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We calculate the partition function of partially quenched chiral perturbation theory in the epsilon regime at next-to-leading order using the supersymmetry method in the formulation without a singlet particle. We include a nonzero imaginary…

High Energy Physics - Lattice · Physics 2009-11-30 Christoph Lehner , Tilo Wettig

When chiral symmetry is spontaneously broken, the low-energy part of the Dirac operator spectrum can be computed analytically in the chiral limit. The tool is effective field theory or, equivalently in this case, Random Matrix Theory.

High Energy Physics - Phenomenology · Physics 2007-05-23 P. H. Damgaard

We summarise recent results for the chiral Random Two-Matrix Theory constructed to describe QCD in the epsilon-regime with imaginary chemical potential. The virtue of this theory is that unquenched Lattice simulations can be used to…

High Energy Physics - Theory · Physics 2008-11-26 G. Akemann

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

In the first part of these lectures, I consider chiral perturbation theory in the presence of matter fields. It allows to systematically work out the consequences of the broken chiral symmetry of QCD. As examples, threshold pion photo- and…

High Energy Physics - Phenomenology · Physics 2015-06-25 Ulf-G. Meißner

We re-analyze data from available finite-temperature QCD simulations near the chiral transition, with the help of Chiral Random Matrix Theory (chRMT). Statistical properties of the lowest-lying eigenvalues of the staggered Dirac operator…

High Energy Physics - Lattice · Physics 2009-10-31 F. Farchioni , Ph. de Forcrand , I. Hip , C. B. Lang , K. Splittorff

The low-lying eigenvalue spectrum of the QCD Dirac operator in the epsilon-regime is expected to match with that of chiral Random Matrix Theory (ChRMT). We study this correspondence for the case including sea quarks by performing two-flavor…

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

We use the law of addition in random matrix theory to analyze the spectral distributions of a variety of chiral random matrix models as inspired from QCD whether through symmetries or models. In terms of the Blue's functions recently…

High Energy Physics - Phenomenology · Physics 2009-10-28 Maciej A. Nowak , Gábor Papp , Ismail Zahed

The distributions of the quark number and chiral condensate over the gauge fields are computed for QCD in Euclidean space at nonzero quark chemical potential. As both operators are non-hermitian the distributions are in the complex plane.…

High Energy Physics - Lattice · Physics 2014-11-20 M. P. Lombardo , K. Splittorff , J. J. M. Verbaarschot

Chiral perturbation theory at finite four-volume V (=L^3T) is reconsidered with a view towards finding a computational scheme that can deal with any value of M_\pi L, where M_\pi is a generic Nambu-Goldstone mass. The momentum zero modes…

High Energy Physics - Lattice · Physics 2009-09-18 Poul H. Damgaard , Hidenori Fukaya

A recent Monte Carlo study of {\em quenched} QCD showed that the chiral condensate is non-vanishing above $T_c$ in the phase where the average of the Polyakov loop $P$ is complex. We show how this is related to the dependence of the…

High Energy Physics - Lattice · Physics 2009-10-28 M. A. Stephanov

We present simulation results for lattice QCD with chiral fermions in small volumes, where the epsilon-expansion of chiral perturbation theory applies. Our data for the low lying Dirac eigenvalues, as well as mesonic correlation functions,…

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

Normality and $\ga$-hermiticity are what gives rise to chiral properties and rules. The Ginsparg-Wilson (GW) relation is only one of the possible spectral constraints. The sum rule for chiral differences of real modes has important…

High Energy Physics - Lattice · Physics 2015-06-25 Werner Kerler

We discuss the various aspects of two-dimensional $QCD_{2}(N\rightarrow\infty)$ (the 't Hooft model\cite{Hooft}). Our main interest (motivated by the corresponding analysis in the four dimensional QCD) is the vacuum structure of the theory.…

High Energy Physics - Phenomenology · Physics 2009-10-28 Boris Chibisov , Ariel R. Zhitnitsky

We investigate two-point correlation functions of left-handed currents computed in quenched lattice QCD with the Neuberger-Dirac operator. We consider two lattice spacings a~0.09,0.12 fm and two different lattice extents L~ 1.5, 2.0 fm;…

High Energy Physics - Lattice · Physics 2010-02-03 L. Giusti , P. Hernandez , S. Necco , C. Pena , J. Wennekers , H. Wittig

We revisit the concept of chiral disorder in QCD in the presence of a QED magnetic field |eH|. Weak magnetism corresponds to |eH| < 1/rho^2 with rho\approx (1/3) fm the vacuum instanton size, while strong magnetism the reverse. Asymptotics…

High Energy Physics - Phenomenology · Physics 2013-05-01 Maciej A. Nowak , Mariusz Sadzikowski , Ismail Zahed

We review the exact results for microscopic Dirac operator spectra based on either Random Matrix Theory, or, equivalently, chiral Lagrangians. Implications for lattice calculations are discussed.

High Energy Physics - Lattice · Physics 2007-05-23 P. H. Damgaard

We study the eigenvalues of Dirac operators in QCD with two mass degenerate dynamical fermions. The gauge configurations have been obtained with HMC and the so-called Chirally Improved fermionic action. We compare eigenvalues obtained for…

High Energy Physics - Lattice · Physics 2009-04-14 Martina Joergler , C. B. Lang

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 find the lattice spacing dependence of the eigenvalue density of the non-Hermitian Wilson Dirac operator in the $\epsilon$-domain. The starting point is the joint probability density of the corresponding random matrix theory. In addition…

High Energy Physics - Lattice · Physics 2012-02-09 Mario Kieburg , Jacobus J. M. Verbaarschot , Savvas Zafeiropoulos