Fri·Nov 25, 2022Friday·November 25, 2022

1. 01*

   Dynamical fermions, centre vortices, and emergent phenomena

   Derek Leinweber🇦🇺 · James Biddle🇦🇺 · Waseem Kamleh🇦🇺 · Adam Virgili (CSSM, University of Adelaide)🇦🇺

   The non-trivial ground-state vacuum fields of QCD form the foundation of matter. Here we examine the centre vortices identified within the ground-state fields of lattice QCD. We aim to understand the manner in which dynamical fermions in the QCD vacuum alter the centre-vortex structure. Using modern visualisation techniques, the centre-vortex structure of pure-gauge and dynamical-fermion fields is quantified and compared. We then explore the impact this modified structure has on measures of confinement and dynamical mass generation. The string tension of the static quark potential, positivity-violation in the gluon propagator, and dynamical mass generation in the overlap quark propagator are of particular interest. The impact of dynamical fermions is significant and provides new insights into the role of centre vortices in underpinning both confinement and dynamical chiral symmetry breaking in QCD.

   hep-lathep-phnucl-thEPJ Web Conf.(2022)·6 citations
2. 02*

   Measurement of hadron masses in 2-color finite density QCD

   Kotaro Murakami🇯🇵 · Daiki Suenaga🇯🇵 · Kei Iida🇯🇵 · Etsuko Itou🇯🇵

   We investigate hadron spectra in 2-color QCD using lattice simulation with $N_f=2$ at low temperature and finite density in which there appears not only the hadronic phase but also the superfluid phase. We first calculate the pion and rho meson spectrum, which is well-known from previous works. The spectral ordering of these mesons flips around the quark chemical potential $\mu =m_{\pi }^0/2$ ($m_{\pi }^0$: the pion mass at $\mu =0$), where the phase transition between the hadronic and superfluid phases occurs. For $\mu \gtrsim m_{\pi }^0/2$, the effective mass for the pion linearly increases while the one for the rho meson monotonically decreases. Furthermore, we measure hadron spectra with the isospin $I=0$ and the angular momentum $J^P=0^{\pm }$. The effective masses for the meson, diquark, and antidiquark with the same quantum number become degenerate just below $\mu =m_{\pi }^0/2$, and the three hadrons have the same mass in the superfluid phase. It suggests that mixing occurs between spectra associating with mesons and baryons due to the $U(1{)}_B$ symmetry breaking. This phenomenon can be explained in the linear sigma model with the approximate $SU(4)$ Pauli-Gursey symmetry.

   hep-lathep-phnucl-thPoS(2023)·18 citations
3. 03*

   Thermal QCD for non-perturbative renormalization of composite operators

   Matteo Bresciani🇮🇹 · Mattia Dalla Brida🇨🇭 · Leonardo Giusti🇮🇹 · Michele Pepe🇮🇹

   We present our progresses in the use of the non-perturbative renormalization framework based on considering QCD at finite temperature with shifted and twisted (for quarks only) boundary conditions in the compact direction. We report our final results in the application of this method for the non-perturbative renormalization of the flavor-singlet local vector current. We then discuss the more challenging case of the renormalization of the energy-momentum tensor, and show preliminary results on the relevant one-point functions for the computation of the renormalization constants of its non-singlet components.

   hep-latPoS(2023)·2 citations
4. 04*

   Hadrons at high temperature: an update from the FASTSUM collaboration

   Jon-Ivar Skullerud🇮🇪 · Gert Aarts🇬🇧 · Chris Allton🇬🇧 · M. Naeem Anwar🇬🇧 · Ryan Bignell🇬🇧 · Tim Burns🇬🇧 · Sergio Chaves García-Mascaraque🇬🇧 · Simon Hands🇬🇧 · Rachel Horohan D'Arcy🇮🇪 · Benjamin Jäger🇩🇰 · Seyong Kim🇰🇷 · Maria Paola Lombardo🇮🇹 and 7 other authors

   We present the most recent results from the FASTSUM collaboration for hadron properties at high temperature. This includes the temperature dependence of the light and charmed meson and baryon spectrum, as well as properties of heavy quarkonia. The results are obtained using anisotropic lattices with a fixed scale approach. We also present the status of our next generation gauge ensembles.

   hep-lathep-phnucl-thEPJ Web Conf.(2022)·7 citations
5. 05*

   MRHS multigrid solver for Wilson-clover fermions

   Daniel Richtmann🇩🇪 · Nils Meyer🇩🇪 · Tilo Wettig🇩🇪

   We describe our implementation of a multigrid solver for Wilson-clover fermions, which increases parallelism by solving for multiple right-hand sides (MRHS) simultaneously. The solver is based on Grid and thus runs on all computing architectures supported by the Grid framework. We present detailed benchmarks of the relevant kernels, such as hopping and clover term on the various multigrid levels, intergrid operators, and reductions. The benchmarks were performed on the JUWELS Booster system at Jülich Supercomputing Centre, which is based on Nvidia A100 GPUs. For example, solving a $24^3\times 128$ lattice on 16 GPUs, the overall speedup obtained solely from MRHS is about 10x.

   hep-latcs.DCPoS(2023)·4 citations
6. 06*

   Sea-quark loop contributions to the $\bar{d}$-$\bar{u}$ asymmetry in the proton

   Derek B. Leinweber🇦🇺 · Anthony W. Thomas (CSSM, University of Adelaide)🇦🇺

   QCD interactions for equal-mass fermion flavors are flavor blind. This fact is often used to state that disconnected sea-quark loop contributions are equal for $u$ and $d$ quarks in the mass symmetric case and therefore these disconnected sea-quark loop contributions cannot contribute to the well-known $\bar{d}-\bar{u}$ asymmetry in the proton. Instead, it is argued that one must look to the connected sector of lattice QCD correlation functions to find this difference. In this presentation, we note that these statements are true provided unphysical contributions in the sea-quark loop sector are included, contributions from baryons that do not appear in the physical spectrum. To respect the Pauli principle, these unphysical contributions from the disconnected sea-quark loop sector must cancel equally unphysical contributions in the connected sector. The remaining disconnected sea-quark loop contributions no longer have a balance between $\bar{d}$ and $\bar{u}$. Upon considering only physically observed baryons in the loop contributions, we illustrate an important contribution from the sea-quark loop sector to $\bar{d}-\bar{u}$ that enhances the leading connected contribution by 12\%.

   ↳ hep-phhep-latnucl-thPRD(2024)·4 citations
7. 07*

   Inverse Problem Approach for Non-Perturbative QCD: Theoretical Foundation

   Ao-Sheng Xiong🇨🇳 · Fu-Sheng Yu🇨🇳 · Yong Zheng🇨🇳 · Ting Wei🇨🇳

   A novel theoretical framework, the inverse problem approach, is proposed to calculate non-perturbative quantities in quantum chromodynamics (QCD). Based on the dispersion relation of quantum field theory, this approach determines unknown low-energy non-perturbative quantities from known high-energy perturbative inputs via solving an inverse problem. The resulting inverse problem is rigorously proven to be ill-posed, with the solutions being unique but unstable. To address this instability, the well-established Tikhonov regularization is employed, yielding stable approximate solutions that converge to the true values as input errors vanish. The key features of this approach are illustrated through three toy models, demonstrating that solution precision can be systematically improved through reduced input errors and optimized regularization strategies.

   ↳ hep-thhep-exhep-lathep-ph+121 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.