney, Asaf Aharoni, Nathan Lintz, Tiago Cardal Pais, Henrik Jacobsson, Idan Szpektor, Nan-Jiang Jiang, Krishna Haridasan, Ahmed Omran, Nikunj Saunshi, Dara Bahri, Gaurav Mishra, Eric Chu , et al. (3410 additional authors not shown)

Abstract: In this report, we introduce the Gemini 2.X model family: Gemini 2.5 Pro and Gemini 2.5 Flash, as well as our earlier Gemini 2.0 Flash and Flash-Lite models. Gemini 2.5 Pro is our most capable model yet, achieving SoTA performance on frontier coding and reasoning benchmarks. In addition to its incredible coding and reasoning skills, Gemini 2.5 Pro is a thinking model that excels at multimodal unde… ▽ More In this report, we introduce the Gemini 2.X model family: Gemini 2.5 Pro and Gemini 2.5 Flash, as well as our earlier Gemini 2.0 Flash and Flash-Lite models. Gemini 2.5 Pro is our most capable model yet, achieving SoTA performance on frontier coding and reasoning benchmarks. In addition to its incredible coding and reasoning skills, Gemini 2.5 Pro is a thinking model that excels at multimodal understanding and it is now able to process up to 3 hours of video content. Its unique combination of long context, multimodal and reasoning capabilities can be combined to unlock new agentic workflows. Gemini 2.5 Flash provides excellent reasoning abilities at a fraction of the compute and latency requirements and Gemini 2.0 Flash and Flash-Lite provide high performance at low latency and cost. Taken together, the Gemini 2.X model generation spans the full Pareto frontier of model capability vs cost, allowing users to explore the boundaries of what is possible with complex agentic problem solving. △ Less

Submitted 19 December, 2025; v1 submitted 7 July, 2025; originally announced July 2025.

Comments: 72 pages, 17 figures

From Bulk to Nanowire: A Dimensional Journey with CeIn$_3$

Authors: M. H. Carvalho, D. Zau, A. P. Reyes, R. Cong, S. D. House, H. P. Pizzi, A. M. Caffer, D. S. Passos, R. C. Santos, G. S. Freitas, K. R. Pirota, R. R. Urbano, P. J. G. Pagliuso

Abstract: In this work, we have explored the Metallic-Flux Nanonucleation method to synthesize single crystals and nanowires (diameter $\approx$ 170 nm) of CeIn$_{3}$ and compare their properties. The effects of reduced dimensionality were systematically investigated using Energy Dispersive Spectroscopy (EDS), Selected area electron diffraction (SAED), magnetic susceptibility, heat capacity, and Nuclear Mag… ▽ More In this work, we have explored the Metallic-Flux Nanonucleation method to synthesize single crystals and nanowires (diameter $\approx$ 170 nm) of CeIn$_{3}$ and compare their properties. The effects of reduced dimensionality were systematically investigated using Energy Dispersive Spectroscopy (EDS), Selected area electron diffraction (SAED), magnetic susceptibility, heat capacity, and Nuclear Magnetic Resonance (NMR). Semi-quantitative EDS analysis revealed a Ce:In ratio of 1:3.1(1), and the SAED results confirmed that the nanowires are polycrystalline with a cubic unit cell. Magnetic susceptibility, specific heat, and NMR data indicated a suppression of the antiferromagnetic transition to $T_N$ $\approx$ 2.4 K compared to the bulk value ($\approx$ 10 K). Furthermore, NMR analysis at temperatures below 2.8 K showed a reduced quadrupole frequency, $ν_Q$ $\approx$ 1.77(2) MHz, and provided evidence of polycrystalline nanowires formed within the nanoporous alumina template, in agreement with SAED results. We attribute these findings to an increasing magnetic order frustration induced by dimensionality in CeIn$_{3}$ nanowires. △ Less

Submitted 4 August, 2025; v1 submitted 6 July, 2025; originally announced July 2025.

Performance Prediction for Large Systems via Text-to-Text Regression

Authors: Yash Akhauri, Bryan Lewandowski, Cheng-Hsi Lin, Adrian N. Reyes, Grant C. Forbes, Arissa Wongpanich, Bangding Yang, Mohamed S. Abdelfattah, Sagi Perel, Xingyou Song

Abstract: In many industries, predicting metric outcomes of large systems is a fundamental problem, driven largely by traditional tabular regression. However, such methods struggle on complex systems data in the wild such as configuration files or system logs, where feature engineering is often infeasible. We propose text-to-text regression as a general, scalable alternative. For predicting resource efficie… ▽ More In many industries, predicting metric outcomes of large systems is a fundamental problem, driven largely by traditional tabular regression. However, such methods struggle on complex systems data in the wild such as configuration files or system logs, where feature engineering is often infeasible. We propose text-to-text regression as a general, scalable alternative. For predicting resource efficiency on Borg, Google's massive compute cluster scheduling system, a 60M parameter encoder-decoder, trained from random initialization, achieves up to a near perfect 0.99 (0.9 average) rank correlation across the entire fleet, and 100x lower MSE than tabular approaches. The model also easily adapts to new tasks in only 500 few-shot examples and captures the densities of complex outcome distributions. Ablation studies highlight the importance of using encoders, increasing sequence length, and the model's inherent uncertainty quantification. These findings pave the way for universal simulators of real-world outcomes. △ Less

Submitted 26 June, 2025; originally announced June 2025.

