Tue·Dec 27, 2022Tuesday·December 27, 2022

1. 01*

   Optimizing Staggered Multigrid for Exascale performance

   Venkitesh Ayyar🇺🇸 · Richard Brower🇺🇸 · M.A. Clark🇺🇸 · Mathias Wagner🇺🇸 · Evan Weinberg🇺🇸

   Adaptive multi-grid methods have proven very successful in dealing with critical slow down for the Wilson-Dirac solver in lattice gauge theory. Multi-grid algorithms developed for Staggered fermions using the Kähler-Dirac preconditioning~\cite{Brower:2018ymy} have shown remarkable success. In this work, we discuss the performance of this staggered multi-grid algorithm in four dimensions. We also demonstrate that offloading some components of a multi-shift solve to a multi-grid solver leads to a significant performance improvement in an existing MILC spectrum workflow on the Summit and Selene supercomputers.

   hep-latPoS(2023)·6 citations
2. 02*

   Unpolarized proton PDF at NNLO from lattice QCD with physical quark masses

   Xiang Gao🇺🇸 · Andrew D. Hanlon🇺🇸 · Jack Holligan🇺🇸 · Nikhil Karthik🇺🇸 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸 · Sergey Syritsyn🇺🇸 · Yong Zhao🇺🇸

   We present a lattice QCD calculation of the unpolarized isovector quark parton distribution function (PDF) of the proton utilizing a perturbative matching at next-to-next-to-leading-order (NNLO). The calculations are carried out using a single ensemble of gauge configurations generated with $N_f=2+1$ highly-improved staggered quarks with physical masses and a lattice spacing of $a=0.076$ fm. We use one iteration of hypercubic smearing on these gauge configurations, and the resulting smeared configurations are then used for all aspects of the subsequent calculation. For the valence quarks, we use the Wilson-clover action with physical quark masses. We consider several methods for extracting information on the PDF. We first extract the lowest four Mellin moments using the leading-twist operator product expansion approximation. Then, we determine the $x$ dependence of the PDF through a deep neural network within the pseudo-PDF approach and additionally through the framework of large-momentum effective theory utilizing a hybrid renormalization scheme. This is the first application of the NNLO matching coefficients for the nucleon directly at the physical point.

   hep-lathep-exhep-phnucl-ex+1PRD(2023)·57 citations
3. 03*

   D-meson semileptonic decays to pseudoscalars from four-flavor lattice QCD

   Alexei Bazavov🇺🇸 · Carleton DeTar🇺🇸 · Aida X. El-Khadra🇺🇸 · Elvira Gámiz🇪🇸 · Zechariah Gelzer🇺🇸 · Steven Gottlieb🇺🇸 · William I. Jay🇺🇸 · Hwancheol Jeong🇺🇸 · Andreas S. Kronfeld🇺🇸 · Ruizi Li🇺🇸 · Andrew T. Lytle🇺🇸 · Paul B. Mackenzie🇺🇸 and 7 other authors

   We present lattice-QCD calculations of the hadronic form factors for the semileptonic decays $D\to \pi \ell \nu$, $D\to K\ell \nu$, and $D_s\to K\ell \nu$. Our calculation uses the highly improved staggered quark (HISQ) action for all valence and sea quarks and includes $N_f=2+1+1$ MILC ensembles with lattice spacings ranging from $a\approx 0.12$ fm down to $0.042$ fm. At most lattice spacings, an ensemble with physical-mass light quarks is included. The HISQ action allows all the quarks to be treated with the same relativistic light-quark action, allowing for nonperturbative renormalization using partial conservation of the vector current. We combine our results with experimental measurements of the differential decay rates to determine $|V_{cd}{|}^{D\to \pi }=0.2238(11{)}^{\mathrm{Expt}}(15{)}^{\mathrm{QCD}}(04{)}^{\mathrm{EW}}(02{)}^{\mathrm{SIB}}[22{]}^{\mathrm{QED}}$ and $|V_{cs}{|}^{D\to K}=0.9589(23{)}^{\mathrm{Expt}}(40{)}^{\mathrm{QCD}}(15{)}^{\mathrm{EW}}(05{)}^{\mathrm{SIB}}[95{]}^{\mathrm{QED}}$ This result for $|V_{cd}|$ is the most precise to date, with a lattice-QCD error that is, for the first time for the semileptonic extraction, at the same level as the experimental error. Using recent measurements from BES III, we also give the first-ever determination of $|V_{cd}{|}^{D_s\to K}=0.258(15{)}^{\mathrm{Expt}}(01{)}^{\mathrm{QCD}}[03{]}^{\mathrm{QED}}$ from $D_s\to K\ell \nu$. Our results also furnish new Standard Model calculations of the lepton flavor universality ratios $R^{D\to \pi }=0.98671(17{)}^{\mathrm{QCD}}[500{]}^{\mathrm{QED}}$, $R^{D\to K}=0.97606(16{)}^{\mathrm{QCD}}[500{]}^{\mathrm{QED}}$, and $R^{D_s\to K}=0.98099(10{)}^{\mathrm{QCD}}[500{]}^{\mathrm{QED}}$, which are consistent within $2\sigma$ with experimental measurements. Our extractions of $|V_{cd}|$ and $|V_{cs}|$, when combined with a value for $|V_{cb}|$, provide the most precise test of second-row CKM unitarity, finding agreement with unitarity at the level of one standard deviation.

