Parity flipping mediated by a quantum dot in Majorana Josephson junctions

TL;DR

This paper investigates how a quantum dot influences parity flipping in Majorana Josephson junctions, revealing Landau-Zener transitions and interference patterns that can serve as signatures of Majorana bound states.

Contribution

It introduces a quantum dot into Majorana Josephson junctions and studies the resulting parity flipping and interference phenomena, providing new detection signals for Majorana bound states.

Findings

Landau-Zener transitions induce parity flips in the junction.

Periodic QD modulation causes Landau-Zener-Stückelberg interference.

Distinct interference patterns depend on driving frequency.

Abstract

The detection of the Majorana bound states (MBSs) is a central issue in the current investigation of the topological superconductors, and the topological Josephson junction is an important system for resolving this issue. In this work, we introduce an external quantum dot (QD) to Majorana Josephson junctions (MJJs), and study the parity flipping of the junction induced by the coupling between the QD and the MBSs. We demonstrate Landau-Zener (LZ) transitions between opposite Majorana parity states when the energy level of the QD is modulated. The resulted parity flipping processes exhibit voltage signals across the junction. In the presence of a periodic modulation on the QD level, we show Landau-Zener-St\"{u}ckelberg (LZS) interference on the parity states. We demonstrate distinctive interference patterns at distinct driving frequencies. These results can be used as signals for detecting the existence of the MBSs.