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

The magnetization process of the S = 1 antiferromagnetic chain with the biquadratic interaction is investigated using the numerical diagonalization. As a result, it is found that the quantum spin nematic liquid phase appears below the saturation magnetization for sufficiently large negative biquadratic interaction. The ground state phase diagram is also presented. This result is consistent with the previous density matrix renormalization group study. In addition the present study confirms that the two magnon excitation is gapless, while the single magnon one is gapped in the spin nematic liquid phase.