Ground State Energy Calculations of the \nu=1/2 and the \nu=5/2 FQHE System

Abstract

We reconsider energy calculations of the spin polarized $\nu=1/2$ Chern-Simons theory. We show that one has to be careful in the definition of the Chern-Simons path integral in order to avoid an IR divergent magnetic ground state energy in RPA as in \cite{di1}. We correct the path integral and get a well behaved magnetic energy by considering the energy of the maximal divergent graphs as well as the Hartree-Fock graphs. Furthermore, we consider the $\nu=1/2$ and the $\nu=5/2$ system with spin degrees of freedom. In doing this we formulate a Chern-Simons theory of the $\nu=5/2$ system by transforming the interaction operator to the next lower Landau level. We calculate the Coulomb energy of the spin polarized as well as the spin unpolarized $\nu=1/2$ and the $\nu=5/2$ system as a function of the interaction strength in RPA. These energies are in good agreement with numerical simulations of interacting electrons in the first as well as in the second Landau level. Furthermore, we calculate the compressibility, the effective mass and the excitations of the spin polarized $\nu=2+1/\tilde{\phi}$ systems where $\tilde{\phi}$ is an even number.