Top-transmon: hybrid superconducting qubit for parity-protected quantum computation

TL;DR

This paper proposes a hybrid superconducting transmon qubit system that enables parity-protected quantum operations on topological qubits, offering improved noise resilience and precise control for quantum computing.

Contribution

It introduces a novel approach combining transmon qubits with topological qubits to achieve parity-protected operations with switchable coupling and reduced charge noise sensitivity.

Findings

Coupling can be switched on and off with exponential accuracy.

Enhanced protection against charge noise compared to flux qubit-based methods.

Potential for more robust topological quantum computation.

Abstract

Qubits constructed from uncoupled Majorana fermions are protected from decoherence, but to perform a quantum computation this topological protection needs to be broken. Parity-protected quantum computation breaks the protection in a minimally invasive way, by coupling directly to the fermion parity of the system --- irrespective of any quasiparticle excitations. Here we propose to use a superconducting charge qubit in a transmission line resonator (a socalled transmon) to perform parity-protected rotations and read-out of a topological (top) qubit. The advantage over an earlier proposal using a flux qubit is that the coupling can be switched on and off with exponential accuracy, promising a reduced sensitivity to charge noise.