Characterization of the positivity of the density matrix in terms of the coherence vector representation
Characterization of the positivity of the density matrix in terms of the coherence vector representation
A parameterization of the density operator, a coherence vector representation, which uses a basis of orthogonal, traceless, Hermitian matrices is discussed. Using this parameterization we find the region of permissible vectors which represent a density operator. The inequalities which specify the region are shown to involve the Casimir invariants of …