A potential quantum leap - Harvard Gazette

"The dream of creating game-changing quantum computers - supermachines that encode information in single atoms rather than conventional bits - has been hampered by the formidable challenge known as quantum error correction. In a paper published Monday in Nature, Harvard researchers demonstrated a new system capable of detecting and removing errors below a key performance threshold, potentially providing a workable solution to the problem. "For the first time, we combined all essential elements for a scalable, error-corrected quantum computation in an integrated architecture," said Mikhail Lukin, co-director of the Quantum Science and Engineering Initiative, Joshua and Beth Friedman University Professor, and senior author of the new paper. "These experiments - by several measures the most advanced that have been done on any quantum platform to date - create the scientific foundation for practical large-scale quantum computation.""

"In the new paper, the team demonstrated a "fault tolerant" system using 448 atomic quantum bits manipulated with an intricate sequence of techniques to detect and correct errors. The key mechanisms include physical entanglement, logical entanglement, logical magic, and entropy removal. For example, the system employs the trick of "quantum teleportation" - transferring the quantum state of one particle to another elsewhere without physical contact."

""There are still a lot of technical challenges remaining to get to very large-scale computer with millions of qubits, but this is the first time we have an architecture that is conceptually scalable," said lead author Dolev Bluvstein, Ph.D. '25, who did the research during his graduate studies at Harvard and is now an assistant professor at Caltech. "It's going to take a lot of effort and tech"

A system capable of detecting and removing quantum errors below a key performance threshold has been demonstrated. The system implements fault-tolerant operation across 448 atomic qubits using an intricate sequence of techniques to detect and correct errors. Key mechanisms include physical entanglement, logical entanglement, logical magic, entropy removal, and quantum teleportation to transfer quantum states without physical contact. The architecture is conceptually scalable toward much larger machines. Substantial technical challenges remain before reaching very large-scale computers with millions of qubits.

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