Improving the performance of noisy quantum computers supporting qubit and qutrit operations

As fault-tolerance is not expected to become available in the immediate future, designing alternative methods to suppress noise in today's quantum computers is of timely importance. In this talk, we describe Noiseless Output Extrapolation (NOX), a recently developed error mitigation protocol that can significantly enhance the performance of noisy, intermediate-scale quantum devices. By leveraging efficient protocols for noise characterization, NOX can mitigate a wide range of noise processes that afflict the existing devices, such as crosstalk and gate-dependent noise. We demonstrate the effectiveness of NOX by testing it on various platforms of different sizes, the largest of which contains sixteen qubits. We also test NOX on a superconducting processor that supports operations on qutrits, performing one of the first error-mitigation experiments on three-level quantum systems. Our tests reveal the significant benefits of performing error mitigation on the available quantum computers, as well the challenges in performing it.