Exchange striction

Warning

This is wrong, the mapping can not be performed in the formalism of the attempt #1. See attempt #3, there this problem is resolved.

Exchange striction involves two sites and two entities. Therefore, it can be expressed via the term \(\mathcal{H}_{2, 2}\).

  • \(k = 2\)

  • \(l = 2\)

  • \(m_{2,2} = 2\)

\[\begin{split}\mathcal{H}_{2,2} = C_{2, 2} \sum_{\substack{\mu_1, \mu_2,\\ \alpha_1, \alpha_2,\\ i_1, i_2}} V_{\mu_1, \mu_2; \alpha_1, \alpha_2}^{i_1, i_2} X_{\mu_1; \alpha_1}^{i_1} X_{\mu_2; \alpha_2}^{i_2}\end{split}\]

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

Code

McPhase

\(\mathcal{H}\)

\[\begin{split}\hat{\mathcal{H}} = - \dfrac{1}{2} \sum_{\substack{nn^{\prime},\alpha\beta\alpha^{\prime}\gamma=1,2,3\\\beta^{\prime}=1-6}} \Biggl( \dfrac{\partial \mathcal{J}_{\alpha\beta}}{\partial \epsilon_{\beta^{\prime}}} + \dfrac{\partial \mathcal{J}_{\alpha\beta}}{\partial R_{nn^{\prime}}^{\alpha^{\prime}}} \dfrac{\partial \epsilon_{\alpha^{\prime}\gamma} R_{nn^{\prime}}^{\gamma}}{\partial \epsilon_{\beta^{\prime}}} \Biggr) \epsilon_{\beta^{\prime}} \hat{\mathcal{I}}_{\alpha}^n \hat{\mathcal{I}}_{\beta}^{n^{\prime}}\end{split}\]

Indices renaming

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

\(C_{2, 2}\)

\(-\dfrac{1}{2}\)

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

\[\begin{split}\sum_{\alpha^{\prime}\gamma=1,2,3\\\beta^{\prime}=1-6} \Biggl( \dfrac{\partial \mathcal{J}_{i_1,i_2}}{\partial \epsilon_{\beta^{\prime}}} + \dfrac{\partial \mathcal{J}_{i_1,i_2}}{\partial R_{\mu_1,\mu_2;\alpha_1,\alpha_2}^{\alpha^{\prime}}} \dfrac{\partial \epsilon_{\alpha^{\prime}\gamma} R_{\mu_1,\mu_2;\alpha_1,\alpha_2}^{\gamma}}{\partial \epsilon_{\beta^{\prime}}} \Biggr) \epsilon_{\beta^{\prime}}\end{split}\]

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

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

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

\(\hat{\mathcal{I}}_{i_2}^{\mu_2,\alpha_2}\)