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Related papers: Random Matrix Models for Dirac Operators at finite…

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The application of Random Matrix Theory to the Dirac operator of QCD yields predictions for the probability distributions of the lowest eigenvalues. We measured Dirac operator spectra using massless overlap fermions in quenched QCD at…

High Energy Physics - Lattice · Physics 2009-11-10 S. Shcheredin , W. Bietenholz , T. Chiarappa , K. Jansen , K. -I. Nagai

In quantum chromodynamics (QCD) at nonzero chemical potential, the eigenvalues of the Dirac operator are scattered in the complex plane. Can the fluctuation properties of the Dirac spectrum be described by universal predictions of…

High Energy Physics - Lattice · Physics 2009-10-31 H. Markum , R. Pullirsch , T. Wettig

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…

I make a number of observations concerning discretization errors in twisted-mass lattice QCD that can be deduced by applying chiral perturbation theory including lattice artifacts. (1) The line along which the PCAC quark mass vanishes in…

High Energy Physics - Lattice · Physics 2011-07-19 Stephen R. Sharpe

We show how to introduce a quark chemical potential in the overlap Dirac operator. The resulting operator satisfies a Ginsparg-Wilson relation and has exact zero modes. It is no longer gamma_5-hermitian, but its nonreal eigenvalues still…

High Energy Physics - Lattice · Physics 2009-01-14 Jacques Bloch , Tilo Wettig

I discuss the constraints on the lattice spacing, a, the quark masses, m, the box size, L, and particularly the residual mass, m_res, such that one can successfully calculate phenomenologically interesting quantities using Domain Wall…

High Energy Physics - Lattice · Physics 2007-06-05 Stephen R. Sharpe

In the first part of these lectures we discuss the infrared limit of the spectrum of the QCD Dirac operator. We discuss the global symmetries of the QCD partition function and show that the Dirac spectrum near zero virtuality is determined…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. J. M. Verbaarschot

We evaluate level spacing and smallest eigenvalue distributions of chiral random matrix ensembles transiting from symplectic or orthogonal to unitary symmetry classes with a crossover parameter rho. As expected from the effective sigma…

High Energy Physics - Lattice · Physics 2013-12-18 Shinsuke M. Nishigaki

We analyze the eigenvalue statistics of the staggered Dirac operator above $T_{c}$ in QCD with 2+1 flavors of dynamical quarks. We use physical quark masses in our simulations. We compare the eigenvalue statistics from several parts of the…

High Energy Physics - Lattice · Physics 2011-11-16 Tamás G. Kovács , Ferenc Pittler

One dimensional system of Dirac fermions with a random-varying mass is studied by the transfer-matrix methods which we developed recently. We investigate the effects of nonlocal correlation of the spatial-varying Dirac mass on the…

Condensed Matter · Physics 2009-10-31 Koujin Takeda , Ikuo Ichinose

In these two lectures given at the 1997 Zakopane workshop on "New Developments in Quantum Field Theory" we review recent results on universal fluctuations in QCD Dirac spectra. We start the first lecture with a review of some general…

High Energy Physics - Theory · Physics 2007-05-23 J. J. M. Verbaarschot

Properties of the proton and neutron are studied in partially-quenched chiral perturbation theory at finite lattice spacing. Masses, magnetic moments, the matrix elements of isovector twist-2 operators and axial-vector currents are examined…

High Energy Physics - Lattice · Physics 2009-11-10 Silas R. Beane , Martin J. Savage

We consider a lattice-inspired random matrix model for the QCD chiral phase transition at finite chemical potential. Useful features of the usual RMM for QCD at finite chemical potential are reobtained, some being brought closer to their…

High Energy Physics - Lattice · Physics 2007-05-23 M. A. Halasz

Recently the existence of a random critical line in two dimensional Dirac fermions is confirmed. In this paper, we focus on its scaling properties, especially in the critical region. We treat Dirac fermions in two dimensions with two types…

Disordered Systems and Neural Networks · Physics 2009-10-31 Y. Morita , Y. Hatsugai

We use the chiral quark model to estimate the coefficients of the weak chiral lagrangian as obtained from the bosonization of the ten relevant operators of the $\Delta S = 1$ effective quark lagrangian. All contributions of order $N_c^2$ as…

High Energy Physics - Phenomenology · Physics 2009-10-28 V. Antonelli , S. Bertolini , J. O. Eeg , M. Fabbrichesi , E. I. Lashin

We derive the distributions of individual eigenvalues for the Hermitian Wilson Dirac Operator D5 as well as for real eigenvalues of the Wilson Dirac Operator DW. The framework we provide is valid in the epsilon regime of chiral perturbation…

High Energy Physics - Lattice · Physics 2012-05-07 G. Akemann , A. C. Ipsen

We define and study the probability current and the Hamiltonian operator for a fully general set of Dirac matrices in a flat spacetime with affine coordinates, by using the Bargmann-Pauli hermitizing matrix. We find that with some weak…

Quantum Physics · Physics 2011-08-31 Mayeul Arminjon , Frank Reifler

It is well-known that staggered fermions do not necessarily satisfy the same global symmetries as the continuum theory. We analyze the mechanism behind this phenomenon for arbitrary dimension and gauge group representation. For this purpose…

High Energy Physics - Lattice · Physics 2018-07-31 Mario Kieburg , Tim R. Würfel

We present one-loop perturbative results of the renormalization functions for a complete set of nonlocal quark bilinear operators containing an asymmetric staple-shaped Wilson line, using a family of improved lattice actions. This study is…

High Energy Physics - Lattice · Physics 2023-12-01 Gregoris Spanoudes , Martha Constantinou , Haralambos Panagopoulos

We study two-dimensional Dirac fermions in a random non-Abelian vector potential by using lattice regularization. We consider U(N) random vector potential for large $N$. The ensemble average with respect to random vector potential is taken…

Condensed Matter · Physics 2009-10-31 Ikuo Ichinose