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@ARTICLE{Piskor:910674,
      author       = {Piskor, Tomislav and Reiner, Jan-Michael and Zanker,
                      Sebastian and Vogt, Nicolas and Marthaler, Michael and
                      Wilhelm-Mauch, Frank and Eich, Florian G.},
      title        = {{U}sing gradient-based algorithms to determine ground-state
                      energies on a quantum computer},
      journal      = {Physical review / A},
      volume       = {105},
      number       = {6},
      issn         = {2469-9926},
      address      = {Woodbury, NY},
      publisher    = {Inst.},
      reportid     = {FZJ-2022-04047},
      pages        = {062415},
      year         = {2022},
      abstract     = {Variational algorithms are promising candidates to be
                      implemented on near-term quantum computers. In our work, we
                      investigate the variational Hamiltonian ansatz (VHA), where
                      a parametrized trial state of the quantum mechanical wave
                      function is optimized to obtain the ground-state energy. In
                      the VHA, the trial state is given by a noninteracting
                      reference state modified by unitary rotations using
                      generators that are part of the Hamiltonian describing the
                      system. The lowest energy is obtained by optimizing the
                      angles of those unitary rotations. A standard procedure to
                      optimize the variational parameters is to use gradient-based
                      algorithms. However, shot noise and the intrinsic noise of
                      the quantum device affect the evaluation of the required
                      gradients. We study how different methods for obtaining the
                      gradient, specifically the finite-difference and the
                      parameter-shift rule, are affected by shot noise and the
                      noise of the quantum computer. To this end, we simulate a
                      simple quantum circuit, as well as the two-site and six-site
                      Hubbard models.},
      cin          = {PGI-12},
      ddc          = {530},
      cid          = {I:(DE-Juel1)PGI-12-20200716},
      pnm          = {5223 - Quantum-Computer Control Systems and Cryoelectronics
                      (POF4-522)},
      pid          = {G:(DE-HGF)POF4-5223},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000812337800004},
      doi          = {10.1103/PhysRevA.105.062415},
      url          = {https://juser.fz-juelich.de/record/910674},
}