Quantum Memory Survives at Room Temperature for a World Record of 39 Minutes

For the first time, a normally fragile quantum memory state was maintained at room temperature for a world record of 39 minutes, smashing previous record of few seconds.  

A team of international physicists for the first time have shown a normally fragile quantum state surviving at room temperature for 39 minutes. They have created a quantum world record and have overcome a major barrier in building ultrafast quantum computers.

"39 minutes may not seem very long but as it only takes one-hundred-thousandth of a second to flip the nuclear spin of a phosphorus ion -- the type of operation used to run quantum calculations -- in theory over 2 million operations could be applied in the time it takes for the superposition to naturally decay by one percent. Having such robust, as well as long-lived, qubits could prove very helpful for anyone trying to build a quantum computer," Stephanie Simmons of Oxford University's Department of Materials, an author of the paper said in a statement.

This major breakthrough clearly indicates that storage of quantum bits of data referred as 'qubits' is possible even at a room temperature for a surprising length of time. An international team of physicists led by Mike Thewalt of Simon Fraser University, Canada, set this new benchmark.

Generally in the conventional computers, data is stored as a string of 1s and 0s. Whereas in the current experiment, physicists put the quantum bits of information (qubits) into a superposition state in which both 1s and 0s existed together at the same time.

"Quantum bits support an exponential amount of information, so this can give rise to an exponential speed-up in computation time," Simmons told LiveScience.

The major setback with qubits is their instability. That is they lose their memory in less than a second. Till date unofficial record for the previous solid state system ranged from 2-25 seconds at room temperature (three minutes under cryogenic conditions), according to BBC.

In the current experiment, the team prepared a sample in which encoded information in the nuclei of phosphorous atoms kept in a sliver of purified silicon, at a temperature ranging from -269 degree Celsius to 25 degree Celsius. The sample was placed in a magnetic field and magnetic field pulses were used to tilt the direction of the nuclear spin and create the superposition states.

On getting the temperature of the system to room temperature i.e. more than 25 degree Celsius, they noticed that the superposition states managed to survive for a world record of 39 minutes. Adding to this achievement, they also found that they could manipulate the qubits as the system's temperature increased.  Also, qubits were strong enough for the information to survive from being refrozen.

"This opens up the possibility of truly long-term coherent information storage at room temperature," said Mike Thewalt of Simon Fraser University.

This latest finding is a high performance qubits. The report was documented in the journal Science.