Recent content by July Zou

We have the three-phonon interactions Hamiltonian $$H_{\mathrm{ph}-\mathrm{ph}}=\sum_{i j k} M_{i j k}\left(b_{-i}^{\dagger}+b_i\right)\left(b_{-j}^{\dagger}+b_j\right)\left(b_{-k}^{\dagger}+b_k\right).$$ We will not need the explicit expression for the $$M_{ijk}$$ here, but only note that it is...