One major challenge has been that quantum computers can store or manipulate information incorrectly, preventing them from executing algorithms that are long enough to be useful. The new research from Google Quantum AI and its academic collaborators demonstrates that they can actually add components to reduce these errors. Previously, because of limitations in engineering, adding more components to the quantum computer tended to introduce more errors. Ultimately, the work bolsters the idea that error correction is a viable strategy toward building a useful quantum computer. Some critics had doubted that it was an effective approach, according to physicist Kenneth Brown of Duke University, who was not involved in the research.
“This error correction stuff really works, and I think it’s only going to get better,” wrote Michael Newman, a member of the Google team, on X. (Google, which posted the research to the preprint server arXiv in August, declined to comment on the record for this story.)
Quantum computers encode data using objects that behave according to the principles of quantum mechanics. In particular, they store information not only as 1s and 0s, as a conventional computer does, but also in “superpositions” of 1 and 0. Storing information in the form of these superpositions and manipulating their value using quantum interactions such as entanglement (a way for particles to be connected even over long distances) allows for entirely new types of algorithms.
In practice, however, developers of quantum computers have found that errors quickly creep in because the components are so sensitive. A quantum computer represents 1, 0, or a superposition by putting one of its components in a particular physical state, and it is too easy to accidentally alter those states. A component then ends up in a physical state that does not correspond to the information it’s supposed to represent. These errors accumulate over time, which means that the quantum computer cannot deliver accurate answers for long algorithms without error correction.
