The Canadian company Nord Quantique published an article on the arXiv website in which it announced the creation of an alternative qubit architecture. The value of the development is that each logical qubit involved in calculations can be represented by just one physical qubit. All errors arising in the process are corrected by itself without the involvement of other physical qubits, which opens the way to mass quantum computers.
Nord Quantique is a subsidiary of the Department of Quantum Physics at the University of Sherbrooke, one of the leading centers for quantum research in Canada. This presupposes a strong theoretical basis for the company’s developments in addition to the ability to produce equipment at the Sherbrooke plant. Nord Quantique created its “alternative” qubit in one copy. The article and work are based on testing its work outside the framework of calculations, which will begin towards the end of this year.
Interestingly, the Canadians have actually turned on its head the architecture long used in quantum computers by IBM and Google in the form of so-called transmonium superconducting qubits. The qubits in IBM and Google computers store information in a superconducting loop and are controlled by a microwave cavity in which microwave photons are delayed for some time. The Nord Quantique qubit, by contrast, stores information—quantum states—in microwave photons trapped in resonators, and a superconducting loop controls its state.
The trick is that you can fire an excess number of photons into the cavity. The more there are, the less likely an error will occur. Redundancy is a well-tested and proven way to reduce errors and is widely used in conventional computing.
Nord Quantique’s work showed that the proposed qubit architecture reduced the probability of error by 14%. Unfortunately, overall accuracy is still low and starts at around 85%, which is significantly lower than other systems that have been in development for many years. And yet, in some cases, the bosonic qubit, as Nord Quantique called it, showed an accuracy of 99%. In other words, it has prospects if the company begins to quickly catch up with its competitors.
It would be tempting to see large-scale applications of the Nord Quantique qubit. For IBM and Google qubits, error-free qubit operation means that each logical qubit must be made up of 1000 physical qubits. For a Nord Quantique logical qubit, you need only one physical qubit, or at least tens, not thousands of all these loops, resonators, coaxial connectors and other little things, which on a scale represent what we see in modern photographs of quantum systems: huge chrome chandeliers.
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