By Fractions of a Second

Quantum computing is an exciting field. Yet, this powerful technology is still riddled with limitations, thanks to the very nature of the quantum objects and the states they rely on. For one, the problem of maintaining "superposition" or extending the life of quantum bits (qubits) still persists – which is perhaps the biggest hurdle scientists have been trying to leap through when it comes to quantum computing.

But we may have actually taken a leap — or at least a huge step — in overcoming this problem, thanks to the work of researchers from the University of Sydney. They were actually able to 'see' the future of a quantum system.

In a study published in Nature Communications, the researchers discussed how they managed to accurately predict the decay of a quantum system (or decoherence), which entirely randomizes the quantum state and renders it useless. They even managed to prevent this breakdown from occurring.

"Much the way the individual components in mobile phones will eventually fail, so too do quantum systems," said senior author Michael J. Biercuk. "But in quantum technology the lifetime is generally measured in fractions of a second, rather than years."

It wasn't easy to do, explains Biercuk:

Humans routinely employ predictive techniques in our daily experience; for instance, when we play tennis we predict where the ball will end up based on observations of the airborne ball. But what if the rules changed randomly while the ball was on its way to you? In that case it's next to impossible to predict the future behavior of that ball. This situation is exactly what we had to deal with because the disintegration of quantum systems is random.

Credits: Michael Biercuk

A Sustainable Quantum Computing Future

The key was to come up with a system to predict when decoherence will occur. More than just predicting the decay of a quantum system, the researchers also wanted to figure out how to prevent it from happening. Thus, the team turned to machine learning and big data.

The team used a quantum model using trapped Ytterbium ions that represented the qubits. Their machine learning algorithm was trained to analyze this seemingly random behavior by giving it time-stamped measurements of qubits as they reached decoherence. And for a computer, it was possible to predict a quantum state's future even without direct observation.

According to the team, the predictions were very accurate. This allowed them to extend the useful life of qubits, using a bit of guesswork to compensate for the anticipated changes. Even better, their technique can be replicated and applied to any type of qubit designed by any particular technology, including those used by major corporations.

It's important to study this in order to understand just how well can we sustain qubits — and hopefully bring us closer to more practical quantum computers. Biercuk is hopeful. "We're excited to be developing new capabilities that turn quantum systems from novelties into useful technologies, he said. "The quantum future is looking better all the time."

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