Australian engineers have proven that a quantum version of computer code can be written, and manipulated, using two quantum bits in a silicon microchip.

The result was obtained by quantum computing specialists at the University of New South Wales who said this latest advance removed lingering doubts that operations like this can be made reliably enough to allow powerful quantum computers to become a reality.

The quantum code written by UNSW researchers is built on the ‘quantum entanglement’ phenomena where sub-atomic particles become so entwined that they share the same properties even when they have been separated.

This allows for counterintuitive phenomena such as the measurement of one particle instantly affecting another – even if they are at opposite ends of the universe.

“This effect is famous for puzzling some of the deepest thinkers in the field, including Albert Einstein, who called it ‘spooky action at a distance,’” said professor Andrea Morello of the School of Electrical Engineering & Telecommunications at UNSW.

“Einstein was skeptical about entanglement because it appears to contradict the principles of ‘locality’, which means that objects cannot be instantly influenced from a distance,” Morello said.

UNSW said physicists have struggled to establish a clear boundary between the everyday world and the strange quantum world. For 50 years, the best guide to this boundary has been the ‘Bell’s Inequality’ theorem, which says that no local description of the world can reproduce all of the predictions of quantum mechanics.

Bell’s Inequality demands a stringent test to verify if two particles are entangled, known as the ‘Bell test.’

“A key aspect of the Bell test is that it is extremely unforgiving: any imperfection in the preparation, manipulation and read-out protocol will cause the particles to fail the test,” said Dr Juan Pablo Dehollain, a UNSW research associate.

“Nevertheless, we have succeeded in passing the test, and we have done so with the highest score ever recorded in an experiment,” Dehollain said.