Majorana zero modes in Y-shape interacting Kitaev wires

Motivated by recent experimental realizations of minimal Kitaev chains using quantum dots, the authors investigate Majorana zero modes (MZMs) in Y-shaped Kitaev wires. They solve the Kitaev model analytically at the sweet spot (t⊥ = Δ), deriving exact MZM wavefunctions in this geometry. They uncover exotic multi-site MZMs near the junction, located on nearby edge sites of each leg—an important result for braiding and Y-junction performance in quantum-dot arrays. Using density matrix renormalization group (DMRG), they study the stability of both single-site and multi-site MZMs under Coulomb repulsion. Site-resolved local density of states (LDOS) shows that multi-site MZMs are as topologically protected as single-site MZMs, including away from the sweet spot.