Quantum State Transfer via a Multimode Resonator

Large-scale fault-tolerant superconducting quantum computation needs rapid quantum communication to network qubits fabricated on different chips and long-range couplers to implement efficient quantum error correction codes. Quantum channels used for these purposes are best modeled by multimode resonators, which lie between single-mode cavities and waveguides with a continuum of modes. In this Letter, we propose a non-Markovian formalism for quantum state transfer using coupling strengths comparable to the channel's free spectral range (g∼Δ_{FSR}). Our scheme merges features of both the stimulated-Raman-adiabatic-passage-based methods for single-mode cavities and the pitch-and-catch protocol for long waveguides, integrating their advantages of low loss and high speed. It is immune to thermal channel occupations if using harmonic resonators for the sender and receiver.