Example Concept: Randomized benchmarking involves applying a sequence of random quantum gates followed by an inversion gate to return the system to its initial state. By varying the sequence length and measuring the fidelity, one can extract the average error rate of the gates. Gate set tomography provides a complete characterization of the gate set, including systematic errors, while cross-entropy benchmarking, often used in quantum supremacy experiments, measures the fidelity of complex circuits by comparing the output distribution to the ideal theoretical distribution.