Thu·Oct 18, 2001Thursday·October 18, 2001

1. 01*

   Large Field Cutoffs Make Perturbative Series Converge

   Yannick Meurice🇺🇸

   For lambda phi^4 problems, convergent perturbative series can be obtained by cutting off the large field configurations. The modified series converge to values exponentially close to the exact ones. For lambda larger than some critical value, the method outperforms Pade approximants and Borel summations. We discuss some aspects of the semi-classical methods used to calculate the modified Feynman rules and estimate the error associated with the procedure. We provide a simple numerical example where the procedure works despite the fact that the Borel sum has singularities on the positive real axis.

   hep-latcond-mathep-thNucl.Phys.B Proc.Suppl.(2002)·1 citation
2. 02*

   Highly Improved Naive and Staggered Fermions

   Howard D. Trottier🇨🇦 · G. Peter Lepage🇺🇸 · Paul B. Mackenzie🇺🇸 · Quentin Mason🇺🇸 · Matthew A. Nobes🇨🇦

   We present a new action for highly improved staggered fermions. We show that perturbative calculations for the new action are well-behaved where those of the conventional staggered action are badly behaved. We discuss the effects of the new terms in controlling flavor mixing, and discuss the design of operators for the action.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·9 citations
3. 03*

   Quantum Link Models with Many Rishon Flavors and with Many Colors

   O. Baer · R. Brower🇺🇸 · B. Schlittgen🇺🇸 · U.-J. Wiese🇺🇸

   Quantum link models are a novel formulation of gauge theories in terms of discrete degrees of freedom. These degrees of freedom are described by quantum operators acting in a finite-dimensional Hilbert space. We show that for certain representations of the operator algebra, the usual Yang-Mills action is recovered in the continuum limit. The quantum operators can be expressed as bilinears of fermionic creation and annihilation operators called rishons. Using the rishon representation the quantum link Hamiltonian can be expressed entirely in terms of color-neutral operators. This allows us to study the large N_c limit of this model. In the 't Hooft limit we find an area law for the Wilson loop and a mass gap. Furthermore, the strong coupling expansion is a topological expansion in which graphs with handles and boundaries are suppressed.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·9 citations
4. 04*

   Thermodynamic properties of QCD with two flavors of Wilson-type lattice quarks

   Kazuyuki Kanaya · CP-PACS Collaboration

   I report on a study of finite temperature QCD by the CP-PACS Collaboration toward a precise determination of the equation of state with dynamical u,d quarks. Based on a systematic simulation using improved Wilson-type quarks on lattices with temporal size $N_t=4$ and 6, the energy density and pressure are calculated as functions of temperature and renormalized light quark mass in the range $T/T_c\approx 0.7$--2.5 and $m_{\mathrm{PS}}/m_{\mathrm{V}}=0.65$--0.95. Results for $N_t=4$ are found to contain significant scaling violations, while results for $N_t=6$ are suggested to be not far from the continuum limit. On the other hand, the quark mass dependence in the EOS turned out to be small for $m_{\mathrm{PS}}/m_{\mathrm{V}}\text{simlt}0.8$.

   hep-latNPA(2002)·4 citations
5. 05*

   Numerical study of Frohlich and Marchetti monopole creation operator

   V.A. Belavin🇷🇺 · M.N. Chernodub🇷🇺 · M.I. Polikarpov🇷🇺

   The monopole creation operator proposed recently by Frohlich and Marchetti is investigated in the Abelian Higgs model with compact gauge field. We show numerically that the creation operator detects the condensation of monopoles in the presence of the dynamical matter field.

   hep-lathep-phhep-thNucl.Phys.B Proc.Suppl.(2002)·3 citations
6. 06*

   I=2 Pion Scattering Length and Phase Shift with Wilson Fermions

   CP-PACS Collaboration : S. Aoki🇯🇵 · R. Burkhalter🇯🇵 · M. Fukugita🇯🇵 · S. Hashimoto🇯🇵 · N. Ishizuka🇯🇵 · Y. Iwasaki🇯🇵 · K. Kanaya🇯🇵 · T. Kaneko🇯🇵 · Y. Kuramashi🇯🇵 · V. Lesk🇯🇵 · M. Okawa🇯🇵 · Y. Taniguchi🇯🇵 · A. Ukawa🇯🇵 · T. Yoshié🇯🇵

   We present preliminary results of scattering length and phase shift for I=2 S-wave $\pi \pi$ system with the Wilson fermions in the quenched approximation. The finite size method presented by Lüscher is employed, and calculations are carried out at $\beta =5.9$ on a $24^3\times 60$ and $32^3\times 60$ lattice.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·16 citations
7. 07*

