Questions tagged [postselection]

In quantum computing theory post-selection refers to giving a quantum computer the power to choose the outcomes of certain measurements, which greatly increases its computational power. In this case the, perhaps exponentially many, extra runs required to obtain the output are ignored. The important point is that an interference pattern is not produced immediately. (https://physics.stackexchange.com/a/38938)

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Following the group non-isomophism protocol, how efficient would it be to prepare an invariant state by post-selection?

In Watrous's celebrated paper defining the Quantum Merlin-Arthur (QMA) class, he provides a protocol for Arthur to test whether an element $h$ is not in a group $\mathcal{H}=\langle g_0,g_1,\cdots, ...
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Does strong error reduction for PostQMA exist?

$\mathsf{PostQMA}$ can be defined as the following (see Morimae-Nishimura and Usher-Hoban-Browne): A promise problem $\mathcal{L}=(\mathcal{L_{yes},L_{no}})$ is in $\mathsf{PostQMA(c,s)}$ if there ...
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How is postselection used in quantum tomography?

I refer to this paper but reproduce a simplified version of their argument. Apologies if I have misrepresented the argument of the paper! Alice has a classical description of a quantum state $\rho$. ...
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HHL algorithm — problem with the outcome of postselection

See edit at the end of the question All the references in this question refer to Quantum algorithm for solving linear systems of equations (Harrow, Hassidim & Lloyd, 2009). HHL algorithm ...
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What is postselection in quantum computing?

A quantum computer can efficiently solve problems lying in the complexity class BQP. I have seen a claim the one can (potentially, because we don't know whether BQP is a proper subset or equal to PP) ...