1. A method for characterizing noise in a quantum system, comprising: determining pulse sequences for unitary twirling operations; applying twirling processes to a quantum system to calibrate errors; applying twirling processes to the quantum system to determine channel parameters; determining noise characteristics from calibration data collected to calibrate the errors and to determine the channel parameters; and characterizing the noise characteristics to determine if the noise is independent relaxation of qubits or collective relaxation of qubits.