Lattice Gauge Theory...
at Brookhaven National Laboratory
continued...
"This new supercomputer will be a world-leading facility
which will drive major advances in our understanding of nature,"
said Lee, who played a critical role in the creation of the RBRC
in 1997 and has been director since it was founded. Lee, who was
instrumental in securing the funds from RIKEN, said: "This is a
remarkable opportunity for the physicists at Columbia and the
RBRC to make new discoveries on the frontier of particle and
nuclear physics".
The project builds on important work already underway at
Columbia
University: the development of a highly cost-effective QCDOC
supercomputer architecture and the collaborative research
program at the RIKEN Laboratory and Columbia involving a
previous generation of QCDSP supercomputers.
The name QCDOC derives from Quantum Chromodynamics On a Chip,
where Quantum Chromodynamics is the underlying theory of the
quark-gluon interaction. This computer design project has been
underway at Columbia since the fall of 1999 and represents a
close collaboration between Columbia, the T.J. Watson Research
Laboratory of IBM, RIKEN and a large collaboration in the United
Kingdom known as UKQCD, centered at the University of Edinburgh.
There are currently two large Columbia-designed QCDSP (Quantum
Chromodynamics on Digital Signal Processors) installations: a
400 Glfops (or 400 billion arithmetic operations per second)
machine at Columbia and a second 600 Gflops computer at the RBRC.
Completed in 1998, these computers are among today's fastest
computers being used for fundamental research in nuclear and
particle physics.
Both theoretical and experimental research groups in the
Columbia Physics Department are major participants in the RBRC
research program. The computational field theory group at
Columbia, lead by Professors Norman Christ and Robert Mawhinney,
plays a leading role in both the design and construction of the
QCDSP and QCDOC computers and the physics program supported by
these machines.
This group explores the transition between normal nuclear matter
and a new state of matter called the quark-gluon plasma, which
is believed to have existed for a fleeting moment as the
Universe cooled, for a few microseconds following the Big Bang.
The properties of this phase of matter can be studied by both
theoretical simulations with powerful computers and through
actual collisions between heavy nuclei produced by the
Relativistic Heavy Ion Collider (RHIC) recently commissioned at
the Brookhaven Laboratory.
The group also studies the underlying properties of quarks. Of
particular interest is a single small parameter which spoils the
symmetry between quarks and anti-quarks and which may explain
why our present Universe is predominantly composed of matter
rather than anti-matter.
At an international meeting in Berlin last year, the
Columbia-Brookhaven-RIKEN collaboration announced the results of
a three-year calculation which determined two experimentally
measured quantities in rare particle decays in terms of this
single small parameter. (Similar results were presented by an
independent Japanese group at this same meeting.)
While these calculations successfully determined a number of
quantities involved in these rare particle decays, their
prediction for the matter-antimatter asymmetry are surprisingly
different from experiments.
"The question is whether this disagreement is caused by a flaw
in the standard model of particle physics or by the numerical
approximations in the calculation," said Professor Christ,
adding that this crucial question is likely to be solved through
calculations made possible by this new supercomputer.
On the experimental side, the Physics Department's heavy ion
research group, composed of Professors Brian Cole, James Nagle
and William Zajc, is attempting to create and detect the
quark-gluon plasma in the laboratory, using RHIC, Brookhaven's
newest particle accelerator. RHIC produces the world's highest
energy nuclear collisions, which are then measured in the $100M
PHENIX detector. Professor Zajc is the spokesperson for this
400-member international collaboration, which began taking data
with the PHENIX apparatus in the year 2000. The PHENIX
experiment is also designed to make fundamental measurements
elucidating the origin of the proton spin, using instrumentation
which was also funded as part of the RIKEN program.
Last Modified: September 3, 2008
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