HEP Lattice·hep-lat

Tue·Jun 30, 2026Tuesday·June 30, 2026

9 papers—5 primary·4 cross-listed

01
Highly improved staggered quarks on anisotropic lattices
Alexei Bazavov🇺🇸 · Yannis Trimis🇺🇸 · Johannes Heinrich Weber🇩🇪
We present a study of tuning of the anisotropic highly improved staggered quark (aHISQ) action on pure gauge ensembles with the renormalized anisotropy ranging from 1 to 8. We discuss multiple gradient flow schemes for tuning the gauge anisotropy and comment on what scheme may be optimal for anisotropic simulations. Next, we compare tuning of the fermion anisotropy for the naive staggered and aHISQ actions. Finally, we study the dependence of the staggered pion taste mass splittings on anisotropy for the two actions and develop an empirical model that captures the main features of the aHISQ spectrum. We observe qualitatively different behavior of the naive and aHISQ taste spectrum with anisotropy.
hep-lat0 citations
02
Complete Access to Leading-Twist $Λ$ -Baryon Light-Cone Distribution Amplitudes from Lattice QCD
Mu-Hua Zhang🇨🇳 · Haoyang Bai🇨🇳 · Min-Huan Chu🇵🇱 · Jun Hua🇨🇳 · Xiangdong Ji🇨🇳 · Xiangyu Jiang🇨🇳 · Jian Liang🇨🇳 · Cai-Dian Lü🇨🇳 · Andreas Schäfer🇩🇪 · Wei Wang🇨🇳 · Yi-Bo Yang🇨🇳 · Jian-Hui Zhang🇨🇳 · Jia-Lu Zhang🇨🇳 · Qi-An Zhang🇨🇳
We report the first complete lattice-QCD determination of the leading-twist light-cone distribution amplitudes (LCDAs) of the $Λ$ baryon, obtained as full two-dimensional functions of the valence-quark momentum fractions. The calculation employs large-momentum effective theory to relate the light-cone amplitudes to equal-time nonlocal three-quark matrix elements of boosted $Λ$ baryons. Controlled physical extrapolations to the continuum, physical pion mass, and infinite momentum, together with hybrid renormalization, large- $λ$ extrapolation, and perturbative matching, yield the three leading-twist LCDAs $V$ , $A$ , and $T$ . Using the lattice-determined LCDAs in place of the asymptotic form, we find an $O (10%)$ shift in the $Λ$ electromagnetic form factor at perturbative scales, demonstrating that the full two-dimensional LCDAs, rather than only their asymptotic shapes or lowest moments, are required for precision baryonic phenomenology. This work, together with the companion paper [1] detailing the baryon-LaMET framework, provides the first complete multi-dimensional $x$ -dependent baryon LCDAs from first principles and establishes a benchmark for lattice access to multi-dimensional baryon structure.
hep-lathep-ph3 citations
03
The topological susceptibility slope $χ^{'}$ in the large- $N$ limit
Claudio Bonanno🇪🇸
This paper presents the first non-perturbative lattice determination of the Yang--Mills topological susceptibility slope $χ^{'}$ in the large- $N$ limit. This quantity represents the $O (p^{2})$ term of the momentum expansion of the topological charge density two-point correlator, and has important theoretical and phenomenological implications for strong interactions. This calculation is based on a novel algorithm that avoids topological freezing at large $N$ on fine lattices, and on a novel method to reliably compute $χ^{'}$ on the lattice. The results of this study are relevant for the description of the proton spin in deep inelastic scattering experiments via the Shore--Veneziano formula.
hep-lathep-phhep-th0 citations
04
Isospin-Driven Splitting of Chemical Potentials in Isobar Collisions from Lattice QCD
Heng-Tong Ding🇨🇳 · Jin-Biao Gu🇨🇳 · Arpith Kumar🇨🇳 · Jia Ni🇨🇳
Strong magnetic fields produced in relativistic heavy-ion collisions can modify fluctuations of conserved charges and, consequently, their associated chemical potentials. We present first-principles $(2 + 1)$ -flavor lattice-QCD results for isospin-driven splittings of conserved-charge chemical potentials between the isobar systems $_{44}^{96} Ru +_{44}^{96} Ru$ and $_{40}^{96} Zr +_{40}^{96} Zr$ in the QCD crossover region, both at vanishing and nonzero magnetic fields along the pseudo-critical line $T_{p c} (e B)$ . We outline a framework that, under strangeness neutrality and charge-to-baryon ratio $r \equiv n_{Q} / n_{B}$ , maps the isospin difference between two nuclei, as encoded in $r_{Zr}$ and $r_{Ru}$ , onto splitting ratios $Δ μ_{Q} /Δ μ_{B}$ , $Δ μ_{S} /Δ μ_{B}$ , and $Δ μ_{S} /Δ μ_{Q}$ as functions of $μ_{B} (r_{Ru}) /Δ μ_{B}$ . Using continuum-estimated lattice results for the leading-order coefficients $q_{1} \equiv (μ_{Q} / μ_{B})_{LO}$ and $s_{1} \equiv (μ_{S} / μ_{B})_{LO}$ , we find that, at vanishing magnetic field, the splitting ratios are of similar magnitude to recent Bayesian extractions from STAR isobar data and yield $Δ μ_{Q} < 0$ and $Δ μ_{S} > 0$ , with the electric-charge sector dominating. At nonzero magnetic fields, the splitting ratios show only moderate $e B$ dependence. We therefore further examine Ru--Zr differences in the normalized magnetic-field response of chemical-potential ratios, particularly those involving $μ_{Q} / μ_{B}$ , which display a pronounced enhancement in lattice QCD. We also present hadron resonance gas (HRG) results and experimentally motivated proxy observables with kinematic cuts to facilitate contact with experiment.
hep-lathep-phnucl-exnucl-th1 citation
05
Baryon Light-Cone Distribution Amplitudes from Lattice QCD: Formalism, Renormalization, Extrapolation, and Matching
Mu-Hua Zhang🇨🇳 · Haoyang Bai🇨🇳 · Min-Huan Chu🇵🇱 · Jun Hua🇨🇳 · Xiangdong Ji🇨🇳 · Xiangyu Jiang🇨🇳 · Jian Liang🇨🇳 · Cai-Dian Lü🇨🇳 · Andreas Schäfer🇩🇪 · Wei Wang🇨🇳 · Yi-Bo Yang🇨🇳 · Jian-Hui Zhang🇨🇳 · Jia-Lu Zhang · Qi-An Zhang🇨🇳
Baryon light-cone distribution amplitudes (LCDAs) are inherently multidimensional objects parametrized by two independent longitudinal momentum fractions, making their first-principles determination substantially more challenging than that of meson LCDAs. We present a systematic large-momentum effective theory (LaMET) framework for determining baryon leading-twist LCDAs from lattice QCD. The framework covers the complete path from equal-time three-quark quasi-distribution amplitudes to physical baryon LCDAs. We formulate the leading-twist $V$ , $A$ , and $T$ quasi-DAs and analyze their spin-flavor and coordinate-space symmetries, including antisymmetric amplitudes with vanishing local limits. We develop a hybrid renormalization prescription on the $(z_{1}, z_{2})$ plane, introduce a newly developed large- $λ$ extrapolation strategy based on the asymptotic large-distance behavior of Euclidean correlators, and derive the corresponding one-loop LaMET matching relation in the hybrid renormalization scheme. As a demonstration, we apply the complete analysis pipeline to the $Λ$ -baryon $A$ -structure quasi-DAs using seven $2 + 1$ --flavor lattice ensembles, and use this amplitude to examine the impact of large-distance extrapolation, perturbative matching, and extrapolation to the continuum, physical-pion-mass, and infinite-momentum limits, together with the associated systematic uncertainties. This work provides the formalism, renormalization, extrapolation, and matching infrastructure for first-principles determinations of $x$ -dependent baryon LCDAs.
hep-lathep-ph3 citations
06
Spectral phase transitions and trainability in neural network learning dynamics
Chanju Park🇬🇧 · Dario Bocchi · Francesco D'Amico · Biagio Lucini🇬🇧 · Gert Aarts🇬🇧
The emergence of low-dimensional structures in the spectra of neural network weight matrices is a common empirical feature of trained models, but the dynamical origin of this phenomenon during learning remains an open problem. We formulate neural network training as the stochastic evolution of an initially random matrix ensemble, driven by stochastic gradient descent (SGD) updates that reshape the spectral bulk while amplifying signal strength. This induces a Baik-Ben Arous-Péché (BBP) transition during training, where isolated eigenvalues detach from the random bulk distribution, providing a dynamical framework for representation formation in high-dimensional learning dynamics. We demonstrate this in a solvable linear teacher-student model, where spectral evolution is analytically tractable and a phase diagram of trainability governed by the step size (or learning rate) and initial weight variance is obtained, and subsequently extend our formalism beyond the linear regime to nonlinear and stochastic settings. Numerical simulations in realistic settings support this picture, showing robust emergence of spectral alignment during training. Our results suggest that spectral analysis may provide a unified perspective of stochastic learning dynamics, linking trainability, optimisation hyperparameters, spectral phase transitions, and representation learning in neural networks.
