Landau-Zener-Stückelberg spectroscopy of a superconducting flux qubit

We proposed a different method to measure the energy spectrum of a superconducting flux qubit. Different from the conventional frequency spectroscopy, a linear triangle pulse was used to drive the qubit through the anticrossing and to generate Landau-Zener-St\"uckelberg interference patterns, from which the information of the energy spectrum can be extracted. This method facilitates the spectroscopy in regimes of very large energies. Moreover, without installing microwaves lines one can simplify the experimental setup and reduce the unwanted effects of noise. The idea can be applied to other quantum systems as well, opening the possibility of calibrating and manipulating qubits with linear pulses.