The automorphism group of separable states in quantum information theory
Shmuel Friedland, Chi-Kwong Li, Yiu‐Tung Poon, Nung-Sing Sze · Journal of Mathematical Physics · 2011
We show that the linear group of automorphism of Hermitian matrices which preserves the set of separable states is generated by natural automorphisms: change of an orthonormal basis in each tensor factor, partial transpose in each tensor factor, and interchanging two tensor factors of the same dimension. We apply our results to the preservers of the product numerical range.