Comments: Code can be found at https://github.com/google-deepmind/regress-lm

Science Prospects for the Southern Wide-field Gamma-ray Observatory: SWGO

Authors: SWGO Collaboration, P. Abreu, R. Alfaro, A. Alfonso, M. Andrade, E. O. Angüner, E. A. Anita-Rangel, O. Aquines-Gutiérrez, C. Arcaro, R. Arceo, J. C. Arteaga-Velázquez, P. Assis, H. A. Ayala Solares, A. Bakalova, E. M. Bandeira, P. Bangale, U. Barres de Almeida, P. Batista, I. Batković, J. Bazo, E. Belmont, J. Bennemann, S. Y. BenZvi, A. Bernal, W. Bian , et al. (295 additional authors not shown)

Abstract: Ground-based gamma-ray astronomy is now well established as a key observational approach to address critical topics at the frontiers of astroparticle physics and high-energy astrophysics. Whilst the field of TeV astronomy was once dominated by arrays of atmospheric Cherenkov Telescopes, ground-level particle detection has now been demonstrated to be an equally viable and strongly complementary app… ▽ More Ground-based gamma-ray astronomy is now well established as a key observational approach to address critical topics at the frontiers of astroparticle physics and high-energy astrophysics. Whilst the field of TeV astronomy was once dominated by arrays of atmospheric Cherenkov Telescopes, ground-level particle detection has now been demonstrated to be an equally viable and strongly complementary approach. Ground-level particle detection provides continuous monitoring of the overhead sky, critical for the mapping of extended structures and capturing transient phenomena. As demonstrated by HAWC and LHAASO, the technique provides the best available sensitivity above a few tens of TeV, and for the first time access to the PeV energy range. Despite the success of this approach, there is so far no major ground-level particle-based observatory with access to the Southern sky. HESS, located in Namibia, is the only major gamma-ray instrument in the Southern Hemisphere, and has shown the extraordinary richness of the inner galaxy in the TeV band, but is limited in terms of field of view and energy reach. SWGO is an international effort to construct the first wide-field instrument in the south with deep sensitivity from 100s of GeV into the PeV domain. The project is now close to the end of its development phase and planning for construction of the array in Chile has begun. Here we describe the baseline design, expected sensitivity and resolution, and describe in detail the main scientific topics that will be addressed by this new facility and its initial phase SWGO-A. We show that SWGO will have a transformational impact on a wide range of topics from cosmic-ray acceleration and transport to the nature of dark matter. SWGO represents a key piece of infrastructure for multi-messenger astronomy in the next decade, with strong scientific synergies with the nearby CTA Observatory. △ Less

Submitted 25 June, 2025; v1 submitted 2 June, 2025; originally announced June 2025.

Comments: Revised version

Nilpotent graphs over skew PBW extensions

Authors: Sebastián Higuera, Armando Reyes

Abstract: We investigate the diameter and girth of the nilpotent graph for skew PBW extensions over $2$-primal rings, generalizing similar results on skew polynomial rings. Under certain compatibility conditions, we establish bounds for the diameter of the nilpotent graph and prove invariance of the girth under polynomial extensions. We investigate the diameter and girth of the nilpotent graph for skew PBW extensions over $2$-primal rings, generalizing similar results on skew polynomial rings. Under certain compatibility conditions, we establish bounds for the diameter of the nilpotent graph and prove invariance of the girth under polynomial extensions. △ Less

Submitted 31 May, 2025; originally announced June 2025.

Comments: 15 pages

MSC Class: 05C12; 05C20; 13A99; 16S15; 16S30; 16S32; 16S36; 16S38 16U99

Differential smoothness of bi-quadratic algebras with PBW basis

Authors: Andrés Rubiano, Armando Reyes

Abstract: We investigate the differential smoothness of bi-quadratic algebras with PBW basis. We investigate the differential smoothness of bi-quadratic algebras with PBW basis. △ Less

Submitted 19 May, 2025; originally announced May 2025.

Comments: 23 pages

MSC Class: 16E45; 16S30; 16S32; 16S36; 16S38; 16S99; 16T05; 58B34

On the boundary polynomial of a graph

Authors: Walter Carballosa, Marcos Masip, Francisco A. Reyes

Abstract: In this work, we introduce the boundary polynomial of a graph $G$ as the ordinary generating function in two variables $B(G;x,y):= \displaystyle\sum_{S\subseteq V(G)} x^{|B(S)|}y^{|S|}$, where $B(S)$ denotes the outer boundary of $S$. We investigate this graph polynomial obtaining some algebraic properties of the polynomial. We found that some parameters of $G$ are algebraically encoded in… ▽ More In this work, we introduce the boundary polynomial of a graph $G$ as the ordinary generating function in two variables $B(G;x,y):= \displaystyle\sum_{S\subseteq V(G)} x^{|B(S)|}y^{|S|}$, where $B(S)$ denotes the outer boundary of $S$. We investigate this graph polynomial obtaining some algebraic properties of the polynomial. We found that some parameters of $G$ are algebraically encoded in $B(G;x,y)$, \emph{e.g.}, domination number, Roman domination number, vertex connectivity, and differential of the graph $G$. Furthermore, we compute the boundary polynomial for some classic families of graphs. We also establish some relationships between $B(G;x,y)$ and $B(G^\prime;x,y)$ for the graphs $G^\prime$ obtained by removing, adding, and subdividing an edge from $G$. In addition, we prove that a graph $G$ has an isolated vertex if and only if its boundary polynomial has a factor ($y+1$). Finally, we show that the classes of complete, complete without one edge, empty, path, cycle, wheel, star, double-star graphs, and many others are characterized by the boundary polynomial. △ Less

Submitted 6 May, 2025; originally announced May 2025.

