Talk:Open Quantum Systems/The Density Matrix

Partly question, partly suggestion: "Since the Pauli matrices ${\displaystyle \sigma _{x},\sigma _{y},\sigma _{z}}$ and the identity ${\displaystyle \sigma _{0}}$ form a basis for the vector space of hermitian ${\displaystyle 2\times 2}$ complex matrices, we can expand any observable..." I would mention the fact (? is it so?). --Nobelium (discusscontribs) 18:56, 12 April 2014 (UTC)