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.