In physics, the plasmaron was proposed by Lundqvist in 1967 as a quasiparticle arising in a system that has strong plasmon - electron interactions. In the original work, the plasmaron was proposed to describe a secondary peak (or satellite) in the photoemission spectral function of the electron gas. More precisely it was defined as an additional zero of the quasi-particle equation ( ω ω − − ϵ ϵ H − − R e [ Σ Σ ( ω ω ) ] = 0 ) . The same authors pointed out, in a subsequent work, that this extra solution might be an artifact of the used approximations: