28 research outputs found
Status and Future Perspectives for Lattice Gauge Theory Calculations to the Exascale and Beyond
In this and a set of companion whitepapers, the USQCD Collaboration lays out
a program of science and computing for lattice gauge theory. These whitepapers
describe how calculation using lattice QCD (and other gauge theories) can aid
the interpretation of ongoing and upcoming experiments in particle and nuclear
physics, as well as inspire new ones.Comment: 44 pages. 1 of USQCD whitepapers
Jade Java Agent
Multi-agent systems are used in situations where you have to solve the problem
of a diffuse character, or a complex calculation eg search information on the
web, management of telecommunications networks, air traffic control, as well
as in more mundane situations, which is eg control and running appliances. Java
Agent Development framework, in short JADE is an environment that supports
the construction of multi-agent systems written in Java. Allows you to construct
and administer agents. This publication contains basic information about agents,
the criteria for their creation and standards of JADE
First results from 2+1-Flavor Domain Wall QCD: Mass Spectrum, Topology Change and Chiral Symmetry with
We present results for the static interquark potential, light meson and
baryon masses, and light pseudoscalar meson decay constants obtained from
simulations of domain wall QCD with one dynamical flavour approximating the
quark, and two degenerate dynamical flavours with input bare masses ranging
from to approximating the and quarks. We compare these
quantities obtained using the Iwasaki and DBW2 improved gauge actions, and
actions with larger rectangle coefficients, on lattices. We seek
parameter values at which both the chiral symmetry breaking residual mass due
to the finite lattice extent in the fifth dimension and the Monte Carlo time
history for topological charge are acceptable for this set of quark masses at
lattice spacings above 0.1 fm. We find that the Iwasaki gauge action is best,
demonstrating the feasibility of using QCDOC to generate ensembles which are
good representations of the QCD path integral on lattices of up to 3 fm in
spatial extent with lattice spacings in the range 0.09-0.13 fm. Despite large
residual masses and a limited number of sea quark mass values with which to
perform chiral extrapolations, our results for light hadronic physics scale and
agree with experimental measurements within our statistical uncertainties.Comment: RBC and UKQCD Collaborations. 82 pages, 34 figures Typos correcte
The pion's electromagnetic form factor at small momentum transfer in full lattice QCD
We compute the electromagnetic form factor of a "pion" with mass m_pi=330MeV
at low values of Q^2\equiv -q^2, where q is the momentum transfer. The
computations are performed in a lattice simulation using an ensemble of the
RBC/UKQCD collaboration's gauge configurations with Domain Wall Fermions and
the Iwasaki gauge action with an inverse lattice spacing of 1.73(3)GeV. In
order to be able to reach low momentum transfers we use partially twisted
boundary conditions using the techniques we have developed and tested earlier.
For the pion of mass 330MeV we find a charge radius given by
_{330MeV}=0.354(31)fm^2 which, using NLO SU(2) chiral perturbation
theory, extrapolates to a value of =0.418(31)fm^2 for a physical pion,
in agreement with the experimentally determined result. We confirm that there
is a significant reduction in computational cost when using propagators
computed from a single time-slice stochastic source compared to using those
with a point source; for m_pi=330MeV and volume (2.74fm)^3 we find the
reduction is approximately a factor of 12.Comment: 20 pages, 3 figure
Computational Physics on Graphics Processing Units
The use of graphics processing units for scientific computations is an
emerging strategy that can significantly speed up various different algorithms.
In this review, we discuss advances made in the field of computational physics,
focusing on classical molecular dynamics, and on quantum simulations for
electronic structure calculations using the density functional theory, wave
function techniques, and quantum field theory.Comment: Proceedings of the 11th International Conference, PARA 2012,
Helsinki, Finland, June 10-13, 201