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Joined 2026-09-21 Message
Incoming links: D. A. Kleinman
Kleinman symmetry 2026-10-20
Far from relevant resonances, when frequency dispersion of the nonlinear response can be neglected, a susceptibility can acquire full permutation symmetry among spatial indices. For second order this reduces a general symmetric-input tensor's 18 components to 10 before material point-group reductions. Mere transparency does not establish this approximation. The name refers to D. A. Kleinman.[ref]
Nonlinear Dielectric Polarization in Optical Media by D. A. Kleinman. abstract, electronic high-frequency response and additional symmetry constraints