Quantum Computing Breakthrough Brings Ultra-Powerful Machines Closer to the Real World

quantum computing breakthrough qubit microsoft sydney
A prototype of the microwave circulator, shown next to a coin. The component is 1,000-times smaller than its predecessors. Alice Mahoney/ University of Sydney

Researchers have invented a device considered crucial for scaling up quantum computing, potentially paving the way for scientific breakthroughs using the ultra-powerful machines on an unprecedented scale.

A team from the University of Sydney, Australia, and Microsoft created a component capable of being manufactured in large quantities for quantum computers, which until now have been the exclusive domain of major companies and organizations like NASA, Google and the CIA.

The breakthrough, detailed in a paper published in the journal Nature Communications, means a key component in quantum computers—known as a microwave circulator—can be miniaturized by a factor of 1,000.

They achieved this by exploiting the properties of topological insulators—a newly discovered phase of matter that earned the scientists who discovered it the 2016 Nobel Prize in Physics. The shrinked device can fit hundreds of thousands of the fundamental part of quantum computers: Qubits.

Quantum computers don't use traditional bits—the "ones" and "zeros" used in digital communications—and instead use quantum bits, or qubits. Qubits exist in a state of superposition, meaning they can be in two states at once—both a "one" and a "zero"—rather than being restricted to a single binary state in the way traditional computers function.

"It is not just about qubits, the fundamental building blocks for quantum machines. Building a large-scale quantum computer will also need a revolution in classical computing and device engineering," said David Reilly, a professor at the University of Sydney.

"Even if we had millions of qubits today, it is not clear that we have the classical technology to control them. Realizing a scaled-up quantum computer will require the invention of new devices and techniques at the quantum-classical interface."

The scientists say the advance brings forward the real-world potential of quantum computers, solving computing challenges that are currently beyond the reach of today's fastest supercomputers.

Since they were first theorized by the physicist Richard Feynman in 1982, quantum computers have promised to bring about a new era of ultra-powerful computing. One of the field's pioneers, physicist David Deutsch, famously claimed that quantum computers hold the potential to solve problems that would take a classical computer longer than the age of the universe.

"Such compact circulators could be implemented in a variety of quantum hardware platforms, irrespective of the particular quantum system used," said the study's lead author, Alice Mahoney.