Guaranteed Accuracy Formalism for Imaginary Time Calculations

ORAL

Abstract

Finite-temperature Green's function calculations of quantum systems are frequently performed in the Matsubara formalism, with calculation steps alternating between imaginary time steps (e.g. solution of a lattice model) and Matsubara frequencies (e.g. solution of a Dyson equation). In large systems, these transforms and the ill-conditioned nature of the Matsubara equations often lead to the amplification of small roundoff and cutoff errors.
In this talk I will show how calculations can be performed in imaginary time only. Error accumulation from Fourier transforms can thereby be avoided, and accuracy guarantees can be given for all calculation steps.

*This work was funded by the Simons foundation via the Simons Collaboration on the Many-Electron Problem.

Presenters

  • Emanuel Gull

    • Univ of Michigan - Ann Arbor
    • Physics, Univ of Michigan - Ann Arbor
    • Physics, University Of Michigan
    • Univ of Michigan
    • Physics and Astronomy, University of Michigan
    • Physics, Univ of Michigan
    • University of Michigan
    • Department of Physics, University of Michigan
    • Physics, University of Michigan

Authors

  • Emanuel Gull

    • Univ of Michigan - Ann Arbor
    • Physics, Univ of Michigan - Ann Arbor
    • Physics, University Of Michigan
    • Univ of Michigan
    • Physics and Astronomy, University of Michigan
    • Physics, Univ of Michigan
    • University of Michigan
    • Department of Physics, University of Michigan
    • Physics, University of Michigan
  • Dominika Zgid

    • Univ of Michigan - Ann Arbor