Related papers: Simulations with different lattice Dirac operators…
We study lattice QCD with staggered sea and Ginsparg-Wilson valence quarks. The Symanzik effective action for this mixed lattice theory, including the lattice spacing contributions of O(a^2), is derived. Using this effective theory we…
We present first results of a mixed action project. We analyze gauge configurations generated with two flavors of dynamical twisted mass fermions. Neuberger's overlap Dirac operator is used for the valence sector. The various choices in the…
We report on our first experiences in simulating Neuberger valence fermions on CLS $N_f=2$ configurations with light sea quark masses and small lattice spacings. Valence quark masses are considered that allow to explore the matching to…
We study the phase structure of mixed-action QCD with two Wilson sea quarks and two chiral valence quarks, starting from the chiral lagrangian. A priori, the effective theory allows for a rich phase structure, including a phase with a…
The O(a^2) contributions to the chiral effective Lagrangian for lattice QCD with Wilson fermions are constructed. The results are generalized to partially quenched QCD with Wilson fermions as well as to the "mixed'' lattice theory with…
We introduce a lattice QCD mixed action approach that employs Wilson-type quarks in the sea and valence sectors. The sea sector is based on gauge ensembles with $N_{\rm f}=2+1$ flavours of non-perturbatively O($a$)-improved Wilson fermions…
We discuss a Lattice QCD mixed action investigation employing Wilson maximally twisted mass sea and overlap valence fermions. Using four values of the lattice spacing, we demonstrate that the overlap Dirac operator assumes a point-like…
We discuss a mixed-action approach in which sea quarks are regularised using non-perturbatively ${\rm O}(a)$ improved Wilson fermions, while a fully-twisted tmQCD action is used for valence quarks. In this setup, automatic ${\rm O}(a)$…
We report our progress in simulating Neuberger valence fermions on N_f=2 Wilson O(a)-improved sea quarks. We compute correlators with valence quark masses both in the p- and in the epsilon-regime, and we match the results with the…
Considering Ginsparg-Wilson type fermions dynamically in lattice QCD simulations is a challenging task. The hope is to be able to approach smaller pion masses and to eventually reach physical situations. The price to pay is substantially…
We discuss some of the implications of simulating QCD when the action used for the sea quarks is different from that used for the valence quarks. We present exploratory results for the hadron mass spectrum and pseudoscalar meson decay…
We report on our simulations with Neuberger valence fermions on CLS $N_f=2$ configurations with non-perturbatively $O(a)$-improved Wilson sea quarks. We consider the matching of QCD to ChPT in the so called mixed-regime in which the sea…
I review the theoretical foundations, properties as well as the simulation results obtained so far of a variant of the Wilson lattice QCD formulation: Wilson twisted mass lattice QCD. Emphasis is put on the discretization errors and on the…
We study the phase structure of mixed-action QCD with two Wilson sea quarks and any number of chiral valence quarks (and ghosts), starting from the chiral lagrangian. A priori, the effective theory allows for a rich phase structure,…
We construct the chiral effective Lagrangian for two lattice theories: one with Wilson fermions and the other with Wilson sea fermions and Ginsparg-Wilson valence fermions. For each of these theories we construct the Symanzik action through…
With the advent of chiral fermion formulations, the simulation of light valence quarks has finally become realistic for numerical simulations of lattice QCD. The simulation of light dynamical quarks, however, remains one of the major…
We report on our first experiences with a mixed action setup with overlap valence quarks and non-perturbatively O(a) improved Wilson sea quarks. For the latter we employ CLS Nf=2 configurations with light sea quark masses at small lattice…
We present simulation results for lattice QCD with chiral fermions in small volumes, where the epsilon-expansion of chiral perturbation theory applies. Our data for the low lying Dirac eigenvalues, as well as mesonic correlation functions,…
In lattice QCD it is possible, in principle, to determine the parameters in the effective chiral lagrangian (including weak interaction couplings) by performing numerical simulations in the $\epsilon$--regime, i.e. at quark masses where the…
Starting from the chiral Lagrangian for Wilson fermions at nonzero lattice spacing we have obtained compact expressions for all spectral correlation functions of the Hermitian Wilson Dirac operator in the $\epsilon$-domain of QCD with…