225 citations · 474 across the 21 of their papers we have counts for
24 papers · 1 filter
How perturbative are heavy sea quarks?
Andreas Athenodorou, Jacob Finkenrath, Francesco Knechtli +4
Effects of heavy sea quarks on the low energy physics are described by an effective theory where the expansion parameter is the inverse quark mass, 1/. At leading order in 1/…
Power corrections from decoupling of the charm quark
Francesco Knechtli, Tomasz Korzec, Björn Leder +1
Decoupling of heavy quarks at low energies can be described by means of an effective theory as shown by S. Weinberg in Ref. [1]. We study the decoupling of the charm quark by latti…
Lattice and string worldsheet in AdS/CFT: a numerical study
Valentina Forini, Lorenzo Bianchi, Marco S. Bianchi +2
We consider a possible discretization for the gauge-fixed Green-Schwarz (two-dimensional) sigma-model action for the Type IIB superstring and use it for measuring the cusp anomalou…
Perturbative versus non-perturbative decoupling of heavy quarks
Francesco Knechtli, Mattia Bruno, Jacob Finkenrath +2
We simulate a theory with heavy quarks of mass . At energies much smaller than the heavy quarks decouple and the theory can be described by an effective theory which…
Tuning of the strange quark mass with optimal reweighting
Björn Leder, Jacob Finkenrath
Quark mass reweighting can be used to tune the mass of dynamical quarks. The basic idea is to use gauge field ensembles generated at some bare mass parameters to evaluate observabl…
Isospin Effects by Mass Reweighting
Jacob Finkenrath, Francesco Knechtli, Björn Leder
Most of today's lattice simulations are performed in the isospin symmetric limit of the light quark sector. Mass reweighting is a technique to include effects of isospin breaking i…
Physical and cut-off effects of heavy sea quarks
Francesco Knechtli, Andreas Athenodorou, Mattia Bruno +4
We simulate a theory with two dynamical O() improved Wilson quarks whose mass ranges from a factor eight up to a factor two below the charm quark mass and at three values of…
On the effects of heavy sea quarks at low energies
Mattia Bruno, Jacob Finkenrath, Francesco Knechtli +2
We present a factorisation formula for the dependence of light hadron masses and low energy hadronic scales on the mass of a heavy quark: apart from an overall factor , rati…
Multigrid Preconditioning for the Overlap Operator in Lattice QCD
James Brannick, Andreas Frommer, Karsten Kahl +3
The overlap operator is a lattice discretization of the Dirac operator of quantum chromodynamics, the fundamental physical theory of the strong interaction between the quarks. As o…
One flavor mass reweighting: foundations
Björn Leder, Jacob Finkenrath, Francesco Knechtli
Reweighting is not a new method in lattice QCD, but a comprehensive analysis is missing in the literature. We close this gap by presenting: (i) a proof of an integral representatio…
An adaptive aggregation based domain decomposition multilevel method for the lattice wilson dirac operator: multilevel results
A. Frommer, K. Kahl, S. Krieg +2
In lattice QCD computations a substantial amount of work is spent in solving linear systems arising in Wilson's discretization of the Dirac equations. We show first numerical resul…
One flavor mass reweighting in lattice QCD
Jacob Finkenrath, Francesco Knechtli, Björn Leder
One flavor mass reweighting can be used in lattice QCD computations to fine tune the quark masses to their physical values. We present a new method that utilizes an unbiased stocha…
Adaptive Aggregation Based Domain Decomposition Multigrid for the Lattice Wilson Dirac Operator
Andreas Frommer, Karsten Kahl, Stefan Krieg +2
In lattice QCD computations a substantial amount of work is spent in solving discretized versions of the Dirac equation. Conventional Krylov solvers show critical slowing down for…
Application of Domain Decomposition to the Evaluation of Fermion Determinant Ratios
Jacob Finkenrath, Francesco Knechtli, Björn Leder
We analyze the fluctuations in the case of mass reweighting for N_f=2 Wilson fermions. We use a domain decomposition factorization of the fermion determinant. Ratios of determinant…
The strange quark mass and Lambda parameter of two flavor QCD
Patrick Fritzsch, Francesco Knechtli, Björn Leder +4
We complete the non-perturbative calculations of the strange quark mass and the Lambda parameter in two flavor QCD by the ALPHA collaboration. The missing lattice scale is determin…
Fermions as Global Correction: the QCD Case
Jacob Finkenrath, Francesco Knechtli, Björn Leder
It is widely believed that the fermion determinant cannot be treated in global acceptance-rejection steps of gauge link configurations that differ in a large fraction of the links.…
Aggregation-based Multilevel Methods for Lattice QCD
Andreas Frommer, Karsten Kahl, Stefan Krieg +2
In Lattice QCD computations a substantial amount of work is spent in solving the Dirac equation. In the recent past it has been observed that conventional Krylov solvers tend to cr…
Fermions as global correction in lattice QCD
Jacob Finkenrath, Francesco Knechtli, Björn Leder
The fermion determinant is a highly non-local object and its logarithm is an extensive quantity. For these reasons it is widely believed that the determinant cannot be treated in a…
The shape of the static potential with dynamical fermions
Francesco Knechtli, Björn Leder
We present the analysis of the static potential extracted from Wilson loops measured on CLS ensembles generated with Wilson gauge action and Nf=2 flavors of O(a) improved Wilson qu…
Testing universality and automatic O(a) improvement in massless lattice QCD with Wilson quarks
Bjorn Leder, Stefan Sint
The chirally rotated Schroedinger functional provides a test bed for universality and automatic O(a) improvement. We here report on extensive quenched simulations of lattice QCD wi…
B meson spectrum and decay constant from Nf=2 simulations
Benoit Blossier, John Bulava, Michele Della Morte +8
We report on the status of an ALPHA Collaboration project to extract quantities for B physics phenomenology from Nf=2 lattice simulations. The framework is Heavy Quark Effective Th…
Determination of the Static Potential with Dynamical Fermions
Michael Donnellan, Francesco Knechtli, Björn Leder +1
We present in detail a technique to extract the potential between a static quark and anti-quark pair from Wilson loops measured on dynamical configurations. This technique is based…
Scale r_0 and the static potential from the CLS lattices
Francesco Knechtli, Björn Leder
We report on the measurement of the static potential and the scale r_0 from HYP-smeared Wilson loops in two flavour QCD. We analyse the quark mass dependence of the potential and r…
Universality in the Gross-Neveu model
F. Knechtli, T. Korzec, B. Leder +1
We consider universal finite size effects in the large-N limit of the continuum Gross-Neveu model as well as in its discretized versions with Wilson and with staggered fermions. Af…