Quantum spin nematic liquid in the S=1 antiferromagnetic chain with the biquadratic interaction

The magnetization process of the S = 1 antiferromagnetic chain with thebiquadratic interaction is investigated using the numericaldiagonalization. As a result, it is found that the quantum spin nematicliquid phase appears below the saturation magnetization for sufficientlylarge negative biquadratic interaction. The ground state phase diagramis also presented. This result is consistent with the previous densitymatrix renormalization group study. In addition the present studyconfirms that the two magnon excitation is gapless, while the singlemagnon one is gapped in the spin nematic liquid phase