dorsal/arxiv
View SchemaEvery NAND formula of size N can be evaluated in time N^{1/2+o(1)} on a quantum computer
| Authors | Andrew M. Childs, Ben W. Reichardt, Robert Spalek, Shengyu Zhang |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0703015 |
| URL | https://arxiv.org/abs/quant-ph/0703015 |
Abstract
For every NAND formula of size N, there is a bounded-error N^{1/2+o(1)}-time quantum algorithm, based on a coined quantum walk, that evaluates this formula on a black-box input. Balanced, or ``approximately balanced,'' NAND formulas can be evaluated in O(sqrt{N}) queries, which is optimal. It follows that the (2-o(1))-th power of the quantum query complexity is a lower bound on the formula size, almost solving in the positive an open problem posed by Laplante, Lee and Szegedy.
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"abstract": "For every NAND formula of size N, there is a bounded-error N^{1/2+o(1)}-time\nquantum algorithm, based on a coined quantum walk, that evaluates this formula\non a black-box input. Balanced, or ``approximately balanced,\u0027\u0027 NAND formulas\ncan be evaluated in O(sqrt{N}) queries, which is optimal. It follows that the\n(2-o(1))-th power of the quantum query complexity is a lower bound on the\nformula size, almost solving in the positive an open problem posed by Laplante,\nLee and Szegedy.",
"arxiv_id": "quant-ph/0703015",
"authors": [
"Andrew M. Childs",
"Ben W. Reichardt",
"Robert Spalek",
"Shengyu Zhang"
],
"categories": [
"quant-ph"
],
"title": "Every NAND formula of size N can be evaluated in time N^{1/2+o(1)} on a quantum computer",
"url": "https://arxiv.org/abs/quant-ph/0703015"
},
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"execution_id": "018d11ce-14bf-4442-b94b-be890b9fb719",
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"type": "Model",
"variant": "snapshot-2026-03-01",
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