  We present and validate a novel method for noise injection of arbitrary
spectra in quantum circuits that can be applied to any system capable of
executing arbitrary single qubit rotations, including cloud-based quantum
processors. As the consequences of temporally-correlated noise on the
performance of quantum algorithms are not well understood, the capability to
engineer and inject such noise in quantum systems is paramount. To date, noise
injection capabilities have been limited and highly platform specific,
requiring low-level access to control hardware. We experimentally validate our
universal method by comparing to a direct hardware-based noise-injection
scheme, using a combination of quantum noise spectroscopy and classical signal
analysis to show that the two approaches agree. These results showcase a highly
versatile method for noise injection that can be utilized by theoretical and
experimental researchers to verify, evaluate, and improve quantum
characterization protocols and quantum algorithms for sensing and computing.
