Golden mean renormalization for the Harper equation: The strong coupling fixed point

We construct a renormalization fixed point corresponding to the strong coup ling limit of the golden mean Harper equation. We give an analytic expressi on for this fixed point, establish its existence and uniqueness, and verify properties previously seen only in numerical calculations. The spectrum of the linearization of the renormalization operator at this fixed point is a lso explicitly determined. This strong coupling fixed point also helps desc ribe the onset of a strange nonchaotic attractor in quasiperiodically force d systems. (C) 2000 American Institute of Physics. [S0022- 2488(00)01501-8] .