  Hartree-Fock theory predicted stripe or bubble phase in the third and higher
Landau levels for two-dimensional electrons, and experimental evidences has
been accumulated. In this paper theoretical confirmation of the stripe phase
and bubble phase in higher Landau level is given by means of the density matrix
renormalization group (DMRG) method, which can give essentially exact ground
state for electron systems with up to 18 electrons. From the study of the pair
correlation function, the stripe phase, bubble phase, and the Wigner crystal
phase are identified, and phase diagram is obtained. The reentrant integer
quantum Hall state is identified as the bubble state. The phase diagram of the
fourth Landau level shows more diversity than the third level.
