Quantum computers are very real, but because of the fragility of quantum information, they are still unable to do everything that normal computers do, faster. A team of researchers from the University of Sydney and Dartmouth College have found a way to make quantum information more reliable.
“In these superconducting systems, quantum information is only stored for 100 microseconds — tiny fractions of a second,” says Dr. Michael J. Birkuk, director of the quantum control laboratory at the University of Sydney School of Physics.
This breakdown of information is called decoherence. The problem occurs even when the information is in standby mode. Nevertheless, Birkuk and his colleagues found a way to preserve quantum information for several hours.
Quantum computation uses the unique properties of quantum particles, creating what is called “qubits”, to conduct operations. Researchers believe that this new generation of computers will one day be able to solve certain problems in fractions of a second, and in complexity they will surpass those that are allocated to the share of modern ones. In this direction, scientists have already achieved certain successes.
For example, not so long ago, Google and NASA bought a car created by the Canadian company D-Wave , which is one of the contenders for the role of creator of a working quantum computer. However, many scientists are skeptical about the company's statements, especially that D-Wave can surpass traditional computers - it’s difficult to even call it quantum. Others, like IBM, built a quantum computer on the basis of "paper" representations, but it did not pass the decoherence test.
“The construction of a large-scale quantum computer requires the need to store and process quantum information with a very low probability of error,” Birkuk notes. In other words, you need a reliable form of quantum memory.
Birkuk and the company solve the problem by using what is called a quantum repeater, which can "amplify" the signal represented by part of the quantum information. In the past, quantum repeaters were already created, but according to Birkuk, the new approach will be more reliable.
The Sydney-Dartmouth repeater is based on ytterbium ions. In the process of dynamic isolation, interference occurs, which negates errors. The concept had already been experimentally demonstrated earlier, but Birkuk experimentally found that the theoretical part of the model was limited by how often quantum information was activated. The new method allows you to access information stored in memory at any time without a chance to damage it.
Discoveries in the field of quantum memory continue. In March, a group from Yale found a way to make quantum information written at will, but read-only at any other time.
Birkuk notes that the new method will ultimately be compatible with other quantum computing techniques, including the aforementioned.
“Some improvements in superconductor technology will be needed to solve a rather unpleasant problem - energy relaxation,” he says. “But if this stage is overcome, there will be great hopes that our quantum repeaters may well be used in the quantum computers of the future.”
The article is based on materials .
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