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Related papers: Impact of Dynamical Fermions on QCD Vacuum Structu…

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Overlap fermions, which preserve exact chiral symmetry on the lattice, provide a powerful tool for investigating the topological structure of the vacuum. Applying this formulation to zero-temperature quenched SU(3) configurations generated…

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

We study the two-point Topological Charge Density Correlator (TCDC) in lattice QCD with two degenerate flavours of naive Wilson fermions and unimproved Wilson gauge action at two values of lattice spacings and different volumes, for a range…

High Energy Physics - Lattice · Physics 2012-12-03 Abhishek Chowdhury , Asit K. De , A. Harindranath , Jyotirmoy Maiti , Santanu Mondal

Monte Carlo studies of pure glue SU(3) gauge theory using the overlap-based topological charge operator have revealed a laminar structure in the QCD vacuum consisting of extended, thin, coherent, locally 3-dimensional sheets of topological…

High Energy Physics - Theory · Physics 2008-11-26 H. B. Thacker

We introduce the Dirac eigenmode filtering of topological charge density associated with Ginsparg-Wilson fermions as a tool to investigate the local structure of topological charge fluctuations in QCD. The resulting framework is used to…

High Energy Physics - Lattice · Physics 2008-11-26 I. Horvath , S. J. Dong , T. Draper , F. X. Lee , K. F. Liu , J. B. Zhang , H. B. Thacker

This presentation examines the centre vortex structure of Monte-Carlo generated gauge-field configurations using modern visualisation techniques. This time, the manner in which light dynamical fermion degrees of freedom impact the…

High Energy Physics - Lattice · Physics 2022-04-12 Derek Leinweber , James Biddle , Waseem Kamleh

The role of instanton-like objects in the QCD vacuum on the mass spectrum of low-lying light hadrons is explored in lattice QCD. Using over-improved stout-link smearing, tuned to preserve instanton-like objects in the QCD vacuum, the…

High Energy Physics - Lattice · Physics 2015-12-02 Samuel D. Thomas , Waseem Kamleh , Derek B. Leinweber

Using lattice QCD simulations with $N_f = 2$ dynamical fermions, we study the axial $U(1)$ symmetry, topological charge, and Dirac eigenvalue spectra in the high-temperature phase in which the chiral symmetry is restored. Our gauge…

High Energy Physics - Lattice · Physics 2020-07-10 Kei Suzuki , Sinya Aoki , Yasumichi Aoki , Guido Cossu , Hidenori Fukaya , Shoji Hashimoto

The introduction of non-orthogonal electric and magnetic fields in the QCD vacuum enhances the weight of topological sectors with a nonzero topological charge. For weak fields, there is a linear response for the expectation value of the…

High Energy Physics - Lattice · Physics 2022-12-13 Bastian Brandt , Francesca Cuteri , Gergely Endrődi , José Javier Hernández Hernández , Gergely Markó

We suggest that clusters or domains of topological charge and action density occur in the QCD vacuum as an effect of singularities in gauge fields and can simultaneously lead to confinement and chiral symmetry breaking. The string constant,…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. C. Kalloniatis , S. N. Nedelko

In this paper, we show a comparison of different definitions of the topological charge on the lattice. We concentrate on one small-volume ensemble with 2 flavours of dynamical, maximally twisted mass fermions and use three more ensembles to…

We present results on QCD with four dynamical flavors in the temperature range $150$ MeV $\lesssim T \lesssim 500$ MeV. We have performed lattice simulations with Wilson fermions at maximal twist and measured Polyakov loop, chiral…

High Energy Physics - Lattice · Physics 2018-11-09 Florian Burger , Ernst-Michael Ilgenfritz , Maria Paola Lombardo , Anton Trunin

We study the renormalization group behaviour of the topological charge density in full QCD on the lattice. We propose a way of extracting the necessary renormalization functions from Monte Carlo simulations.

High Energy Physics - Lattice · Physics 2009-10-28 B. Alles , A. Di Giacomo , H. Panagopoulos , E. Vicari

The link between dynamical chiral symmetry breaking and centre vortices in the gauge fields of pure $\mathrm{SU}(3)$ gauge theory is studied using the overlap-fermion quark propagator in Lattice QCD. Overlap fermions provide a lattice…

High Energy Physics - Lattice · Physics 2021-04-08 Amalie Trewartha , Waseem Kamleh , Derek Leinweber

In this paper we study the properties of QCD at nonzero chiral density $\rho_5$, which is introduced through chiral chemical potential $\mu_5$. The study is performed within lattice simulation of QCD with dynamical rooted staggered…

High Energy Physics - Lattice · Physics 2019-10-14 N. Yu. Astrakhantsev , V. V. Braguta , A. Yu. Kotov , D. D. Kuznedelev , A. A. Nikolaev

This talk is a review of our studies of instantons and their properties as seen in our lattice simulations of SU(2) gauge theory. We have measured the topological susceptibility and the size distribution of instantons in the QCD vacuum. We…

High Energy Physics - Lattice · Physics 2016-09-01 T. DeGrand , Anna Hasenfratz , Tamas Kovacs

We present a study of the topological susceptibility in lattice QCD with two degenerate flavors of dynamical quarks. The topological charge is measured on gauge configurations generated with a renormalization group improved gauge action and…

We consider a recent proposal by Horv\'ath {\em et al.} to address the question whether topological charge fluctuations in QCD are instanton dominated via the response of fermions using lattice fermions with exact chiral symmetry, the…

High Energy Physics - Lattice · Physics 2014-11-17 Robert G. Edwards , Urs M. Heller

We discuss the utility of low-lying Dirac eigenmodes for studying the nature of topological charge fluctuations in QCD. The implications of previous results using the local chirality histogram method are discussed, and the new results using…

High Energy Physics - Lattice · Physics 2008-11-26 S. J. Dong , T. Draper , I. Horvath , N. Isgur , F. X. Lee , J. McCune , J. B. Zhang , H. B. Thacker

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

A proposal is presented for simulating an improvement on quenched QCD with dynamical fermions which interact with the gluon configuration only via the topological index of the latter. Strengths and shortcomings of the method are discussed…

High Energy Physics - Lattice · Physics 2016-08-15 Stephan Dürr