Diagrammatic Expansion for Positive Spectral Functions in the Steady-State Limit
Abstract
Recently, a method was presented for constructing self‐energies within many‐body perturbation theory that is guaranteed to produce a positive spectral function for equilibrium systems, by representing the self‐energy as a product of half‐diagrams on the forward and backward branches of the Keldysh contour [Phys. Rev. B 2014, 90, 115134]. An alternative half‐diagram representation that is based on products of retarded diagrams is derived here. This approach extends the method to systems out of equilibrium. When a steady‐state limit exists, it is shown that our approach yields a positive definite spectral function in the frequency domain.
Main Authors
Format
Articles
Research article
Published
2019
Series
Subjects
Publication in research information system
Publisher
Wiley - VCH Verlag GmbH & Co. KGaA
The permanent address of the publication
https://urn.fi/URN:NBN:fi:jyu-202001081106Use this for linking
Review status
Peer reviewed
ISSN
0370-1972
DOI
https://doi.org/10.1002/pssb.201800615
Language
English
Published in
Physica Status Solidi. B: Basic Research
Citation
- Hyrkäs, M., Karlsson, D., & van Leeuwen, R. (2019). Diagrammatic Expansion for Positive Spectral Functions in the Steady-State Limit. Physica Status Solidi. B: Basic Research, 256(7), 1800615. https://doi.org/10.1002/pssb.201800615
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Funder(s)
Research Council of Finland
Research Council of Finland
Funding program(s)
Tutkijatohtori, SA
Akatemiahanke, SA
Postdoctoral Researcher, AoF
Academy Project, AoF
Additional information about funding
D.K. acknowledges the Academy of Finland for funding under Project No. 308697. M.H. thanks the Finnish Cultural Foundation for support. R.v.L. acknowledges the Academy of Finland for funding under Project No. 317139.
Copyright© 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim