Better quantum physics undoubtedly results in better timing. But it’s also true that better clocks give us ‘better quantum’.
In 2023, a ‘better clock’ developed by EQUS researchers in the Quantum Technologies and Dark Matter Laboratory at UWA, was applied by EQUS researchers at the University of Sydney to significantly improve quantum computing performance.
EQUS researchers in the in the UWA Quantum Technologies and Dark Matter Laboratory (led by Michael Tobar and Maxim Goryachev) demonstrated a microwave oscillator with record-low phase noise, based on a cryogenic sapphire resonator.
The cryogenic sapphire oscillator is unique because it produces an extremely clean signal near 10 GHz, working by leveraging a resonance in a high-purity sapphire crystal cooled to about 5 Kelvin.
As part of a project funded by EQUS’ Translational Research Program, the team phase-referenced the microwave sapphire oscillator to a stable microwave source, demonstrating the device could be used as a high-performance frequency reference for advanced applications. Building on this, the current research focuses on achieving the best possible phase noise performance through novel approaches in vibration isolation and interferometric noise suppression. The developed vibration isolation techniques have broad applicability to other quantum systems that are limited by mechanical noise, while the interferometric noise suppression methods are relevant to a wide range of ultra-low-noise measurement systems, including those used in quantum technologies and fundamental physics experiments.
The new oscillator technology was commercialised by a company called QuantX, which had been involved throughout the TRP project.
One of the first applications of the improved timing system was in the trapped-ytterbium-ion system used to simulate chemical dynamics in the USYD Quantum Control Laboratory (led by EQUS’ Michael Biercuk).
Integrating the new oscillator into their trapped-ion quantum computer, the USYD team led by Ting Rei Tan was able to improve the qubit coherence time of a trapped ytterbium ion qubit by a factor of 10 over the previous system.
This significant improvement is enabled by the ultra-low-noise signal stemming from the new oscillator technology developed at UWA.
Following the improvement, the ytterbium qubit coherence time is approximately 8.7 seconds, which currently holds the world record for a ytterbium system.
Clocks flagship an outstanding collaborative environment
The work highlights the high levels of inter-node collaboration characterised by Clocks Flagship projects.
“When we look back in the future, a key legacy of EQUS will be having served as the ‘multiplier’ that brings together basic research in materials and scientific instrumentation, translation, and talented scientists to amplify the overall impact of quantum technologies.” – Dr Ting Rei Tan, University of Sydney
The Clock Flagship was envisioned as a two-way exchange: exploring how quantum systems can advance clocks, and how clocks can enhance quantum systems for broader applications. It created an outstanding collaborative environment, connecting all nodes of the Centre and enabling the free flow of materials, ideas, expertise, and people. All nodes actively collaborated on clock-related projects, leveraging complementary strengths to accelerate progress, particularly benefiting from UWA’s decades-long leadership in world-class timekeeping research.
Clock-related activities were further supported through initiatives such as the Translational Research Program, Early Career Researcher travel schemes, and regular collaborative meetings. The flagship’s lasting legacy is a strong, Australia-wide community dedicated to clocks and timekeeping, which has led to multiple joint inter-institutional grant proposals and ongoing collaborations. This momentum has also attracted interest from external partners, including international research groups and industry.
Low-noise oscillators are also vital components in radar, timing and communication networks, so the team’s work will potentially have wide-ranging application.
The team were also awarded further funding from EQUS’ Translational Research Program in 2023 to improve the microwave sapphire resonator, by using a new type of frequency reference and reducing phase noise further using interferometric feedback.