Comments: 20 pages, 1 figure

MSC Class: 05C31; 05C69

Analysis of Preheat Propagation in MagLIF-like Plasmas

Authors: Fernando Garcia-Rubio, Scott Davidson, C. Leland Ellison, Nathan B. Meezan, Douglas S. Miller, Nantas Nardelli, Adam Reyes, Paul F. Schmit, Hardeep Sullan

Abstract: The preheating and pre-magnetization of fusion fuel are key features in Magnetized Liner Inertial Fusion (MagLIF) configurations. Typically, the energy of the preheat laser is deposited in a central region of the fuel and propagates outward, generating magneto-hydrodynamic structures that impact the fuel mass distribution and magnetic flux compression during the subsequent implosion. We present a… ▽ More The preheating and pre-magnetization of fusion fuel are key features in Magnetized Liner Inertial Fusion (MagLIF) configurations. Typically, the energy of the preheat laser is deposited in a central region of the fuel and propagates outward, generating magneto-hydrodynamic structures that impact the fuel mass distribution and magnetic flux compression during the subsequent implosion. We present a theoretical analysis of preheat propagation in a magnetized plasma under conditions typical for MagLIF. The analysis is based on the acoustic time scale for the propagation of pressure disturbances being much shorter than the conductive time scale for heat diffusion. In this regime, the preheat-driven expansion induces the stratification of the fuel and magnetic field, which accumulate in a dense outer shelf bounded by the leading shock. We derive self-similar solutions of the model that describe the hydrodynamic profiles of the expansion, and evaluate the evolution of the magnetic field in this configuration. These solutions are supported by FLASH simulations of preheat propagation. Our analysis shows that, asymptotically in time, the regions where the magnetization of the fuel is significant tend to become localized at the interface separating the outer shelf from the inner hot core. We assess the implications of this stratification on the magnetic flux conservation and performance of fully integrated MagLIF FLASH simulations. △ Less

Submitted 1 May, 2025; v1 submitted 15 April, 2025; originally announced April 2025.

Comments: 20 pages, 9 figures

Validation of FLASH for magnetically driven inertial confinement fusion target design

Authors: C. Leland Ellison, Jonathan Carroll-Nellenback, Chiatai Chen, Scott Davidson, Bryan Ferguson, Fernando Garcia-Rubio, Edward C. Hansen, Yannick de Jong, Jacob R King, Patrick Knapp, Keith LeChien, Anthony Link, Nathan B. Meezan, Douglas S. Miller, Philip Mocz, Kassie Moczulski, Nantas Nardelli, Adam Reyes, Paul F. Schmit, Hardeep Sullan, Petros Tzeferacos, Daan van Vugt, Alex B. Zylstra

Abstract: FLASH is a widely available radiation magnetohydrodynamics code used for astrophysics, laboratory plasma science, high energy density physics, and inertial confinement fusion. Increasing interest in magnetically driven inertial confinement fusion (ICF), including Pacific Fusion's development of a 60 MA Demonstration System designed to achieve facility gain, motivates the improvement and validation… ▽ More FLASH is a widely available radiation magnetohydrodynamics code used for astrophysics, laboratory plasma science, high energy density physics, and inertial confinement fusion. Increasing interest in magnetically driven inertial confinement fusion (ICF), including Pacific Fusion's development of a 60 MA Demonstration System designed to achieve facility gain, motivates the improvement and validation of FLASH for modeling magnetically driven ICF concepts, such as MagLIF, at ignition scale. Here we present a collection of six validation benchmarks from experiments at the Z Pulsed Power Facility and theoretical and simulation studies of scaling MagLIF to high currents. The benchmarks range in complexity from focused experiments of linear hydrodynamic instabilities to fully integrated MagLIF fusion experiments. With the latest addition of physics capabilities, FLASH now obtains good agreement with the experimental data, theoretical results, and leading ICF target design simulation code results across all six benchmarks. These results establish confidence in FLASH as a useful tool for designing magnetically driven ICF targets on facilities like Z and Pacific Fusion's upcoming Demonstration System. △ Less

Submitted 14 April, 2025; originally announced April 2025.

Comments: 30 pages, 19 figures

Affordable, manageable, practical, and scalable (AMPS) high-yield and high-gain inertial fusion

Authors: Andrew Alexander, Laura Robin Benedetti, Indrani Bhattacharyya, Jared Bowen, June Cabatu, Virgil Cacdac, Chhavi Chhavi, Chiatai Chen, Karen Chen, Dan Clark, Jerry Clark, Tyler Cope, Will Dannemann, Scott Davidson, David DeHaan, John Dugan, Mindy Eihusen, C. Leland Ellison, Carlos Esquivel, David Ethridge, Blake Ferguson, Bryan Ferguson, Jon Fry, Fernando Garcia-Rubio, Tarun Goyal , et al. (41 additional authors not shown)

Abstract: High-yield inertial fusion offers a transformative path to affordable clean firm power and advanced defense capabilities. Recent milestones at large facilities, particularly the National Ignition Facility (NIF), have demonstrated the feasibility of ignition but highlight the need for approaches that can deliver large amounts of energy to fusion targets at much higher efficiency and lower cost. We… ▽ More High-yield inertial fusion offers a transformative path to affordable clean firm power and advanced defense capabilities. Recent milestones at large facilities, particularly the National Ignition Facility (NIF), have demonstrated the feasibility of ignition but highlight the need for approaches that can deliver large amounts of energy to fusion targets at much higher efficiency and lower cost. We propose that pulser-driven inertial fusion energy (IFE), which uses high-current pulsed-power technology to compress targets to thermonuclear conditions, can achieve this goal. In this paper, we detail the physics basis for pulser IFE, focusing on magnetized liner inertial fusion (MagLIF), where cylindrical metal liners compress DT fuel under strong magnetic fields and pre-heat. We discuss how the low implosion velocities, direct-drive efficiency, and scalable pulser architecture can achieve ignition-level conditions at low capital cost. Our multi-dimensional simulations, benchmarked against experiments at the Z facility, show that scaling from 20 MA to 50-60 MA of current enables net facility gain. We then introduce our Demonstration System (DS), a pulsed-power driver designed to deliver more than 60 MA and store approximately 80 MJ of energy. The DS is designed to achieve a 1000x increase in effective performance compared to the NIF, delivering approximately 100x greater facility-level energy gain -- and importantly, achieving net facility gain, or Qf>1 -- at just 1/10 the capital cost. We also examine the engineering requirements for repetitive operation, target fabrication, and chamber maintenance, highlighting a practical roadmap to commercial power plants. △ Less

Submitted 14 April, 2025; originally announced April 2025.

