The difference The effect to Quantum Bit It causes global phase on qubit The representation using Hermite As we can see in my articles (https://eye.kohei-kevin.com/2024/06/27/why-unitary-is-represented-using-hermite/, https://eye.kohei-kevin.com/2024/06/20/pure-state-representation-using-density-matrix/), U(2) and SU(2) In the case of U(2), Hermite H can take any Hermite matrix, but in the case of SU(2), Hermite H should have traceless basis. Because of … Continue reading Distinguish Unitary U and Special Unitary SU