And for the case of N, this steady value is nearly independent of the length of the chain, and only determined by the NNN coupling constant J.

• 若我们进一步考察N则还可以发现，纠缠上下震荡的平衡值与Heisenberg链的长度几乎无关，而仅由它们的次近邻耦合常数J决定。