Magneto-elastic interaction

Magneto-elastic interaction involves two entities. Therefore, it can be expressed as a \(\mathcal{H}_2\) term.

\[\begin{split}\mathcal{H}_2 = C_2 \sum_{\substack{\mu_1, \mu_2,\\ \alpha_1, \alpha_2,\\ i_1, i_2}} V_{\mu_1, \mu_2; \alpha_1, \alpha_2}^{i_1, i_2} X_{\mu_1; \alpha_1}^{i_1} X_{\mu_2; \alpha_2}^{i_2}\end{split}\]

The summary of the mapping for each code is given in the tables below.

Magneto-elastic interaction (1)

Code

McPhase

\(\mathcal{H}\)

\[\hat{\mathcal{H}}_{ME1} = - \sum_n \sum_{\alpha=1,\dots,6, lm} G^{\alpha,l,m}_{\text{cfph}}(n) \epsilon_{\alpha} O_{lm}(\hat{\mathbf{J}}^n)\]

Renaming of indices

\(n \rightarrow (\mu_1; \alpha_1)\), \(\alpha \rightarrow i_1\), \((l,m) \rightarrow i_2\)

\(C_2\)

\(-1\)

\(V_{\mu_1, \mu_2; \alpha_1, \alpha_2}^{i_1,i_2}\)

\(G^{i_1, i_2}_{\text{cfph}}(\mu_2,\alpha_2)\delta_{\mu_1, \mu_2}\delta_{\alpha_1, \alpha_2}\)

\(X_{\mu_1, \alpha_1}^{i_1}\)

\(\epsilon_{i_1}\)

\(X_{\mu_2; \alpha_2}^{i_2}\)

\(O_{i_2}(\hat{\mathbf{J}}^{\mu_2, \alpha_2})\)

Note

  • Pair of indices \((l,m)\) run over the finite set of the integer pairs. Therefore, they can be enumerated with a single integer and mapped to the index \(i_2\).

  • Index \(i_1 = 1, \dots, 6\), while index \(i_2\) runs over all pairs of integers \((l,m)\) of the original Hamiltonian.

Magneto-elastic interaction (2)

Code

McPhase

\(\mathcal{H}\)

\[\begin{split}\hat{\mathcal{H}}_{ME2} = - \sum_{\substack{n<n^{\prime},lm,\\\alpha=1,2,3}} \Gamma^{\alpha,l,m}(nn^{\prime}) \hat{u}_n^{\alpha} O_{lm}(\hat{\mathbf{J}}^{n^{\prime}})\end{split}\]

Renaming of indices

\(n \rightarrow (\mu_1; \alpha_1)\), \(n^{\prime} \rightarrow (\mu_2; \alpha_2)\), \(\alpha \rightarrow i_1\), \((l,m) \rightarrow i_2\)

\(C_2\)

\(-1\)

\(V_{\mu_1, \mu_2; \alpha_1, \alpha_2}^{i_1, i_2}\)

\(\Gamma^{i_1, i_2}(\mu_1, \alpha_1, \mu_2, \alpha_2)\)

\(X_{\mu_1; \alpha_1}^{i_1}\)

\(\hat{u}_{\mu_1, \alpha_1}^{i_1}\)

\(X_{\mu_2; \alpha_2}^{i_2}\)

\(O_{i_2}(\hat{\mathbf{J}}^{\mu_2, \alpha_2})\)

Note

  • Pair of indices \((l,m)\) run over the finite set of the integer pairs. Therefore, they can be enumerated with a single integer and mapped to the index \(i_2\).

  • Index \(i_1 = x, y, z\), while index \(i_2\) runs over all pairs of integers \((l,m)\) of the original Hamiltonian.