Quantum leap


A team of physicists, including a member of the University’s Materials Department, have overcome a key barrier to the construction of ultra-fast quantum computers.

Stephanie Simmons, Junior Research Fellow at St John’s, was part of a team that sustained a normally fragile quantum state at room temperature for 39 minutes. The previous world record was around two seconds.

This is potentially a significant step for computing. Conventional computers store information as a series of 1s and 0s, but in the experiment quantum bits of information known as ‘quibits’ were put into a ‘superposition’ state in which they could be 1s and 0s at the same time, enabling the performance of multiple calculations simultaneously.

Simmons said: “Thirty-nine minutes may not seem very long, but as it only takes one-hundred-thousandth of a second to flip the nuclear spin of a phospurus ion – the type of operation used to run quantum calculations – in theory over two million operations could be applied in the time it takes for the superposition to naturally decay by 1%”.

Mike Thewalt of Simon Fraser University, also on the team, added: “This opens up the possibility of truly long-term coherent information storage at room temperature”.

The team have not yet discovered how to replicate these computations on a large scale. The nuclear spins of the phospurus ions used in this experiment were all placed in the same quantum state, but different quibits would have to be placed in different states in order to run quantum calculations.

“The last big remaining challenge”, said Simmons, “is to have them controllably talking to one another”.

Nathan King, undergraduate Physicist at Queen’s, spoke optimistically about the effect this research will have on the future of computing: “I think it’s fantastic that the University is carrying out research on an area that is this important to the development of technology; hopefully it won’t be long until quantum computers are up and running, which would be fantastic for use with future research and could potentially lead to a big leap forward in consumer electronics.”

A report of the research is published in this week’s journal Science.