Date: Thu, 27 Sep 07 00:00:30 GMT Subject: hep-lat daily 8 new + 3 crosses received by eprepget ------------------------------------------------------------------------------ ------------------------------------------------------------------------------ Send any complaints regarding submissions directly to submitter. ------------------------------------------------------------------------------ Point your www client at http://arXiv.org/ To unsubscribe, e-mail To: hep-lat@arXiv.org, Subject: cancel ------------------------------------------------------------------------------ received by eprepget from Mon 24 Sep 07 20:00:03 GMT to Wed 26 Sep 07 20:00:01 GMT ------------------------------------------------------------------------------ \\ arXiv:0709.4076 Date: Wed, 26 Sep 2007 04:13:22 GMT (81kb) Title: Numerical results of two-dimensional N=(2,2) super Yang-Mills theory Authors: Hidenori Fukaya, Issaku Kanamori, Hiroshi Suzuki and Tomohisa Takimi Categories: hep-lat Comments: 7 pages, Presented at the XXV International Symposium on Lattice Field Theory, July 30 - August 4 2007, Regensburg, Germany Report-no: RIKEN-TH-114 Journal-ref: PoS(LATTICE 2007)264 \\ We report the results of a numerical simulation of a lattice formulation of the two-dimensional N=(2,2) super Yang-Mills theory proposed by Suzuki and Taniguchi. We measure the 1-point functions and 2-point functions. The scenario is that only tuning of the scalar mass to a specific value gives a supersymmetric continuum limit. Our results are consistent with this scenario although conclusive results on the restoration of supersymmetry have not been obtained. \\ ( http://arxiv.org/abs/0709.4076 , 81kb) ------------------------------------------------------------------------------ \\ arXiv:0709.4110 Date: Wed, 26 Sep 2007 09:05:33 GMT (383kb) Title: Logarithmic link smearing for full QCD Authors: Stephan Durr Categories: hep-lat Comments: 28 pages, 7 figures \\ A new Lie-algebra based recipe for analytic link smearing in lattice QCD is presented. It is more efficient in suppressing UV-noise than the standard ``stout'' smearing, roughly comparable to traditional APE smearing. It may be used together with the hypercubic nesting trick, and the advantage is that this LOG/HYL smearing yields differentiable ``fat'' links, which makes it attractive for a HMC approach to full QCD. \\ ( http://arxiv.org/abs/0709.4110 , 383kb) ------------------------------------------------------------------------------ \\ arXiv:0709.4130 Date: Wed, 26 Sep 2007 11:00:20 GMT (84kb) Title: Dynamical simulations with HYP-link Wilson fermions Authors: Anna Hasenfratz, Roland Hoffmann, Stefan Schaefer Categories: hep-lat Comments: 7 pages, 5 figures, contribution to XXV International Symposium on Lattice Field Theory, July 2007, Regensburg, Germany Report-no: DESY 07-163 \\ We present results from simulations of two dynamical flavors of improved Wilson fermions with nHYP smeared gauge links. We demonstrate that the simulation is stable at a pseudo-scalar mass of 360MeV, a 2.1fm box and a lattice spacing of 0.13fm. \\ ( http://arxiv.org/abs/0709.4130 , 84kb) ------------------------------------------------------------------------------ \\ arXiv:0709.4167 Date: Wed, 26 Sep 2007 14:02:25 GMT (75kb) Title: Automatic generation of vertices for the Schroedinger functional Authors: Shinji Takeda, Ulli Wolff Categories: hep-lat Comments: 7 pages, 2 figures, 1 table, contribution to Lattice 2007, Regensburg, Germany Report-no: HU-EP-07/44, SFB/CPP-07-54 \\ We present a multiplication algorithm to recursively construct vertices for the Schroedinger functional in the abelian background field case. The algorithm is suited for automatic perturbative calculations with a variety of actions. As first applications, we derive ratios of the lambda parameters between the lattice scheme (improved gauge actions including six link loops) and the $\bar{\rm MS}$ scheme, and one-loop results for the Schroedinger functional coupling with a lattice $T=L \pm a$, which is motivated by considering staggered fermions. \\ ( http://arxiv.org/abs/0709.4167 , 75kb) ------------------------------------------------------------------------------ \\ arXiv:0709.4170 Date: Wed, 26 Sep 2007 14:21:18 GMT (64kb) Title: Subleading properties of the QCD flux-tube in 3-d lattice gauge theory Authors: N.D. Hari Dass and Pushan Majumdar Categories: hep-lat Comments: 7 pages. 