System and Method for Quantum Computer Calibration and Performance Estimation

A system and method for characterizing noise in a quantum system includes determining pulse sequences for unitary twirling operations. Twirling processes are applied to a quantum system to calibrate errors and to determine channel parameters. Noise characteristics are determined from calibration data collected to calibrate the errors and to determine the channel parameters. The noise characteristics are characterized to determine if the noise is independent relaxation of qubits or collective relaxation of qubits.