Related papers: Lattice QCD without tuning, mixing and current ren…
We have studied lattice QCD with an additional, irrelevant 4-fermion interaction having a U(1)xU(1) chiral symmetry, at finite temperatures. Adding this 4-fermion term allowed us to work at zero quark mass, which would have otherwise been…
Lattice QCD using fermions whose Dirac operator obeys the Ginsparg-Wilson relation, is perhaps the best known formulation of QCD with a finite cutoff. It reproduces all the low energy QCD phenomenology associated with chiral symmetry at…
We have simulated lattice QCD with an irrelevant 4-fermion interaction and 2 zero mass quarks. The chiral phase transition is observed to be second order and we discuss extraction of critical exponents.
In these lectures I explain how chiral symmetry of continuum QCD naturally leads to a class of lattice regularisations known as twisted mass QCD (tmQCD). As compared to standard Wilson quarks, its advantages are the absence of unphysical…
The overlap Dirac operator, which satisfies the Ginsparg-Wilson relation, realizes exact chiral symmetry on the lattice without any unphysical doubler modes. To perform the path integrals, one should, however, note that the overlap fermion…
We simulate lattice QCD with an irrelevant chiral 4-fermion interaction which allows us to simulate at zero quark mass. This enables us to study the finite-temperature chiral-symmetry-restoring phase transition for 2 massless quark…
In this review we discuss the general features of maximally twisted lattice QCD. In particular, we illustrate how automatic O(a) improvement can be achieved and how it is possible to set up a lattice regularization scheme where the problem…
The problem of unphysical zero modes in lattice QCD with Wilson fermions can be solved in a clean way by including a mass term proportional to $i \psibar \gamma_5 \tau^3 \psi$ in the standard lattice theory with Nf=2 mass degenerate Wilson…
In this paper we discuss how the peculiar properties of twisted lattice QCD at maximal twist can be employed to set up a consistent computational scheme in which, despite the explicit breaking of chiral symmetry induced by the presence of…
We present results for the non-perturbative determination of the improvement and renormalization factors of the isovector axial current for lattice QCD with two flavors of dynamical Wilson quarks. The improvement and normalization…
Lattice QCD with Wilson quarks and a chirally twisted mass term represents a promising alternative regularization of QCD, which does not suffer from unphysical fermion zero modes. We show how the correlation functions of the renormalized…
Lattice QCD with staggered quarks is augmented by the addition of a chiral 4-fermion interaction. The Dirac operator is now non-singular at $m_q=0$, decreasing the computing requirements for light quark simulations by at least an order of…
Lattice formulations of QCD with Wilson fermions and a chirally twisted quark mass matrix provide an attractive framework for non-perturbative numerical studies. Owing to reparameterization invariance, the limiting continuum theory is just…
Non-perturbative lattice studies of QCD in the chiral thermodynamic regime, where chiral symmetry is spontaneously broken, require to deal with almost quark zero modes in a theoretically clean and computationally efficient way. We discuss…
We formulate lattice theories in which chiral symmetry is realized nonlinearly on the fermion fields. In this framework the fermion mass term does not break chiral symmetry. This property allows us to use the Wilson term to remove the…
We present a method of simulating lattice QCD at nonzero chemical potential in the chiral limit. By adding a weak four-fermi interaction to the standard staggered fermion SU(3) QCD action, we produce an algorithm in which the limit of…
To date numerical simulations of lattice QCD have not found a chiral phase transition of first order which is expected to occur for sufficiently light pions. We show how the restoration of an exact global chiral symmetry can strongly…
We study QCD with twelve light flavors at intermediate values of the bare lattice coupling. We contrast the results for the order parameter with different theoretical models motivated by the physics of the Goldstone phase and of the…
A mean field analysis of finite density QCD is presented including the effects of additional chiral invariant four-fermion interactions. A lattice regularization is used with N_f=4 flavors of staggered fermions. The use of the four-fermion…
We present the lattice QCD simulation with the 2+1+1 flavor full QCD ensembles using near-physical quark masses and different spatial sizes $L$, at $a\sim$ 0.055 fm. The results suggest that spontaneous chiral symmetry breaking is…