---
_id: '8161'
abstract:
- lang: eng
  text: The polynomial-time hierarchy (PH) has proven to be a powerful tool for providing
    separations in computational complexity theory (modulo standard conjectures such
    as PH does not collapse). Here, we study whether two quantum generalizations of
    PH can similarly prove separations in the quantum setting. The first generalization,
    QCPH, uses classical proofs, and the second, QPH, uses quantum proofs. For the
    former, we show quantum variants of the Karp-Lipton theorem and Toda's theorem.
    For the latter, we place its third level, Q Sigma_3, into NEXP using the Ellipsoid
    Method for efficiently solving semidefinite programs. These results yield two
    implications for QMA(2), the variant of Quantum Merlin-Arthur (QMA) with two unentangled
    proofs, a complexity class whose characterization has proven difficult. First,
    if QCPH=QPH (i.e., alternating quantifiers are sufficiently powerful so as to
    make classical and quantum proofs "equivalent"), then QMA(2) is in the Counting
    Hierarchy (specifically, in P^{PP^{PP}}). Second, unless QMA(2)= Q Sigma_3 (i.e.,
    alternating quantifiers do not help in the presence of "unentanglement"), QMA(2)
    is strictly contained in NEXP.
author:
- first_name: Sevag
  full_name: Gharibian, Sevag
  id: '71541'
  last_name: Gharibian
  orcid: 0000-0002-9992-3379
- first_name: Miklos
  full_name: Santha, Miklos
  last_name: Santha
- first_name: Jamie
  full_name: Sikora, Jamie
  last_name: Sikora
- first_name: Aarthi
  full_name: Sundaram, Aarthi
  last_name: Sundaram
- first_name: Justin
  full_name: Yirka, Justin
  last_name: Yirka
citation:
  ama: 'Gharibian S, Santha M, Sikora J, Sundaram A, Yirka J. Quantum Generalizations
    of the Polynomial Hierarchy with Applications to QMA(2). In: Potapov I, Spirakis
    P, Worrell J, eds. <i>43rd International Symposium on Mathematical Foundations 
    of Computer Science (MFCS 2018)</i>. Vol 117. Leibniz International Proceedings
    in Informatics (LIPIcs). Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik; 2018:58:1-58:16.
    doi:<a href="https://doi.org/10.4230/LIPIcs.MFCS.2018.58">10.4230/LIPIcs.MFCS.2018.58</a>'
  apa: Gharibian, S., Santha, M., Sikora, J., Sundaram, A., &#38; Yirka, J. (2018).
    Quantum Generalizations of the Polynomial Hierarchy with Applications to QMA(2).
    In I. Potapov, P. Spirakis, &#38; J. Worrell (Eds.), <i>43rd International Symposium
    on Mathematical Foundations  of Computer Science (MFCS 2018)</i> (Vol. 117, p.
    58:1-58:16). Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik. <a href="https://doi.org/10.4230/LIPIcs.MFCS.2018.58">https://doi.org/10.4230/LIPIcs.MFCS.2018.58</a>
  bibtex: '@inproceedings{Gharibian_Santha_Sikora_Sundaram_Yirka_2018, place={Dagstuhl,
    Germany}, series={Leibniz International Proceedings in Informatics (LIPIcs)},
    title={Quantum Generalizations of the Polynomial Hierarchy with Applications to
    QMA(2)}, volume={117}, DOI={<a href="https://doi.org/10.4230/LIPIcs.MFCS.2018.58">10.4230/LIPIcs.MFCS.2018.58</a>},
    booktitle={43rd International Symposium on Mathematical Foundations  of Computer
    Science (MFCS 2018)}, publisher={Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik},
    author={Gharibian, Sevag and Santha, Miklos and Sikora, Jamie and Sundaram, Aarthi
    and Yirka, Justin}, editor={Potapov, Igor and Spirakis, Paul and Worrell, James},
    year={2018}, pages={58:1-58:16}, collection={Leibniz International Proceedings
    in Informatics (LIPIcs)} }'
  chicago: 'Gharibian, Sevag, Miklos Santha, Jamie Sikora, Aarthi Sundaram, and Justin
    Yirka. “Quantum Generalizations of the Polynomial Hierarchy with Applications
    to QMA(2).” In <i>43rd International Symposium on Mathematical Foundations  of
    Computer Science (MFCS 2018)</i>, edited by Igor Potapov, Paul Spirakis, and James
    Worrell, 117:58:1-58:16. Leibniz International Proceedings in Informatics (LIPIcs).
    Dagstuhl, Germany: Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, 2018. <a
    href="https://doi.org/10.4230/LIPIcs.MFCS.2018.58">https://doi.org/10.4230/LIPIcs.MFCS.2018.58</a>.'
  ieee: 'S. Gharibian, M. Santha, J. Sikora, A. Sundaram, and J. Yirka, “Quantum Generalizations
    of the Polynomial Hierarchy with Applications to QMA(2),” in <i>43rd International
    Symposium on Mathematical Foundations  of Computer Science (MFCS 2018)</i>, Liverpool,
    UK, 2018, vol. 117, p. 58:1-58:16, doi: <a href="https://doi.org/10.4230/LIPIcs.MFCS.2018.58">10.4230/LIPIcs.MFCS.2018.58</a>.'
  mla: Gharibian, Sevag, et al. “Quantum Generalizations of the Polynomial Hierarchy
    with Applications to QMA(2).” <i>43rd International Symposium on Mathematical
    Foundations  of Computer Science (MFCS 2018)</i>, edited by Igor Potapov et al.,
    vol. 117, Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, 2018, p. 58:1-58:16,
    doi:<a href="https://doi.org/10.4230/LIPIcs.MFCS.2018.58">10.4230/LIPIcs.MFCS.2018.58</a>.
  short: 'S. Gharibian, M. Santha, J. Sikora, A. Sundaram, J. Yirka, in: I. Potapov,
    P. Spirakis, J. Worrell (Eds.), 43rd International Symposium on Mathematical Foundations 
    of Computer Science (MFCS 2018), Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik,
    Dagstuhl, Germany, 2018, p. 58:1-58:16.'
conference:
  location: Liverpool, UK
  name: 43rd International Symposium on Mathematical Foundations  of Computer Science
    (MFCS 2018)
date_created: 2019-03-01T11:29:44Z
date_updated: 2023-02-28T11:01:03Z
department:
- _id: '623'
- _id: '7'
doi: 10.4230/LIPIcs.MFCS.2018.58
editor:
- first_name: Igor
  full_name: Potapov, Igor
  last_name: Potapov
- first_name: Paul
  full_name: Spirakis, Paul
  last_name: Spirakis
- first_name: James
  full_name: Worrell, James
  last_name: Worrell
external_id:
  arxiv:
  - '1805.11139'
intvolume: '       117'
keyword:
- Complexity Theory
- Quantum Computing
- Polynomial Hierarchy
- Semidefinite Programming
- QMA(2)
- Quantum Complexity
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: http://drops.dagstuhl.de/opus/frontdoor.php?source_opus=9640
oa: '1'
page: 58:1-58:16
place: Dagstuhl, Germany
publication: 43rd International Symposium on Mathematical Foundations  of Computer
  Science (MFCS 2018)
publication_identifier:
  unknown:
  - 978-3-95977-086-6
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik
series_title: Leibniz International Proceedings in Informatics (LIPIcs)
status: public
title: Quantum Generalizations of the Polynomial Hierarchy with Applications to QMA(2)
type: conference
user_id: '71541'
volume: 117
year: '2018'
...