Comments: 41 pages, 21 figures

Music Information Retrieval on Representative Mexican Folk Vocal Melodies Through MIDI Feature Extraction

Authors: Mario Alberto Vallejo Reyes

Abstract: This study analyzes representative Mexican folk vocal melodies using MIDI feature extraction, examining ambitus, pitch-class entropy, and interval distribution. It also explores the relationship between these features and song popularity, as measured by Spotify plays. The study employs MATLAB and the MIDI Toolbox for extracting musical features and performing statistical analysis. The findings rev… ▽ More This study analyzes representative Mexican folk vocal melodies using MIDI feature extraction, examining ambitus, pitch-class entropy, and interval distribution. It also explores the relationship between these features and song popularity, as measured by Spotify plays. The study employs MATLAB and the MIDI Toolbox for extracting musical features and performing statistical analysis. The findings reveal a significant variation in ambitus, with values ranging from 8 to 27 semitones, indicating a diverse compositional style and vocal demand across the genre. The analysis of pitch-class entropy showcases a broad spectrum of melodic complexity, with Armando Manzanero's `Somos Novios' displaying the highest entropy, suggesting varied and complex melodic structures, while traditional pieces like `La Bamba' exhibit lower entropy, indicating simpler, more repetitive patterns. The interval distribution predominantly features prime intervals (P1), major and minor seconds (M2, m2), pointing to a compositional preference for close, contiguous intervals that contribute to the melodies' accessibility and appeal. Statistical analysis do not establish a significant correlation between the ambitus or entropy and the number of Spotify plays. △ Less

Submitted 31 March, 2025; originally announced March 2025.

Comments: 10 pages, 5 figures, 2 tables

Kaon Physics: A Cornerstone for Future Discoveries

Authors: Jason Aebischer, Atakan Tugberk Akmete, Riccardo Aliberti, Wolfgang Altmannshofer, Fabio Ambrosino, Roberto Ammendola, Antonella Antonelli, Giuseppina Anzivino, Saiyad Ashanujjaman, Laura Bandiera, Damir Becirevic, Véronique Bernard, Johannes Bernhard, Cristina Biino, Johan Bijnens, Monika Blanke, Brigitte Bloch-Devaux, Marzia Bordone, Peter Boyle, Alexandru Mario Bragadireanu, Francesco Brizioli, Joachim Brod, Andrzej J. Buras, Dario Buttazzo, Nicola Canale , et al. (131 additional authors not shown)

Abstract: The kaon physics programme, long heralded as a cutting-edge frontier by the European Strategy for Particle Physics, continues to stand at the intersection of discovery and innovation in high-energy physics (HEP). With its unparalleled capacity to explore new physics at the multi-TeV scale, kaon research is poised to unveil phenomena that could reshape our understanding of the Universe. This docume… ▽ More The kaon physics programme, long heralded as a cutting-edge frontier by the European Strategy for Particle Physics, continues to stand at the intersection of discovery and innovation in high-energy physics (HEP). With its unparalleled capacity to explore new physics at the multi-TeV scale, kaon research is poised to unveil phenomena that could reshape our understanding of the Universe. This document highlights the compelling physics case, with emphasis on exciting new opportunities for advancing kaon physics not only in Europe but also on a global stage. As an important player in the future of HEP, the kaon programme promises to drive transformative breakthroughs, inviting exploration at the forefront of scientific discovery. △ Less

Submitted 28 March, 2025; originally announced March 2025.

Comments: 10 pages, one figure, submitted to the European Strategy for Particle Physics Update

Photon Absorption in a Doubly Special Relativity Model with Undeformed Free Propagation and Total Momentum Conservation

Authors: J. M. Carmona, J. L. Cortés, F. Rescic, M. A. Reyes, T. Terzić

Abstract: The lack of a dynamical framework within doubly special relativity theories has impeded the development of a corresponding phenomenology of modified interactions. In this work we show that in a model based on the classical basis of $κ$-Poincaré and total momentum conservation, one has a well-defined cross section of the photon-photon annihilation process, once a prescription for the channel treatm… ▽ More The lack of a dynamical framework within doubly special relativity theories has impeded the development of a corresponding phenomenology of modified interactions. In this work we show that in a model based on the classical basis of $κ$-Poincaré and total momentum conservation, one has a well-defined cross section of the photon-photon annihilation process, once a prescription for the channel treatment is set. The modification of the interaction can lead to observable effects in the opacity of the Universe to very high-energy gamma rays when the gamma-ray energy approaches the energy scale of the deformation. The magnitude and observability of this deformation are examined as functions of the gamma-ray energy and source distance. △ Less

Submitted 16 September, 2025; v1 submitted 19 March, 2025; originally announced March 2025.

Comments: 11 pages, 6 figures

Journal ref: JCAP 07, 066 (2025)

An implicit shock tracking method for simulation of shock-dominated flows over complex domains using mesh-based parametrizations

