<Dl> <Dd> (2 2 + i 4 2 − i 3 i 4 − i 1) (\ displaystyle (\ begin (bmatrix) 2&2 + i&4 \ \ 2 - i&3&i \ \ 4& - i&1 \ \ \ end (bmatrix))) </Dd> </Dl> <Dd> (2 2 + i 4 2 − i 3 i 4 − i 1) (\ displaystyle (\ begin (bmatrix) 2&2 + i&4 \ \ 2 - i&3&i \ \ 4& - i&1 \ \ \ end (bmatrix))) </Dd> <P> The diagonal elements must be real, as they must be their own complex conjugate . </P> <P> Well - known families of Pauli matrices, Gell - Mann matrices and their generalizations are Hermitian . In theoretical physics such Hermitian matrices are often multiplied by imaginary coefficients, which results in skew - Hermitian matrices (see below). </P>

The diagonal elements of a harmitian matrix are