1 table and 3 figures. Contributed to The XXV International Symposium on Lattice Field Theory, Regensburg, Germany Report-no: MS-TP-07-26 \\ We study the continuum limit of the string-like behaviour of flux tubes formed between static quarks and anti-quarks in three dimensional SU(2) lattice gauge theory. We compare our simulation data with the predictions of both effective string models as well as perturbation theory. On the string side we obtain clear evidence for convergence of data to predictions of Nambu-Goto theory. We comment on the scales at which the static potential starts departing from one loop perturbation theory and then again being well described by effective string theories. We also estimate the leading corrections to the one-loop perturbative potential as well as the Nambu-Goto effective string. In the intermediate regions we find an empirical formula which gives surprisingly good fits. \\ ( http://arxiv.org/abs/0709.4170 , 64kb) ------------------------------------------------------------------------------ \\ arXiv:0709.4193 Date: Wed, 26 Sep 2007 15:39:29 GMT (16kb) Title: Exact Vacuum Energy of Orbifold Lattice Theories Authors: So Matsuura Categories: hep-lat Comments: 14 pages, no figure, LaTeX2e \\ We investigate the orbifold lattice theories constructed from supersymmetric Yang-Mills matrix theories (mother theories) with four and eight supercharges. We show that the vacuum energy of these theories vanishes exactly and the classical flat directions remain flat even if we take into account quantum effects. \\ ( http://arxiv.org/abs/0709.4193 , 16kb) ------------------------------------------------------------------------------ \\ arXiv:0709.4213 Date: Wed, 26 Sep 2007 17:12:17 GMT (115kb) Title: Hamiltonian Lattice QCD near the Light Cone Authors: H.J. Pirner, D. Grunewald, E.-M. Ilgenfritz, E.V. Prokhvatilov Categories: hep-lat Comments: 7 pages, 2 figures, Based on a talk given by H.J. Pirner at the XXV International Symposium on Lattice Field Theory, University of Regensburg, July 30 - August 4, 2007 \\ We give a status report of our work on light cone Hamiltonian lattice QCD. We have derived an effective Hamiltonian $H_{eff}$ which is only quadratic in the momenta and therefore can be simulated by standard methods. For this Hamiltonian we determine variationally an approximate ground state wave functional in the light cone limit. \\ ( http://arxiv.org/abs/0709.4213 , 115kb) ------------------------------------------------------------------------------ \\ arXiv:0709.4224 Date: Wed, 26 Sep 2007 17:58:20 GMT (492kb) Title: Methods for Pseudoscalar Flavour-Singlet Mesons with Staggered Fermions Authors: Eric B. Gregory, Alan C. Irving, Chris M. Richards, Craig McNeile Categories: hep-lat Comments: 44 pages,24 Figures \\ We present the first 2+1 flavour lattice QCD calculations of pseudoscalar flavour-singlet propagators using improved staggered fermions. We explore the relevant techniques and discuss prospects for the larger scale studies now in progress. The disconnected correlator is shown to have a highly non-Gaussian distribution and reliable estimates of the errors require care. \\ ( http://arxiv.org/abs/0709.4224 , 492kb) %-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%- ------------------------------------------------------------------------------ \\ arXiv:0709.3269 (*cross-listing*) Date: Thu, 20 Sep 2007 17:46:41 GMT (42kb) Title: Magnetic bion condensation: A new mechanism of confinement and mass gap in four dimensions Authors: Mithat Unsal Categories: hep-th hep-lat hep-ph Comments: 32 pages, 3 figures \\ In recent work, we derived the long distance confining dynamics of certain QCD-like gauge theories formulated on small $S^1 \times \R^3$ based on symmetries, an index theorem and abelian duality. Here, we give the microscopic derivation. The solution reveals a new mechanism of confinement in QCD(adj) in the regime where we have control over both perturbative and nonperturbative aspects. In particular, consider $SU(2) QCD(adj)$ theory with $1 \leq n_f \leq 4$ Majorana fermions, a theory which undergoes gauge symmetry breaking at small $S^1$. If the magnetic charge of the BPS monopole is normalized to unity, we show that confinement occurs due to condensation of objects with magnetic charge 2, not 1. Due to index theorems, we know that such an object cannot be a two identical monopole configuration. Its net topological charge must vanish, and hence it must be topologically indistinguishable from the perturbative vacuum. We construct such objects, the magnetically charged, topologically null molecules of a BPS monopole and ${\overline{\rm KK}}$ antimonopole, which we refer as magnetic bions. An immediate puzzle