Without reading the paper or watching the video. > 1) What does it mean that entangled particles are supercorrelated? How can S(A|B) = 2 or -1? The density ma

Without reading the paper or watching the video. > 1) What does it mean that entangled particles are supercorrelated? How can S(A|B) = 2 or -1? The density matrix does not have the same properties of a joint probability distribution, so quantum entropy doesn't really have the same properties of classical entropy. [1] > 2) The formula for Von Neumann entropy is S = -Tr(p log(p)), where p is the density matrix. How do you take a log of a matrix? The log of a matrix is defined as the inverse of the matrix exponential. The matrix exponential can be defined as the usual power series, only using matrices rather than scalars. What one usually does is: diagonalize the matrix (if possible), take the log of the eigenvalues and rotate again. Obviously taking the log of a matrix is a little trickier than the exponential because if you have negative or complex-valued eigenvalues you have to be a bit more careful. [1] http://arxiv.org/abs/quant-ph/9610005 http://arxiv.org/abs/quant-ph/9610005