Hybrid Six-Level Rydberg Atomic Quantum Receiver for Multi-Band RF Communication

Rydberg atomic receivers have recently emerged as a promising platform for radio-frequency (RF) sensing and reception due to their intrinsic broadband response and calibration-free operation. Most existing receivers rely on four-level ladder-type electromagnetically induced transparency (EIT) schemes, which limit the number of simultaneously accessible RF transitions within a given atomic manifold. In this paper, a six-level hybrid Rydberg atomic quantum receiver (H-RAQR) architecture is proposed that combines cascaded and parallel RF coupling pathways to enable simultaneous multi-band RF reception within a single vapor-cell platform. A physically consistent system and electromagnetic coupling model is developed, and a steady-state analytical expression for the probe coherence is derived, establishing a direct relationship between the incident RF fields and the optical probe transmission. The analytical model is validated through numerical simulations of the Lindblad master equation with realistic relaxation and detuning parameters. Using the resulting communication signal representation, the achievable ergodic sum-rate performance of the receiver is evaluated. Numerical results demonstrate that the proposed hybrid architecture enables four simultaneous RF channels within the same six-level system and achieves higher throughput than conventional cascade Rydberg state (CRS) and parallel Rydberg state (PRS) receivers. These results demonstrate the potential of hybrid Rydberg receiver architectures for scalable multi-channel RF sensing and communication systems.