Spin-Exchange Induced Spillover on Poor Man's Majoranas in Minimal Kitaev Chains
Abstract
The "Poor Man's Majoranas" (PMMs) [Phys. Rev. B 86, 134528 (2012)] 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 [Nature 614, 445 (2023) and Nature 630, 329 (2024)]. Based on this scenario, we propose the spillover of the PMM when its QD is exchange coupled to a quantum spin . We show that if this QD is perturbed by the exchange coupling , solely the half of the fine structure stays explicit for a fermionic (bosonic) Concurrently, the other half squeezes itself as the delocalized MF zero-mode. Particularly, turning-off the superconductivity the multiplicity holds regardless the spin statistics. Meanwhile, the PMM spillover induced by 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.
Cite
@article{arxiv.2504.20321,
title = {Spin-Exchange Induced Spillover on Poor Man's Majoranas in Minimal Kitaev Chains},
author = {J. E. Sanches and L. T. Lustosa and L. S. Ricco and H. Sigurðsson and M. de Souza and M. S. Figueira and E. Marinho and A. C. Seridonio},
journal= {arXiv preprint arXiv:2504.20321},
year = {2025}
}