Diagrammatic content of the dynamical mean-field theory for the Holstein polaron problem in finite dimensions (CROSBI ID 135656)
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Podaci o odgovornosti
Barišić, Osor Slaven
engleski
Diagrammatic content of the dynamical mean-field theory for the Holstein polaron problem in finite dimensions
In the context of the Holstein polaron problem it is shown that the dynamical mean field theory (DMFT) corresponds to the summation of a special class of local diagrams in the skeleton expansion of the self-energy. In the real space representation, these local diagrams are characterized by the absence of vertex corrections involving phonons at different lattice sites. Such corrections vanish in the limit of infinite dimensions, for which the DMFT provides the exact solution of the Holstein polaron problem. However, for finite dimensional systems the accuracy of the DMFT is limited. In particular, it cannot describe correctly the adiabatic spreading of the polaron over multiple lattice sites. Arguments are given that the DMFT limitations on vertex corrections found for the Holstein polaron problem persist for finite electron densities and arbitrary phonon dispersion.
dynamical mean field theory; skeleton expansion; finite dimensions; polaron
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Podaci o izdanju
76 (19)
2007.
193106-1-193106-4
objavljeno
1098-0121
10.1103/PhysRevB.76.193106