Characterizing pulse distortions and crosstalks for superconducting qubits

Characterizing pulse distortions and crosstalks is essential to building scalable quantum computers. However, quantum chips are often operated at ultra low temperatures and insulated from the environment. This prevents one from direct characterizing the control electronics at the qubit level. We use superconducting qubits as a probe to estimate pulse distortions and crosstalks. Compared to former methods, ours does not require knowing a priori the qubit response as a function of the control pulse strengths. Moreover, its precision is not limited by the finite widths of the control pulses.