Flux-controlled quantum computation with Majorana fermions

TL;DR

This paper proposes a flux-controlled method for braiding and readout of Majorana-based topological qubits, enabling scalable quantum operations and error correction without microscopic tunnel control.

Contribution

It introduces a minimal circuit for Majorana braiding and measurement, and the Random Access Majorana Memory for scalable multi-qubit parity measurements.

Findings

Flux-controlled braiding and readout demonstrated

Scalable circuit for multi-qubit parity measurement proposed

Enhanced quantum error correction protocols enabled

Abstract

Majorana fermions hold promise for quantum computation, because their non-Abelian braiding statistics allows for topologically protected operations on quantum information. Topological qubits can be constructed from pairs of well-separated Majoranas in networks of nanowires. The coupling to a superconducting charge qubit in a transmission line resonator (transmon) permits braiding of Majoranas by external variation of magnetic fluxes. We show that readout operations can also be fully flux-controlled, without requiring microscopic control over tunnel couplings. We identify the minimal circuit that can perform the initialization--braiding--measurement steps required to demonstrate non-Abelian statistics. We introduce the Random Access Majorana Memory, a scalable circuit that can perform a joint parity measurement on Majoranas belonging to a selection of topological qubits. Such multi-qubit measurements allow for the efficient creation of highly entangled states and simplify quantum error correction protocols by avoiding the need for ancilla qubits.