Editing Fermi liquid theory (section)

===Structure===
The structure of the "bare" particles (as opposed to quasiparticle) [[Green's function (many-body theory)|many-body Green's function]] is similar to that in the Fermi gas (where, for a given momentum, the Green's function in frequency space is a delta peak at the respective single-particle energy). The delta peak in the density-of-states is broadened (with a width given by the quasiparticle lifetime). In addition (and in contrast to the quasiparticle Green's function), its weight (integral over frequency) is suppressed by a quasiparticle weight factor <math>0<Z<1</math>. The remainder of the total weight is in a broad "incoherent background", corresponding to the strong effects of interactions on the fermions at short time scales.