Authors: Alexander M. Perez Reyes, Matthew J. Zahr

Abstract: A mesh-based parametrization is a parametrization of a geometric object that is defined solely from a mesh of the object, e.g., without an analytical expression or computer-aided design (CAD) representation of the object. In this work, we propose a mesh-based parametrization of an arbitrary $d'$-dimensional object embedded in a $d$-dimensional space using tools from high-order finite elements. Usi… ▽ More A mesh-based parametrization is a parametrization of a geometric object that is defined solely from a mesh of the object, e.g., without an analytical expression or computer-aided design (CAD) representation of the object. In this work, we propose a mesh-based parametrization of an arbitrary $d'$-dimensional object embedded in a $d$-dimensional space using tools from high-order finite elements. Using mesh-based parametrizations, we construct a boundary-preserving parametrization of the nodal coordinates of a computational mesh that ensures all nodes remain on all their original boundaries. These boundary-preseving parametrizations allow the nodes of the mesh to move only in ways that will not change the computational domain. They also ensure nodes will not move between boundaries, which would cause issues assigning boundary conditions for partial differential equation simulations and lead to inaccurate geometry representations for non-smooth boundary transitions. Finally, we integrate boundary-preserving, mesh-based parametrizations into high-order implicit shock tracking, an optimization-based discontinuous Galerkin method that moves nodes to align mesh faces with non-smooth flow features to represent them perfectly with inter-element jumps, leaving the intra-element polynomial basis to represent smooth regions of the flow with high-order accuracy. Mesh-based parametrizations enable implicit shock tracking simulations of shock-dominated flows over geometries without simple analytical parametrizations. Several demonstrations of mesh-based parametrizations are provided. △ Less

Submitted 7 March, 2025; originally announced March 2025.

Comments: 25 pages, 17 figures

Neutron-capture Element Abundances of 491 Stars in Milky Way Dwarf Satellite Galaxies from Medium-Resolution Spectra

Authors: Lauren E. Henderson, Evan N. Kirby, Mithi A. C. de los Reyes, Roman Gerasimov, Viraj Manwadkar

Abstract: The chemical compositions of evolved stars in Local Group dwarf spheroidal galaxies (dSphs) provide insight into the galaxy's past star formation and nucleosynthesis. Neutron-capture element abundances are especially interesting. In particular, s-process elements can provide a third chemical clock for resolving star formation histories in addition to core collapse and Type Ia supernovae. Likewise,… ▽ More The chemical compositions of evolved stars in Local Group dwarf spheroidal galaxies (dSphs) provide insight into the galaxy's past star formation and nucleosynthesis. Neutron-capture element abundances are especially interesting. In particular, s-process elements can provide a third chemical clock for resolving star formation histories in addition to core collapse and Type Ia supernovae. Likewise, the primary sites of the r-process are still areas of extensive research. Until now, the number of stars with neutron-capture element abundances in dSphs has been limited by the need for stars bright enough for high-resolution spectroscopy. We present abundance measurements of the neutron-capture elements Sr, Y, Ba, and Eu with errors < 0.4 dex - as well as new measurements of Mg - in 491 stars in Sculptor, Fornax, Draco, Sextans, and Ursa Minor. The large number of stars in our sample is possible because we used medium-resolution spectra from the DEIMOS spectrograph, assembling the largest homogeneous set of neutron-capture abundances in dwarf spheroidal galaxies to date. By utilizing the abundances of both s- and r-process elements, we find evidence of an s-process contribution at early times in Sculptor from our measurements of [Ba/Fe]. This is a potential signature of s-process nucleosynthesis in fast-rotating massive stars. By comparing our measurements of [Eu/Fe] with [Mg/Fe], we show the need for an r-process source that has a short delay time to enrich stars in the dSphs. Thus, neutron star mergers are likely not the sole source of r-process material in dSphs. △ Less

Submitted 9 March, 2025; v1 submitted 23 February, 2025; originally announced February 2025.

Comments: submitted to ApJ

Nuclear spin coherence in superconducting Nb$_3$Sn

Authors: Gan Zhai, William P. Halperin, Arneil P. Reyes, Sam Posen, Chiara Tarantini, Manish Mandal, David C. Larbalestier

Abstract: We have investigated the normal and superconducting states of the technologically important compound Nb$_3$Sn using $^{93}$Nb nuclear magnetic resonance. From spin-lattice relaxation we find strong suppression of the zero-temperature superconducting order parameter by magnetic field. Additionally we have identified an anomalously large electron-nuclear exchange interaction from spin-spin relaxatio… ▽ More We have investigated the normal and superconducting states of the technologically important compound Nb$_3$Sn using $^{93}$Nb nuclear magnetic resonance. From spin-lattice relaxation we find strong suppression of the zero-temperature superconducting order parameter by magnetic field. Additionally we have identified an anomalously large electron-nuclear exchange interaction from spin-spin relaxation measurements, an order of magnitude beyond that of the nuclear dipolar coupling. This RKKY interaction evolves from normal to superconducting states, becoming essentially Lorentzian in the low temperature limit. △ Less

Submitted 17 June, 2025; v1 submitted 1 February, 2025; originally announced February 2025.

