We argue that the chaotic temperature effect predicted in Ising spin glasses
should be stronger when one considers continuous (XY, Heisenberg) kind of
spins, due to bigger entropic fluctuations. We then discuss the behavior of 3d
spin glasses using the Migdal-Kadanoff Renormalization Group for Ising and XY
spins, where we show explicitly that the chaotic length scale, the length
beyond which equilibrium configurations are completly reshuffled when one
changes temperature, could be far smaller for XY than for Ising spins. These
results could thus explain why experiments are seeing a stronger rejuvenation
effect for continuous spins.Comment: 7 pages, 6 figures, accepted for publicatio
