Mitigating Temporal Fragility in the XY Surface Code
The paper introduces a new state preparation protocol for XY surface codes that fixes fragile temporal boundaries. Standard methods suffer from symmetry loss, degrading performance to a 11% threshold under infinite bias noise. The new method uses local GHZ states before measurements, allowing half of the Y-stabilizers to be used for error detection, guaranteeing a 50% code capacity threshold during state preparation.