Topological two-body bands in a multiband Hubbard model

Abstract

In a multiband Hubbard model the self-consistency relations for the two-body bound-state bands are in the form of a nonlinear eigenvalue problem. Assuming that the resultant eigenvectors form an orthonormal set, e.g., in the strong-binding regime, here we reformulate their Berry curvatures and the associated Chern numbers. As an illustration we solve the two-body problem in a Haldane-Hubbard model with attractive onsite interactions, and analyze its topological phase diagrams from weak to strong couplings, i.e., by keeping track of the gap closings in between the low-lying two-body bands. The resultant Chern numbers are consistent with the lobe structure of the phase diagrams in the strong-coupling regime.

arXiv comment9 pages with 2 figures (after first round of revision)

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Cited by in corpus (5)

• "Quantum Geometric Nesting" and Solvable Model Flat-Band Systems
• Topological pumping induced by spatiotemporal modulation of interaction
• Effects of Peierls phases in open linear chains
• Chern numbers for the two-body Hofstadter-Hubbard butterfly
• Topological two-body interaction obstructing trivial ground states: an indicator of fractional Chern insulators