2 Search Results for "Kuperberg, Greg"


Document
The Acrobatics of BQP

Authors: Scott Aaronson, DeVon Ingram, and William Kretschmer

Published in: LIPIcs, Volume 234, 37th Computational Complexity Conference (CCC 2022)


Abstract
One can fix the randomness used by a randomized algorithm, but there is no analogous notion of fixing the quantumness used by a quantum algorithm. Underscoring this fundamental difference, we show that, in the black-box setting, the behavior of quantum polynomial-time (BQP) can be remarkably decoupled from that of classical complexity classes like NP. Specifically: - There exists an oracle relative to which NP^{BQP} ⊄ BQP^{PH}, resolving a 2005 problem of Fortnow. As a corollary, there exists an oracle relative to which 𝖯 = NP but BQP ≠ QCMA. - Conversely, there exists an oracle relative to which BQP^{NP} ⊄ PH^{BQP}. - Relative to a random oracle, PP is not contained in the "QMA hierarchy" QMA^{QMA^{QMA^{⋯}}}. - Relative to a random oracle, Σ_{k+1}^𝖯 ⊄ BQP^{Σ_k^𝖯} for every k. - There exists an oracle relative to which BQP = P^#P and yet PH is infinite. (By contrast, relative to all oracles, if NP ⊆ BPP, then PH collapses.) - There exists an oracle relative to which 𝖯 = NP ≠ BQP = 𝖯^#P. To achieve these results, we build on the 2018 achievement by Raz and Tal of an oracle relative to which BQP ⊄ PH, and associated results about the Forrelation problem. We also introduce new tools that might be of independent interest. These include a "quantum-aware" version of the random restriction method, a concentration theorem for the block sensitivity of AC⁰ circuits, and a (provable) analogue of the Aaronson-Ambainis Conjecture for sparse oracles.

Cite as

Scott Aaronson, DeVon Ingram, and William Kretschmer. The Acrobatics of BQP. In 37th Computational Complexity Conference (CCC 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 234, pp. 20:1-20:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


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@InProceedings{aaronson_et_al:LIPIcs.CCC.2022.20,
  author =	{Aaronson, Scott and Ingram, DeVon and Kretschmer, William},
  title =	{{The Acrobatics of BQP}},
  booktitle =	{37th Computational Complexity Conference (CCC 2022)},
  pages =	{20:1--20:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-241-9},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{234},
  editor =	{Lovett, Shachar},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CCC.2022.20},
  URN =		{urn:nbn:de:0030-drops-165820},
  doi =		{10.4230/LIPIcs.CCC.2022.20},
  annote =	{Keywords: BQP, Forrelation, oracle separations, Polynomial Hierarchy, query complexity}
}
Document
Another Subexponential-time Quantum Algorithm for the Dihedral Hidden Subgroup Problem

Authors: Greg Kuperberg

Published in: LIPIcs, Volume 22, 8th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2013)


Abstract
We give an algorithm for the hidden subgroup problem for the dihedral group D_N, or equivalently the cyclic hidden shift problem, that supersedes our first algorithm and is suggested by Regev's algorithm. It runs in exp(O(sqrt(log N))) quantum time and uses exp(O(sqrt(log N))) classical space, but only O(log N) quantum space. The algorithm also runs faster with quantumly addressable classical space than with fully classical space. In the hidden shift form, which is more natural for this algorithm regardless, it can also make use of multiple hidden shifts. It can also be extended with two parameters that trade classical space and classical time for quantum time. At the extreme space-saving end, the algorithm becomes Regev's algorithm. At the other end, if the algorithm is allowed classical memory with quantum random access, then many trade-offs between classical and quantum time are possible.

Cite as

Greg Kuperberg. Another Subexponential-time Quantum Algorithm for the Dihedral Hidden Subgroup Problem. In 8th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2013). Leibniz International Proceedings in Informatics (LIPIcs), Volume 22, pp. 20-34, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2013)


Copy BibTex To Clipboard

@InProceedings{kuperberg:LIPIcs.TQC.2013.20,
  author =	{Kuperberg, Greg},
  title =	{{Another Subexponential-time Quantum Algorithm for the Dihedral Hidden Subgroup Problem}},
  booktitle =	{8th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2013)},
  pages =	{20--34},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-55-2},
  ISSN =	{1868-8969},
  year =	{2013},
  volume =	{22},
  editor =	{Severini, Simone and Brandao, Fernando},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.TQC.2013.20},
  URN =		{urn:nbn:de:0030-drops-43213},
  doi =		{10.4230/LIPIcs.TQC.2013.20},
  annote =	{Keywords: quantum algorithm, hidden subgroup problem, sieve, subexponential time}
}
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