| Quantum chromodynamics
(QCD) is our theory of the strong interaction, the most powerful
of the four fundamental interactions in nature (the others are
gravity, electromagnetism, and the weak nuclear interaction). It
has been used with great success to describe how quarks and
gluons are produced at accelerators, and to calculate the mass of
the proton. That result, one of the greatest in the history of
science, was achieved through efforts of the lattice gauge theory
community. It gives a new and fundamental account, based on
equations of high symmetry, of how most of the mass of matter
arises from pure energy.
QCD is potentially our most perfect theory. Uniquely among the
fundamental theories of physics, it gives us precise equations
that can be extrapolated to arbitrarily small distances or
arbitrarily high energies without breaking down. As befits the
grandeur and generality of these equations, they are difficult to
solve. To build upon our success, and do justice to QCD's
potential to describe extreme conditions in the early universe,
the deep interior of neutron stars, supernovae explosions, and
more — not to mention more conventional nuclear and
accelerator physics — we must continue to harness the full
power of modern computing, and keep pushing it further.
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