Polynomial scaling of the quantum approximate optimization algorithm for ground-state preparation of the fully connected p -spin ferromagnet in a transverse field

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

Dokumenter

  • Matteo M. Wauters
  • Glen B. Mbeng
  • Giuseppe E. Santoro

We show that the quantum approximate optimization algorithm (QAOA) can construct, with polynomially scaling resources, the ground state of the fully connected p-spin Ising ferromagnet, a problem that notoriously poses severe difficulties to a vanilla quantum annealing (QA) approach due to the exponentially small gaps encountered at first-order phase transition for p≥3. For a target ground state at arbitrary transverse field, we find that an appropriate QAOA parameter initialization is necessary to achieve good performance of the algorithm when the number of variational parameters 2P is much smaller than the system size N because of the large number of suboptimal local minima. Instead, when P exceeds a critical value PN∗N, the structure of the parameter space simplifies, as all minima become degenerate. This allows achieving the ground state with perfect fidelity with a number of parameters scaling extensively with N and with resources scaling polynomially with N.

OriginalsprogEngelsk
Artikelnummer062404
TidsskriftPhysical Review A
Vol/bind102
Udgave nummer6
Antal sider10
ISSN2469-9926
DOI
StatusUdgivet - 3 dec. 2020

Bibliografisk note

Funding Information:
We acknowledge fruitful discussions with E. Panizon. Research was partly supported by EU Horizon 2020 under ERC-ULTRADISS, Grant Agreement No. 834402. G.E.S. acknowledges that his research was conducted within the framework of the Trieste Institute for Theoretical Quantum Technologies (TQT).

Publisher Copyright:
© 2020 American Physical Society.

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