A chain of three quantum dots coupled through a superconductor can mimic a topological superconductor and may host so-called poor man's Majorana modes, but conductance measurements alone cannot prove their non-local nature. Theorists propose current–current cross-correlations as a more reliable test.

They show that how robust these modes are, as the system is tuned away from its optimal 'sweet spot', is encoded in the relative strength of non-local transport processes, which cross-correlations capture well. Their features stay remarkably stable around the sweet spot, offering a diagnostic for true poor man's Majoranas even in short chains. QMAT's Pertti Hakonen of Aalto University co-authored the work with researchers at the Indian Institute of Technology Bombay and the Centre de Physique Théorique in Marseille.

The preprint has not yet been peer reviewed.

Figure: Patnaik et al., arXiv:2607.23498 (2026), CC BY 4.0