Incommensurability effects in odd length J1-J2 quantum spin chains: On-site magnetization and entanglement

For the antiferromagnetic J1-J2 quantum spin chain with an even number of sites, the point J2d=J1/2 is a disorder point. It marks the onset of incommensurate real space correlations for J2>J2d. At a distinct larger value of J2L=0.52036(6)J1, the Lifshitz point, the peak in the static structure factor begins to move away from k=π. Here, we focus on chains with an odd number of sites. In this case, the disorder point is also at J2d=J1/2 but the …