Scientists claim major quantum computing milestone after getting two silicon qubits to communicate with each other

Scientists in Australia have found a way to pair two quantum qubits

Scientists in Australia have reached what they claim is a "major quantum computing milestone" after getting two silicon qubits to communicate with each other.

Led by researchers at University of New South Wales, the project was aimed at transforming the way that atom qubits interact on silicon. The researchers claimed that they were able to "see the exact position of their qubits in the solid state".

The team explained that it created the atom qubits by "precisely positioning and encapsulating individual phosphorus atoms within a silicon chip". Information is stored on a single phosphorus electron.

According to researchers, this is the first ever "observation of controllable interactions between two of these qubits". They have published the findings in the academic journal Nature Communications.

Feynman said: 'What I cannot create, I do not understand'. We are enacting that strategy systematically, from the ground up, atom by atom

In the past, the scientists said they used this "unique approach" to build a quantum computer from scratch.

However, they have now been able to utilise a nano-manufacturing process to develop so-called "quantum circuitry".

The scientists discovered the electron spin qubit with the longest ever lifetime too. They found an example that lasted for about 30 seconds in a nano-electric device.

Michelle Simmons, who led the study, said: "The combined results from these three research papers confirm the extremely promising prospects for building multi-qubit systems using our atom qubits."

In January, Simmons received the 2018 Australian of the Year award for her recent quantum computing breakthroughs. She said her work pays homage to famed physicist Richard Feynman.

In placing our phosphorus atoms in the silicon to make a qubit, we have demonstrated that we can use a scanning probe to directly measure the atom's wave function

"Feynman said: 'What I cannot create, I do not understand'. We are enacting that strategy systematically, from the ground up, atom by atom," said Simmons.

"In placing our phosphorus atoms in the silicon to make a qubit, we have demonstrated that we can use a scanning probe to directly measure the atom's wave function, which tells us its exact physical location in the chip.

"We are the only group in the world who can actually see where our qubits are."

In the latest study, the researchers said they "placed two qubits 16 nanometres apart in a silicon chip".

Matthew Broome, who also worked on the study, said: "Using electrodes that were patterned onto the chip with similar precision techniques, we were able to control the interactions between these two neighbouring qubits, so the quantum spins of their electrons became correlated.

"It was fascinating to watch. When the spin of one electron is pointing up, the other points down, and vice versa.

"This is a major milestone for the technology. These type of spin correlations are the precursor to the entangled states that are necessary for a quantum computer to function and carry out complex calculations."