Probing Majorana localization in minimal Kitaev chains through a quantum dot

Abstract

Artificial Kitaev chains, formed by quantum dots coupled via superconductors, have emerged as a promising platform for realizing Majorana bound states. Even a minimal Kitaev chain (a quantum dot--superconductor--quantum dot setup) can host Majorana states at discrete sweet spots. However, unambiguously identifying Majorana sweet spots in such a system is still challenging. In this work, we propose an additional dot coupled to one side of the chain as a tool to identify good sweet spots in minimal Kitaev chains. When the two Majorana states in the chain overlap, the extra dot couples to both and thus splits an even--odd ground-state degeneracy when its level is on resonance. In contrast, a ground-state degeneracy will persist for well-separated Majorana states. This difference can be used to identify points in parameter space with spatially separated Majorana states, using tunneling spectroscopy measurements. We perform a systematic analysis of different relevant situations. We show that the additional dot can help distinguishing between Majorana sweet spots and other trivial zero-energy crossings. We also characterize the different conductance patterns, which can serve as a guide for future experiments aiming to study Majorana states in minimal Kitaev chains.

10 pages, 7 figures

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Cited by in corpus (33)

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• Robustness of Majorana edge states of short-length Kitaev chains coupled with environment
• Fate of poor man's Majoranas in the long Kitaev chain limit
• Quantum-dot-based Kitaev chains: Majorana quality measures and scaling with increasing chain length
• Interplay between Majorana and Shiba states in a minimal Kitaev chain coupled to a superconductor
• Machine-learned tuning of artificial Kitaev chains from tunneling-spectroscopy measurements
• Majorana sweet spots in 3-site Kitaev chains
• Coupling of quantum-dot states via elastic-cotunneling and crossed Andreev reflection in a minimal Kitaev chain
• Non-Hermitian minimal Kitaev chains
• Emergent pair symmetries in systems with poor man's Majorana modes
• Interaction-induced strong zero modes in short quantum dot chains with time-reversal symmetry
• Scaling up a sign-ordered Kitaev chain without magnetic flux control
• Subgap states in semiconductor-superconductor devices for quantum technologies: Andreev qubits and minimal Majorana chains
• Nonlocal correlations transmitted between quantum dots via short topological superconductor
• Braiding Majoranas in a linear quantum dot-superconductor array: Mitigating the errors from Coulomb repulsion and residual tunneling
• Spin-Exchange Induced Spillover on Poor Man's Majoranas in Minimal Kitaev Chains
• Nonlocal Josephson diode effect in minimal Kitaev chains
• Effect of interatomic repulsion on Majorana zero modes in a coupled quantum-dot-superconducting-nanowire hybrid system
• Characterizing local Majorana properties using Andreev states
• Entangled states from arborescent knots
• Properties and prevalence of false poor man's Majoranas in two- and three-site artificial Kitaev chains
• Revisiting the Poor Man's Majoranas: The Spin-Exchange Induced Spillover Effect
• Entangling gates from cabling of knots
• Signatures of quantum phases in a dissipative system
• Quantifying robustness and locality of Majorana bound states in interacting systems
• Interplay of correlations and Majorana mode from local solution perspective
• Entanglement dynamics in minimal Kitaev chains
• Optimal Majoranas in Mesoscopic Kitaev Chains
• Quantum capacitance and parity switching of a quantum-dot-based Kitaev chain
• Distinguishing Majorana bound states from accidental zero-energy modes with a microwave cavity