MatrixSimilarity

Abstract

Eigenvalues under unitary similarity.

A Hermitian matrix unitarily similar to a real diagonal matrix has the same eigenvalues up to a permutation. The characteristic polynomial and its roots provide the spectral identification used for compound matrices.

The source is Alex Meiburg’s Apache-2.0 Physlib at revision b9043cc548ef6d63a28454cf3a57fb12a0c2e142. These results support the Schatten product Holder inequality. No mathematical originality is claimed.