Universal Transition from Quasiperiodicity to Chaos in Dissipative Systems

An exact renormalization-group transformation is developed which describes how the transition to chaos may occur in a universal manner if the frequency ratio in the quasi-periodic regime is held fixed. The principal low-frequency peaks in an experimental spectrum are universally determined at the transition. Our approach is a natural extension of Kolmogorov-Arnold-Moser theory to strong coupling.