Hideaki Aiso

Towards understanding of confinement of gluons

Abstract We report large scale numerical simulation data for gluon propagators together with an analysis based on the generalized Feynman rules of an extended perturbation scheme. Zwanzigers stochastic gauge fixing algorithm is employed to limit the path integration inside the Gribov region. Obtained propagators do not show a simple physical pole behavior, rather complex-conjugate pairs of singularities in the p2 plain.

Gluon propagators and confinement

We present SU(3) gluon propagators calculated on 48*48*48*N_t lattices at beta=6.8 where N_t=64 (corresponding the confinement phase) and N_t=16 (deconfinement) with the bare gauge parameter,alpha, set to be 0.1. In order to avoid Gribov copies, we employ the stochastic gauge fixing algorithm. Gluon propagators show quite different behavior from those of massless gauge fields: (1) In the confinement phase, G(t) shows massless behavior at small and large t, while around 5<t<15 it behaves as massive particle, and (2) effective mass observed in G(z) becomes larger as z increases. (3) In the deconfinement phase, G(z) shows also massive behavior but effective mass is less than in the confinement case. In all cases, slope masses are increasing functions of t or z, which can not be understood as addtional physical poles.We present SU(3) gluon propagators calculated on 48*48*48*N_t lattices at beta=6.8 where N_t=64 (corresponding the confinement phase) and N_t=16 (deconfinement) with the bare gauge parameter,alpha, set to be 0.1. In order to avoid Gribov copies, we employ the stochastic gauge fixing algorithm. Gluon propagators show quite different behavior from those of massless gauge fields: (1) In the confinement phase, G(t) shows massless behavior at small and large t, while around 5<t<15 it behaves as massive particle, and (2) effective mass observed in G(z) becomes larger as z increases. (3) In the deconfinement phase, G(z) shows also massive behavior but effective mass is less than in the confinement case. In all cases, slope masses are increasing functions of t or z, which can not be understood as addtional physical poles.

Conservation properties of vectorial operator splitting

This work is concerned with the conservation properties of a new vectorial operator splitting scheme for solving the incompressible Navier-Stokes equations. It is proven that the difference approximation of the advection operator conserves square of velocity components and the kinetic energy as the differential operator does, while pressure term conserves only the kinetic energy. Some analytical requirements necessary to be satisfied of difference schemes for incompressible Navier-Stokes equations are formulated and discussed. The properties of the methods are illustrated with results from numerical computations for lid-driven cavity flow.

QCD on a highly parallel vector computer

We report the first QCD calculations on a parallel vector computer, NWT, which has the peak performance of 236 GFLOPS and 35 GByte memory. After discussing its architecture, our parallel programming strategy, and QCD code performance, we present gluon propagators on a 48 3 × 64 lattice at β = 6.8, which shows the large deviation from the behavior of free massless gauge particles.

Comparison Between Experimental and Numerical Results of a Mould Filling with Viscous Fluid

Dramatically viscous fluids are required to fill missiles, rockets and the boosters of the Ariane V Rocket. Such a rocket engine is called solid propellant engine, since the dynamic viscosity of the casted material increases in the course of time. At the end of the operation, the propellant becomes solid. Since the geometries we deal with are relatively complex, we solve the three-dimensional Navier-Stokes equations together with the transport of the fluid interface. The rheological behavior of the fluid involved, (the propellant, modelled as a fluid) is Newtonian.