Emission and Coherent Control of Levitons in Graphene

TL;DR

This paper demonstrates the on-demand generation and manipulation of electronic flying qubits, called Levitons, in graphene, showcasing coherent control over propagating quantum states in a solid-state system.

Contribution

It introduces a method to inject and manipulate single Leviton states in graphene quantum Hall edge channels, advancing electronic flying qubit technology.

Findings

Successful on-demand injection of single Levitons.

Coherent manipulation of itinerant electronic states.

Potential for scalable quantum information processing.

Abstract

Flying qubits encode quantum information in propagating modes instead of stationary discrete states. Although photonic flying qubits are available, the weak interaction between photons limits the efficiency of conditional quantum gates. Conversely, electronic flying qubits can use Coulomb interactions, but the weaker quantum coherence in conventional semiconductors has hindered their realization. In this work, we engineered on-demand injection of a single electronic flying qubit state and its manipulation over the Bloch sphere. The flying qubit is a Leviton propagating in quantum Hall edge channels of a high-mobility graphene monolayer. Although single-shot qubit readout and two-qubit operations are still needed for a viable manipulation of flying qubits, the coherent manipulation of an itinerant electronic state at the single-electron level presents a highly promising alternative to conventional qubits.