
What is the opposite of measurement, in a quantum circuit? - peter_d_sherman
https://quantumcomputing.stackexchange.com/questions/9780/what-is-the-opposite-of-measurement-in-a-quantum-circuit
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peter_d_sherman
While I don't have the expertise to know if it's right or wrong, I find Martin
Vesely's answer to this question the most intriguing of the bunch:

Martin Vesely: "A measurement leads to collapse of a wave function describing
qubits, they get to one particular state and remain in that state. To do
reverse operation you have to repeat measurement many times. Based on
resulting probability distribution you can reconstruct the state of qubits and
prepare it again.

The reconstruction of probability distribution is done with quantum
tomography.

Arbitrary state can be prepared with method in this paper: Transformation of
quantum states using uniformly controlled rotations
([https://arxiv.org/abs/quant-ph/0407010](https://arxiv.org/abs/quant-
ph/0407010))."

Comments?

