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Pairing and charge-density-wave correlations in the Holstein model at half-filling

1990; American Physical Society; Volume: 42; Issue: 4 Linguagem: Inglês

10.1103/physrevb.42.2416

1095-3795

F. Marsiglio,

Quantum, superfluid, helium dynamics

We study the two-dimensional Holstein model at half-filling for small systems using quantum Monte Carlo methods and through diagrammatic perturbation techniques in the Migdal-Eliashberg approximation. It is found that the latter approximation is very accurate as long as the phonon self-energy is taken into account in a self-consistent way. Vertex corrections are not required.