Lattice QCD Thermodynamics on the Grid
Abstract
We describe how we have used simultaneously nodes of the EGEE Grid, accumulating ca. 300 CPU-years in 2-3 months, to determine an important property of Quantum Chromodynamics. We explain how Grid resources were exploited efficiently and with ease, using user-level overlay based on Ganga and DIANE tools above standard Grid software stack. Application-specific scheduling and resource selection based on simple but powerful heuristics allowed to improve efficiency of the processing to obtain desired scientific results by a specified deadline. This is also a demonstration of combined use of supercomputers, to calculate the initial state of the QCD system, and Grids, to perform the subsequent massively distributed simulations. The QCD simulation was performed on a lattice. Keeping the strange quark mass at its physical value, we reduced the masses of the up and down quarks until, under an increase of temperature, the system underwent a second-order phase transition to a quark-gluon plasma. Then we measured the response of this system to an increase in the quark density. We find that the transition is smoothened rather than sharpened. If confirmed on a finer lattice, this finding makes it unlikely for ongoing experimental searches to find a QCD critical point at small chemical potential.
Keywords
Cite
@article{arxiv.0911.5682,
title = {Lattice QCD Thermodynamics on the Grid},
author = {Jakub T. Mościcki and Maciej Woś and Massimo Lamanna and Philippe de Forcrand and Owe Philipsen},
journal= {arXiv preprint arXiv:0911.5682},
year = {2014}
}