Physics and Astronomy Colloquium

                    Tuesday, February 20, 2001
           4:10pm, Room 118 Physics-Astronomy Building

               Michael Duff, University of Michigan


               THE THEORY FORMERLY KNOWN AS STRINGS

Superunification of all the fundamental interactions underwent a major 
paradigm shift in 1984 when eleven-dimensional supergravity was 
knocked off its pedestal by ten-dimensional superstrings. These last 
five years have witnessed a new shift of equal proportions: 
perturbative ten-dimensional superstrings have in their turn been 
superseded by a new non-perturbative theory called M-theory
which describes supermembranes and superfivebranes, which subsumes 
all five consistent string theories and whose low energy limit is, 
ironically, eleven-dimensional supergravity.