The Maldacena conjecture suggests that N=4 gauge theories in the planar (‘t Hooft) limit have a special simplicity in the structure of their perturbative expansions. We demonstrate explicitly that such a simple relation exists between two-loop and one-loop four-point amplitudes. An analogous relationship is expected to hold for n-point amplitudes. Several arguments suggest that a similar structure should continue to all loop orders. General properties of interacting higher spin gauge theories will be discussed. Some emphasize will be on the ünfolded formulation” of dynamical equations in the form of covariant constancy conditions and its application to the manifestly sp(8) covariant formulation of the free higher spin dynamics in the generalized ten-dimensional space-time with matrix co-ordinates. Lóbjectif est de donner une introduction à la biologie moléculaire, en montrant en particulier límportance des idées issues de la physique pour la compréhension du vivant.

SPhT, CEA/Saclay