Abstract: Computer systems and methods for estimating errors for a quantum system comprising a set of n qubits are provided in which is the projective n-qubit Pauli group for the quantum system, and n is a fixed integer of three or greater. At least a first and second subset of Pauli matrices are identified. The Pauli fidelities f1 of the first subset of Pauli fidelities are estimated. The fixed probability distribution ?2 for the second subset of Pauli matrices are reconstructed using the Pauli fidelities f1 of the first subset of Pauli matrices, thereby estimating errors for the quantum system.

Abstract: In a general aspect, randomized compiling techniques for quantum computing are described. In some aspects, an initial quantum-logic gate sequence is received. A modified quantum-logic gate sequence is generated by applying virtual random gates to the initial quantum-logic gate sequence, such that the initial quantum-logic gate sequence is logically equivalent to the modified quantum-logic gate sequence. The modified quantum-logic gate sequence can be provided to a quantum information processor for execution.

Abstract: Systems and methods for executing a quantum computation comprising a plurality gates on a quantum information processor are provided. An initial quantum-logic gate sequence comprising the plurality of gates is received. Then, for each instance in a plurality of instances, a procedure is performed. In each instance of the procedure a respective modified quantum-logic gate sequence is generated by applying a virtual random gate to a first single-qubit gate in the plurality of gates. The respective modified quantum-logic gate sequence is then executed on the quantum device to obtain a respective outcome. The respective outcome across the plurality of instances of the procedure is averaged to obtain a noise-tailored outcome for the initial quantum-logic gate sequence.