Disordered systems display an immense variety of complex static and dynamic phenomena. The most interesting and the least understood are those in which the ground state itself is dominated by randomness. The canonical example is the spin-glass, which was discussed in the lectures by Eric Vincent and Marc Mezard. It contains a great deal of fascinating physics, but I think it is fair to say still defies a thorough understanding.
The disordered elastic systems discussed in these notes share many of the features of spin-glasses, including non-trivial complex ground states and slow dynamics. Luckily, they are not completely equivalent in difficulty. Instead, the presence of elasticity gives a starting point for analytical and numerical studies not possible in the spin-glass case.
In putting together the course I was faced with the choice of attempting to cover a reasonable fraction of the important physical concepts or focusing instead in depth and technical detail on a small number of simpler aspects of these systems. I chose to take the former approach, and to provide a review largely from the point of view of scaling and physical arguments. After the fact, I am not sure that this was the best approach. If it was too fast and/or too shallow for you, I apologize for your trouble. I hope that at least these notes can serve as a useful reference to guide you in learning and investigating the problems at your own pace.