Did I ever tell you that I really like this EP? Like, really.
Me too. Also if you play the video you can bring the forum up over the top and leave it playing underneath and it loops. Now how cool is that?
Quantum discord quantifies nonclassical correlations in a quantum system including those not captured by entanglement. Thus, only states with zero discord exhibit strictly classical correlations. We prove that these states are negligible in the whole Hilbert space: typically a state picked out at random has positive discord and, given a state with zero discord, a generic arbitrarily small perturbation drives it to a positive-discord state. These results hold for any Hilbert-space dimension and have direct implications for quantum computation and for the foundations of the theory of open systems. In addition, we provide a simple necessary criterion for zero quantum discord. Finally, we show that, for almost all positive- discord states, an arbitrary Markovian evolution cannot lead to a sudden, permanent vanishing of discord.