The source article is pretty interesting: https://cloudblogs.microsoft.c...
From what I understand, it's using a hybrid approach of taking the physical qubit and moving it to a virtual (logical) qubit to reduce error rates.
This part caught my attention:
"Three fundamental criteria to advance from noisy, intermediate-scale quantum computing to reliable quantum computing are:
1) Achieve a large separation between logical and physical error rates.
2) Correct all individual circuit errors.
3) Generate entanglement between at least two logical qubits.
We have demonstrated, for the first time on record, that all three of the above criteria have been met. For the first criterion, we achieved an 800x improvement in logical error rate compared to the physical error rate. To quantify this 800x improvement, we entangled qubits and performed runtime error diagnostics and error corrections on the measurements (as seen in Figures 1 and 2), thus satisfying the second and third criteria.
In addition to meeting the three criteria above, we have demonstrated several rounds of active syndrome extraction on two logical qubits, which marks the transition to reliable quantum computing. This achievement is a prerequisite for building a hybrid classical-quantum supercomputer that outperforms even the most powerful classical computers."