Physicists at Google have proven that errors can be completely eliminated in quantum computing.
A qubit is the smallest unit of information in a quantum computer and is analogous to a bit in a conventional computer, which is used for quantum computing. Any noise in the system destroys the states of the qubits and leads to errors.
A logical qubit can maintain a quantum state without destruction for an indefinitely long time, whereas today, in the same cryogenic installation Google Sycamore, noise destroys the quantum state of a qubit in about 15 μs.
In order to create a logical qubit that is reliable and suitable for programmable quantum computing, about 1,000 physical qubits are needed. And, most importantly, physicists have proven that the retention time of the quantum state of a logical qubit grows exponentially with the number of physical qubits per logical qubit.
During the experiment, it turned out that with 11 physical qubits per logical qubit, the probability of a quantum state confinement error after 50 μs was reduced from 40 to 0.2%.
However, it is not yet possible to simultaneously correct both types of errors: with random bit flips and with random phase flips.
This is planned to be eliminated using the so-called surface codes – two-dimensional matrices of logical and physical qubits. Surface codes promise to significantly reduce the need for physical qubits for error correction.