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Abstract
We present a generalization of the maximum entropy method to the analytic continuation of matrixvalued Green's functions. To treat offdiagonal elements correctly based on Bayesian probability theory, the entropy term has to be extended for spectral functions that are possibly negative in some frequency ranges. In that way, all matrix elements of the Green's function matrix can be analytically continued; we introduce a computationally cheap elementwise method for this purpose. However, this method cannot ensure important constraints on the mathematical properties of the resulting spectral functions, namely positive semidefiniteness and Hermiticity. To improve on this, we present a full matrix formalism, where all matrix elements are treated simultaneously. We show the capabilities of these methods using insulating and metallic dynamical meanfield theory (DMFT) Green's functions as test cases. Finally, we apply the methods to realistic material calculations for LaTiO3, where offdiagonal matrix elements in the Green's function appear due to the distorted crystal structure.
Original language  English 

Article number  155128 
Number of pages  14 
Journal  Physical Review B 
Volume  96 
DOIs  
Publication status  Published  2017 
Fields of Expertise
 Advanced Materials Science
Treatment code (Nähere Zuordnung)
 Basic  Fundamental (Grundlagenforschung)
 Theoretical
Cooperations
 NAWI Graz
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Dive into the research topics of 'Maximum entropy formalism for the analytic continuation of matrixvalued Green’s functions'. Together they form a unique fingerprint.Projects
 2 Finished

FWF  TOPOMAT  Topological states of matter from first principles
1/11/14 → 31/10/22
Project: Research project

FWF  Thermangas  Thermoelectricity in Manganese Arsenides
1/04/14 → 31/03/17
Project: Research project