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Quantum computers will be much faster than conventional ones. But their error rate is still too high. It’s hoped Google's new processing chip will improve their performance and make them ready for everyday use.
In some scientific fields, such as data encryption, drug and materials research or machine learning and artificial intelligence , conventional or "classical" computers have reached their limits. The calculations that researchers need in these fields are taking an infinitely long time to complete, or have become simply impossible. That's why researchers around the world are working to tap into the enormous potential of quantum computers — they could solve mathematical problems much faster than the fastest conventional computers.
What is special about quantum computers? The potential of current computing technology has been completely exhausted. Computers work with bits that know only two states: 1 for "on" and 0 for "off". Quantum bits , also known as qubits, on the other hand, can assume an infinite number of states.
As a result, quantum computers can calculate much faster , but are also more prone to errors. "Disturbances from the outside, such as thermal radiation or noise from the electronics, or from the inside, such as material defects" can cause calculation errors, according to Stefan Filipp, a professor in quantum computing at the Technical University of Munich (TUM). "Although these are now very small — one thousandth to one ten-thousandth of every operation goes wrong — they are not yet small enough [for quantum computers] to run sufficiently long algorithms, " says Filipp.
Quantum computers become reality To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video What has Google achieved with its ‘Willow' chip? The development of quantum computers is still in its infancy . Researchers are currently working with 100 qubits of computing power. Soon there will be 10,000 qubits, and 10,000,000 qubits are also conceivable in the future.
But the systems that have been developed so far are too small and make too many mistakes to deliver any real value. And their error rate tends to increase with additional computing power. Without a reliable way to correct such errors, quantum computers will be useless in the real-world .
Markus Müller, Professor of Theoretical Quantum Technology at RWTH Aachen University, said the Google team succeeded for the first time in achieving quantum error correction with error rates below a recognized threshold. That's led to their developing Willow. German computer scientist Hartmut Neven wrote in the journal Nature that with Willow, Google was paving the way for quantum computing to become common.
Neven is the founder and director of Google's Quantum Artificial Intelligence Laboratory. Will quantum computers arrive soon? The short answer is "no". While researchers in the field say Google has taken a significant step, Google concedes that Willow's error rate is still too high for quantum computing to be useful in an applied setting.
Willow consists of 105 superconducting qubits. That is less than 10% of the 1,457 physical qubits they say they need to achieve satisfactory error rates. Quantum computers become reality To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video "In order to ultimately be able to calculate virtually error-free and thus reliably, the error correction rate must increase faster than the error rate, " said Michael Hartmann, a professor of theoretical physics at the Friedrich Alexander University in Erlangen-Nürnberg.
"With the current quality of qubits, you will need 100,000 to one million qubits to be able to perform large, fault-tolerant calculations," said Hartmann. This shows, he said, how far quantum computing still has to travel. This article was translated from the original piece written in German Source: Neven H et al.
(2024): Quantum error correction below the surface code threshold. Nature. DOI: 10.
1038/s41586-024-08449-y ..