with this proposal is the apparent Coulomb repulsion between BPS-${\overline{\rm KK}}$ pair. An attraction which overcomes the Coulomb repulsion between the two is induced by $2n_f$-fermion exchange. Bion condensation is also the mechanism of confinement in $\N=1$ SYM on the same four-manifold. The $SU(N)$ generalization hints a possible hidden integrability behind nonsupersymmetric QCD of affine Toda type, and allows us to analytically compute the string tensions and thicknesses. We currently do not know the extension to $\R^4$. \\ ( http://arxiv.org/abs/0709.3269 , 42kb) ------------------------------------------------------------------------------ \\ arXiv:0709.3948 (*cross-listing*) Date: Tue, 25 Sep 2007 14:06:32 GMT (283kb) Title: Rho meson condensation at finite isospin chemical potential in a holographic model for QCD Authors: Ofer Aharony, Kasper Peeters, Jacob Sonnenschein and Marija Zamaklar Categories: hep-th hep-lat hep-ph Comments: 33 pages, 7 figures Report-no: DCPT-07/55, ITP-UU-07/49, TAUP-2865/07, WIS/16/07-SEPT-DPP \\ We analyze the effect of an isospin chemical potential \mu_I in the Sakai-Sugimoto model, which is the string dual of a confining gauge theory related to large N_c QCD, at temperatures below the chiral symmetry restoration temperature. For small chemical potentials we show that the results agree with expectations from the low-energy chiral Lagrangian, and the charged pion condenses. When the chemical potential reaches a critical value \mu_I = \mu_{crit} ~ 1.7 m_{\rho}, the lowest vector meson (the "rho meson") becomes massless, and it condenses (in addition to the pion condensate) for \mu_I > \mu_{crit}. This spontaneously breaks the rotational symmetry, as well as a residual U(1) flavor symmetry. We numerically construct the resulting new ground state for \mu_I > \mu_{crit}. \\ ( http://arxiv.org/abs/0709.3948 , 283kb) ------------------------------------------------------------------------------ \\ arXiv:0709.3963 (*cross-listing*) Date: Tue, 25 Sep 2007 14:25:22 GMT (15kb) Title: Two-Point Functions of Coulomb Gauge Yang-Mills Theory Authors: Peter Watson, Hugo Reinhardt Categories: hep-th hep-lat hep-ph Comments: 12 pages, no figures \\ The functional approach to Coulomb gauge Yang-Mills theory is considered within the standard, second order, formalism. The Dyson-Schwinger equations and Slavnov-Taylor identities concerning the two-point functions are derived explicitly and one-loop perturbative results are presented. \\ ( http://arxiv.org/abs/0709.3963 , 15kb) %%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%% ------------------------------------------------------------------------------ \\ arXiv:hep-lat/0607006 replaced with revised version Wed, 26 Sep 2007 07:57:51 GMT (55kb) Title: Rationale for UV-filtered clover fermions Authors: Stefano Capitani, Stephan Durr and Christian Hoelbling Categories: hep-lat Comments: 25 pages, 4 figures; v2: typo in eqn. (37) fixed [agrees with published version] Journal-ref: JHEP 0611 (2006) 028 \\ ( http://arxiv.org/abs/hep-lat/0607006 , 55kb) ------------------------------------------------------------------------------ \\ arXiv:0708.2246 replaced with revised version Wed, 26 Sep 2007 14:03:00 GMT (70kb) Title: Monopoles, topology of the Standard Model, and unification of interactions at Tev scale Authors: M. A. Zubkov Categories: hep-lat hep-ph Comments: a version to appear in the proceedings of LATTICE 2007 Report-no: ITEP-LAT/2007-14 \\ ( http://arxiv.org/abs/0708.2246 , 70kb) ------------------------------------------------------------------------------ \\ arXiv:0709.0664 replaced with revised version Wed, 26 Sep 2007 14:21:11 GMT (93kb) Title: Excited mesons on dynamical clover-Wilson lattices Authors: Tommy Burch, Christian Ehmann, Christian Hagen, Martin Hetzenegger, Andreas Sch\"afer Categories: hep-lat Comments: 7 pages with 4 figures and 1 table, poster presented at the Lattice 2007, minor correction, some typos fixed \\ ( http://arxiv.org/abs/0709.0664 , 93kb) %%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%--- For subscribe options to combined physics archives, e-mail To: physics@arXiv.org, Subject: subscribe ----------------------------------------------------------------------------- For help on viewing and making submissions, see http://arXiv.org/help/ For a list of archive mirror sites, see http://arXiv.org/servers.html ----------------------------------------------------------------------------- Third-party submissions cause excessive problems. 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