Researchers broke a world record when a quantum state survived at room temperature for 39 minutes, paving the way for future ultrafast quantum computers.
In most of today's computers data is stored on a "string of ones and zeros." In this experiment "quibits" ("quantum bits of information") were put in a special "superposition" state which allowed them to be both one and zero at the same time, a University of Oxford news release reported.
The team raised the system ("in which information is encoded in the nuclei of phosphorus atoms in silicon") temperature from negative 269 degrees Celsius to 25 degrees, and found the superposition state allowed the quibits to survive for an impressive 39 minutes. The best time researchers had achieved in the past was only two seconds.
"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 phosphorus 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 [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.
The feat has exiting implications for the future.
"This opens up the possibility of truly long-term coherent information storage at room temperature," Mike Thewalt, who performed the test at Simon Fraser University, said.
The team encoded quantum information on the nuclei of phosphorous atoms contained in silicon. A property of the nuclei called "spin" acts as a "tiny bar magnet." These spins can be maneuvered to point up, which would represent zero; and down, which would represent one. It could also be manipulated to represent angles in between, which would result in the effective superposition.
The sample was prepared at negative 269 degrees Celsius and exposed to a magnetic field. The team used magnetic pulses to manipulate the "spins," resulting in the superposition state. The team found that when this temperature was maintained, the spins of around 37 percent of the ions were able to stay intact for about three hours. When the temperature was raised to 25 degrees they were able to stay in their superposition state for 39 minutes.
"These lifetimes are at least ten times longer than those measured in previous experiments,' Simmons said. 'We've managed to identify a system that seems to have basically no noise. They're high-performance qubits."
All of the spins were put in the same quantum state for the demonstration; in order to move forward the researchers will need to learn to place the quibits in different states.
These lifetimes are at least ten times longer than those measured in previous experiments," Simmons said.
