A team of researchers has managed to keep quantum memory ‘coherent’ for 39 minutes at room temperature
A team from Simon Fraser University in British Columbia has managed to maintain a quantum memory ‘superposition’ state at room temperature for 39 minutes – almost 100 times longer than ever before.
Quantum computing systems are notoriously hard to work with, and usually require temperatures close to absolute zero, or −273 °C. However, the BBC reports that a team led by Mike Thewalt successfully kept the sample ‘coherent’ at 25 °C.
The previous record for a solid state quantum system at room temperature – 25 seconds – was held by Dr Thaddeus Ladd, formerly of Stanford University’s Quantum Information Science.
Long live the qubit
The reports are particularly interesting given that British Columbia is also the home of the world’s only commercial quantum computer company, D-Wave, which has sold some of its designs to clients including Google and NASA. D-Wave’s systems operate at very low temperatures – which is a major factor in their cost. They have experienced ongoing argument with academics about just how “quantum” they really are, but the company has a close relationship with the SFU quantum science department.
In this case, however, there’s no link between Thewalt’s work and D-Wave. “While we are discussing possible areas of collaboration with D-Wave, this result is not related to their effort,” Thewalt told TechWeekEurope. “Our study relates to the mainstream ‘gate-based’ type of quantum computation, while D-Wave is pursuing a different approach, called adiabatic, or quantum annealing, based quantum computation.”
Gate-based quantum computers offer a massive improvement over conventional computers because they make use of the fact that quantum systems exist in multiple states at the same time, an effect made famous by Schrodinger’s cat paradox, in which a cat sealed in a box away from all interactions can be simultaneously alive and dead.
They interact with information using quantum bits or ‘qubits’, which can mean both ‘1’ and’0’ simultaneously.
Quantum computers can process multiple inputs at the same time – effectively in parallel universes – and determine the right answer to problems which have a huge numbers of possible solutions, as long as their qubits can be kept in a coherent state, isolated from the outside world.
According to Thewalt, the latest experiment “opens the possibility of truly long-term storage of quantum information at room temperature.” The 39 minute half-life was achieved by magnetically encoding information into the nuclei of phosphorus atoms held in isotopically purified silicon.
As usual, the sample was prepared in the environment kept at -269 °C, but when it was raised to room temperature, the quibits maintained their properties. According to the team, the sample can also be cooled down again, increasing information coherence time to three hours.
Plenty of issues with quantum computing remain unsolved, but the experiment proves that the technology is slowly moving closer to being commercialised.
TechWeekEurope editor Peter Judge contributed to this story.
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