October 16, 2024 -- A major challenge in realizing quantum computers is the development of quantum error correction technology. This technology offers a solution for addressing errors that occur in the qubit, the basic unit of quantum computation, and prevents them from being amplified during the computation.

Without quantum error correction, it would be impossible for quantum computers to outperform their classical counterparts, and thus efforts to advance this technology are ongoing worldwide.

Dr. Seung-Woo Lee's research team at the Korea Institute of Science and Technology (KIST)'s Quantum Technology Research Center has developed the world's first hybrid quantum error correction technique for discrete variables (DV) and continuous variables (CV), and designed a fault-tolerant quantum computing architecture based on hybrid technique.

The findings are published in the journal PRX Quantum.

Qubits implementing quantum error correction are called logical qubits, and they can be realized in two different ways: Discrete Variable (DV) and Continuous Variable (CV). Companies such as IBM, Google, Quera, and PsiQuantum are developing quantum computers using the DV method, while Amazon (AWS), Xanadu, and others are adopting the CV method. Each of these two approaches has advantages and disadvantages regarding manipulation difficulty and resource efficiency.

KIST researchers have proposed a method to integrate the error correction of DV and CV qubits, which were previously developed separately. They developed a fault-tolerant architecture based on the hybrid technology and demonstrated through numerical simulations that it combines the advantages of both methods, enabling more efficient and effective quantum computation and error correction.

In particular, in optical quantum computing, the hybrid approach can achieve the photon loss threshold up to four times higher than existing techniques and can improve resource efficiency by more than 13 times while maintaining the same level of logic error rate.

"The hybrid quantum error correction technology developed in this study can be combined not only with optical systems but also with superconductors and ion trap systems," said Dr. Jaehak Lee of KIST.

"This research provides a new direction for the development of quantum computing," said Dr. Seung-Woo Lee of KIST, who led the research. "Hybrid technologies that integrate the advantages of different platforms are expected to play a crucial role in developing and commercializing large-scale quantum computers."