Fixed phase diffusion Monte Carlo study of finite width effect in FQHE*

In FQHE, it is customary to include finite width effects by calculating the transverse wave function at zero magnetic field in LDA, and assuming that it does not change as a high perpendicular magnetic field is applied. We instead determine the transverse density profile directly at a high magnetic field through the fixed phase diffusion Monte Carlo method, where the phase is fixed by the in-plane FQHE state. While the results are in qualitative agreement with those obtained from zero-field LDA, there are interesting quantitative deviations. We will discuss the implications of our study to experiments.