Incidence equivalence and the Bloch-Beilinson filtration

Authors: Pablo Pelaez, Araceli Reyes

Abstract: Let $X$ be a smooth projective variety of dimension $d$ over an arbitrary base field $k$ and $CH^n(X)_{\mathbb Q}$ be the $\mathbb Q$-vector space of codimension $n$ algebraic cycles of $X$ modulo rational equivalence, $1\leq n \leq d$. Consider the $\mathbb Q$-vector subspaces $CH^n(X)_{\mathbb Q} \supseteq CH^n_{\mathrm{alg}}(X)_{\mathbb Q} \supseteq CH^n_{\mathrm{inc}}(X)_{\mathbb Q}$ of algebr… ▽ More Let $X$ be a smooth projective variety of dimension $d$ over an arbitrary base field $k$ and $CH^n(X)_{\mathbb Q}$ be the $\mathbb Q$-vector space of codimension $n$ algebraic cycles of $X$ modulo rational equivalence, $1\leq n \leq d$. Consider the $\mathbb Q$-vector subspaces $CH^n(X)_{\mathbb Q} \supseteq CH^n_{\mathrm{alg}}(X)_{\mathbb Q} \supseteq CH^n_{\mathrm{inc}}(X)_{\mathbb Q}$ of algebraic cycles which are, respectively, algebraically and incident (in the sense of Griffiths) equivalent to zero. Our main result computes $CH^d_{\mathrm{inc}}(X)_{\mathbb Q}$ (which coincides with the Albanese kernel $T(X)_{\mathbb Q}$ when $k$ is algebraically closed) in terms of Voevodsky's triangulated category of motives $DM_k$, namely, we show that $CH^d_{\mathrm{inc}}(X)_{\mathbb Q}$ is given by the second step of the orthogonal filtration $F^{\bullet}$ on $CH^d(X)_{\mathbb Q}$, i.e. $F^2 CH^d (X)_{\mathbb Q}= CH^d_{\mathrm{inc}}(X)_{\mathbb Q}$. The orthogonal filtration $F^\bullet$ on $CH^n(X)_{\mathbb Q}$ was introduced by the first author, and is an unconditionally finite filtration satisfying several of the properties of the still conjectural Bloch-Beilinson filtration. We also prove that the exterior product and intersection product of algebraic cycles algebraically equivalent to zero is contained in the second step of the orthogonal filtration. Furthermore, if we assume that the field $k$ is either finite or the algebraic closure of a finite field, then the main result holds in any codimension, i.e. $F^2 CH^n_{\mathrm{alg}}(X)_{\mathbb Q}= CH^n_{\mathrm{inc}}(X)_{\mathbb Q}$. We also compute in the whole Chow group, $CH^n(X)_{\mathbb Q}$, the second step of the orthogonal filtration $F^2 CH^n(X)_{\mathbb Q}$ in terms of the vanishing of several intersection pairings. △ Less

Submitted 31 January, 2025; originally announced January 2025.

Comments: 23 pages

MSC Class: 14C15; 14C17; 14C25; 14C35; 19E15

Self-consistent solution to the semiclassical Einstein equations of a star

Authors: Pietro Paolo Melella, Ignacio A. Reyes

Abstract: We present the interior solution for a static, spherically symmetric perfect fluid star backreacted by QFT in four dimensions invoking no arbitrary parameters. It corresponds to a constant energy density star and is fully non-perturbative. The space of solutions includes ultra-compact configurations that have neither singularities nor light rings inside the star and can exist arbitrarily close to… ▽ More We present the interior solution for a static, spherically symmetric perfect fluid star backreacted by QFT in four dimensions invoking no arbitrary parameters. It corresponds to a constant energy density star and is fully non-perturbative. The space of solutions includes ultra-compact configurations that have neither singularities nor light rings inside the star and can exist arbitrarily close to the Schwarzschild limit, showing that the classical paradigm of astrophysics does not hold once QFT in curved space is taken into account. △ Less

Submitted 16 January, 2025; originally announced January 2025.

Comments: 7 pages, 2 figures

Stellar occultation observations of (38628) Huya and its satellite: a detailed look into the system

Authors: F. L. Rommel, E. Fernández-Valenzuela, B. C. N. Proudfoot, J. L. Ortiz, B. E. Morgado, B. Sicardy, N. Morales, F. Braga-Ribas, J. Desmars, R. Vieira-Martins, B. J. Holler, Y. Kilic, W. Grundy, J. L. Rizos, J. I. B. Camargo, G. Benedetti-Rossi, A. Gomes-Júnior, M. Assafin, P. Santos-Sanz, M. Kretlow, M. Vara-Lubiano, R. Leiva, D. A. Ragozzine, R. Duffard, H. Kučáková , et al. (56 additional authors not shown)

Abstract: The physical and orbital parameters of Trans-Neptunian Objects (TNOs) provide valuable information about the Solar System's formation and evolution. In particular, the characterization of binaries provides insights into the formation mechanisms that may be playing a role at such large distances from the Sun. Studies show two distinct populations, and (38628) Huya occupies an intermediate position… ▽ More The physical and orbital parameters of Trans-Neptunian Objects (TNOs) provide valuable information about the Solar System's formation and evolution. In particular, the characterization of binaries provides insights into the formation mechanisms that may be playing a role at such large distances from the Sun. Studies show two distinct populations, and (38628) Huya occupies an intermediate position between the unequal-size binaries and those with components of roughly equal sizes. In this work, we predicted and observed three stellar occultation events by Huya. Huya and its satellite - S/2012 (38628) 1 - were detected during occultations in March 2021 and again in June 2023. Additionally, an attempt to detect Huya in February 2023 resulted in an additional single-chord detection of the secondary. A spherical body with a minimum diameter of D = 165 km can explain the three single-chord observations and provide a lower limit for the satellite size. The astrometry of Huya's system, as derived from the occultations and supplemented by observations from the Hubble Space Telescope and Keck Observatory, provided constraints on the satellite orbit and the mass of the system. Therefore, assuming the secondary is in an equatorial orbit around the primary, the limb fitting was constrained by the satellite orbit position angle. The system density, calculated by summing the most precise measurement of Huya's volume to the spherical satellite average volume, is $ρ_{1}$ = 1073 $\pm$ 66 kg m$^{-3}$. The density that the object would have assuming a Maclaurin equilibrium shape with a rotational period of 6.725 $\pm$ 0.01 hours is $ρ_{2}$ = 768 $\pm$ 42 kg m$^{-3}$. This difference rules out the Maclaurin equilibrium assumption for the main body shape. △ Less

Submitted 16 January, 2025; originally announced January 2025.

Comments: Manuscript accepted by Planetary Science Journal (PSJ)

Hidden magnetic phases in i-MAX compounds

Authors: Dror Yahav, Ariel Maniv, Daniel Potashnikov, Asaf Pesach, El'ad N. Caspi, Arneil P. Reyes, Quanzheng Tao, Johanna Rosen, Eran Maniv

Abstract: We uncover a high-field magnetic phase in i-MAX compounds exhibiting a canted antiferromagnetic (AFM) order with unprecedented properties, revealed through NMR and AC susceptibility. Intriguingly, as the atomic number of Rare Earth increases, the transition field of this canted AFM phase grows at the expense of the lower-field AFM state. Our findings point to the complexity of the magnetic structu… ▽ More We uncover a high-field magnetic phase in i-MAX compounds exhibiting a canted antiferromagnetic (AFM) order with unprecedented properties, revealed through NMR and AC susceptibility. Intriguingly, as the atomic number of Rare Earth increases, the transition field of this canted AFM phase grows at the expense of the lower-field AFM state. Our findings point to the complexity of the magnetic structure in i-MAX compounds, demonstrating a non-trivial evolution of their phase diagram while increasing both the atomic number of the Rare Earth element and the external field. △ Less

Submitted 3 December, 2024; originally announced December 2024.

