English
Related papers

Related papers: Dynamical overlap fermions, results with HMC algor…

200 papers

We perform dynamical QCD simulations with $n_f=2$ overlap fermions by hybrid Monte-Carlo method on $6^4$ to $8^3\times 16$ lattices. We study the problem of topological sector changing. A new method is proposed which works without…

High Energy Physics - Lattice · Physics 2009-11-11 G. I. Egri , Z. Fodor , S. D. Katz , K. K. Szabo

We present first, exploratory results of a hybrid Monte-Carlo algorithm for dynamical, n_f=2, four-dimensional QCD with overlap fermions. As expected, the computational requirements are typically two orders of magnitude larger for the…

High Energy Physics - Lattice · Physics 2010-02-03 Z. Fodor , S. D. Katz , K. K. Szabo

We apply the Hybrid Monte Carlo method to the simulation of overlap fermions. We give the fermionic force for the molecular dynamics update. We present early results on a small dynamical chiral ensemble.

High Energy Physics - Lattice · Physics 2009-11-10 N. Cundy , S. Krieg , A. Frommer , Th. Lippert , K. Schilling

We investigate the algorithms for dynamical overlap fermions aiming at improving the performance for large-scale simulations. We look for the best combination of Hybrid Monte Carlo options and iterative quark solvers with respect to the…

We summarize our recent investigations of lattice QCD with dynamical overlap fermions. We sketch algorithmic issues and our approach to solving them. We show our measurement of the topological susceptibility. We describe a computation of…

High Energy Physics - Lattice · Physics 2007-05-23 Stefan Schaefer , Thomas DeGrand

We discuss the adaptation of the Hybrid Monte Carlo algorithm to overlap fermions. We derive a method which can be used to account for the delta function in the fermionic force caused by the differential of the sign function. We discuss the…

High Energy Physics - Lattice · Physics 2009-11-11 Nigel Cundy

We discuss the impact of various improvements on simulations of dynamical overlap fermions using the Hybrid Monte Carlo algorithm. We focus on the usage of fat links and multiple pseudo-fermion fields.

High Energy Physics - Lattice · Physics 2011-07-18 Thomas DeGrand , Stefan Schaefer

We study QCD thermodynamics using two flavors of dynamical overlap fermions with quark masses corresponding to a pion mass of 350 MeV. We determine several observables on N_t=6 and 8 lattices. All our runs are performed with fixed global…

High Energy Physics - Lattice · Physics 2012-08-03 S. Borsanyi , Y. Delgado , S. Durr , Z. Fodor , S. D. Katz , S. Krieg , T. Lippert , D. Nogradi , K. K. Szabo

We present a set of related Hybrid Monte Carlo methods to simulate an arbitrary number of dynamical overlap fermions. Each fermion is represented by a chiral pseudo-fermion field. The new algorithm reduces critical slowing down in the…

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

We describe an HMC algorithm for dynamical overlap fermions which makes use of their good chiral properties. We test the algorithm in the Schwinger model. Topological sectors are readily changed even in the massless case.

High Energy Physics - Lattice · Physics 2007-05-23 Achim Bode , Urs M. Heller , Robert G. Edwards , Rajamani Narayanan

Using a reweighting technique combined with a low-mode truncation of the fermionic determinant, we estimate the quark-mass dependence of the QCD topological susceptibility with overlap fermions. In contrast to previous lattice simulations…

High Energy Physics - Lattice · Physics 2009-09-25 Tamas G. Kovacs

An overview of the current status of algorithmic approaches to dynamical overlap fermions is given. In particular the issue of changing the topological sector is discussed.

High Energy Physics - Lattice · Physics 2008-11-26 Stefan Schaefer

The extreme computational costs of calculating the sign of the Wilson matrix within the overlap operator have so far prevented four dimensional dynamical overlap simulations on realistic lattice sizes, because the computational power…

High Energy Physics - Lattice · Physics 2008-12-18 N. Cundy , S. Krieg , G. Arnold , A. Frommer , Th. Lippert , K. Schilling

We describe a new Hybrid Monte Carlo (HMC) algorithm for dynamical overlap fermions, which improves the rate of topological index changes by adding an additional (intensive) term to the action for the molecular dynamics part of the…

High Energy Physics - Lattice · Physics 2012-02-28 Nigel Cundy , Weonjong Lee

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

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 propose a modification of the Hybrid-Monte-Carlo algorithm that allows for a larger step-size of the integration scheme at constant acceptance rate. The key ingredient is the splitting of the pseudo-fermion action into two parts. We test…

High Energy Physics - Lattice · Physics 2015-06-25 M. Hasenbusch , K. Jansen

HMC histories for light dynamical overlap fermions tend to stay in a fixed topological sector for many trajectories, so that the different sectors are not sampled properly. Therefore the suitable summation of observables, which have been…

High Energy Physics - Lattice · Physics 2010-01-21 Wolfgang Bietenholz , Ivan Hip

We present two improvements to our previous dynamical overlap HMC algorithm. We introduce a new method of differentiating the eigenvectors of the Kernel operator, which removes an instability in the fermionic force. Secondly, by simulating…

High Energy Physics - Lattice · Physics 2009-04-14 N. Cundy , S. Krieg , T. Lippert , A Schaefer

We study the finite temperature transition in QCD with two flavors of dynamical fermions at a pseudoscalar pion mass of about 350 MeV. We use lattices with temporal extent of $N_t$=8, 10 and 12. For the first time in the literature a…

High Energy Physics - Lattice · Physics 2015-10-13 Sz. Borsanyi , Z. Fodor S. D. Katz S. Krieg , T. Lippert , D. Nogradi , F. Pittler , K. K. Szabo , B. C. Toth
‹ Prev 1 2 3 10 Next ›