Conditional displacement interaction in ultrastrong-coupling regime

Abstract: We investigate the realization of conditional displacement interaction in the transversal direction in ultrastrongly coupled circuit quantum electrodynamics by adjusting parameters of external magnetic fields. The special interaction is derived in the system of charge qubit(s) coupled to a LC resonator. We consolidate the implementation of quantum gates and the generation of superposed coherent states based on the transversal conditional displacement interaction numerically. The conditional displacement interaction in the ultrastrong coupling regime enhances quantum process to operate at the time scale of nanoseconds.