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Low-Lying Excitations in the S=1 Antiferromagnetic Heisenberg Chain

Shoji Yamamoto·Seiji Miyashita
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Abstract

In order to confirm the picture of domain-wall excitations in the hidden antiferromagnetic order of the Haldane phase, the structure of the low-lying excitations in the S=1 antiferromagnetic Heisenberg chain is studied by a quantum Monte Carlo method. It is confirmed that there exists a finite energy gap between the first- and the second-excited states at $k=π$ as well as between the ground state and the first-excited state at $k=π$. In the thermodynamic limit, the second-excited state at $k=π$ is separated from the ground state by the gap which is three times as large as the Haldane gap. From the size dependences of the low-lying-excitation energies, the interactions between the elementary excitations in the excited states are concluded to be repulsive.

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Shoji Yamamoto, Seiji Miyashita. 1997-08-26. Low-Lying Excitations in the S=1 Antiferromagnetic Heisenberg Chain. https://doi.org/10.1016/s0375-9601(97)00662-2

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