KAIST Achieves 3D Cluster 'Quantum Entanglement' State Implementation

KAIST announced on the 25th that the research team led by Professor Young-Sik Ra from the Department of Physics has succeeded in experimentally realizing a three-dimensional cluster quantum entanglement state, which is a core technology for quantum error correction.

(From left) Yoon Young-do, Integrated MS-PhD Program, Department of Physics, KAIST; Noh Chan, Integrated MS-PhD Program; Professor Ra Young-sik; Kwak Geun-hee, Integrated MS-PhD Program. Provided by KAIST

Quantum computing is a quantum technology that can efficiently solve problems that are difficult for classical computers to compute. To perform complex calculations accurately, quantum computers must correct quantum errors that occur during the computation process. However, implementing quantum entanglement states has long been considered a significant challenge.

In particular, measurement-based quantum computing is a new paradigm of quantum computing that implements quantum operations by measuring cluster states with special quantum entanglement structures, and the creation of cluster quantum entanglement states is considered essential. Two-dimensional cluster states are used for universal quantum computing.

On the other hand, to advance to fault-tolerant quantum computing that can correct quantum errors occurring in quantum operations, a more complex three-dimensional cluster state structure is required.

However, previous studies have mainly reported the creation of two-dimensional cluster states, and the three-dimensional cluster states necessary for fault-tolerant quantum computing have not been experimentally realized due to the highly complex structure of quantum entanglement.

To overcome this, the research team developed a technology to implement quantum entanglement by controlling femtosecond time-frequency modes and succeeded in generating a three-dimensional cluster quantum entanglement state.

A femtosecond laser is a device that emits strong light pulses in an extremely short time, and the research team incident femtosecond laser pulses into a nonlinear crystal to simultaneously generate quantum light sources in multiple frequency modes. Using this, they were able to generate three-dimensional cluster quantum entanglement.

Professor Young-Sik Ra said, "This research is the first case of successfully creating a three-dimensional cluster quantum entanglement state, which was difficult to realize with existing technologies," and added, "It is expected to be an important stepping stone for future research on measurement-based quantum computing and fault-tolerant quantum computing."

Meanwhile, this research was conducted with support from the National Research Foundation of Korea, the Institute for Information & Communications Technology Planning & Evaluation, and the U.S. Air Force Research Laboratory.

This content was produced with the assistance of AI translation services.