Researchers have proposed a novel four-level architecture for neutral-atom quantum computing that aims to overcome the limitations of short-range two-qubit gates. Traditionally, these gates rely on Rydberg blockade, which requires atom shuttling to achieve long-range connectivity. The new proposal integrates ground-state qubits, known for their long lifetimes, with Rydberg states that couple to a microwave cavity. This cavity-mediated coupling would enable the implementation of long-range quantum gates, a crucial advancement for the scalability of neutral-atom quantum computers.

The study analyzed the thermal dependence of two established gate protocols: the dispersive iSWAP gate, intrinsic to the Tavis-Cummings model, and a controlled-phase gate generated by driving the cavity. Simulations were performed considering factors such as Rydberg decay, thermal photons, and finite cavity linewidth, yielding fidelities that align with theoretical bounds. Furthermore, a bichromatic Raman gate was introduced, which, by virtually populating the Rydberg states, mitigates dispersive shifts and, consequently, atomic and cavity decay, achieving a fidelity of F = 0.997.

The application of this technology to a full optical tweezer array within a microwave cavity demonstrates a significant impact on quantum error correction. The authors show that using a cavity-mediated gate to close the periodic boundaries of the toric code reduces the time for an error correction round by a factor of 2.3 for realistic array sizes. This improvement extends to the broader family of bivariate bicycle codes, where a 4.8-fold reduction in round time is observed for the gross code, underscoring the potential of this architecture to enhance the efficiency and robustness of quantum systems.