Nonuniversality and metric properties of a forced nonlinear oscillator.

We report on experiments with a forced nonlinear oscillator which reveal, for the first time, the existence of systems with a large variety of one-dimensional maps which do not exhibit universality. These new classes of maps are characterized by the local and global asymmetry of the return map which exhibits different functional forms at either side of its maximum. The local asymmetry leads to a new type of nonuniversal classes without convergence to a single metric constant. The general features observed are reproduced in simulations with maps analogous to those observed experimentally.