UNITARY MATRICES AND COMMUTATORS
Yorick Hardy, W.‐H. Steeb · International Journal of Geometric Methods in Modern Physics · 2011
Unitary matrices are the quantum gates in quantum computing. We study the question under which conditions is the commutator of two unitary matrices again a unitary matrix. We consider the general case and a complete solution for the 2 × 2 unitary matrices. We also consider Kronecker products and direct sums of unitary matrices.