Module 1 - Introduction

Photonic Quantum Computing

Our understanding of information processing has been transformed by quantum physics, which has enabled computation speedups to perform some tasks much faster with quantum computers than classical computers. By utilizing quantum effects such as superposition, entanglement, and interference, quantum computers can explore vast computational spaces and eventually find a solution for problems that are even unsolvable with ordinary computers.

The development and application of miniaturized complex integrated photonic interferometric chips have gained a promising role in quantum computing and in many relevant fields such as photonics neural networks and experimental quantum information processing and quantum simulation.

The availability of single-photon sources and detectors is already showing remarkable results, and a number of powerful techniques have been developed to fully characterize general quantum processes.

Quantum Integrated Photonics is expected to provide stable and mass-produced large-scale quantum information protocols, among others technologies for teleportation, logic gates, quantum networks and light manipulation.

Every Photonic Quantum Computer (PQC) is basically consist of 3 parts, including:

1. the non-classical photon sources which generate the input quantum light.
2. The quantum photonic processor, which is composed of interferometer arrays to manipulate the input quantum light and that's exactly where the computation goes on.
3. The Superconductor Nanowire Single Photon detectors, which determine the output result of the computation.

Additionally, using photonics technology for quantum computing would have the following advantages:

• The Photonic processors individually could operate in room-temperature operation and by now the only part of the system that needs the cryogenic temperature would be the single photon detector sources.
• Scalability and reconfigurability.
• Due to overlaps between the existing traditional photonics applications and technologies and the PQC chip development, technology maturity is already in a high level.
• According to experts, PQCs are among the rare platforms with quantum advantages (aka supremacy) over the other quantum hardware technologies.

This tutorial presents the fundamentals concepts of photonic quantum information processing where information is encoded in the photons' polarization. The basics of quantum integrated photonics chips as well as some applications are introduced. Furthermore, it is shown how these are of high interest in both industry and academia. The course includes interactive materials and interesting insights in the photonic quantum world.