- #1

naima

Gold Member

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## Main Question or Discussion Point

Let us begin with a state belonging to the four dimensional tensor product of two particles.

[tex] \sqrt {p_1}|+_x>|+_{x'}> + \sqrt {p_2}|+_x>|-_{x'}> + \sqrt {p_3}|-_x>|+_{x'}> + \sqrt {p_4}|-_x>|-_{x'}> [/tex]

We can compute the Von Neumann entropy by tracing out and taking the log of the matrix.

Suppose now than Bob and Alice receive a lot of pairs of particles prepared in this state.

They ignore the directions x and x'. Can they get the entropy out of theirs results when they compare them?

[tex] \sqrt {p_1}|+_x>|+_{x'}> + \sqrt {p_2}|+_x>|-_{x'}> + \sqrt {p_3}|-_x>|+_{x'}> + \sqrt {p_4}|-_x>|-_{x'}> [/tex]

We can compute the Von Neumann entropy by tracing out and taking the log of the matrix.

Suppose now than Bob and Alice receive a lot of pairs of particles prepared in this state.

They ignore the directions x and x'. Can they get the entropy out of theirs results when they compare them?