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@ARTICLE{Angelides:619665,
      author       = {Angelides, Takis and Naredi, Pranay and Crippa, Arianna and
                      Jansen, Karl and Kühn, Stefan and Tavernelli, Ivano and
                      Wang, Derek S.},
      title        = {{F}irst-{O}rder {P}hase {T}ransition of the {S}chwinger
                      {M}odel with a {Q}uantum {C}omputer},
      reportid     = {PUBDB-2024-07804, arXiv:2312.12831},
      year         = {2024},
      note         = {21 pages, 10 figures, 1 table},
      abstract     = {We explore the first-order phase transition in the lattice
                      Schwinger model in the presence of a topological
                      $\theta$-term by means of the variational quantum
                      eigensolver (VQE). Using two different fermion
                      discretizations, Wilson and staggered fermions, we develop
                      parametric ansatz circuits suitable for both
                      discretizations, and compare their performance by simulating
                      classically an ideal VQE optimization in the absence of
                      noise. The states obtained by the classical simulation are
                      then prepared on the IBM's superconducting quantum hardware.
                      Applying state-of-the art error-mitigation methods, we show
                      that the electric field density and particle number,
                      observables which reveal the phase structure of the model,
                      can be reliably obtained from the quantum hardware. To
                      investigate the minimum system sizes required for a
                      continuum extrapolation, we study the continuum limit using
                      matrix product states, and compare our results to continuum
                      mass perturbation theory. We demonstrate that taking the
                      additive mass renormalization into account is vital for
                      enhancing the precision that can be obtained with smaller
                      system sizes. Furthermore, for the observables we
                      investigate we observe universality, and both fermion
                      discretizations produce the same continuum limit.},
      keywords     = {hardware: quantum (INSPIRE) / mass: renormalization
                      (INSPIRE) / fermion: staggered (INSPIRE) / computer: quantum
                      (INSPIRE) / critical phenomena (INSPIRE) / variational
                      quantum eigensolver (INSPIRE) / continuum limit (INSPIRE) /
                      Schwinger model (INSPIRE) / error mitigation (INSPIRE) /
                      particle number (INSPIRE) / density (INSPIRE) / universality
                      (INSPIRE) / superconductivity (INSPIRE) / topological
                      (INSPIRE) / electric field (INSPIRE) / lattice (INSPIRE) /
                      optimization (INSPIRE) / perturbation theory (INSPIRE) /
                      noise (INSPIRE) / performance (INSPIRE) / parametric
                      (INSPIRE)},
      cin          = {CQTA},
      cid          = {I:(DE-H253)CQTA-20221102},
      pnm          = {611 - Fundamental Particles and Forces (POF4-611) / QUEST -
                      QUantum computing for Excellence in Science and Technology
                      (101087126)},
      pid          = {G:(DE-HGF)POF4-611 / G:(EU-Grant)101087126},
      experiment   = {EXP:(DE-MLZ)NOSPEC-20140101},
      typ          = {PUB:(DE-HGF)25},
      eprint       = {2312.12831},
      howpublished = {arXiv:2312.12831},
      archivePrefix = {arXiv},
      SLACcitation = {$\%\%CITATION$ = $arXiv:2312.12831;\%\%$},
      doi          = {10.3204/PUBDB-2024-07804},
      url          = {https://bib-pubdb1.desy.de/record/619665},
}