Fast preparing W state via a chosen path shortcut in circuit QED

Abstract

We present a scheme of choosing a dressed state as an evolutive path to prepare three-superconducting qubit (SQ) W state. In the circuit quantum electrodynamics, there are three SQs trapped, respectively, in three coplanar waveguide resonators, which are coupled to a superconducting coupler qubit. With the help of quantum Zeno dynamics, we get the effective Hamiltonian of the system. Our strategy is adding two auxiliary pulses to the effective Hamiltonian. New driving pulses can cancel non-adiabatic transitions, so the whole system will evolve exactly along the chosen path. By setting boundary conditions, the W state can be obtained in a short time. Furthermore, in the chosen evolutive path state, the intermediate state’s population can be restricted by setting appropriate parameters, which is very useful for resisting the effects of dissipation. Numerical simulations indicate that the proposed scheme is robust against spontaneous emissions, dephasing, the cavity photon leakage and the parameter fluctuations.