Thermodynamics of the Quasiperiodic Set at the Transition to Chaos: Experimental Results

A periodically driven relaxation-oscillator circuit is used to study experimentally the multifractal structure of the quasiperiodic set at the transition to chaos. The experimental data provide strong evidence for a first-order phase transition in the thermodynamic free energy q(tau). The experimentally measured f(alpha) spectrum compares well with that obtained from the sine circle map.