Silicon photonic processor of two-qubit entangling quantum logic

TL;DR

This paper presents a silicon photonic chip capable of generating, manipulating, and analyzing two-qubit entangled states, advancing integrated quantum photonics for scalable quantum information processing.

Contribution

It introduces a silicon photonic device with integrated photon sources, a reconfigurable interferometer, and a switchable entangling gate, enabling on-chip quantum state control.

Findings

Successful generation of various entangled states

Demonstration of a switchable controlled-Z gate

On-chip quantum state analysis via tomography

Abstract

Entanglement is a fundamental property of quantum mechanics, and is a primary resource in quantum information systems. Its manipulation remains a central challenge in the development of quantum technology. In this work, we demonstrate a device which can generate, manipulate, and analyse two-qubit entangled states, using miniature and mass-manufacturable silicon photonics. By combining four photon-pair sources with a reconfigurable six-mode interferometer, embedding a switchable entangling gate, we generate two-qubit entangled states, manipulate their entanglement, and analyse them, all in the same silicon chip. Using quantum state tomography, we show how our source can produce a range of entangled and separable states, and how our switchable controlled-Z gate operates on them, entangling them or making them separable depending on its configuration.