32nd International Symposium on Lattice Field Theory (Lattice 2014)

Session

Chiral Symmetry

11

23 Jun 2014, 14:15

Columbia University

Conveners

Chiral Symmetry: Parallel 1G

• Artan Borici (Uiversity of Tirana)

Chiral Symmetry: Parallel 5D

• Maarten Golterman (San Francisco State University)

47. Phase Diagram of Wilson and Twisted Mass Fermions at finite isospin chemical potential

Dr Mario Kieburg (University Bielefeld)

23/06/2014, 14:15

Chiral Symmetry

Talk

A finite lattice spacing may have a crucial impact on the phase diagram of QCD. The existence of the Aoki phase for Wilson fermions underlines this point. Sharpe and Wu already showed that this kind of lattice artifacts carry over to finite twisted mass. The next task is the calculation of the phase diagram at finite chemical potential. I will present the phase diagram of Wilson fermions of...

134. Phase diagram of non-degenerate twisted mass fermions

Derek Horkel (University of Washington)

23/06/2014, 14:35

Chiral Symmetry

Talk

In this talk, I will summarize recent work with Prof. Stephen Sharpe in mapping out the phase diagram and pion spectrum for chiral perturbation theory with twisted-mass fermions in the presence of non-degeneracy between the up and down quark and discretization errors. I will show how the CP-violating phase of the continuum theory, which occurs for sufficiently large non-degeneracy, is...

422. Individual eigenvalue distributions for chGSE-chGUE crossover and determination of low-energy constants in two-color QCD+QED

Dr Shinsuke M. Nishigaki (Shimane University)

23/06/2014, 14:55

Chiral Symmetry

Talk

We evaluate the individual distributions of four smallest eigenvalues from chiral random matrix ensembles interpolating chGSE and chGUE by the quadrature method applied to the Fredholm Pfaffian of dynamical Bessel kernel containing a crossover parameter. These distributions are then fitted with the staggered Dirac spectra of the quenched SU(2) lattice gauge theory in the presence of...

119. Mesons upon low-lying Dirac mode exclusion

Mr Mikhail Denissenya (University of Graz)

23/06/2014, 15:15

Chiral Symmetry

Talk

We study the iso-scalar and iso-vector mesons under the exclusion of the low-lying Dirac modes from valence quarks with the overlap operator within the two flavour lattice QCD. We study mesonic correlators and extract states at each level of such low-mode truncation. Our observations support a simultaneous restoration of both SU(2)_L \times SU(2)_R and U(1)_A symmetries. We finally observe...

274. Fine lattice simulations with the Ginsparg-Wilson fermions

Dr Junichi Noaki (KEK)

23/06/2014, 15:35

Chiral Symmetry

Talk

We report the status of 2+1-flavor simulations with the Mobius domain-wall fermions on fine lattices of 1/a = 2.4 and 3.6 GeV. The violation of the Ginsparg-Wilson relation is controlled at the level of 0.5 MeV or better. Analyses of the Wilson flow observables, heavy quark potential and light-hadron correlator are presented.

203. The Chiral Condensate of One-Flavor QCD and the Dirac Spectrum at $\theta =0$

Prof. Jacobus Verbaarschot (Stony Brook University)

25/06/2014, 09:00

Chiral Symmetry

Talk

In a sector of fixed topological charge, the chiral condensate has a discontinuty given by the Banks-Casher formula also in the case of one-flavor QCD. However, at fixed $\theta$ angle, the chiral condensate remains constant when the quark mass crosses zero. To reconcile these contradictory observations, we have evaluated the spectral density of one-flavor QCD at $\theta =0$. For negative...

223. Chiral condensate in nf=2 QCD from the Banks-Casher relation

Dr Georg Engel (Universita' Milano-Bicocca)

25/06/2014, 09:20

Chiral Symmetry

Talk

Exploiting the Banks-Casher relation, we present a direct determination of the chiral condensate in two-flavor QCD, computing the mode number of the O(a)-improved Wilson-Dirac operator below various cutoffs. We make use of CLS-configurations with three different lattice spacings in the range of 0.05-0.08 fm and pion masses down to 190 MeV. Our data indicates a finite density of eigenmodes near...

163. Topological susceptibility from the Dirac spectrum and the Witten-Veneziano formula.

Dr Elena Garcia Ramos (HU Berlin / DESY-Zeuthen)

25/06/2014, 09:40

Chiral Symmetry

Talk

We present our results for the topological susceptibility in the quenched case and attempt a non-perturbative test on the Witten-Veneziano formula. We perform a continuum limit extrapolation of the topological susceptibility computed using spectral projectors. The physical situation of the quenched ensembles was matched to the maximally twisted mass dynamical simulations used to compute the...

161. Comparison of different lattice definitions of the topological charge

Dr Krzysztof Cichy (DESY Zeuthen)

25/06/2014, 10:00

Chiral Symmetry

Talk

We present a comparison of different definitions of the topological charge on the lattice, with 2 and 2+1+1 flavours of dynamical twisted mass fermions. We give detailed results at one lattice spacing and also show that the correlation between different definitions increases as one approaches the continuum limit. The investigated definitions are: index of the overlap Dirac operator, spectral...

248. Chiral Properties of Pseudoscalar Meson in Lattice QCD with Domain-Wall Fermion

Dr Tung-Han Hsieh (Academia Sinica)

25/06/2014, 10:20

Chiral Symmetry

Talk

We study the chiral properties of the pseudoscalar meson in 2-flavors lattice QCD with optimal domain-wall fermion. The gauge ensembles are generated on the ${24}^3\times 48$ lattice with the extent in the fifth dimension $N_s=16$, and the plaquette gauge action at $\beta =6.10$, for three sea-quark masses corresponding to the pion masses in the range 265-465 MeV. We calculate the mass...