QuEra, a pioneering startup, is on the verge of launching the world’s first commercial fault-tolerant quantum computer featuring “logical qubits,” a groundbreaking technology aimed at significantly reducing errors in quantum computing. Logical qubits, formed by connecting physical quantum bits (qubits) through quantum entanglement, mitigate errors by storing identical data in multiple locations, diversifying potential points of failure during computational processes.
Scheduled for a late 2024 debut, QuEra’s upcoming quantum computer boasts 256 physical qubits and 10 logical qubits. This development follows a recent study, published in the journal Nature on December 6, 2023, where QuEra researchers, alongside collaborators from various institutions, successfully demonstrated a functional quantum computer with 48 logical qubits—an unprecedented achievement in quantum error correction.
Harry Zhou, a physicist at QuEra and Harvard University and co-author of the study, highlighted the significance of this achievement as the first machine with quantum error correction. While the computational power of this quantum computer alone may not be substantial, it serves as a crucial platform for software programmers to commence testing code for future, more powerful quantum computers.
The Need for Quantum Error Correction: Quantum computers, unlike conventional computers using bits with fixed values of 0 or 1, utilize qubits that exist in a superposition between 0 and 1 due to quantum mechanics laws. Although qubits, connected through quantum entanglement, can perform calculations at remarkable speeds, their vulnerability to disturbances makes them prone to errors. Quantum computers experience a higher failure rate, approximately 1 in 1,000, compared to the exceptional reliability of conventional computers, which have a failure rate of 1 in 1 billion billion bits.
Logical Qubits: A Solution to Quantum Noise: The newly developed error-correction system relies on data redundancy, where the same data is stored in multiple locations. Logical qubits enable consistent calculations across various physical qubits, significantly reducing error rates in the event of physical qubit failures. By applying error-correcting computer code to regular qubits and establishing logical gates between them, researchers entangle the qubits, allowing the quantum computer to calculate a ‘syndrome’ that gauges the likelihood of errors. Using this information, the quantum computer corrects errors and proceeds with subsequent steps.
QuEra’s Remarkable Progress: QuEra’s error rate with 48 logical qubits stands at 0.5%, a noteworthy advancement compared to Google Quantum AI Lab’s 2.9% error rate using three logical qubits in 2023. While the University of Oxford leads with an error rate of less than 0.01% in two-qubit gates, QuEra’s achievements mark substantial progress.
Future Plans: QuEra plans a series of quantum computers in the coming years, starting with a 30-logical-qubit, 3,000-physical-qubit machine slated for release in 2025. The ambitious 2026 roadmap includes a quantum machine featuring more than 10,000 physical qubits and 100 logical qubits, capable of outperforming today’s supercomputers in correct calculations, according to Harry Zhou.
