Microsoft, Atom Computing Leap Ahead On the Quantum Frontier With Logical Qubits

An anonymous reader quotes a report from GeekWire: Microsoft and Atom Computing say they've reached a new milestone in their effort to build fault-tolerant quantum computers that can show an advantage over classical computers. Microsoft says it will start delivering the computers' quantum capabilities to customers by the end of 2025, with availability via the Azure cloud service as well as through on-premises hardware. 'Together, we are co-designing and building what we believe will be the world's most powerful quantum machine,' Jason Zander, executive vice president at Microsoft, said in a LinkedIn posting.

Like other players in the field, Microsoft's Azure Quantum team and Atom Computing aim to capitalize on the properties of quantum systems -- where quantum bits, also known as qubits, can process multiple values simultaneously. That's in contrast to classical systems, which typically process ones and zeros to solve algorithms. Microsoft has been working with Colorado-based Atom Computing on hardware that uses the nuclear spin properties of neutral ytterbium atoms to run quantum calculations. One of the big challenges is to create a system that can correct the errors that turn up during the calculations due to quantum noise. The solution typically involves knitting together 'physical qubits' to produce an array of 'logical qubits' that can correct themselves.

In a paper posted to the ArXiv preprint server, members of the research team say they were able to connect 256 noisy neutral-atom qubits using Microsoft's qubit-virtualization system in such a way as to produce a system with 24 logical qubits. 'This represents the highest number of entangled logical qubits on record,' study co-author Krysta Svore, vice president of advanced quantum development for Microsoft Azure Quantum, said today in a blog posting. 'Entanglement of the qubits is evidenced by their error rates being significantly below the 50% threshold for entanglement.' Twenty of the system's logical qubits were used to perform successful computations based on the Bernstein-Vazirani algorithm, which is used as a benchmark for quantum calculations. 'The logical qubits were able to produce a more accurate solution than the corresponding computation based on physical qubits,' Svore said. 'The ability to compute while detecting and correcting errors is a critical component to scaling to achieve scientific quantum advantage.'

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