# Mott physics and collective modes: an atomic approximation of the four-particle irreducible functional

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Abstract : We discuss a generalization of the dynamical mean field theory (DMFT) for strongly correlated systems close to a Mott transition based on a systematic approximation of the fully irreducible four-point vertex. It is an atomic-limit approximation of a functional of the one- and two-particle Green functions, built with the second Legendre transform of the free energy with respect to the two-particle Green function. This functional is represented diagrammatically by four-particle irreducible (4PI) diagrams. Like the dynamical vertex approximation (D$\Gamma$A), the fully irreducible vertex is computed from a quantum impurity model whose bath is self-consistently determined by solving the parquet equations. However, in contrast with D$\Gamma$A and DMFT, the interaction term of the impurity model is also self-consistently determined. The method interpolates between the parquet approximation at weak coupling and the atomic limit, where it is exact. It is applicable to systems with short-range and long-range interactions.
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Cited literature [12 references]

https://hal-cea.archives-ouvertes.fr/cea-01341620
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Submitted on : Monday, July 4, 2016 - 2:57:12 PM
Last modification on : Wednesday, April 14, 2021 - 12:11:43 PM
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1605.09048v1.pdf
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• HAL Id : cea-01341620, version 1
• ARXIV : 1605.09048

### Citation

Thomas Ayral, Olivier Parcollet. Mott physics and collective modes: an atomic approximation of the four-particle irreducible functional. 2016. ⟨cea-01341620⟩

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