  We propose simple protocols for performing quantum noise spectroscopy based
on the method of transfer tensor maps (TTM), [Phys. Rev. Lett. 112, 110401
(2014)]. The TTM approach is a systematic way to deduce the memory kernel of a
time-nonlocal quantum master equation via quantum process tomography. With
access to the memory kernel it is possible to (1) assess the non-Markovianity
of a quantum process, (2) reconstruct the noise spectral density beyond pure
dephasing models, and (3) investigate collective decoherence in multiqubit
devices. We illustrate the usefulness of TTM spectroscopy on the IBM Quantum
Experience platform, and demonstrate that the qubits in the IBM device are
subject to mild non-Markovian dissipation with spatial correlations.
