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Related papers: The eigenvalue spectrum for dynamical Chirally Imp…

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We simulate two dynamical, mass degenerate light quarks on 16^3x32 lattices with a spatial extent of 2.4 fm using the Chirally Improved Dirac operator. The simulation method, the implementation of the action and signals of equilibration are…

High Energy Physics - Lattice · Physics 2009-11-06 Christof Gattringer , Christian Hagen , C. B. Lang , Markus Limmer , Daniel Mohler , Andreas Schäfer

We investigate the eigenvalue spectrum of the staggered Dirac matrix in two-color QCD at nonzero temperature and at baryon density when the eigenvalues become complex. The quasi-zero modes and their role for chiral symmetry breaking and the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Elmar Bittner , Maria-Paola Lombardo , Harald Markum , Rainer Pullirsch

We present results from simulations of two flavors of dynamical overlap fermions on 8^4 lattices at three values of the sea quark mass and a lattice spacing of about 0.16 fm. We measure the topological susceptibility and the chiral…

High Energy Physics - Lattice · Physics 2009-11-11 Thomas DeGrand , Stefan Schaefer

We present numerical results for the 2-flavour Schwinger model with dynamical chiral lattice fermions. We insert an approximately chiral hypercube Dirac operator into the overlap formula to construct the overlap hypercube operator. This is…

High Energy Physics - Lattice · Physics 2012-04-26 Wolfgang Bietenholz , Ivan Hip , Stanislav Shcheredin , Jan Volkholz

We present simulation results for the 2-flavour Schwinger model with dynamical Ginsparg-Wilson fermions. Our Dirac operator is constructed by inserting an approximately chiral hypercube operator into the overlap formula, which yields the…

High Energy Physics - Lattice · Physics 2008-11-26 Jan Volkholz , Wolfgang Bietenholz , Stanislav Shcheredin

The microscopic spectral eigenvalue correlations of QCD Dirac operators in the presence of dynamical fermions are calculated within the framework of Random Matrix Theory (RMT). Our approach treats the low--energy correlation functions of…

High Energy Physics - Lattice · Physics 2008-11-26 G. Akemann , E. Kanzieper

Complete spectra of the staggered Dirac operator $\Dirac$ are determined in four-dimensional $SU(2)$ gauge fields with and without dynamical fermions. An attempt is made to relate the performance of multigrid and conjugate gradient…

High Energy Physics - Lattice · Physics 2009-10-22 Thomas Kalkreuter

The distribution of individual Dirac eigenvalues is derived by relating them to the density and higher eigenvalue correlation functions. The relations are general and hold for any gauge theory coupled to fermions under certain conditions…

High Energy Physics - Theory · Physics 2009-11-10 G. Akemann , P. H. Damgaard

We compute by Monte Carlo methods the individual distributions of the $k$th smallest Dirac operator eigenvalues in QCD, and compare them with recent analytical predictions. We do this for both massless and massive quarks in an SU(3) gauge…

High Energy Physics - Lattice · Physics 2009-10-31 P. H. Damgaard , U. M. Heller , R. Niclasen , K. Rummukainen

The spectral properties of a variety of improved staggered operators are studied in quenched QCD. The systematic dependence of the infrared eigenvalue spectrum on i) improvement in the staggered operator, ii) improvement in the gauge field…

High Energy Physics - Lattice · Physics 2009-11-10 Kit Yan Wong , R. M. Woloshyn

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…

High Energy Physics - Lattice · Physics 2011-12-05 K. Splittorff , J. J. M. Verbaarschot

We investigate general properties of the eigenvalue spectrum for improved staggered quarks. We introduce a new chirality operator $[\gamma_5 \otimes 1]$ and a new shift operator $[1 \otimes \xi_5]$, which respect the same recursion relation…

In this preliminary study, we examine the chiral properties of the parametrized Fixed-Point Dirac operator D^FP, see how to improve its chirality via the Overlap construction, measure the renormalized quark condensate Sigma and the…

High Energy Physics - Lattice · Physics 2015-06-25 P. Hasenfratz , S. Hauswirth , K. Holland , T. Jorg , F. Niedermayer

We use the graded eigenvalue method, a variant of the supersymmetry technique, to compute the universal spectral correlations of the QCD Dirac operator in the presence of massive dynamical quarks. The calculation is done for the chiral…

High Energy Physics - Theory · Physics 2009-10-31 Burkhard Seif , Tilo Wettig , Thomas Guhr

We study the spectrum properties for a recently constructed fixed point lattice Dirac operator. We also consider the problem of the extraction of the fermion condensate, both by direct computation, and through the Banks-Casher formula by…

High Energy Physics - Lattice · Physics 2009-10-31 F. Farchioni , C. B. Lang , M. Wohlgenannt

We study the lattice artefacts of the Wilson Dirac operator for QCD with two colors and fermions in the fundamental representation from the viewpoint of chiral perturbation theory. These effects are studied with the help of the following…

High Energy Physics - Lattice · Physics 2015-08-26 Mario Kieburg , Jacobus J. M. Verbaarschot , Savvas Zafeiropoulos

We present simulation results for lattice QCD with light pions. For the quark fields we apply chirally symmetric lattice Dirac operators, in particular the overlap hypercube operator, along with the standard overlap operator for comparison.…

High Energy Physics - Lattice · Physics 2007-05-23 W. Bietenholz , S. Shcheredin

I apply a recently developed algorithm for reweighting simulations of lattice QCD from one quark mass to another to simulations performed with overlap fermions in the epsilon regime. I test it by computing the condensate from distributions…

High Energy Physics - Lattice · Physics 2009-01-08 Thomas DeGrand

Chiral perturbation theory for eigenvalue distributions, and equivalently random matrix theory, has recently been extended to include lattice effects for Wilson fermions. We test the predictions by comparison to eigenvalue distributions of…

High Energy Physics - Lattice · Physics 2013-01-15 Poul H. Damgaard , Urs M. Heller , Kim Splittorff

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,…

High Energy Physics - Lattice · Physics 2009-11-11 W. Bietenholz , T. Chiarappa , K. Jansen , K. -I. Nagai , S. Shcheredin