Figure 6

Analysis of the neutral gap. Neutral energy gap as a function of \(g_{2}\) for \(t/\Omega=0.25\), i.e., along the vertical cut depicted in Figure 2. In the left panel, the different curves are for various system sizes according to the legend, and for a fixed number of kept states \(m=80\) in the DMRG algorithm. The right panel evidences the convergence of the data, at fixed \(L=80\), by increasing m (see also the inset, where we show the behavior of \(\Delta E_{n}\) as a function of m, for three different values of \(g_{2}\)).