Simultaneous excitation of two atoms by a single photon using shortcut to adiabaticity

Abstract In this paper, we propose a protocol to accelerate a weak nonlinear quantum process: a single photon simultaneously excites two atoms using shortcut to adiabaticity. We consider a physical model composed of a transmission-line resonator and two flux qubits, where the frequency of the resonator is approximately equal to the sum of the frequencies of the two qubits. Using unitary transformation and a series of approximate methods, the system can be reduced to an equivalent two-level model. Since this transition is a weak high-order process, it is relatively sensitive to errors and decoherence. To overcome the flaws, we use the shortcut to adiabaticity method based on Lewis–Riesenfeld invariant for inverse engineering of the effective Hamiltonian, so that the transition rate can be accelerated. The robustness of the system against noise and decoherence can be improved. Therefore, the protocol we proposed can be applicable to quantum information processing and quantum optics in the microwave regime.