dorsal/arxiv
View SchemaQuantum complexities of ordered searching, sorting, and element distinctness
| Authors | Peter Hoyer, Jan Neerbek, Yaoyun Shi |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0102078 |
| URL | https://arxiv.org/abs/quant-ph/0102078 |
| DOI | 10.1007/3-540-48224-5_29 |
| Journal | 28th ICALP, LNCS 2076, pp. 346-357, July 2001 |
Abstract
We consider the quantum complexities of the following three problems: searching an ordered list, sorting an un-ordered list, and deciding whether the numbers in a list are all distinct. Letting N be the number of elements in the input list, we prove a lower bound of \frac{1}{\pi}(\ln(N)-1) accesses to the list elements for ordered searching, a lower bound of \Omega(N\log{N}) binary comparisons for sorting, and a lower bound of \Omega(\sqrt{N}\log{N}) binary comparisons for element distinctness. The previously best known lower bounds are {1/12}\log_2(N) - O(1) due to Ambainis, \Omega(N), and \Omega(\sqrt{N}), respectively. Our proofs are based on a weighted all-pairs inner product argument. In addition to our lower bound results, we give a quantum algorithm for ordered searching using roughly 0.631 \log_2(N) oracle accesses. Our algorithm uses a quantum routine for traversing through a binary search tree faster than classically, and it is of a nature very different from a faster algorithm due to Farhi, Goldstone, Gutmann, and Sipser.
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"abstract": "We consider the quantum complexities of the following three problems:\nsearching an ordered list, sorting an un-ordered list, and deciding whether the\nnumbers in a list are all distinct. Letting N be the number of elements in the\ninput list, we prove a lower bound of \\frac{1}{\\pi}(\\ln(N)-1) accesses to the\nlist elements for ordered searching, a lower bound of \\Omega(N\\log{N}) binary\ncomparisons for sorting, and a lower bound of \\Omega(\\sqrt{N}\\log{N}) binary\ncomparisons for element distinctness. The previously best known lower bounds\nare {1/12}\\log_2(N) - O(1) due to Ambainis, \\Omega(N), and \\Omega(\\sqrt{N}),\nrespectively. Our proofs are based on a weighted all-pairs inner product\nargument.\n In addition to our lower bound results, we give a quantum algorithm for\nordered searching using roughly 0.631 \\log_2(N) oracle accesses. Our algorithm\nuses a quantum routine for traversing through a binary search tree faster than\nclassically, and it is of a nature very different from a faster algorithm due\nto Farhi, Goldstone, Gutmann, and Sipser.",
"arxiv_id": "quant-ph/0102078",
"authors": [
"Peter Hoyer",
"Jan Neerbek",
"Yaoyun Shi"
],
"categories": [
"quant-ph"
],
"doi": "10.1007/3-540-48224-5_29",
"journal_ref": "28th ICALP, LNCS 2076, pp. 346-357, July 2001",
"title": "Quantum complexities of ordered searching, sorting, and element distinctness",
"url": "https://arxiv.org/abs/quant-ph/0102078"
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