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Graduate Students - First Year 

Teaching Award-Dr. Roxanne Springer 
 
Dr. N. Russell Roberson retires 
 
New Focus in Teaching Labs 
 
Math and Physics Library Renovations 
 
FEL Construction 
 
Visiting Lecturer - Dr. Carlos Frenk 
 
Dr. Larry Evans retires as Chairman 
 
Dr. Daniel Gauthier receives tenure 

Altavista

 

New Faculty:  Shailesh Chandrasekharan “The World on a Lattice”

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.