Available for quantum memory Australian team improves spectrometer accuracy by a factor of 1 million!

In a recent paper published in the journal Science Advances, Associate Professor Jarryd Pla's team from the School of Electrical Engineering and Telecommunications at the University of New South Wales, along with Scientia Professor Andrea Morello, describe a novel engineering device capable of measuring spin in materials with high precision.

"The spin of an electron, whether it is pointing up or down, is a fundamental property of nature," said A/Prof. Pla. "It is used in magnetic hard drives that store information, nuclear magnetic resonance machines use the spin of water molecules to create images of the inside of our bodies, and spin is even used to build quantum computers."

"So being able to detect spin inside materials is important for a range of applications, particularly in chemistry and biology, where it can be used to understand the structure and uses of materials, allowing us to design better chemicals, drugs and so on."

In research fields such as chemistry, biology, physics and medicine, the tools used to measure spin are called spin resonance spectrometers. Typically, commercially produced spectrometers require billions to trillions of spins to get accurate readings, but Professor A/Pla and his colleagues were able to measure thousands of orders of magnitude of electron spins, meaning the new tool is about a million times more sensitive.

Jarryd Pla

This is quite a feat, as there are a range of systems that cannot be measured with commercial tools, such as microscopic samples, two-dimensional materials and high-quality solar cells that have too little spin to produce a measurable signal.

The breakthrough happened almost by accident, as the team was developing a quantum memory element for a superconducting quantum computer. The goal of the memory element is to transfer quantum information from a superconducting circuit to an aggregate of spins placed beneath the circuit.

"We noticed that while the device did not work exactly as planned as a memory element, it was very good at measuring the spin ensemble," said Wyatt Vine, the study's lead author. "We found that by sending microwave power to the device when the spin sends a signal, we can amplify the signal before it leaves the device. What's more, this amplification can be done with very little additional noise, almost to the limit set by quantum mechanics."

While other high-sensitivity spectrometers using superconducting circuits have been developed in the past, they require multiple components, are incompatible with magnetic fields, and must operate in very cold environments with expensive dilution chillers that can reach temperatures as low as 0.01 Kelvin.

Device design and resonator characterization.

In this new development, Prof. Pla says he and his team have succeeded in integrating these components on a single chip.

"Our new technique integrates several important parts of the spectrometer into a single device and is compatible with relatively large magnetic fields. This is important because measuring spins they need to be placed in a magnetic field of about 0.5 Tesla, which is 10,000 times stronger than the Earth's magnetic field."

"In addition, our device operates at temperatures more than 10 times higher than previous demonstrations, which means we don't need to use dilution chillers."

Professor Pla said the UNSW team had patented the technology with a view to potential commercialization, but stressed that there was still work to be done.

"There is the potential to package and commercialise this, which would enable other researchers to plug it into their existing commercial systems, allowing them to get a sensitivity increase."

"If this new technology is properly developed, it could help chemists, biologists and medical researchers who currently rely on these tools made by large technology companies that are effective, but could do better."