Comments: 8 pages, 5 figures

Towards a Physics Engine to Simulate Robotic Laser Surgery: Finite Element Modeling of Thermal Laser-Tissue Interactions

Authors: Nicholas E. Pacheco, Kang Zhang, Ashley S. Reyes, Christopher J. Pacheco, Lucas Burstein, Loris Fichera

Abstract: This paper presents a computational model, based on the Finite Element Method (FEM), that simulates the thermal response of laser-irradiated tissue. This model addresses a gap in the current ecosystem of surgical robot simulators, which generally lack support for lasers and other energy-based end effectors. In the proposed model, the thermal dynamics of the tissue are calculated as the solution to… ▽ More This paper presents a computational model, based on the Finite Element Method (FEM), that simulates the thermal response of laser-irradiated tissue. This model addresses a gap in the current ecosystem of surgical robot simulators, which generally lack support for lasers and other energy-based end effectors. In the proposed model, the thermal dynamics of the tissue are calculated as the solution to a heat conduction problem with appropriate boundary conditions. The FEM formulation allows the model to capture complex phenomena, such as convection, which is crucial for creating realistic simulations. The accuracy of the model was verified via benchtop laser-tissue interaction experiments using agar tissue phantoms and ex-vivo chicken muscle. The results revealed an average root-mean-square error (RMSE) of less than 2 degrees Celsius across most experimental conditions. △ Less

Submitted 21 November, 2024; originally announced November 2024.

Comments: Submitted to the International Symposium on Medical Robotics 2025

A note on the differential smoothness of skew PBW extensions

Authors: Andrés Rubiano, Armando Reyes

Abstract: We investigate the differential smoothness of a certain family of skew Poincaré-Birkhoff-Witt extensions. We investigate the differential smoothness of a certain family of skew Poincaré-Birkhoff-Witt extensions. △ Less

Submitted 25 May, 2025; v1 submitted 17 October, 2024; originally announced October 2024.

Comments: 22 pages. arXiv admin note: substantial text overlap with arXiv:2409.10264, arXiv:2409.18947, arXiv:2408.16648, arXiv:2410.12701, arXiv:2403.15001; text overlap with arXiv:1410.6587 by other authors

MSC Class: 16E45; 16S30; 16S32; 16S36; 16S38; 16S99; 16W20; 16T05; 58B34

Smooth Geometry of Diffusion Algebras

Authors: Andrés Rubiano, Armando Reyes

Abstract: In this paper, we study the differential smoothness of diffusion algebras. In this paper, we study the differential smoothness of diffusion algebras. △ Less

Submitted 29 May, 2025; v1 submitted 16 October, 2024; originally announced October 2024.

Comments: 32 pages. arXiv admin note: text overlap with arXiv:2409.18947, arXiv:2408.16648, arXiv:2409.10264; text overlap with arXiv:math/0202068 by other authors

MSC Class: 16E45; 16S32; 16S36; 16S37; 16S38; 16W20; 16W50; 58B34

Smooth geometry of skew PBW extensions over commutative polynomial rings I

Authors: Andrés Rubiano, Armando Reyes

Abstract: In this paper, we investigate the differential smoothness of skew PBW extensions over commutative polynomial rings on one and two indeterminates. In this paper, we investigate the differential smoothness of skew PBW extensions over commutative polynomial rings on one and two indeterminates. △ Less

Submitted 25 May, 2025; v1 submitted 27 September, 2024; originally announced September 2024.

Comments: 60 pages. arXiv admin note: text overlap with arXiv:2408.16648, arXiv:2409.10264; text overlap with arXiv:1410.6587 by other authors

MSC Class: 16S30; 16S32; 16S36; 16S38; 16S99; 16W20; 16T05; 58B32

SAGAbg II: the Low-Mass Star-Forming Sequence Evolves Significantly Between 0.05<z<0.21

Authors: Erin Kado-Fong, Marla Geha, Yao-Yuan Mao, Mithi A. C. de los Reyes, Risa H. Wechsler, Benjamin Weiner, Yasmeen Asali, Nitya Kallivayalil, Ethan O. Nadler, Erik J. Tollerud, Yunchong Wang

Abstract: The redshift-dependent relation between galaxy stellar mass and star formation rate (the Star-Forming Sequence, or SFS) is a key observational yardstick for galaxy assembly. We use the SAGAbg-A sample of background galaxies from the Satellites Around Galactic Analogs (SAGA) Survey to model the low-redshift evolution of the low-mass SFS. The sample is comprised of 23258 galaxies with H$α$-based sta… ▽ More The redshift-dependent relation between galaxy stellar mass and star formation rate (the Star-Forming Sequence, or SFS) is a key observational yardstick for galaxy assembly. We use the SAGAbg-A sample of background galaxies from the Satellites Around Galactic Analogs (SAGA) Survey to model the low-redshift evolution of the low-mass SFS. The sample is comprised of 23258 galaxies with H$α$-based star formation rates (SFRs) spanning $6<\log_{10}(\rm M_\star/[M_\odot])<10$ and $z<0.21$ ($t<2.5$ Gyr). Although it is common to bin or stack galaxies at $z \lesssim 0.2$ for galaxy population studies, the difference in lookback time between $z=0$ and $z=0.21$ is comparable to the time between $z=1$ to $z=2$. We develop a model to account for both the physical evolution of low-mass SFS and the selection function of the SAGA survey, allowing us to disentangle redshift evolution from redshift-dependent selection effects across the SAGAbg-A redshift range. Our findings indicate significant evolution in the SFS over the last 2.5 Gyr, with a rising normalization: $\langle {\rm SFR}({\rm M_\star=10^{8.5} M_\odot)}\rangle(z)=1.24^{+0.25}_{-0.23}\ {\rm z} -1.47^{+0.03}_{-0.03}$. We also identify the redshift limit at which a static SFS is ruled out at the 95% confidence level, which is $z=0.05$ based on the precision of the SAGAbg-A sample. Comparison with cosmological hydrodynamic simulations reveals that some contemporary simulations under-predict the recent evolution of the low-mass SFS. This demonstrates that the recent evolution of the low-mass SFS can provide new constraints on the assembly of the low-mass Universe and highlights the need for improved models in this regime. △ Less

