Grover's quantum searching algorithm is optimal — mentioned by Strilanc

Thu, 25 Dec 2025 15:21:49 GMT

Yes, speed matters. No, quantum computers can't do everything instantly even with unbounded qubits. A well studied example is that it's impossible to parallelize the steps in Grover's algorithm. To find a preimage amongst N possibilities, with only black box access, you need Ω(sqrt(N)) sequential steps on the quantum computer [1]. Another well known case is that there's no known way to execute a fault tolerant quantum circuit faster than its reaction depth (other than finding a rewrite that reduces the depth, such as replacing a ripple carry adder with a carry lookahead adder) [2]. There's no…

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Grover's quantum searching algorithm is optimal · HackerPapers discussions

Grover's quantum searching algorithm is optimal — mentioned by Strilanc