Developing a Spin-Based Ultra-Low-Noise Amplifier for Microwave Quantum Technologies

While the quantum computing industry has been growing rapidly and advanced quantum technologies are finding many new applications, it has become critical to develop devices that will enable quantum hardware systems to be used to their full potential. As these systems evolve and scale toward useful applications, it is increasingly important that the signals used for computation and communication can be amplified while adding as little noise as possible. However, the currently available superconducting Josephson parametric amplifiers are susceptible to even modest static magnetic fields and they may suffer from limited saturation power when used for microwave-frequency signals. To amplify signals without adding noise in magnetic resonance spectrometers or superconducting quantum computers, which operate at microwave frequencies and at low temperatures, a new approach may be needed.

In a project supported by the OIST Proof of Concept (POC) Program, researchers from the OIST Hybrid Quantum Device Team led by Dr. Yuimaru Kubo are developing an ultra-low-noise amplifier based on the stimulated emission of impurity spins in gem crystals, such as ruby. By using this approach, Dr. Kubo's team is creating a new type of maser-based device that can amplify microwave signals at millikelvin temperatures and with a saturation power much larger than that of existing, state-of-the-art superconducting Josephson parametric amplifiers — without adding noise and even in a modest magnetic field.

Quantum computers and related technologies are expected to outperform the current state of the art when it comes to some difficult problems such as discovering new drugs and functional materials, but they could also transform fundamental research. As Dr. Kubo's team continues their work, they will be transforming this new amplifier from a prototype into a market-ready product and integrate it into commercial quantum instruments that will enable a new generation of microwave quantum technologies.

Find more information about this project in English and in Japanese.