TL;DR: Bacon-Shor codes are subsystem codes that use fewer physical qubits than surface codes for the same code distance. They achieve O(d) overhead instead of O(d²) by using gauge qubits that don't need to
Bacon-Shor codes are subsystem codes that use fewer physical qubits than surface codes for the same code distance. They achieve O(d) overhead instead of O(d²) by using gauge qubits that don't need to be corrected. This makes them attractive for near-term systems with limited qubit counts, though their lower threshold means they require higher-fidelity gates.
Overhead
O(d) physical qubits per logical qubit (better than surface code's O(d²))
Threshold
~0.2% (lower than surface code)
Key Result
Lower qubit overhead than surface code; demonstrated on small systems