Field Theory of the Fractional Quantum Hall Effect-I

We provide details of a shorter letter and cond-mat/9702098 and some new results. We describe a Chern-Simons theory for the fractional quantum Hall states in which magnetoplasmon degrees of freedom enter. We derive correlated wavefunctions, operators for creating quasiholes and composite fermions and bosons (which are electrons bound to zeros). We show how the charge of these particles and mass gets renormalized to the final values and compute the effective mass approximately. By deriving a hamiltonian description of the composite fermions and bosons and their charge and current operators, we make precise and reconcile many notions that have been associated with them.Comment: 42 pages Latex To appear in Composite Fermions, edited by Olle Heinonen. Replacement has single spacin

The ν=12\nu={1\over2} Landau level: Half-full or half-empty?

We show here that an extension of the Hamiltonian theory developed by us over the years furnishes a composite fermion (CF) description of the $\nu =\frac{1}{2}$ state that is particle-hole (PH) symmetric, has a charge density that obeys the magnetic translation algebra of the lowest Landau level (LLL), and exhibits cherished ideas from highly successful wave functions, such as a neutral quasi-particle with a certain dipole moment related to its momentum. We also a provide an extension away from $\nu=\frac{1}{2}$ which has the features from $\nu=\frac{1}{2}$ and implements the the PH transformation on the LLL as an anti-unitary operator ${\cal T}$ with ${\cal T}^2=-1$. This extension of our past work was inspired by Son, who showed that the CF may be viewed as a Dirac fermion on which the particle-hole transformation of LLL electrons is realized as time-reversal, and Wang and Senthil who provided a very attractive interpretation of the CF as the bound state of a semion and anti-semion of charge $\pm {e\over 2}$. Along the way we also found a representation with all the features listed above except that now ${\cal T}^2=+1$. We suspect it corresponds to an emergent charge-conjugation symmetry of the $\nu =1$ boson problem analyzed by Read.Comment: 10 pages, no figures. Two references and a section on HF adde