Félix Fossati | Searcharxiv

arXiv2026

Emergent Topology from Nonlocal Electronic Correlations in One Dimension

We demonstrate that electronic correlations in low-dimensional systems can induce topological phases starting from a topologically trivial noninteracting band structure. Using an advanced cluster-diagrammatic many-body approach applied to the one-dimensional extended Hubbard model, we show that tuning the nonlocal Coulomb interaction drives the emergence of bond-order-wave (BOW) and charge-density-wave (CDW) phases. Despite being interaction-driven and symmetry-broken, these states admit an effective low-energy single-particle description. In particular, the BOW phase maps onto an effective Su-Schrieffer-Heeger model, while the CDW phase, with subleading bond-order correlations, corresponds to a Rice-Mele model. Both phases exhibit a nontrivial topological character, manifested by the presence of localized edge states. Our results establish a mechanism by which nonlocal electronic correlations generate emergent topology in correlated systems.

cond-mat.str-el↗

arXiv2026

Dual-space cluster-diagrammatic approach to nonlocal electronic correlations

In this work, we extend the dual triply irreducible local expansion (D-TRILEX) approach for correlated electronic systems by introducing a cluster reference system for the diagrammatic expansion. This framework allows us to consistently combine the exact treatment of short-range correlation effects within the cluster, with an efficient diagrammatic description of the long-range charge and spin collective fluctuations beyond the cluster. We demonstrate the effectiveness of our approach by applying it to the one-dimensional nano-ring Hubbard model, where the low dimensionality enhances non-local correlations. Our results show that the cluster extension of D-TRILEX accurately reproduces the electronic self-energy at momenta corresponding to the Fermi energy, in good agreement with the reliable Hirsch-Fye quantum Monte Carlo solution of the problem. We further compare this method with the more computationally demanding parquet dynamical vertex approximation and find that, our method yields substantially more accurate results at momenta associated with the Fermi surface. We show that the D-TRILEX diagrammatic extension drastically reduces the periodization ambiguity of cluster quantities when mapping back to the original lattice, compared to cluster dynamical mean-field theory (CDMFT). Furthermore, we identify the CDMFT impurity problem as the main source of the translational-symmetry breaking and propose a computational scheme for improving the starting point for the cluster-diagrammatic expansion.

cond-mat.str-el↗