When will world's first stable quantum computer appear?

The world's first fault-tolerant quantum computer may appear before the end of 2024. The American startup QuEra from Harvard University plans to put it into operation. The quantum machine will receive 256 physical and 10 logical qubits. The latter reduces the number of errors in quantum computers by storing the same data in different places.

Stable quantum computers: What's the challenge?

According to LiveScience, conventional computers store information in bits with a value of 0 or 1, while quantum computers use qubits (quantum bits), in which, in addition to 0 and 1, there is a third value in the form of a superposition between them. This allows these computers to perform calculations in parallel rather than sequentially, as is the case with standard computers. And therefore quantum computers work much faster than standard ones.

But the problem is that qubits are extremely unstable compared to bits: about one in every 1,000 qubits fails, while the failure rate in conventional computers is 1 error in 1 billion billion bits. The high failure rate of qubits creates problems with their scaling.

Solution?

QuEra specialists managed to significantly reduce the error rate in qubits thanks to the so-called quantum correction. The system they propose is based on data redundancy, in which the same piece of information is stored in several places. Logical qubits duplicate computing processes, and if one of them fails, the others can continue computing.

In 2023, Google's Quantum AI Lab demonstrated an error rate of 2.9% using three logical qubits. QuEra goes even further: they have an error rate of 0.5% with 48 logical qubits. The world leader so far remains the University of Oxford, which has achieved an error level of less than 0.01%, but only between modules of two qubits.

In 2026, QuEra plans to launch a machine with more than 10,000 physical qubits and 100 logical qubits, with computing power expected to surpass any current supercomputer.