Year: 2025
Type: article
Abstract: The ‘poor man’s Majoranas’ (PMMs) (Leijnse and Flensberg 2012 Phys. Rev. B 86 134528) devoid of topological protection can ‘spill over’ from one edge into another of the minimal Kitaev chain when perturbed electrostatically. As aftermath, this leads to a delocalized Majorana fermion (MF) at both the edges. Additionally, according to recent differential conductance measurements in a pair of superconducting and spinless quantum dots (QDs), such a PMM picture was brought to reality (Dvir et al 2023 Nature 614 445; ten Haaf et al 2024 Nature 630 329). Based on this scenario, we propose the spillover of the PMM when its QD is exchange coupled to a quantum spin S. We show that if this QD is perturbed by the exchange coupling J, solely the half 2 S + 1 ( 2 S + 2 ) of the fine structure stays explicit for a fermionic (bosonic) S . Concurrently, the other half squeezes itself as the delocalized MF zero-mode. Particularly, turning-off the superconductivity the multiplicity 2 S + 1 holds regardless the spin statistics. Meanwhile, the PMM spillover induced by J becomes a statistics dependent effect. Hence, our findings contribute to the comprehension of spin-phenomena interplay with superconductivity in minimal Kitaev chains, offering insights for future quantum computing devices hosting PMMs.
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4409546532