# Tag Info

Accepted

### Ensemble state identification from ensemble state distinction

Your idea is essentially correct. I will just expand it a bit: Let $1_{A}$ denote the indicator random variable that takes value $1$ on event $A$ and $0$ otherwise. Let $\mathcal{M}$ be the POVM that ...
Accepted

### Can you reconstruct some $N$-qubit entangled state only from ($N$-1) qubits?

There is always some amplitude that remains unknown. Let $|\Psi\rangle$ be the pure state of all $N$ qubits. The measurement statistics on all qubits except qubit $A$ are optimally described by the ...
• 51.1k
1 vote

### Can you reconstruct some $N$-qubit entangled state only from ($N$-1) qubits?

Suppose for contradiction that you are able to infer the final qubit's value, and its value is $|0\rangle$. But now suppose Eve comes along and tweaks the preparation of the entangled state so that it ...
• 28.7k

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