[wien2k] rotate the symmetry matrices into the local solver frame (dft_tools#148)#18
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[wien2k] rotate the symmetry matrices into the local solver frame (dft_tools#148)#18krystophny wants to merge 1 commit into
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Fixes the spin-orbit symmetrization error reported in TRIQS/dft_tools#148. case.symqmc / case.sympar store the symmetry representation matrices that relate equivalent atoms in the global frame. Symmetry.symmetrize, however, is applied to the impurity quantity in the rot_mat-equalized local solver frame (the frame eff_atomic_levels returns). The two agree only when rot_mat is trivial, i.e. for centrosymmetric cells, so the bug stayed hidden; for a non-centrosymmetric cell the symmetrization is wrong and shifts the local-Hamiltonian eigenvalues. convert_symmetry_input now rotates each matrix into the local frame, rot_mat[j]^dag . mat . rot_mat[i] with j the atom i maps to under the operation (rot_mat[i] conjugated for a time-inversion operation, matching the conjugation symmetrize applies). rot_mat is the correlated-shell rotation for case.symqmc and rot_mat_all for case.sympar. Verified on a non-centrosymmetric SP+SO case (tellurium, P3_1 21): the symmetrization of the already-symmetric full-BZ local Hamiltonian goes from a 0.130 Ry eigenvalue drift to 2.5e-8 (a no-op), while centrosymmetric CaOs2 stays at ~1e-15 (unchanged).
This was referenced Jun 24, 2026
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Fixes the spin-orbit symmetrization error in TRIQS/dft_tools#148. Independent of the dmftproj Python port, so it can be reviewed and merged on its own.
case.symqmc/case.symparstore the symmetry representation matrices that relate equivalent atoms in the global frame.Symmetry.symmetrize, however, is applied to the impurity quantity in therot_mat-equalized local solver frame (the frameeff_atomic_levelsreturns). The two coincide only whenrot_matis trivial, i.e. for centrosymmetric cells, so the existing centrosymmetric tests never exposed it; for a non-centrosymmetric cell the symmetrization is wrong and shifts the local-Hamiltonian eigenvalues.convert_symmetry_inputnow rotates each matrix into the local frame,rot_mat[j]^dag . mat . rot_mat[i], wherejis the atomimaps to under the operation (rot_mat[i]conjugated for a time-inversion operation, matching the conjugationsymmetrizeapplies). It usesrot_matforcase.symqmcandrot_mat_allforcase.sympar. Centrosymmetric output is unchanged becauserot_matis trivial there.Verification
Non-centrosymmetric SP+SO case, tellurium (P3_1 21, no inversion, full BZ): symmetrizing the already-symmetric full-BZ local Hamiltonian must be a no-op (zero eigenvalue shift).
Before (unstable):
After (this branch):
Centrosymmetric CaOs2 (no regression): 1.998e-15 before, 2.887e-15 after.