Approximate Quantum Fourier Transform and Decoherence — mentioned by Strilanc

Sat, 01 Nov 2025 20:02:25 GMT

> The precision in phase needed to perform an accurate QFT scales EXPONENTIALLY with the number of qubits you're trying to transform. This is false. The gates that appear in the textbook QFT circuit (such as the one shown on wikipedia [1]) do mention angles that are exponentially small in N (the number of qubits being operated upon). That may be what's confusing you. But it's well known that the tolerance on those rotations is high, meaning that simply skipping all the exponentially tiny rotations introduces negligible error [2][3]. Here's a simple model. Each time you get a rotation off by…

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Approximate Quantum Fourier Transform and Decoherence · HackerPapers discussions

Approximate Quantum Fourier Transform and Decoherence — mentioned by Strilanc