How to experimentally evaluate the adiabatic condition for quantum annealing*

We have proposed an experimental method for evaluating the adiabatic condition during quantum annealing (QA). Ordinarily, the adiabatic condition is given by an equation involving the transition matrix element and the energy gap, and our method simultaneously provides these components without diagonalizing the Hamiltonian. The key idea is to measure the power spectrum of a time domain signal by adding an oscillating field during QA, and we evaluate these values of the transition matrix element and energy gap from the measurement output. Our results will provide a powerful experimental basis for analyzing the performance of QA.