4 votes

Is it possible to derive a Schmidt decomposition for a mixed state?

Usually, the Schmidt rank of a mixed state $\rho$ is defined as the minimum of the maximal Schmidt rank of an element in any decomposition of $\rho$ into a mixture of pure states (there are many ...
Danylo Y's user avatar
  • 6,989
2 votes

How can a third party learn the coefficient of a shared $2n$-qubits state using a classical message from each one?

Get Alice and Bob to measure all their qubits in the $X$ basis, and send the $\pm 1$ results to Charlie. The combined answer is a bit string $w$. Charlie discards all the results associated with ...
DaftWullie's user avatar
  • 57.1k
2 votes

What are toy examples of single-copy entanglement conversion?

I always rather enjoyed the examples in this paper: https://arxiv.org/abs/quant-ph/9905071 They are more stated in terms of deterministic conversion, but you could just as well calculate probabilities ...
DaftWullie's user avatar
  • 57.1k
1 vote

cirq entanglement qubits

The problem is that you negate qubit q1 before the measurement. As both qubits are opposite each other under original settings (see the first circuit results), negation gate you added on q1 leads ...
Martin Vesely's user avatar

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