Condensed Matter and Biological Physics Seminars

A system of Fermions in a shell of angular momentum l can form a set of multiplets of total angular momentum L. The composite Fermion (CF) picture picks out the lowest lying energy multiplets by selecting from this set a subset that is "Laughlin correlated," i.e. which maximally avoids pair orbits with the largest pair angular momentum (or smallest relative angular momentum R = 2l – ). We demonstrate that Laughlin correlations occur only when the pseudoptential V ( ) (the interaction energy of a pair as a function of inceases with more rapidly, than the eigenvalue of at the value of (or R) avoided in the Laughlin correlated state. This requirement is not satisfied for quasi-electrons and quantum Hall v = 1/3 and v = 1/5 Laughlin states at R = 1 and R = 3 respectively. At vQE= 1/3 and vQH = 1/5, clustering of quasi-particles gives lower energy than Laughlin correlations. Novel spin polarization incompressible states at v = 4/11 and v = 4/13 cannot be explained as a second generation in the CF hierarchy.