Tue·Nov 1, 2022Tuesday·November 1, 2022

1. 01*

   Gradient flow step-scaling function for SU(3) with $N_f=8$ fundamental flavors

   Anna Hasenfratz🇺🇸 · Claudio Rebbi🇺🇸 · Oliver Witzel🇩🇪

   The step-scaling function, the lattice analog of the renormalization group $\beta$ function, is presented for the SU(3) gauge system with eight flavors in the fundamental representation. Our investigation is based on generating dynamical eight flavor gauge field configurations using stout-smeared Möbius domain wall fermions and Symanzik gauge action. On these gauge field configurations we perform gradient flow measurements using the Zeuthen, Wilson, or Symanzik kernel and consider the Symanzik, Wilson plaquette, or clover operators to determine step-scaling functions for a scale change $s=2$ including large, up to $48^4$, volumes. Considering different flows and operators as well as the optional use of tree-level improvement allows us to check for possible systematic effects. Our result covers the range of renormalized coupling up to $g_c^2\lesssim 10$. In the case of $N_f=8$ we observe that the reach in $g_c^2$ is limited due to an unphysical first order bulk phase transition caused by large ultra-violet fluctuations. We compare our findings to $N_f=4$, 6, 10 or 12 flavors results that are obtained using the same lattice action and analysis. In addition we investigate the phase structure for simulations with different number of flavors using stout-smeared Möbius domain wall fermions and Symanzik gauge actions to shed some light on the limited reach in $g_c^2$.

   hep-lathep-phPRD(2023)·20 citations
2. 02*

   Investigating vector boson scattering: A fully gauge-invariant study

   Bernd Riederer🇦🇹 · Axel Maas🇦🇹

   Vector boson scattering (VBS) plays a central role in the search for new physics at collider experiments such as ATLAS and CMS at the LHC. Usually predictions for this kind of process are obtained using mainly perturbative approaches in fixed gauges. Here we present a fully gauge-invariant study of VBS in the scalar-channel involving three different types of Higgs-like particles characterized by their mass; above (heavy), inside (resonance) or below (stable) the elastic region. To this end, we combine results obtained in a reduced SM setup from (augmented) perturbation theory with those from non-perturbative lattice simulations.

   hep-lathep-phPoS(2022)·3 citations
3. 03*

   Inclusive production of $J/\psi$, $\psi (2S)$, and ${\rm Y}$ states in pNRQCD

   Nora Brambilla🇩🇪 · Hee Sok Chung🇩🇪 · Antonio Vairo🇩🇪 · Xiang-Peng Wang🇩🇪

   Under some assumptions on the hierarchy of relevant energy scales, we compute the nonrelativistic QCD (NRQCD) long-distance matrix elements (LDMEs) for inclusive production of $J/\psi$, $\psi (2S)$, and ${\rm Y}$ states based on the potential NRQCD (pNRQCD) effective field theory. Based on the pNRQCD formalism, we obtain expressions for the LDMEs in terms of the quarkonium wavefunctions at the origin and universal gluonic correlators, which do not depend on the heavy quark flavor or the radial excitation. This greatly reduces the number of nonperturbative unknowns and substantially enhances the predictive power of the nonrelativistic effective field theory formalism. We obtain improved determinations of the LDMEs for $J/\psi$, $\psi (2S)$, and ${\rm Y}$ states thanks to the universality of the gluonic correlators, and obtain phenomenological results for cross sections and polarizations at large transverse momentum that agree well with measurements at the LHC.

   ↳ hep-phhep-exhep-latnucl-thJHEP(2023)·39 citations
4. 04*

   Wavefunction matching for solving quantum many-body problems

   Serdar Elhatisari · Lukas Bovermann · Yuanzhuo Ma · Evgeny Epelbaum · Dillon Frame · Fabian Hildenbrand · Myungkuk Kim · Youngman Kim · Hermann Krebs · Timo A. Lähde · Dean Lee · Ning Li and 6 other authors

   Ab initio calculations play an essential role in our fundamental understanding of quantum many-body systems across many subfields, from strongly correlated fermions to quantum chemistry and from atomic and molecular systems to nuclear physics. One of the primary challenges is to perform accurate calculations for systems where the interactions may be complicated and difficult for the chosen computational method to handle. Here we address the problem by introducing a new approach called wavefunction matching. Wavefunction matching transforms the interaction between particles so that the wavefunctions up to some finite range match that of an easily computable interaction. This allows for calculations of systems that would otherwise be impossible due to problems such as Monte Carlo sign cancellations. We apply the method to lattice Monte Carlo simulations of light nuclei, medium-mass nuclei, neutron matter, and nuclear matter. We use high-fidelity chiral effective field theory interactions and find good agreement with empirical data. These results are accompanied by new insights on the nuclear interactions that may help to resolve long-standing challenges in accurately reproducing nuclear binding energies, charge radii, and nuclear matter saturation in ab initio calculations.

   ↳ nucl-thcond-mat.quant-gashep-latnucl-ex+1Nature(2024)·110 citations
5. 05*

   Finding the ground state of a lattice gauge theory with fermionic tensor networks: a $2+1d$ ${\mathbb{Z}}_2$ demonstration

   Patrick Emonts🇩🇪 · Ariel Kelman🇮🇱 · Umberto Borla🇩🇪 · Sergej Moroz🇸🇪 · Snir Gazit🇮🇱 · Erez Zohar🇮🇱

   Tensor network states, and in particular Projected Entangled Pair States (PEPS) have been a strong ansatz for the variational study of complicated quantum many-body systems, thanks to their built-in entanglement entropy area law. In this work, we use a special kind of PEPS - Gauged Gaussian Fermionic PEPS (GGFPEPS) to find the ground state of $2+1d$ dimensional pure ${\mathbb{Z}}_2$ lattice gauge theories for a wide range of coupling constants. We do so by combining PEPS methods with Monte-Carlo computations, allowing for efficient contraction of the PEPS and computation of correlation functions. Previously, such numerical computations involved the calculation of the Pfaffian of a matrix scaling with the system size, forming a severe bottleneck; in this work we show how to overcome this problem. This paves the way for applying the method we propose and benchmark here to other gauge groups, higher dimensions, and models with fermionic matter, in an efficient, sign-problem-free way.

   ↳ quant-phcond-mat.str-elhep-latPRD(2023)·40 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.