Collective charge modes in a 1D electron liquid

A new behavior of the collective mode in a 1D electron liquid is found. The charge mode frequency goes to zero when the wave number is close to double Fermi wave number, i.e. the soft mode appears in addition to common long-wave plasmons. This mode is related to dynamic short-range electron correlations, which are adequately described in the frame of the Luttinger model. The soft mode is immanent in 1D and is absent in higher-dimensional systems. The results are valid for both Coulomb and short-range electron–electron interaction.