Extension of the Lieb-Schultz-Mattis and Kolb theorem -- a topological aspect
K. Nomura
Abstract
The theorem of Lieb, Schultz and Mattis (LSM), which states that the S=1/2 XXZ spin chain has gapless or degenerate ground states, can be applied to broader models. However, in the original LSM theorem the non-frustrating system was assumed. Independently, Kolb considered the relation between the wave number $q$ and the twisting boundary condition. In our previous paper, reconsidering the LSM theorem and combining Kolb's discussion, we have extended the LSMK theorem for frustrating or non-symmetric cases. However, there remains a complexity in the proof of continuity. In this paper, we will simplify the proof than the previous work. Keywords: Lieb-Schultz-Mattis, rigorous theorem, frustration, one-dimension, topological aspect, Dzyalosinskii-Moriya