Demonstration of active feedforward one-way quantum computing with photon-matter hyperentanglement

TL;DR

This paper demonstrates an active feedforward one-way quantum computing experiment using a hybrid cluster state with photons and atomic ensemble quantum memory, enabling deterministic single-qubit rotations.

Contribution

It introduces a hybrid four-qubit cluster state combining photonic and stationary qubits, and demonstrates memory-assisted feedforward operations in one-way quantum computing.

Findings

Successful creation of a hybrid four-qubit cluster state

Implementation of deterministic single-qubit rotation

First demonstration of active feedforward in hybrid quantum systems

Abstract

We report an optical one-way quantum computing experiment with stationary quantum memory involved. First we create a hybrid four-qubit cluster state with two qubits propagating as photons and the other two stationary and stored in a laser-cooled atomic-ensemble quantum memory, and characterize it with entanglement witness and quantum state tomography. Then, by making use of this cluster state and fast operations of electro-optic modulators, we realize memory-assisted feedforward operations and demonstrate deterministic single-qubit rotation as an example.