Extracting spectral properties from Keldysh Green functions
- Dirks, Andreas Department of Physics, University of Göttingen, Germany - Department of Physics, Georgetown University, Washington, USA
- Eckstein, Martin Max Planck Research Department for Structural Dynamics, University of Hamburg-CFEL, Germany
- Pruschke, Thomas Department of Physics, University of Göttingen, Germany
- Werner, Philipp Department of Physics, University of Fribourg, Switzerland
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21.02.2013
Published in:
- Physical Review E. - 2013, vol. 87, no. 2, p. 023305
English
We investigate the possibility to assist the numerically ill-posed calculation of spectral properties of interacting quantum systems in thermal equilibrium by extending the imaginary-time simulation to a finite Schwinger-Keldysh contour. The effect of this extension is tested within the standard maximum entropy approach to analytic continuation. We find that the inclusion of real-time data improves the resolution of structures at high energy, while the imaginary-time data are needed to correctly reproduce low-frequency features such as quasiparticle peaks. As a nonequilibrium application, we consider the calculation of time-dependent spectral functions from retarded Green function data on a finite time interval, and compare the maximum entropy approach to direct Fourier transformation and a method based on Padé approximants.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
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- English
- Classification
- Physics
- License
- License undefined
- Identifiers
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- RERO DOC 31969
- DOI 10.1103/PhysRevE.87.023305
- Persistent URL
- https://folia.unifr.ch/unifr/documents/303058
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