A class of randomly frustrated systems exhibit striking fragility that their glassy equilibrium states macroscopically deform even by slight changes of the quenched randomness or temperature. These phenomena are called in short as chaos effects. In this talk I first discuss the chaos effects in a directed polymer in random media based on the results of a numerical transfer matrix method and a replica Bethe Ansatz approach. Within the replica approach, the chaos effects are manifested as so called explicit replica symmetry breaking phenomena. Then we discuss chaos effects in an Edwards-Anderson (EA) Ising spin-glass model based on a numerical study on the effective coupling across spin glass samples. We found the sign of the effective coupling chaotically oscillates along the temperature axis strongly suggesting the anticipated temperature chaos effect. Finally we discuss possible connection of such anomalous fragility to the so called rejuvenation effect found in spin-glasses and polymer glasses.

University of Osaka et LPTHE Jussieu