On Ground States and Phase Transitions of λ-Model on the Cayley Tree

In the paper, we consider the $\lambda$-model with spin values $\{1, 2, 3\}$ on the Cayley tree of order two. We first describe ground states of the model. Moreover, we also proved the existence of translation-invariant Gibb measures for the $\lambda$-model which yield the existence of the phase transition. Lastly, we established the exitance of 2-periodic Gibbs measures for the model.