Scientists have demonstrated new behavior, a key breakthrough for building quantum computers.
For the first time, researchers were able to show in an experiment that different quantum computing pieces, taken together, were more accurate than the sum of their parts.
Individually, quantum computers are made up of a series of different pieces, some of which can sometimes break. But in the new experiment, scientists showed that pieces that are glued together may be less prone to error than a particular part.
Such behavior will be necessary if quantum computers are ever to be relied upon for practical purposes. Scientists suggest that the technology could one day change the world – by allowing us to perform calculations faster than ever before – but such fundamental work must first be done to make sure those calculations are reliable.
In the research, scientists took multiple qubits, or the quantum version of bits, and put them together into a single thing called a “logical qubit.” It was assembled so that it could easily detect and correct errors, as well as be able to tolerate defects so that any ill effects could be minimized.
This allowed scientists to show that the logical qubit was more reliable than the most error-prone part of the process of making it. It worked as expected 99.4 percent of the time, despite the fact that it relied on six separate quantum operations that only worked 98.9 percent of the time.
This small-visible difference would be a major improvement when produced in real computers: as quantum computers are scaled into larger and more practical machines, any errors will become complicated and can quickly reduce the usefulness of the computer. .
“Qubits made of identical atomic ions are basically very clean in their own right,” Christopher Monroe said. “However, at some point, when multiple qubits and operations are required, errors must be further reduced, and it is easier to add more qubits and encode the information differently.
“The beauty of error correction codes for atomic ions is that they can be very efficient and can be switched flexibly through software control.”
Like any other system, computers will eventually encounter errors. But in existing computer technologies, the system is able to monitor itself, getting rid of mistakes with sufficient accuracy that the results can be relied upon.
Kenneth Brown, a professor of electrical and computer engineering at Duke and a co-author on the paper, said, “The wonderful thing about fault tolerance is that it is a recipe for taking small unreliable parts and turning them into a very reliable device. ” “And fault-tolerant quantum error correction will enable us to build very reliable quantum computers out of faulty quantum parts.”
The study, ‘Fault-tolerant control of an error-corrected qubit’, is published today Nature.
Credit: www.independent.co.uk /