Quantum capacitance and parity switching of a quantum-dot-based Kitaev chain

TL;DR

This paper investigates the quantum capacitance and parity switching in a quantum-dot-based Kitaev chain, providing insights into topological quantum computing and identifying signatures of Majorana modes.

Contribution

It offers a theoretical analysis of quantum capacitance in a Kitaev chain, revealing how it can identify the chain's optimal operating point and elucidate parity switching mechanisms.

Findings

Quantum capacitance helps identify the Kitaev chain's sweet spot.

Charge stability diagrams correlate with tunnel spectroscopy results.

Parity switching involves coupling to leads and quasiparticle poisoning.

Abstract

An array of quantum dots coupled via superconductivity provides a new platform for creating Kitaev chains with Majorana zero modes, offering a promising avenue toward topological quantum computing. In this work, we theoretically study the quantum capacitance of a minimal Kitaev chain weakly coupled to an external normal lead. We find that in the open regime, charge stability diagrams of quantum capcaitance can help to identify the sweet spot of a Kitaev chain, consistent with tunnel spectroscopy. Moreover, the quantum capacitance of a single quantum dot coupled to Andreev bound states reveals the interplay between two distinct parity switching mechanisms: coupling to an external normal lead and intrinsic quasiparticle poisoning. Our work provides useful physical insights into the quantum capacitance and parity dynamics in a quantum-dot-based Kitaev chain device.