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: 2017
• Jahr: 7 Oct 2017
• Umfang: 8 S.
• Fussnoten: Gesehen am 02.09.2020
• Titel Quelle: Enthalten in: De.arxiv.org
• Ort Quelle: [S.l.] : Arxiv.org, 1991
• Jahr Quelle: 2017
• Band/Heft Quelle: (2017) Artikel-Nummer 1710.02672, 8 Seiten
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: High Energy Physics - Lattice
• Sach-SW: Nuclear Theory
• K10plus-PPN: 1565767543

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 $\omega_0$ and $\omega_1=2\pi T$, 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.