   hep-lathep-phPRD(2023)·70 citations
4. 04*

   Electroweak box diagrams on the lattice for pion and neutron decay

   Jun-Sik Yoo🇺🇸 · Tanmoy Bhattacharya🇺🇸 · Rajan Gupta🇺🇸 · Santanu Mondal🇺🇸 · Boram Yoon🇺🇸

   CKM matrix is unitary by construction in the standard model(SM). The recent analyses on the first row of CKM matrix show $\approx 3\sigma$ tension with unitarity. Nonperturbative calculations of the radiative corrections can reduce the theory uncertainty in CKM matrix elements. Here we compute the electroweak box contribution to the pion and kaon $\beta$ decays using seven $N_f=2+1+1$ HISQ-Clover lattice with various pion mass and lattice spacing. The continuum and chiral limit is taken using the leading dependence on $M_{\pi }$ and $a$, where $M_{\pi }$ extrapolation is taken to the physical pion mass and $SU(3)$ symmetric mass for pion and kaon box contribution, respectively. Our results are ${\square }_{\gamma W}^{VA}{|}_{\pi }=2.820(28)\times 10^{-3}$ and ${\square }_{\gamma W}^{VA}{|}_K=2.384(17)\times 10^{-3}$.

   hep-lathep-exhep-phPoS(2023)·6 citations
5. 05*

   Indication of a p-$\varphi$ bound state from a correlation function analysis

   Emma Chizzali🇨🇭 · Yuki Kamiya🇩🇪 · Raffaele Del Grande🇩🇪 · Takumi Doi🇯🇵 · Laura Fabbietti🇩🇪 · Tetsuo Hatsuda🇯🇵 · Yan Lyu🇨🇳

   The existence of a nucleon-$\varphi$ (N-$\varphi$) bound state has been subject of theoretical and experimental investigations for decades. In this letter, indication of a \pphi bound state is found, using for the first time two-particle correlation functions as alternative to invariant mass spectra. Newly available lattice calculations for the spin 3/2 \Nphi interaction by the HAL QCD collaboration are used to constrain the spin 1/2 counterpart from the fit of the experimental \pphi correlation function measured by ALICE. The corresponding scattering length and effective range are $f_0^{(1/2)}=\left(-1.54_{-0.53}^{+0.53}(stat.{)}_{-0.09}^{+0.16}(syst.)+i\cdot 0.00_{-0.00}^{+0.35}(stat.{)}_{-0.00}^{+0.16}(syst.)\right)$~fm and $d_0^{(1/2)}=\left(0.39_{-0.09}^{+0.09}(stat.{)}_{-0.03}^{+0.02}(syst.)+i\cdot 0.00_{-0.04}^{+0.00}(stat.{)}_{-0.02}^{+0.00}(syst.)\right)$~fm, respectively. The results imply the appearance of a \pphi bound state with an estimated binding energy in the range of $12.8-56.1$ MeV.

   ↳ nucl-exhep-latPLB(2024)·44 citations
6. 06*

   Scalar, fermionic and supersymmetric field theories with subsystem symmetries in d+1 dimensions

   Masazumi Honda🇯🇵 · Taiichi Nakanishi🇯🇵

   We study various non-relativistic field theories with exotic symmetries called subsystem symmetries, which have recently attracted much attention in the context of fractons. We start with a scalar theory called $\varphi$-theory in $d+1$ dimensions and discuss its properties studied in literature for $d\le 3$ such as self-duality, vacuum structure, 't Hooft anomaly, anomaly inflow and lattice regularization. Next we study a theory called chiral $\varphi$-theory which is an analogue of a chiral boson with subsystem symmetries. Then we discuss theories including fermions with subsystem symmetries. We first construct a supersymmetric version of the $\varphi$-theory and dropping its bosonic part leads us to a purely fermionic theory with subsystem symmetries called $\psi$-theory. We argue that lattice regularization of the $\psi$-theory generically suffers from an analogue of doubling problem as previously pointed out in the $d=3$ case. We propose an analogue of Wilson fermion to avoid the ``doubling" problem. We also supersymmetrize the chiral $\varphi$-theory and dropping the bosonic part again gives us a purely fermionic theory. We finally discuss vacuum structures of the theories with fermions and find that they are infinitely degenerate because of spontaneous breaking of subsystem symmetries.

   ↳ hep-thcond-mat.str-elhep-latJHEP(2023)·14 citations
7. 07*

   Matrix Product Renormalization Group: Potential Universal Quantum Many-Body Solver

   Masahiko G. Yamada🇯🇵 · Takumi Sanno · Masahiro O. Takahashi · Yutaka Akagi · Hidemaro Suwa · Satoshi Fujimoto · Masafumi Udagawa🇯🇵

   The density matrix renormalization group (DMRG) is a celebrated tensor network algorithm, which computes the ground states of one-dimensional quantum many-body systems very efficiently. Here we propose an improved formulation of continuous tensor network algorithms, which we name a matrix product renormalization group (MPRG). MPRG is a universal quantum many-body solver, which potentially works at both zero and finite temperatures, in two and higher dimensions, and is even applicable to open quantum systems. Furthermore, MPRG does not rely on any variational principles and thus supports any kind of non-Hermitian systems in any dimension. As a demonstration, we present critical properties of the Yang-Lee edge singularity in one dimension as a representative non-Hermitian system.

   ↳ cond-mat.str-elcond-mat.stat-mechhep-latquant-ph4 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.