QCDpQED--QCD Plus QED and the Stability of Matter
Principal Investigator:
Zoltán Fodor
Affiliation:
Institut für Theoretische Physik, FB-C, Universität Wuppertal (Germany)
Local Project ID:
PRA079
HPC Platform used:
JUQUEEN of JSC
Date published:
In order to understand more deeply not only the origin of the mass of the visible universe but also its composition, i.e. to answer the question why the chemical elements as we know them today exist or why stars form the way they do, tiny differences in the particle masses, especially those of protons and neutrons, are essential. These mass differences, caused by QCD and QED effects and the coupling to the Higgs boson (Nobel prize 2013), however, are tiny - in the permil range - and, therefore, require a much more careful treatment of the aforementioned sub-leading effects.
In this project, the scientists have developed and deployed novel methods that allow to perform such a calculation. The physicists developed a method of reliably including the small corrections from the electromagnetic force into the calculations ab-initio. In addition, they removed the two most prominent simplifying assumptions that are usually used (the equivalence of the mass of the two lightest quarks and ignoring the heavy charm quark), thus obtaining a description of nuclear forces that is accurate at the sub-permil level. Through the supercomputing resources of the GCS the scientists were able to put their methods to the test. In particular, they were able to verify that their new methods reduced the autocorrelations of subsequent measurements, in the full strong plus electromagnetic system, by three orders of magnitude. This allows the physicists to cover a large region of the parameter space and to test these new analysis techniques on the generated data.
The project was made possible through the Partnership for Advanced Computing in Europe (PRACE) using the petascale supercomputing resources of GCS centre Jülich Supercomputing Centre.
Parameter space covered in this study. All in all, more than 40 different ensembles were generated, allowing the scientists to control the different sources of systematic uncertainties through their new analysis methods.
Copyright: Bergische Universität Wuppertal, Theoretische Physik, Fachbereich C
Zoltan Fodor
Theoretische Physik, Fachbereich C - Bergische Universität Wuppertal
D-42097 Wuppertal/Germany
e-mail: fodor@bodri.elte.hu