Generating Majorana qubit coherence in Majorana Aharonov-Bohm interferometer

TL;DR

This paper proposes an Aharonov-Bohm interferometer with topological superconducting chains to generate and control Majorana qubit coherence, demonstrating tunable decoherence rates and the creation of superposition states.

Contribution

It introduces a novel interferometer setup and provides an exact master equation to analyze Majorana qubit dynamics and coherence control.

Findings

Magnetic flux tuning significantly affects decoherence rates.

Dissipationless Majorana zero modes can be generated.

Majorana qubit superpositions can be manipulated via bias voltages.

Abstract

We propose an Aharonov-Bohm interferometer consisted of two topological superconducting chains (TSCs) to generate coherence of Majorana qubits, each qubit is made of two Majorana zero modes (MZMs) with the definite fermion parity. We obtain the generalized exact master equation as well as its solution and study the real-time dynamics of the MZM qubit states under various operations. We demonstrate that by tuning the magnetic flux, the decoherence rates can be modified significantly, and dissipationless MZMs can be generated. By applying the bias voltage to the leads, one can manipulate MZM qubit coherence and generate a nearly pure superposition state of Majorana qubit. Moreover, parity flipping between MZM qubits with different fermion parities can be realized by controlling the coupling between the leads and the TSCs through gate voltages.