Extended Data Fig. 2: Energies of the many-body states in the interacting SSH model around quarter-filling.
From: Engineering topological states in atom-based semiconductor quantum dots
The energies of m + 4, m + 5, and m + 6 electron states for an array of 10 sites as a function of the tunnel coupling ratio, v/w. The energies are calculated at quarter-filling (that is, the ground state is always m + 5 electrons). The ground state evolves from a singly degenerate state for v/w > 1 (bulk-like states) to a two-fold degenerate m + 5 electron state for v/w < 1 (edge-like states). The quarter-filling energy gap between the m + 4 and m + 6 electron ground states reduces as v/w < 1 resulting in nearly degenerate states, reflecting the almost zero-energy cost associated with adding an electron to the topological phase of the array, with a small energy gap due to the inter-site Coulomb interactions.
