A joint research team from Korea and the United States has unveiled a technology to implement quantum computer operations using a relatively common material, magnet, for the first time in the world.
Korea Advanced Institute of Science and Technology (KAIST) announced on the 6th that a research team led by Professor Kim Gap-jin of the Department of Physics has successfully developed a 'photon-magnon hybrid chip' in collaboration with Argonne National Laboratory and the University of Illinois Urbana-Champaign, and has been the first in the world to realize real-time implementation of multi-pulse interference phenomena.
The research results were published last month in the international journals 'NPJ Spintronics' and 'Nature Communications.'
Magnons are states in which the spins of several atoms oscillate collectively when grouped together. In quantum mechanics, which pertains to the microscopic world, spin refers to an intrinsic angular momentum independent of the motion of the particle. It is similar to a small magnet at the atomic level. Magnons have non-reciprocal properties, allowing information to be transmitted in one direction only, which can be utilized in the development of quantum chips that block noise (unwanted signals), and can also be applied as quantum communication devices that transmit quantum information over tens of kilometers. However, there are limitations in the technologies needed to control magnons' phase information.
The researchers arranged two yttrium iron garnet (YIG) magnetic beads at a 12 mm interval and installed superconducting resonators, circuits used in quantum computers such as those made by Google and IBM, between them. They then conducted experiments by inputting signals into one magnet to see if the information could be transmitted to the other magnet. As a result, they confirmed that signals from as short as a few nanoseconds (one billionth of a second) to longer microwave signals could be transmitted without loss.
The researchers emphasized that this experiment demonstrated for the first time in the world that magnets could be utilized as a core component of quantum operations. They expressed hope that this research achievement will contribute to the development of quantum computers made of magnetic materials.
Professor Kim noted, 'We have opened possibilities in the new research field of quantum spintronics,' and said, 'I expect this will be an important turning point for the development of efficient quantum information processing devices.'
References
Nature Communications (2025), DOI: https://doi.org/10.1038/s41467-025-58482-2
npj Spintronics (2025), DOI: https://doi.org/10.1038/s44306-025-00072-5