Study finds clue to ‘practical’ quantum computers

A joint team of researchers in South Korea and Italy have pulled off generating a hybrid entanglement of classical and quantum states of light, which could lead to developing a practical quantum computer, the Ministry of Science, ICT and Future Planning said Sunday.

According to scientists from Korea and Italy, the entanglement between quantum and classical objects has been crucial in understanding quantum mechanics and applying it to information processing. Quantum entanglement refers to a state when pairs or groups of particles interact so that a quantum state of each particle cannot be described independently.

In quantum information processing, the coherent state of light, or what is called classical state, allows efficient calculation but the transmission of information is difficult. It is the opposite with the quantum state, with the quantum bit ― or qubit, a unit of information ― being easily transmitted, but more prone to errors.

A hybrid entanglement between the two states could theoretically allow quantum information processing that is both accurate and quick, according to a team led by Jeong Hyun-seok, an associate professor of physics at the Seoul National University. Jeong’s team worked with a scientists led by Marco Bellini of Istituto Nazionale di Ottica for the study.

The problem is that it’s extremely difficult to induce an interaction between the two states. While it had been possible to cause these two states of light to interact, it was impossible to generate an entanglement.

By using the principle of superposition, the researchers managed to implement a coherent superposition of two distinct quantum operations.

“By implementing an entanglement between these two materials that have different characteristics, we’ve managed to take a big step toward developing a practical quantum computer that far surpasses the proficiency of existing computers,” said Jeong. He added, however, that it would take at least 10 years of further research to apply the findings for commercial use.

The research, named “Generation of hybrid entanglement of light,” was to run on the online edition of Nature Photonics, and will also be published on the July edition of the scientific journal.

By Yoon Min-sik (minsikyoon@heraldcorp.com)