Dynamical vertex approximation in its parquet implementat ion: application to Hubbard nano-rings

Author(s): A. Valli, T. Schäfer, P. Thunström, G. Rohringer, S. Andergassen, G. Sangiovanni, K. Held, A. Toschi

Journal: Phys. Rev. B

Volume: 91

Page(s): 115115

Year: 2015

DOI Number: 10.1103/PhysRevB.91.115115

Link: Link to publication

Abstract:

We have implemented the dynamical vertex approximation (DΓA) in its full parquet-based version to include spatial correlations on all length scales and in all scattering channels. The algorithm is applied to study the electronic self-energies and the spectral properties of finite-size one-dimensional Hubbard models with periodic boundary conditions (nanoscopic Hubbard rings). From a methodological point of view, our calculations and their comparison to the results obtained within dynamical mean-field theory, plain parquet approximation, and the exact numerical solution allow us to evaluate the performance of the DΓA algorithm in the most challenging situation of low dimensions. From a physical perspective, our results unveil how nonlocal correlations affect the spectral properties of nanoscopic systems of various sizes in different regimes of interaction strength.

Note: http://arxiv.org/abs/1410.4733

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