Students - First Year
Award-Dr. Roxanne Springer
N. Russell Roberson retires
Focus in Teaching Labs
and Physics Library Renovations
Lecturer - Dr. Carlos Frenk
Larry Evans retires as Chairman
Daniel Gauthier receives tenure
I joined the Physics Department as an assistant professor in January 1998.
It has been quite an exciting year for me at Duke. There are new
developments in my area of research that had eluded us for the past 15
years. Although I cannot describe to you all the reasons of my excitement,
let me briefly tell you about my research. To begin let me ask you a question.
What would you think if someone told you that the space we live in is actually
a lattice and not a continuum? Perhaps that the person is crazy. Well,
not necessarily! Let me give an example. Consider the cloth that you are
wearing. You might say the cloth does not have any lattice structure. It
is "smooth" and "continuous". But as we all know if you look closely there
is a mesh of threads and there are gaps in between, so tiny that you do
not notice them if you don't look closely. This is perhaps true about our
Universe! Well, on the other hand, perhaps not!! However, it may have convinced
you that there is at least something we do not know about our universe
at very small distances since we can't "look" there.
In today's view of the world, most physicists appreciate this lack
of knowledge at very small distances. Thus if you assumed that the space
was a lattice it wouldn't bother them, as long as you were only interested
in describing phenomena that happen at really long distances compared to
the lattice spacing. Then, like in the example of the cloth, you may not
notice the lattice. There is a whole machinery of mathematical analysis
referred to as "renormalization", which says that if you know the basic
symmetries of the theory, this lack of knowledge at very short distances
can be absorbed in a handful of constants that can be fixed through experiments.
The theory would then predict everything else uniquely!
My research focuses on using this idea to understand the theory of strong
interactions. The theory is referred to as Quantum Chromodynamics (QCD).
It describes interactions between two types of particles which we call
quarks and gluons. QCD has a rich symmetry that constrains the theory very
much. Hence even if I assume that the world is a lattice and choose any
dynamics on the lattice between quarks and gluons but preserve the right
symmetries of QCD and a few other general properties, I am guaranteed to
get the right answers as long as I ask questions that only probe long distances
compared to the lattice spacing. I exploit this freedom to design calculations
on the computer that give us many interesting answers in nuclear and particle
physics. Some of the numbers that I can calculate are, the proton mass,
how fast does a pion decay, the temperature at which a proton melts into
quarks and gluons, and more.