   Quasi particles in hot QCD

   P. Giovannangeli🇫🇷 · C.P Korthals Altes🇫🇷

   We show at very high temperature how the behaviour of the spatial 't Hooft loop in the QCD plasma is simply related to the chromo electric flux of the gluons. This simple picture is vindicated by a systematic quasi classical approach. The spatial Wilson loop 's behaviour is computed by a similar nearly free plasma of magnetic quasiparticles. This model predicts unambiguously ratios of multiply charged Wilson loops. Recent simulations confirm these predictions accurately.

   hep-lathep-phNucl.Phys.B Proc.Suppl.(2002)·3 citations
8. 08*

   Status of APEmille

   APE-Collaboration: A. Bartoloni🇮🇹 · P. Boucaud🇫🇷 · N. Cabibbo🇮🇹 · F. Calvayrac🇫🇷 · M. Della Morte🇩🇪 · R. De Pietri🇮🇹 · P. De Riso🇮🇹 · F. Di Carlo🇮🇹 · F. Di Renzo🇮🇹 · W. Errico🇮🇹 · R. Frezzotti🇮🇹 · T. Giorgino🇩🇪 and 20 other authors

   This paper presents the status of the APEmille project, which is essentially completed, as far as machine development and construction is concerned. Several large installations of APEmille are in use for physics production runs leading to many new results presented at this conference. This paper briefly summarizes the APEmille architecture, reviews the status of the installations and presents some performance figures for physics codes.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·7 citations
9. 09*

   Critical exponents and equation of state of the three-dimensional Heisenberg universality class

   M. Campostrini🇮🇹 · M. Hasenbusch🇩🇪 · A. Pelissetto🇮🇹 · P. Rossi🇮🇹 · E. Vicari🇮🇹

   We improve the theoretical estimates of the critical exponents for the three-dimensional Heisenberg universality class. We find gamma=1.3960(9), nu=0.7112(5), eta=0.0375(5), alpha=-0.1336(15), beta=0.3689(3), and delta=4.783(3). We consider an improved lattice phi^4 Hamiltonian with suppressed leading scaling corrections. Our results are obtained by combining Monte Carlo simulations based on finite-size scaling methods and high-temperature expansions. The critical exponents are computed from high-temperature expansions specialized to the phi^4 improved model. By the same technique we determine the coefficients of the small-magnetization expansion of the equation of state. This expansion is extended analytically by means of approximate parametric representations, obtaining the equation of state in the whole critical region. We also determine a number of universal amplitude ratios.

   ↳ cond-mat.stat-mechhep-latPRB(2002)·202 citations
10. 10*

    Nonanalytic correlation length in Ising systems with one surface defect line

    A. Hucht🇩🇪

    A two-dimensional Ising system with ferromagnetic coupling and one defect line at distance L from the surface is solved exactly using Pfaffians. The system shows a singularity in the surface correlation length at a temperature T_s which is smaller than the transition temperature T_c of the bulk. Numerical studies using the transfer matrix technique suggest that this singularity is also present in an Ising system with two defect lines at distance L.

    ↳ cond-mat.stat-mechhep-latPhysica A(1992)·0 citations
11. 11*

    Chiral Extrapolation: An Analogy with Effective Field Theory

    Gerald V. Dunne🇺🇸 · Anthony W. Thomas🇦🇺 · Stewart V. Wright🇦🇺

    We draw an analogy between the chiral extrapolation of lattice QCD calculations from large to small quark masses and the interpolation between the large mass (weak field) and small mass (strong field) limits of the Euler--Heisenberg QED effective action. In the latter case, where the exact answer is known, a simple extrapolation of a form analogous to those proposed for the QCD applications is shown to be surprisingly accurate over the entire parameter range.

    ↳ hep-thhep-lathep-phPLB(2002)·20 citations
12. 12*

    Dashen's Phenomenon in Gauge Theories with Spontaneously Broken Chiral Symmetries

    G. Akemann🇫🇷 · J. T. Lenaghan🇩🇰 · K. Splittorff🇩🇰

    We examine Dashen's phenomenon in the Leutwyler--Smilga regime of QCD with any number of colors and quarks in either the fundamental or adjoint representations of the gauge group. In this limit, the theories only depend on simple combinations of quark masses, volume, chiral condensate and vacuum angle. Based upon this observation, we derive simple expressions for the chiral condensate and the topological density and show that they are in fact related. By examining the zeros of the various partition functions, we elucidate the mechanism leading to Dashen's phenomena in QCD.

    ↳ hep-thhep-lathep-phPRD(2002)·27 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.