Extracting spectral properties from Keldysh Green functions

被引：12

作者：

Dirks, Andreas ^{[1
,2
]}

Eckstein, Martin ^{[3
]}

Pruschke, Thomas ^{[1
]}

Werner, Philipp ^{[4
]}

机构：

[1] Univ Gottingen, Dept Phys, D-37077 Gottingen, Germany

[2] Georgetown Univ, Dept Phys, Washington, DC 20057 USA

[3] Univ Hamburg, CFEL, Max Planck Res Dept Struct Dynam, Hamburg, Germany

[4] Univ Fribourg, Dept Phys, CH-1700 Fribourg, Switzerland

来源：

PHYSICAL REVIEW E | 2013年 / 87卷 / 02期

关键词：

MAXIMUM-ENTROPY; ANALYTIC CONTINUATION;

D O I：

10.1103/PhysRevE.87.023305

中图分类号：

O35 [流体力学]; O53 [等离子体物理学];

学科分类号：

070204 ; 080103 ; 080704 ;

摘要：

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 Pade approximants. DOI: 10.1103/PhysRevE.87.023305

引用

页数：9

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