South Korea’s Electronics and Telecommunications Research Institute (ETRI), in collaboration with KAIST and the University of Trento, has achieved a significant milestone in quantum computing by developing an integrated quantum circuit chip leveraging photons. This advancement firmly positions the team on the global stage of quantum computation research, marking a substantial leap in the pursuit of scalable quantum technologies.
The core of this innovation is an 8-photon silicon photonic integrated quantum circuit capable of achieving 6-qubit entanglement. This breakthrough is a precursor to the potential development of a 32-qubit system, further pushing the boundaries of quantum capability. The technology of silicon photonics quantum chips presents a groundbreaking approach to manipulating photonic qubits. Notable characteristics include scalability, room-temperature operation, and minimal energy consumption, which collectively make photonic quantum circuits a focal point of ongoing research aimed at universal quantum computers.
The chip operates by encoding photonic qubits along designated propagation paths—where one path signifies 0 and another signifies 1. This sophisticated design requires double the paths for the respective number of qubits, meaning an 8-qubit system demands 16 paths. These quantum states are manipulated on silicon-photonic chips that integrate photon sources, optical filters, and linear-optic switches. The culmination of this process is the measurement through highly sensitive single-photon detectors, which is essential for the proper functioning of the quantum circuit.
Breakthrough in Quantum Circuit Technology
ETRI’s prowess in quantum circuit technology is evident in their ability to control eight photons, facilitating the exploration of complex quantum phenomena such as multipartite entanglement. Their extensive research portfolio includes demonstrating 2-qubit and 4-qubit quantum entanglement, thereby pushing the performance limits of silicon photonics chips. Collaboration with KAIST and the University of Trento has resulted in publications in renowned scientific journals like Photonics Research and APL Photonics, underscoring the team’s contributions to the field.
By recently achieving a record 6-qubit entanglement using an 8-photon control chip, ETRI has paved the way for enhanced computing capabilities. This versatile 8-qubit chip features eight photonic sources and approximately 40 optical switches to manage photonic paths with precision. Half of these switches function as linear-optic quantum gates, providing the framework necessary for executing complex quantum algorithms. The process culminates in measurements conducted through single-photon detectors, which are integral to validating the chip’s quantum computing capabilities.
One of the key experiments conducted by ETRI involved the Hong-Ou-Mandel effect, a quantum phenomenon where two photons arriving from different paths interfere and subsequently share a common path. In addition to this, the team has demonstrated a 4-qubit entangled state on a smaller integrated circuit, successfully expanding their research scope to incorporate 8-photon experiments. Not resting on these accomplishments, ETRI plans to construct 16-qubit chips within the year and aims to eventually develop 32-qubit systems. This forward-looking vision aligns with their long-term objectives, which entail creating scalable quantum computation infrastructures that could revolutionize the field.
Quantum Circuit and Experimental Achievements
Another significant aspect of ETRI’s advancements is their successful demonstration of multipartite quantum phenomena. Their focus on controlling eight photons has allowed them to explore intricate quantum entanglement scenarios that are crucial for the development of future quantum technologies. The team’s dedicated efforts have resulted in notable achievements, such as the demonstration of 2-qubit and 4-qubit entanglements, which are considered fundamental prerequisites for more complex quantum computations.
ETRI’s record-setting demonstration of 6-qubit entanglement using an 8-photon control chip exemplifies their capability to push the limits of quantum technology. This advancement has significantly enhanced their computing capabilities, as the 8-qubit chip integrates eight photonic sources and roughly 40 optical switches. Among these, half serve as linear-optic quantum gates essential for implementing advanced quantum algorithms. These intricate processes are measured through highly sensitive single-photon detectors that ensure the accurate functioning of quantum circuits.