↳ cond-mat.dis-nncs.LGhep-lat0 citations
07
Ab initio $α$ - $α$ scattering with high-fidelity chiral interactions
Avik Sarkar · Serdar Elhatisari🇹🇷 · Timo A. Lähde🇩🇪 · Ulf-G. Meißner🇩🇪
Low-energy $α$ - $α$ scattering underlies stellar helium burning and sharply tests nuclear forces in the reaction regime. We present its first calculation using the high-fidelity N3LO chiral NLEFT interaction, incorporated through wave function matching, on a fine lattice, using the adiabatic projection method. On the fine lattice, the two-cluster norm matrix becomes severely ill-conditioned, and its direct inversion is unstable. We address this with Tikhonov regularization, extrapolating the regulator to zero, and confirm the result with an independent truncated singular-value decomposition. The S- and D-wave phase shifts agree with empirical analyses, extending the validation of this interaction from bound states and charge radii to scattering and providing a practical route to ab initio nuclear reactions on fine lattices
↳ nucl-thhep-lat2 citations
08
Understanding Color Confinement through Quantum Reference Frames and Relational Observables
Kei-Ichi Kondo🇯🇵
We present a formulation for understanding color confinement on the basis of quantum reference frames (QRFs) and relational observables. In the QRF approach to color confinement, colored quantities are not defined as isolated local fields, but rather as relational observables with respect to a color frame or a dressing field. By the Gauss law, local color charge is excluded from the physical bulk algebra, whereas semi-local data such as boundary fluxes and Wilson lines may remain. Color confinement is characterized by the absence of a globally well-defined long-distance color QRF capable of supporting isolated non-singlet relational observables. This formulation preserves the insight of the Kugo-Ojima type picture, while avoiding dependence on a particular covariant gauge, an unbroken global BRST symmetry, and a specific infrared confinement criterion. As concrete examples, we consider (1+1)-dim. Yang-Mills theory, (1+1)-dim. U(1) gauge-Higgs model, and the two-dim. U(1) gauge-Higgs model on $H^{2}$ ( $A d S_{2}$ ) and three-dim. SU(2) gauge-Higgs model on $H^{3}$ ( $A d S_{3}$ ) obtained by dimensional reduction of four-dim. SU(2) Yang-Mills theory restricted to symmetric-instanton sectors. Through explicit calculations in these examples and in controlled sectors, we provide nontrivial consistency checks for the validity of the present formulation. We also discuss prospects for four-dim. Yang-Mills theory and gauge-Higgs theories. QRF-based color confinement provides a relational formulation of why isolated colored asymptotic sectors are absent. At the same time, it clarifies the role played by topological defects and shows that other confinement criteria -- the Wilson-loop area law, the preservation of generalized symmetry, namely center one-form symmetry, and the restoration of residual gauge symmetry -- can be organized as manifestations of a common QRF structure.
↳ hep-thhep-lat0 citations
09
Doubly charmed baryon-light meson scattering in chiral effective theory with lattice constraints
Peng-Qi Wang🇨🇳 · Zhi-Hui Guo🇨🇳
We study the scattering of the ground states of doubly charmed baryons ( $Ξ_{cc}^{++}, Ξ_{cc}^{+}, Ω_{cc}^{+}$ ) and light-flavor pseudoscalar mesons ( $π, K, η$ ) up to the next-to-leading order within chiral effective theory. We perform the unitarization of the $S$ -wave scattering amplitudes in order to study the excited doubly charmed baryons. The unknown next-to-leading order low energy constants are determined through the fits to recent lattice data in the elastic scattering processes based on the CLQCD ensembles. Following the chiral extrapolation to physical quark masses, we predict resonance, virtual and bound doubly-charmed-baryon states arising from the single- and coupled-channel scattering of $Ξ_{cc}^{++}, Ξ_{cc}^{+}, Ω_{cc}^{+}$ with $π, K, η$ . Furthermore, we also calculate the corresponding scattering lengths, effective ranges, phase shifts and inelasticities at physical quark masses, which could shed light on future experimental searches and lattice simulations.
↳ hep-phhep-lat0 citations

Affiliations

first authorsco-authorsvia INSPIRE