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-Stückelberg 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.
DOI: PhysRevB.82.144526
Shuang Xu and Yang Yu*
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
Guozhu Sun
Institute of Superconductor Electronics and Department of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
*yuyang@nju.edu.cn