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Related papers: Dirac spectrum in QCD and Quark Masses

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We numerically study weak, random, spatial velocity modulation ["quenched gravitational disorder" (QGD)] in two-dimensional massless Dirac materials. QGD couples to the spatial components of the stress tensor; the gauge-invariant disorder…

Disordered Systems and Neural Networks · Physics 2020-06-26 Sayed Ali Akbar Ghorashi , Jonas F. Karcher , Seth M. Davis , Matthew S. Foster

We study a random matrix model for QCD at finite density via complex Langevin dynamics. This model has a phase transition to a phase with nonzero baryon density. We study the convergence of the algorithm as a function of the quark mass and…

High Energy Physics - Lattice · Physics 2017-04-05 Jacques Bloch , Jonas Glesaaen , Owe Philipsen , Jacobus Verbaarschot , Savvas Zafeiropoulos

We consider the effect of discretization errors on the microscopic spectrum of the Wilson Dirac operator using both chiral Perturbation Theory and chiral Random Matrix Theory. A graded chiral Lagrangian is used to evaluate the microscopic…

High Energy Physics - Lattice · Physics 2015-03-17 G. Akemann , P. H. Damgaard , K. Splittorff , J. J. M. Verbaarschot

In the framework of Euclidean QCD on a torus, we study the spectrum of the Dirac operator through inverse moments of its eigenvalues, averaged over topological sets of gluonic configurations. The large-volume dependence of these sums is…

High Energy Physics - Phenomenology · Physics 2009-10-31 Sebastien Descotes , Jan Stern

Values for the strange quark mass and average up/down mass have been obtained from quenched lattice QCD simulations using the domain wall fermion action. This discretization preserves the properties of flavor and chiral symmetry at nonzero…

High Energy Physics - Lattice · Physics 2009-10-31 Matthew Wingate

Chiral properties of QCD formulated with the domain-wall fermion (DWQCD) are studied using the anomalous quark mass m_{5q} and the spectrum of the 4-dimensional Wilson-Dirac operator. Numerical simulations are made with the standard…

Three-dimensional lattice QCD is studied by Monte Carlo simulations within the quenched approximation. At zero temperature a quark-antiquark condensate is observed in the limit of vanishing quark masses. The condensate vanishes continuously…

High Energy Physics - Lattice · Physics 2009-10-31 P. H. Damgaard , U. M. Heller , A. Krasnitz , T. Madsen

In quenched lattice QCD with standard Wilson fermions the quark propagator is computed very close to the chiral limit in the zero-temperature case. Starting from our experience with lattice QED we employ a modified statistical method in…

High Energy Physics - Lattice · Physics 2009-10-30 A. Hoferichter , E. Laermann , V. K. Mitrjushkin , M. Müller-Preussker , P. Schmidt

In Quantum Chromodynamics (QCD) the eigenmodes of the Dirac operator with small absolute eigenvalues have a close relationship to the dynamical breaking of the chiral symmetry. In a simulation with two dynamical quarks, we study the…

High Energy Physics - Lattice · Physics 2015-03-19 C. B. Lang , Mario Schröck

We study the spectral gap of the Wilson--Dirac operator in two-flavour lattice QCD as a function of the lattice spacing $a$, the space-time volume $V$ and the current-quark mass $m$. It turns out that the median of the probability…

High Energy Physics - Lattice · Physics 2009-11-11 L. Del Debbio , L. Giusti , M. Lüscher , R. Petronzio , N. Tantalo

We investigate the limit of vanishing quark mass in quenched lattice QCD with unimproved Wilson fermions at $\beta=6.0$. Exploiting the correlations of propagators at different time slices we extract pion masses extremely close to the…

High Energy Physics - Lattice · Physics 2009-10-31 A. Hoferichter , E. Laermann , V. K. Mitrjushkin , M. Müller-Preussker , P. Schmidt

We investigate the Anderson transition found in the spectrum of the Dirac operator of Quantum Chromodynamics (QCD) at high temperature, studying the properties of the critical quark eigenfunctions. Applying multifractal finite-size scaling…

Disordered Systems and Neural Networks · Physics 2015-11-25 L. Ujfalusi , M. Giordano , F. Pittler , T. G. Kovács , I. Varga

We study the singular values of the Dirac operator in dense QCD-like theories at zero temperature. The Dirac singular values are real and nonnegative at any nonzero quark density. The scale of their spectrum is set by the diquark…

High Energy Physics - Phenomenology · Physics 2011-12-15 Takuya Kanazawa , Tilo Wettig , Naoki Yamamoto

We report on the status of our simulations of two-colour QCD with two flavours of Wilson quarks, at nonzero chemical potential and diquark source. Preliminary results are presented for the static quark potential, gluon propagator, and meson…

High Energy Physics - Lattice · Physics 2008-11-26 Jon-Ivar Skullerud , Shinji Ejiri , Simon Hands , Luigi Scorzato

We study the distribution of the phase angle and the magnitude of the fermion determinant as well as its correlation with the chiral condensate and the baryon number for QCD at non-zero quark chemical potential. Results are derived to…

High Energy Physics - Lattice · Physics 2010-03-19 M. P. Lombardo , K. Splittorff , J. J. M. Verbaarschot

Electronic eigen-states of a square graphene quantum dot(GQD) terminated by both zigzag and armchair edges are derived in the theoretical framework of Dirac equation. We find that the Dirac equation can determine the eigen-energy spectrum…

Strongly Correlated Electrons · Physics 2008-11-27 Changlin Tang , Weihua Yan , Yisong Zheng , Guangshe Li , Liping Li

Whereas ground state spectroscopy for quenched QCD is well understood, it is still a challenge to obtain results for excited hadron states. In our study we present results from a new approach for determining spatially optimized operators…

We propose a new way of understanding how chiral symmetry is realized in the high temperature phase of QCD. Based on the finding that a simple free instanton gas precisely describes the details of the lowest part of the spectrum of the…

High Energy Physics - Lattice · Physics 2024-05-24 Tamas G. Kovacs

We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3) and U(1) gauge theory as well as in full QCD with two colors and finite chemical potential. Along the strong-coupling axis up to the phase transition, the…

High Energy Physics - Lattice · Physics 2008-11-26 Elmar Bittner , Maria-Paola Lombardo , Harald Markum , Rainer Pullirsch

The form of the resulting Feynman propagators in a proposed local and gauge invariant QCD for massive fermions suggests the existence of indefinite metric associated to quark states, a property that might relate it with the known Lee-Wick…

High Energy Physics - Theory · Physics 2013-04-03 Alejandro Cabo Montes de Oca