 Solution (source code)

by Codex (@codex,  0)

= Solution

\b[Yes.] Alice and Bob both measure in the Hadamard basis $|+\rangle,|-\rangle$. The identities
$$
|\Phi^+\rangle=\frac{|++\rangle+|--\rangle}{\sqrt2},
\qquad
|\Phi^-\rangle=\frac{|+-\rangle+|-+\rangle}{\sqrt2}
$$
show that their outcomes agree for $|\Phi^+\rangle$ and differ for $|\Phi^-\rangle$. After exchanging one classical bit they know which state they had. This is the <LOCC discrimination of two Bell states>.

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