TOWARDS A FERMI-LIQUID THEORY OF THE NU=1 2 STATE - MAGNETIZED COMPOSITE FERMIONS/

The fermionic Chern-Simons approach has had remarkable success in the description of quantum Hall states at even-denominator filling fractio ns v = 1/2m. In this paper we review a number of recent works concerne d with modelling this state as a Landau-Silin Fermi liquid. We win the n focus on one particular problem with constructing such a Landau theo ry that becomes apparent in the limit of high magnetic field, or equiv alently the limit of small electron band mass m(b). In this limit, the static response of electrons to a spatially varying magnetic field is largely determined by kinetic energy considerations. We then remedy t his problem by attaching an orbital magnetization to each fermion to s eparate the current into magnetization and transport contributions, as sociated with the cyclotron and guiding centre motions respectively. T his leads us to a description of the v = 1/2m state as a Fermi liquid of magnetized composite fermions which correctly predicts the m(b)-dep endence of the static and dynamic response in the limit m(b) --> 0. As an aside, we derive a sum rule for the Fermi liquid coefficients far the Chern-Simons Fermi liquid. This paper is intended to be readable b y people who may not be completely familiar with this field.