FRACTIONAL SPIN FOR QUANTUM HALL-EFFECT QUASI-PARTICLES

We investigate the issue of whether quasiparticles in the fractional q uantum Hall effect possess a fractional intrinsic spin. The presence o f such a spin S is suggested by the spin-statistics relation S = theta /2 pi, with theta being the statistical angle, and, on a sphere, is re quired for consistent quantization of one or more quasiparticles, By p erforming Berry-phase calculations for quasiparticles on a sphere we f ind that there are two terms, of different origin, that couple to the curvature and can be interpreted as parts of the quasiparticle spin. O ne, due to self-interaction, has the same value for both the quasihole and quasielectron, and fulfills the spin-statistics relation. The oth er is a kinematical effect and has opposite signs for the quasihole an d quasielectron. The total spin thus agrees with a generalized spin-st atistics theorem 1/2(S-qh + S-qe) = theta/2 pi. On the plane, we do no t find any corresponding terms.