Physical Review Letters
Large- n Limit of SU ( n ) Quantum "Spin" Chains
Ian K. Affleck
Abstract
A class of $\mathrm{SU}(n)$ antiferromagnetic quantum "spin" chains is solved in the large-$n$ limit. While the low-lying spectrum of the normal spin chain ($n=2$) consists of massless solitons, in the large-$n$ limit the soliton is massive. Furthermore, the models exhibit many features of the $C{P}^{n}$ field theories at nonzero topological charge, which, it was recently argued, they become in the limit of a large representation.