Topologically Protected Synthesizing of Fock States in a Circuit Quantum Electrodynamics Architecture

The preparation of Fock states is important for quantum information storage and processing. Herein, a two-step protocol with topological protection for multi-photon Fock states synthesizing in a circuit quantum electrodynamics (QED) architecture is presented. Due to photon number-dependent vacuum Rabi splitting, the dynamics of the Jaynes-Cummings ladder in the resonant regime can be equivalent to a spin-1/2 chain while a multi-frequency microwave pulse is applied. Based on the topologically assisted quantum state transfer (QST)technique, multi-photon Fock states can be conditionally generated. This method significantly reduces the complexity of experimental manipulation compared with previous multi-step methods and is more robust as a result of topological protection. Furthermore, the protocol indicates that the circuit QED architecture could potentially provide a platform to explore the exotic phase in condensed matter. Mapping the Jaynes-Cummings ladder to a 1D spin-1/2 chain, multi-photon Fock states in circuit quantum electrodynamics (QED) are synthesized by topologically protected quantum state transfer (QST). Leveraging fast adiabatic passage achieves QST within sub-milliseconds to mitigate decoherence effects. In this study, potential applications in quantum optics, information, and simulation within circuit QED are showcased.image (c) 2024 WILEY-VCH GmbH