Nonadiabatic Population Transfer In Two‐Level Non‐Hermitian Systems

ABSTRACT In this study, nonadiabatic population transfer was successfully achieved in a two‐level non‐Hermitian system with non‐conjugation complex Rabi frequencies and a real geometric phase along the superposition of ancillary basis states, by means of the ancillary picture and Lewis‐Riesenfeld (LR) invariant theory. Compared with the quantum adiabatic process, the core advantage of this scheme lies in that the inherent high‐speed characteristic of nonadiabatic evolution can avoid non‐targeted transitions, thus overcoming the limitations of traditional nonadiabatic processes. The Hamiltonian of the system was derived based on the laws of non‐unitary evolution. Time‐dependent complex pulses can be effectively regulated by adjusting control parameters; in the nonadiabatic population transfer process, the target pulses can be obtained simply by determining the relevant parameters in the non‐unitary evolution. Through the analysis of system dynamics via the ancillary picture and LR invariant theory, and verification by numerical simulations, it is shown that population inversion (the core characteristic of nonadiabatic population transfer) exhibits strong anti‐interference ability against system errors. In conclusion, this scheme provides a feasible approach for realizing high‐fidelity nonadiabatic population transfer in the aforementioned two‐level non‐Hermitian system.