Programmable photonic circuits of reconfigurable interferometers can be used to implement arbitrary operations on optical modes, facilitating a flexible platform for accelerating tasks in quantum simulation, signal processing, and artificial intelligence. A major obstacle scaling up these systems is static fabrication error, where small component errors within each device accrue produce signifi...

Fault-tolerant quantum computing will require accurate estimates of the resource overhead under different error correction strategies, but standard metrics such as gate fidelity and diamond distance have been shown to be poor predictors logical performance. We present a scalable experimental approach based on Pauli reconstruction predict performance concatenated codes. Numerical evidence demons...