Improved real-time dynamics from imaginary frequency lattice simulations

• Verfasst von: Pawlowski, Jan M. [VerfasserIn]
• Verfasst von: Rothkopf, Alexander [VerfasserIn]
• Titel: Improved real-time dynamics from imaginary frequency lattice simulations
• Verf.angabe: Jan M. Pawlowski and Alexander Rothkopf
• E-Jahr: 2018
• Jahr: 26 March 2018
• Umfang: 8 S.
• Fussnoten: Gesehen am 02.09.2020
• Titel Quelle: Enthalten in: International Symposium on Lattice Field Theory (35. : 2017 : Granada)35th International Symposium on Lattice Field Theory (Lattice 2017)
• Ort Quelle: Les Ulis : EDP Sciences, 2018
• Jahr Quelle: 2018
• Band/Heft Quelle: (2018) Artikel-Nummer 07001, 8 Seiten
• DOI: doi:10.1051/epjconf/201817507001
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1585713821

Abstract

The computation of real-time properties, such as transport coefficients or bound state spectra of strongly interacting quantum fields in thermal equilibrium is a pressing matter. Since the sign problem prevents a direct evaluation of these quantities, lattice data needs to be analytically continued from the Euclidean domain of the simulation to Minkowski time, in general an ill-posed inverse problem. Here we report on a novel approach to improve the determination of real-time information in the form of spectral functions by setting up a simulation prescription in imaginary frequencies. By carefully distinguishing between initial conditions and quantum dynamics one obtains access to correlation functions also outside the conventional Matsubara frequencies. In particular the range between <i>ω<i/><sub>0<sub/> and <i>ω<i/><sub>1<sub/> = 2<i>π<i/>T, which is most relevant for the inverse problem may be more highly resolved. In combination with the fact that in imaginary frequencies the kernel of the inverse problem is not an exponential but only a rational function we observe significant improvements in the reconstruction of spectral functions, demonstrated in a simple 0+1 dimensional scalar field theory toy model.