EFFECTIVE-MASS OF COMPOSITE FERMIONS AND FERMIONIC CHERN-SIMONS THEORY IN THE TEMPORAL GAUGE

The definitions of the effective mass for the composite fermion are di scussed in half filled lowest-Landau-level systems. In a recent work, Shankar and Murthy show a finite effective mass for the composite ferm ion using a canonical transformation, while the perturbative calculati on gives the logarithmic divergent one at the Fermi surface. We emphas ize that the definition of the effective mass depends on how strong th e low-frequency Chern-Simons fluctuations are in the physical process. We work with the standard Halperin-Lee-Read model in the temporal gau ge. The advantage of this gauge is that the finite effective mass may be calculated in the Hartree-Fock approximation. Furthermore, it is pr ecisely equal to the result obtained by Shankar and Murthy, which fits very well the numerical calculation from the ground-state energy anal ysis as well as the semiclassical estimation. However, if we consider further the random-phase approximation, we find that the divergence of the effective mass at the Fermi surface emerges again whether we work . with the temporal or Coulomb gauge. On the other hand, the behavior of the response functions in the small band mass limit is discussed sy stematically in the lowest-order calculation if there exists a self-in teraction among the magnetoplasmons. [S0163-1829(98)00516-5].