How real are composite fermions?

According to recent theories, a system of electrons at the half-filled Landau level can be transformed to an equivalent system of composite fermions at zero effective magnetic field. In order to test for these new particles, we have studied transport in antidot superlattices in a two-dimensional electron gas. At low magnetic fields electron transport exhibits well-known resonances at fields where the classical cyclotron orbit becomes commensurate with the antidot lattice. At =1/2 we observe the same dimensional resonances. This establishes the semiclassical behavior of composite fermions.