Submitted 18 September, 2024; originally announced September 2024.

Comments: 20 pages, 7 figures. Submitted to ApJ

Fully guaranteed and computable error bounds on the energy for periodic Kohn-Sham equations with convex density functionals

Authors: Andrea Bordignon, Geneviève Dusson, Éric Cancès, Gaspard Kemlin, Rafael Antonio Lainez Reyes, Benjamin Stamm

Abstract: In this article, we derive fully guaranteed error bounds for the energy of convex nonlinear mean-field models. These results apply in particular to Kohn-Sham equations with convex density functionals, which includes the reduced Hartree-Fock (rHF) model, as well as the Kohn-Sham model with exact exchange-density functional (which is unfortunately not explicit and therefore not usable in practice).… ▽ More In this article, we derive fully guaranteed error bounds for the energy of convex nonlinear mean-field models. These results apply in particular to Kohn-Sham equations with convex density functionals, which includes the reduced Hartree-Fock (rHF) model, as well as the Kohn-Sham model with exact exchange-density functional (which is unfortunately not explicit and therefore not usable in practice). We then decompose the obtained bounds into two parts, one depending on the chosen discretization and one depending on the number of iterations performed in the self-consistent algorithm used to solve the nonlinear eigenvalue problem, paving the way for adaptive refinement strategies. The accuracy of the bounds is demonstrated on a series of test cases, including a Silicon crystal and an Hydrogen Fluoride molecule simulated with the rHF model and discretized with planewaves. We also show that, although not anymore guaranteed, the error bounds remain very accurate for a Silicon crystal simulated with the Kohn-Sham model using nonconvex exchangecorrelation functionals of practical interest. △ Less

Submitted 19 February, 2025; v1 submitted 18 September, 2024; originally announced September 2024.

Smooth geometry of double extension regular algebras of type (14641)

Authors: Andrés Rubiano, Armando Reyes

Abstract: In this paper, we prove that double extension regular algebras of type (14641) are not differentially smooth. In this paper, we prove that double extension regular algebras of type (14641) are not differentially smooth. △ Less

Submitted 16 September, 2024; originally announced September 2024.

Comments: 32 pages. arXiv admin note: text overlap with arXiv:2408.16648

MSC Class: 16E45; 16S36; 16S37; 16S38; 16W20; 16W50; 58B34

Stellar Mass Calibrations for Local Low-Mass Galaxies

Authors: Mithi A. C. de los Reyes, Yasmeen Asali, Risa Wechsler, Marla Geha, Yao-Yuan Mao, Erin Kado-Fong, Ragadeepika Pucha, William Grant, Pratik J. Gandhi, Viraj Manwadkar, Anna Engelhardt, Ferah Munshi, Yunchong Wang

Abstract: The stellar masses of galaxies are measured using integrated light via several methods -- however, few of these methods were designed for low-mass ($M_{\star}\lesssim10^{8}\rm{M_{\odot}}$) "dwarf" galaxies, whose properties (e.g., stochastic star formation, low metallicity) pose unique challenges for estimating stellar masses. In this work, we quantify the precision and accuracy at which stellar m… ▽ More The stellar masses of galaxies are measured using integrated light via several methods -- however, few of these methods were designed for low-mass ($M_{\star}\lesssim10^{8}\rm{M_{\odot}}$) "dwarf" galaxies, whose properties (e.g., stochastic star formation, low metallicity) pose unique challenges for estimating stellar masses. In this work, we quantify the precision and accuracy at which stellar masses of low-mass galaxies can be recovered using UV/optical/IR photometry. We use mock observations of 469 low-mass galaxies from a variety of models, including both semi-empirical models (GRUMPY and UniverseMachine-SAGA) and cosmological baryonic zoom-in simulations (MARVELous Dwarfs and FIRE-2), to test literature color-$M_\star/L$ relations and multi-wavelength spectral energy distribution (SED) mass estimators. We identify a list of "best practices" for measuring stellar masses of low-mass galaxies from integrated photometry. We find that literature color-$M_\star/L$ relations are often unable to capture the bursty star formation histories (SFHs) of low-mass galaxies, and we develop an updated prescription for stellar mass based on $g-r$ color that is better able to recover stellar masses for the bursty low-mass galaxies in our sample (with ~0.1 dex precision). SED fitting can also precisely recover stellar masses of low-mass galaxies, but this requires thoughtful choices about the form of the assumed SFH: parametric SFHs can underestimate stellar mass by as much as ~0.4 dex, while non-parametric SFHs recover true stellar masses with insignificant offset (-0.03$\pm$0.11 dex). Finally, we also caution that non-informative (wide) dust attenuation priors may introduce $M_\star$ uncertainties of up to ~0.6 dex. △ Less

Submitted 28 July, 2025; v1 submitted 5 September, 2024; originally announced September 2024.

Comments: 29 pages including references, 11 figures; accepted to ApJ