During one of their key experiments, ETRI explored the Hong-Ou-Mandel effect, where individual photons from different paths interfere and merge to follow a common path—this phenomenon underpins several quantum computing protocols. Furthermore, the successful demonstration of a 4-qubit entangled state on a smaller integrated circuit highlights ETRI’s expanding research capabilities. Their ambitions do not stop there; the team aims to build 16-qubit chips within the current year, further progressing towards 32-qubit systems. This continual advancement is aligned with their long-term goals of establishing scalable, robust quantum computation infrastructures.
Key Experiments and Future Goals
ETRI’s experimental prowess is further highlighted by their exploration of the Hong-Ou-Mandel effect, a pivotal quantum phenomenon. In this landmark experiment, two photons traveling from different directions interfere when they meet and consequently share a single path. This effect is critical for various quantum operations, thus making ETRI’s demonstration a significant milestone in quantum research. Additionally, ETRI successfully showcased a 4-qubit entangled state on a smaller circuit, signaling a step forward in their quest to master quantum entanglement at higher qubit levels.
Building on their recent successes, ETRI’s roadmap includes the ambitious goal of developing 16-qubit chips by the end of the year. The team has a clear vision to scale up to 32-qubit systems, which would mark a groundbreaking advancement in quantum computing. These developments are aligned with their long-term objectives of creating scalable quantum computation infrastructures. Their progress is not limited to chip development; ETRI also plans to advance their hardware technology to support cloud-based quantum computing services. With Assistant Vice President Yoon Chun-Ju at the helm, ETRI’s Quantum Research Division is committed to developing a robust lab-scale system aimed at fortifying research capacity in the domain of quantum computation.
Lee Jong-Moo from ETRI’s Quantum Computing Research Section underscores the global enthusiasm for practical quantum computing, highlighting the necessity of overcoming significant challenges, such as minimizing computational errors caused by quantum process noise. Addressing these challenges requires extensive and long-term research and development efforts, which ETRI is well-prepared to undertake.
Past Achievements and Institutional Support
ETRI’s history of achievements in quantum technology spans across multiple spheres over the past decade. They have successfully demonstrated wireless quantum cryptography communication over a distance of 100 meters and developed quantum computing compilers. Their collaboration with major Korean telecom operators has led to the standardization of quantum cryptography transmission systems. Moreover, they have created essential quantum internet technologies that operate at room temperature, verified cryptographic quantum security, and developed quantum algorithms for post-quantum cryptography. Notably, they have also acquired high-speed homomorphic encryption chip technology.
This legacy of technological prowess underscores ETRI’s global leadership in the realms of quantum computation, communication, and sensor technology development. Their commitment to making quantum technologies commercially viable is evident through their continuous innovation and strategic collaborations. The current quantum chip research is part of ETRI’s in-house “Exploration of Silicon Photonics-Based Quantum Computer” project, receiving significant support from Korea’s National Research Foundation as part of their Quantum Computing Development Project.
About ETRI
South Korea’s Electronics and Telecommunications Research Institute (ETRI), in partnership with KAIST and the University of Trento, has marked a significant advancement in quantum computing by creating an integrated quantum circuit chip that employs photons. This innovation positions the team prominently in the global quantum computation arena, marking a significant stride towards scalable quantum technologies.
Their key achievement is an 8-photon silicon photonic integrated quantum circuit capable of 6-qubit entanglement. This milestone serves as a stepping stone toward potentially developing a 32-qubit system, further expanding quantum computing capabilities. Silicon photonics quantum chips offer a novel way to manage photonic qubits. They are notable for their scalability, ability to operate at room temperature, and low energy consumption, making them central to ongoing research into universal quantum computers.
The chip functions by encoding photonic qubits along specific paths—one path indicates 0, another signifies 1. This intricate design requires double the paths of the number of qubits, so an 8-qubit system demands 16 paths. These quantum states are controlled on silicon photonic chips, which combine photon sources, optical filters, and linear-optic switches. The process is completed through measurements taken by highly sensitive single-photon detectors, which are crucial for the quantum circuit’s proper functioning.
