South Korean Researchers Develop 8-Photon Quantum Computing Chip

South Korean researchers at the Electronics and Telecommunications Research Institute (ETRI) have made a significant breakthrough in quantum computing. They successfully developed an integrated circuit chip that can control eight photons using a photonic integrated circuit chip. This achievement will enhance ETRI’s global competitiveness in quantum computation research.

The team, led by Lee Jong-Moo of ETRI’s Quantum Computing Research Section, demonstrated 6-qubit entanglement using a chip designed to control 8-photonic qubits, a record-breaking achievement in quantum states based on a silicon-photonic chip. This technology has the potential to enable the realization of a universal quantum computer, offering advantages in terms of scalability, room-temperature operation, and low energy consumption.

Yoon Chun-Ju, Assistant Vice President of ETRI’s Quantum Research Division, stated that the division’s main goal is to develop a lab-scale system to strengthen its research capabilities in quantum computation.

Photonic Quantum Circuits: A Breakthrough Towards Scalable Quantum Computation

The development of photonic quantum circuits has taken a significant leap forward with the successful demonstration of an 8-photon qubit chip by researchers at the Electronics and Telecommunications Research Institute (ETRI) in South Korea. This achievement is expected to enhance the team’s global competitiveness in quantum computation research.

Photonic quantum circuits are among the most promising technologies currently under active research for building a universal quantum computer. The advantages of photonic quantum computers lie in their scalability through optical networking, room-temperature operation, and low energy consumption. A photonic qubit can be encoded using a pair of propagation paths of a photon, with one path assigned as 0 and the other as 1. For a 4-qubit circuit, 8 propagation paths are required, and for 8 qubits, 16 paths are needed.

The 8-qubit chip developed by ETRI includes 8 photonic sources and approximately 40 optical switches that control the propagation paths of the photons. About half of these 40 switches are specifically used as linear-optic quantum gates. The setup provides the fundamental framework for a quantum computer by measuring the final quantum states using single-photon detectors.

Quantum States Generation and Manipulation

The research team has demonstrated the generation and manipulation of quantum states on the photonic chip, which includes photon sources, optical filters, and linear-optic switches. They have measured the Hong-Ou-Mandel effect, a fascinating quantum phenomenon in which two different photons entering from other directions can interfere and travel together along the same path.

In another notable experiment, they demonstrated a 4-qubit entangled state on a 4-qubit integrated circuit (5mm x 5mm). Recently, they have expanded their research to 8-photon experiments using an 8-qubit integrated circuit (10mm x 5mm). The researchers plan to fabricate 16-qubit chips within this year, followed by scaling up to 32-qubits as part of their ongoing research towards quantum computation.

Quantum Computing Research and Development

The development of practical quantum computers is highly active worldwide. However, extensive long-term research is still needed to realize practical quantum computation, especially to overcome computational errors caused by noise in the quantum processes. ETRI has achieved significant milestones in the field of quantum technology over the past decade, including the transmission of wireless quantum cryptography communication, development of quantum computing compiler technologies, and standardization of quantum cryptography transmission systems.

Currently, ETRI has emerged as a global leader, concentrating on quantum computation, communication, and sensors, with a strong emphasis on the development and commercialization of quantum technologies. The silicon photonics quantum chip research has been conducted as part of ETRI’s in-house New Concept Research Project, “Exploration of Silicon Photonics-Based Quantum Computer,” and is supported by the National Research Foundation of Korea as part of their Quantum Computing Development Project.

The successful demonstration of the 8-photon qubit chip marks a significant step towards the development of practical quantum computers. ETRI plans to advance its quantum hardware technology for a cloud-based quantum computing service, with the main goal of developing a lab-scale system to strengthen their research capabilities in quantum computation.

As researchers continue to push the boundaries of quantum technology, the potential applications of photonic quantum circuits are vast and varied. From secure communication networks to powerful computational systems, the future of quantum technology holds much promise for revolutionizing various fields.