*October 5, 2007*

#### Colloquium Speaker: Juan Maldacena

Juan Maldacena was born in Buenos Aires, Argentina. He earned an undergraduate degree in physics at Instituto Balserio, Argentina and a Ph.D. in physics at Princeton University. Following a postdoctoral year at Rutgers, he joined the faculty of Harvard University, where he became Professor of Physics after two years. He left Harvard in 2001 to become Professor at the Institute for Advanced Study in Princeton, New Jersey. Juan is the author of around 100 scientific papers. He has received numerous prizes and awards including: Heinemann Prize for mathematical physics (2007), APS E. A. Bouchet award (2004), Pius XI medal (2002), Xanthopoulos Prize (2001), Sackler prize (2000), UNESCO Husein prize (1999), Packard, Sloan, and MacArthur fellowships (1998-1999).

#### Colloquium Topic: QCD, Strings, and Black Holes: A Duality Between Gravity and Field Theory

The theory of strong interactions, QCD (Quantum Chromodynamics), has excitations that are well described by strings. These strings appear most simply in theories with a large number of colors, instead of the three colors we have in QCD. For theories that are similar in spirit to QCD one can relate these gauge theory strings to the strings of quantum gravity. In particular, some ten dimensional geometries are associated to four dimensional quantum field theories. We will describe how to use this relation to learn about strongly interacting quantum field theories. This relation also elucidates some theoretical puzzles regarding black holes, such as the origin of black hole entropy and the question of whether black holes preserve information or not.