Mon·Sep 17, 2001Monday·September 17, 2001

1. 01*

   Heatbath Noise Methods in Lattice QCD

   Walter Wilcox🇺🇸

   In a recent paper, de Forcrand has pointed out that matrix inversions using Gaussian noise need not be iterated to full convergence, but instead may be solved approximately and treated as a heatbath. Gaussian noise however is not optimal for minimizing variance. It shown here how his algorithm may be generalized to a mixture of Gaussian and Z(N) noise, resulting in a smaller effective variance for some operators.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·3 citations
2. 02*

   Deflation of Eigenvalues for GMRES in Lattice QCD

   Ronald B. Morgan🇺🇸 · Walter Wilcox🇺🇸

   Versions of GMRES with deflation of eigenvalues are applied to lattice QCD problems. Approximate eigenvectors corresponding to the smallest eigenvalues are generated at the same time that linear equations are solved. The eigenvectors improve convergence for the linear equations, and they help solve other right-hand sides.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·22 citations
3. 03*

   The order of the metal to superconductor transition

   S. Mo🇳🇴 · J. Hove🇳🇴 · A. Sudbo🇳🇴

   We present results from large-scale Monte Carlo simulations on the full Ginzburg-Landau (GL) model, including fluctuations in the amplitude and the phase of the matter-field, as well as fluctuations of the non-compact gauge-field of the theory. {}From this we obtain a precise critical value of the GL parameter $\text{kct}$ separating a first order metal to superconductor transition from a second order one, $\text{kct}=(0.76\pm 0.04)/\sqrt{2}$. This agrees surprisingly well with earlier analytical results based on a disorder theory of the superconductor to metal transition, where the value $\text{kct}=0.798/\sqrt{2}$ was obtained. To achieve this, we have done careful infinite volume and continuum limit extrapolations. In addition we offer a novel interpretation of $\text{kct}$, namely that it is also the value separating \typeI and \typeII behaviour.<

   ↳ cond-mat.supr-conhep-latPRB(2002)·72 citations
4. 04*

   Equation of state of strongly coupled QCD at finite density

   Yasuo Umino🇪🇸

   Using an effective strongly coupled lattice QCD Hamiltonian and Wilson fermions we calculate the equation of state for cold and dense quark matter by constructing an ansatz which exactly diagonalizes the Hamiltonian to second order in field operators for all densities. This ansatz obeys the free lattice Dirac equation with a chemical potential term and a mass term which is interpreted as the dynamical quark mass. We find that the order of chiral phase transition depends on the values of input parameters. In the phase with spontaneously broken chiral symmetry the quark Fermi sea has negative pressure indicating its mechanical instability. This result is in qualitative agreement with those obtained using continuum field theory models with four--point interactions.

   ↳ hep-phhep-lathep-thnucl-thMod.Phys.Lett. A17 (2002) 2513-2522·0 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.