Determine whether the half-filled spin-polarized stDDW band has vanishing electron quasiparticle weight

Determine whether the electron quasiparticle weight vanishes in the thermodynamic limit for the interacting half-filled spin-polarized lower stDDW band, thereby distinguishing a composite Fermi liquid from a weakly renormalized electron metal.

Background

For a noninteracting half-filled lower stDDW band, adding or removing an electron produces a single eigenstate with unit quasiparticle weight. With same-spin repulsion, the spectral weight is instead distributed among many interacting eigenstates, and the largest pole weight decreases while the participation ratio increases across the finite clusters studied.

These trends are consistent with a composite Fermi liquid, but finite-size exact diagonalization cannot determine whether the electron quasiparticle weight actually vanishes in the thermodynamic limit. Establishing this behavior is necessary to identify the low-energy excitations conclusively.