Steven Pieper and Robert Wiringa, senior scientists at the U.S.
Department of Energy’s (DOE) Argonne National Laboratory, have won
the 2010 Tom W. Bonner Prize in nuclear physics. The award will be presented
by the American Physical Society in Washington, D.C., in February 2010.
Steven Pieper (left) and Robert Wiringa, senior scientists at Argonne National Lab, have won the 2010 Tom W. Bonner Prize in nuclear physics.
Pieper and Wiringa, who are theoretical physicists, won the prize for developing
and applying models of nuclear forces and methods to calculate the properties
of light nuclei. The prize typically recognizes outstanding experimental research
in nuclear physics, but in special circumstances it may be awarded for outstanding
theoretical work.
“We are deeply honored to be chosen for the Bonner Prize,” Wiringa
said. “It has been our life’s work to develop a better understanding
of nuclear forces and nuclei.”
Pieper and Wiringa have been pioneers in developing models of these forces.
Wiringa and his collaborators at Jefferson Lab and elsewhere developed the Argonne
v18 potential, a model of nucleon-nucleon interactions that has become a de
facto standard in the nuclear structure community. The ability to conduct computations
of ever larger nuclei required advances in computers and the algorithms used—issues
that Pieper has been addressing over the past dozen years with a state-of-the-art
quantum Monte Carlo program. This program enabled Pieper and Wiringa, together
with collaborators from the University of Illinois at Urbana-Champaign and Los
Alamos National Laboratory, to develop several models of three-nucleon forces.
“Interactions between nucleons are much more complicated than the interactions
between the electrons and nucleus in an atom,” Wiringa said. “The
interactions depend not only on the separation of the nucleons but on how their
spins and isospins combine, and on the orientation of their spins.” As
a result, calculations of even small nuclei are extremely difficult.
Recently, in collaboration with researchers in Argonne’s Mathematics
and Computer Science Division, Pieper has enhanced the quantum Monte Carlo program
to model nuclear states up to carbon-12. This work, funded by a DOE Scientific
Discovery through Advanced Computing (SciDAC) grant, resulted in a novel subroutine
library for using massive parallel computers. Key to this effort has been access
to the IBM Blue Gene/P supercomputer in the Argonne Leadership Computing Facility.
“We have been able to use more than 133,000 processors of the Blue Gene/P
for these complex calculations,” Pieper said. He and his colleagues receive
large amounts of computer time on the Blue Gene/P through a special grant from
the DOE Innovative and Novel Computational Impact on Theory and Experiment (INCITE)
program.
Pieper has been with Argonne since 1972 and Wiringa since 1981. Both researchers
received a doctoral degree from the University of Illinois at Urbana-Champaign.
Both are Fellows of the American Physical Society, and they shared the 2000
University of Chicago medal for Distinguished Performance at Argonne.
In addition to Pieper and Wiringa, three other Argonne physicists have won
the Bonner Prize – Roy Holt in 2005, Lowell Bollinger in 1986, and John
Schiffer in 1976.