- #1

greypilgrim

- 547

- 38

The classical (Shannon) conditional entropy is never negative. It can be written as ##H(Y|X)=H(X,Y)-H(X)## which allows for a quantum generalization using von Neumann entropy. In the case of entangled states, it can become negative.

I guess it should be possible to construct an entangled, mixed (bipartite) state where ##H(Y|X)## is exactly zero (though I don't know how to exactly do that). Does this have a specific meaning?