English
Related papers

Related papers: Schwinger model simulations with dynamical overlap…

200 papers

We present an update of the light meson spectrum with $N_f$=2+1 overlap fermions on a $16^3\times 48$ lattice at five different up and down quark masses and two strange quark masses. Based on our experience with the previous simulation with…

High Energy Physics - Lattice · Physics 2012-08-27 JLQCD , TWQCD Collaborations , : , J. Noaki , S. Aoki , T. W. Chiu , H. Fukaya , S. Hashimoto , T. H. Hsieh , T. Kaneko , H. Matsufuru , T. Onogi , E. Shintani , N. Yamada

A numerical investigation of the quenched Schwinger model on the lattice using the overlap Dirac operator points to a divergent chiral condensate.

High Energy Physics - Lattice · Physics 2009-10-31 Joe Kiskis , Rajamani Narayanan

We construct new Ginsparg-Wilson fermions for QCD by inserting an approximately chiral Dirac operator - which involves ingredients of a perfect action - into the overlap formula. This accelerates the convergence of the overlap Dirac…

High Energy Physics - Lattice · Physics 2010-04-05 W. Bietenholz

There exist chiral gauge models in two dimensions that have massless composite fermions. Two examples are presented and it is suggested that they be accepted as benchmark test-cases for generic proposals of non-perturbatively regulating…

High Energy Physics - Lattice · Physics 2009-10-28 R. Narayanan , H. Neuberger

1. We compare Monte Carlo results with analytic predictions for the fermion condensate, in the massive one-flavour Schwinger model. 2. We illustrate on the Schwinger model how to facilitate transitions between topological sectors by a…

High Energy Physics - Lattice · Physics 2009-10-30 Ph. de Forcrand , J. E. Hetrick , T. Takaishi , A. J. van der Sijs

We present a detailed study of the interplay between chiral symmetry and spectral properties of the Dirac operator in lattice gauge theories. We consider, in the framework of the Schwinger model, the fixed point action and a fermion action…

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

The inverse eigenvalues of the Dirac operator in the Schwinger model satisfy the same Leutwyler-Smilga sum rules as in the case of QCD with one flavor. In this paper we give a microscopic derivation of these sum rules in the sector of…

High Energy Physics - Theory · Physics 2009-11-11 L. Shifrin , J. J. M. Verbaarschot

We study physics at temperatures just above the QCD phase transition (Tc) using chiral (overlap) Fermions in the quenched approximation of lattice QCD. Exact zero modes of the overlap Dirac operator are localized and their frequency of…

High Energy Physics - Lattice · Physics 2011-07-19 Rajiv V. Gavai , Sourendu Gupta , R. Lacaze

Smearing the gauge links of dynamical configurations removes small scale unphysical vacuum fluctuations and thus improves the chiral properties of lattice fermions. Recently we proposed the hypercubic smearing (HYP) that improves the flavor…

High Energy Physics - Lattice · Physics 2007-05-23 A. Hasenfratz , F. Knechtli

We compute fermionic observables relevant to the study of chiral symmetry in quenched QCD using the Overlap-Dirac operator for a wide range of the fermion mass. We use analytical results to disentangle the contribution from exact zero modes…

High Energy Physics - Lattice · Physics 2009-10-31 Robert G. Edwards , Urs M. Heller , Rajamani Narayanan

Tunneling between different topological sectors with dynamical chiral fermions is difficult because of a poor mass scaling of the pseudo-fermion estimate of the determinant. For small fermion masses it is virtually impossible using standard…

High Energy Physics - Lattice · Physics 2009-02-02 Nigel Cundy , Stefan Krieg , Thomas Lippert , Andreas Schaefer

Qualitative features of Ginsparg-Wilson fermions, as formulated by Neuberger, coupled to two dimensional U(1) gauge theory are studied. The role of the Wilson mass parameter in changing the number of massless flavors in the theory and its…

High Energy Physics - Lattice · Physics 2009-10-31 Shailesh Chandrasekharan

SU(3) gauge theory with overlap fermions in the 2-index symmetric (sextet) and fundamental representations is considered. A priori it is not known what the pattern of chiral symmetry breaking is in a higher dimensional representation…

High Energy Physics - Lattice · Physics 2010-04-30 Zoltan Fodor , Kieran Holland , Julius Kuti , Daniel Nogradi , Chris Schroeder

Overlap fermions are a powerful tool for investigating the chiral and topological structure of the vacuum and the thermal states of QCD. We study various chiral and topological aspects of the finite temperature phase transition of N_f=2…

High Energy Physics - Lattice · Physics 2007-05-23 V. Weinberg , E. -M. Ilgenfritz , K. Koller , Y. Koma , G. Schierholz , T. Streuer

Overlap fermions are particularly well suited to study the finite temperature dynamics of the chiral symmetry restoration transition of QCD, which might be just an analytic crossover. Using gauge field configurations on a 24^3x10 lattice…

High Energy Physics - Lattice · Physics 2008-11-26 V. Weinberg , E. -M. Ilgenfritz , K. Koller , Y. Koma , Y. Nakamura , G. Schierholz , T. Streuer

SU(3) gauge theory with dynamical overlap fermions in the 2-index symmetric (sextet) representation is considered. This model may be a viable model of the electroweak symmetry breaking sector along the lines of the walking technicolor…

High Energy Physics - Lattice · Physics 2010-01-21 Zoltan Fodor , Kieran Holland , Julius Kuti , Daniel Nogradi , Chris Schroeder

Three aspects of symmetry structure of lattice chiral fermion in the overlap formalism are discussed. By the weak coupling expansion of the overlap Dirac operator, the axial anomaly associated to the chiral transformation proposed by…

High Energy Physics - Lattice · Physics 2009-10-31 Y. Kikukawa

We review a number of topics related to block variable renormalisation group transformations of quantum fields on the lattice, and to the emerging perfect lattice actions. We first illustrate this procedure by considering scalar fields.…

High Energy Physics - Lattice · Physics 2008-11-26 W. Bietenholz

We perform a systematic study of low-lying eigenmodes of $H_w$ with various gauge actions to find the optimal choice for dynamical overlap fermion simulations, with which one may achieve lower numerical cost for HMC and better locality…

High Energy Physics - Lattice · Physics 2008-11-26 JLQCD Collaboration , N. Yamada , S. Aoki , H. Fukaya , S. Hashimoto , K-I. Ishikawa , K. Kanaya , T. Kaneko , H. Matsufuru , M. Okamoto , T. Onogi

We estimate the quark-mass dependence of the topological susceptibility with dynamical overlap and clover fermions. Unquenching effects on the susceptibility turn out to be well approximated by a reweighting of a quenched ensemble with a…

High Energy Physics - Lattice · Physics 2015-06-25 Tamas G. Kovacs