Fractional quantum Hall effect in two-layered systems

Abstract
The ground-state wave function is investigated at strong magnetic field for a system that consists of two parallel two-dimensional electron systems, which are coupled by the Coulomb interaction. Ground-state wave functions for finite-size systems on a sphere are obtained numerically and compared with Jastrow-type wave functions at Landau-level filling factors ν=1, (1/2, (2/5, and (1/3. It is shown that the layer separations at which Jastrow-type wave functions give a good approximation to the ground state are filling-factor dependent.