% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Gntgen:1037656,
      author       = {Gäntgen, Christoph and Berkowitz, Evan and Luu, Thomas and
                      Ostmeyer, Johann and Rodekamp, Marcel},
      title        = {{F}ermionic sign problem minimization by constant path
                      integral contour shifts},
      journal      = {Physical review / B},
      volume       = {109},
      number       = {19},
      issn         = {2469-9950},
      address      = {Woodbury, NY},
      publisher    = {Inst.},
      reportid     = {FZJ-2025-00821},
      pages        = {195158},
      year         = {2024},
      abstract     = {The path integral formulation of quantum mechanical
                      problems including fermions is often affected by a severe
                      numerical sign problem. We show how such a sign problem can
                      be alleviated by a judiciously chosen constant imaginary
                      offset to the path integral. Such integration contour
                      deformations introduce no additional computational cost to
                      the Hamiltonian Monte Carlo algorithm, while its effective
                      sample size is greatly increased. This makes otherwise
                      unviable simulations efficient for a wide range of
                      parameters. Applying our method to the Hubbard model, we
                      find that the sign problem is significantly reduced.
                      Furthermore, we prove that it vanishes completely for large
                      chemical potentials, a regime where the sign problem is
                      expected to be particularly severe without imaginary
                      offsets. In addition to a numerical analysis of such
                      optimized contour shifts, we analytically compute the shifts
                      corresponding to the leading and next-to-leading order
                      corrections to the action. We find that such simple
                      approximations, free of significant computational cost,
                      suffice in many cases. We present a simulation of C60
                      fullerenes (buckyballs) that are successful over a wide
                      parameter range.},
      cin          = {JSC / IAS-4 / CASA},
      ddc          = {530},
      cid          = {I:(DE-Juel1)JSC-20090406 / I:(DE-Juel1)IAS-4-20090406 /
                      I:(DE-Juel1)CASA-20230315},
      pnm          = {5111 - Domain-Specific Simulation $\&$ Data Life Cycle Labs
                      (SDLs) and Research Groups (POF4-511) / DFG project
                      G:(GEPRIS)196253076 - TRR 110: Symmetrien und
                      Strukturbildung in der Quantenchromodynamik (196253076) /
                      NRW-FAIR (NW21-024-A)},
      pid          = {G:(DE-HGF)POF4-5111 / G:(GEPRIS)196253076 /
                      G:(NRW)NW21-024-A},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:001237659600003},
      doi          = {10.1103/PhysRevB.109.195158},
      url          = {https://juser.fz-juelich.de/record/1037656},
}