---
_id: '13125'
abstract:
- lang: eng
  text: 'The quantum approximate optimization algorithm (QAOA) is a variational quantum
    algorithm, where a quantum computer implements a variational ansatz consisting
    of p layers of alternating unitary operators and a classical computer is used
    to optimize the variational parameters. For a random initialization, the optimization
    typically leads to local minima with poor performance, motivating the search for
    initialization strategies of QAOA variational parameters. Although numerous heuristic
    initializations exist, an analytical understanding and performance guarantees
    for large p remain evasive.We introduce a greedy initialization of QAOA which
    guarantees improving performance with an increasing number of layers. Our main
    result is an analytic construction of 2p + 1 transition states—saddle points with
    a unique negative curvature direction—for QAOA with p + 1 layers that use the
    local minimum of QAOA with p layers. Transition states connect to new local minima,
    which are guaranteed to lower the energy compared to the minimum found for p layers.
    We use the GREEDY procedure to navigate the exponentially increasing with p number
    of local minima resulting from the recursive application of our analytic construction.
    The performance of the GREEDY procedure matches available initialization strategies
    while providing a guarantee for the minimal energy to decrease with an increasing
    number of layers p. '
acknowledgement: 'We thank V. Verteletskyi for a joint collaboration on numerical
  studies of the QAOA during his internship at ISTA that inspired analytic results
  on TS reported in this work. We acknowledge A. A. Mele and M. Brooks for discussions
  and D. Egger, P. Love, and D. Wierichs for valuable feedback on the manuscript.
  S.H.S., R.A.M., and M.S. acknowledge support by the European Research Council (ERC)
  under the European Union’s Horizon 2020 research and innovation program (Grant Agreement
  No. 850899). R.K. is supported by the SFB BeyondC (Grant No. F7107-N38) and the
  project QuantumReady (FFG 896217). '
article_number: '062404'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Stefan
  full_name: Sack, Stefan
  id: dd622248-f6e0-11ea-865d-ce382a1c81a5
  last_name: Sack
  orcid: 0000-0001-5400-8508
- first_name: Raimel A
  full_name: Medina Ramos, Raimel A
  id: CE680B90-D85A-11E9-B684-C920E6697425
  last_name: Medina Ramos
  orcid: 0000-0002-5383-2869
- first_name: Richard
  full_name: Kueng, Richard
  last_name: Kueng
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
citation:
  ama: Sack S, Medina Ramos RA, Kueng R, Serbyn M. Recursive greedy initialization
    of the quantum approximate optimization algorithm with guaranteed improvement.
    <i>Physical Review A</i>. 2023;107(6). doi:<a href="https://doi.org/10.1103/physreva.107.062404">10.1103/physreva.107.062404</a>
  apa: Sack, S., Medina Ramos, R. A., Kueng, R., &#38; Serbyn, M. (2023). Recursive
    greedy initialization of the quantum approximate optimization algorithm with guaranteed
    improvement. <i>Physical Review A</i>. American Physical Society. <a href="https://doi.org/10.1103/physreva.107.062404">https://doi.org/10.1103/physreva.107.062404</a>
  chicago: Sack, Stefan, Raimel A Medina Ramos, Richard Kueng, and Maksym Serbyn.
    “Recursive Greedy Initialization of the Quantum Approximate Optimization Algorithm
    with Guaranteed Improvement.” <i>Physical Review A</i>. American Physical Society,
    2023. <a href="https://doi.org/10.1103/physreva.107.062404">https://doi.org/10.1103/physreva.107.062404</a>.
  ieee: S. Sack, R. A. Medina Ramos, R. Kueng, and M. Serbyn, “Recursive greedy initialization
    of the quantum approximate optimization algorithm with guaranteed improvement,”
    <i>Physical Review A</i>, vol. 107, no. 6. American Physical Society, 2023.
  ista: Sack S, Medina Ramos RA, Kueng R, Serbyn M. 2023. Recursive greedy initialization
    of the quantum approximate optimization algorithm with guaranteed improvement.
    Physical Review A. 107(6), 062404.
  mla: Sack, Stefan, et al. “Recursive Greedy Initialization of the Quantum Approximate
    Optimization Algorithm with Guaranteed Improvement.” <i>Physical Review A</i>,
    vol. 107, no. 6, 062404, American Physical Society, 2023, doi:<a href="https://doi.org/10.1103/physreva.107.062404">10.1103/physreva.107.062404</a>.
  short: S. Sack, R.A. Medina Ramos, R. Kueng, M. Serbyn, Physical Review A 107 (2023).
corr_author: '1'
date_created: 2023-06-07T06:57:32Z
date_published: 2023-06-02T00:00:00Z
date_updated: 2026-10-15T22:31:12Z
day: '02'
ddc:
- '530'
department:
- _id: MaSe
doi: 10.1103/physreva.107.062404
ec_funded: 1
external_id:
  arxiv:
  - '2209.01159'
  isi:
  - '001016927100012'
file:
- access_level: open_access
  checksum: 0d71423888eeccaa60d8f41197f26306
  content_type: application/pdf
  creator: dernst
  date_created: 2023-06-13T07:28:36Z
  date_updated: 2023-06-13T07:28:36Z
  file_id: '13131'
  file_name: 2023_PhysRevA_Sack.pdf
  file_size: 2524611
  relation: main_file
  success: 1
file_date_updated: 2023-06-13T07:28:36Z
fulldoi: https://doi.org/10.1103/physreva.107.062404
has_accepted_license: '1'
intvolume: '       107'
isi: 1
issue: '6'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
project:
- _id: 23841C26-32DE-11EA-91FC-C7463DDC885E
  call_identifier: H2020
  grant_number: '850899'
  name: 'Non-Ergodic Quantum Matter: Universality, Dynamics and Control'
publication: Physical Review A
publication_identifier:
  eissn:
  - 2469-9934
  issn:
  - 2469-9926
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
  record:
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    status: public
  - id: '14622'
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scopus_import: '1'
status: public
title: Recursive greedy initialization of the quantum approximate optimization algorithm
  with guaranteed improvement
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 107
year: '2023'
...
