Non-Universal Fractional Quantum Hall States in a Quantum Wire

The ground state as well as low-lying excitations in a 2D electron system in strong magnetic fields and a parabolic potential is investigated by the variational Monte Carlo method. Trial wave functions analogous to the Laughlin state are used with the power-law exponent as the variational parameter. Finite size scaling of the excitation energy shows that the correlation function at long distances is characterized by a non-universal exponent in sharp contrast to the standard Laughlin state. The Laughlin-type state becomes unstable depending on the strength of the confining potential.