Researchers at the National Astronomical Observatory of Japan (NAOJ) have made a groundbreaking discovery in the field of microwave technology. They have developed a novel microwave isolator that has the potential to revolutionize the development of quantum computers and large-scale radio cameras.
Isolators are crucial electronic components used to control the direction of signal propagation in various instruments, including quantum computers and radio receivers for astronomy. However, traditional isolators rely on magnetic materials, making it difficult to create miniaturized versions smaller than a few centimeters. This limitation poses a significant obstacle to the realization of large-scale quantum computers with one million qubits. To overcome this challenge, the research team at NAOJ has devised a new approach using frequency mixers.
By employing two sets of frequency mixers instead of magnetic materials, the researchers have successfully demonstrated the principle of the new isolator both theoretically and experimentally. This innovative circuit device operates in the microwave band and offers highly scalable circuits, presenting a significant breakthrough in electrical engineering. The key advantage of this new isolator is its ability to be integrated into a flat circuit on a printed circuit board, enabling miniaturization to the millimeter scale. Compared to conventional isolators, this represents a size reduction of 1,000 times in volume.
The NAOJ research team is now aiming to further enhance the capabilities of their isolator by developing a version that can also amplify signals. Currently, they are utilizing commercially available semiconductor mixers for frequency mixing, but they envision using superconductor-insulator-superconductor (SIS) mixers, which have built-in signal amplification capabilities. By incorporating SIS mixers, the researchers will be able to create a single device that serves both as an isolator and an amplifier.
The potential applications of this research extend to both radio wave observation equipment and quantum computers. The NAOJ, with its expertise in developing observational instruments for various wavelengths, is uniquely positioned to explore the convergence of these two fields. Their ongoing efforts include the establishment of the Social Implementation Program at the NAOJ Advanced Technology Center, which aims to drive technological advancements for the practical application of quantum computers. With their interdisciplinary approach, the research team is committed to pushing the boundaries of scientific innovation in radio astronomy and quantum computing.