Deterministic remote entanglement using a chiral quantum interconnect (Part 1)

Quantum interconnects facilitate entanglement distribution between non-local computational nodes. For superconducting processors, microwave photons are a natural means to mediate this distribution. However, many existing architectures are constrained by limited node connectivity and lack of directionality. In this work, we construct a chiral quantum interconnect between two nominally identical modules in separate microwave packages. We leverage quantum interference to emit and absorb microwave photons on demand and in a chosen direction between these modules [1-3]. We optimize the protocol using model-free reinforcement learning to maximize absorption efficiency. By halting the emission process halfway through its duration, we generate remote entanglement between modules in the form of a four-qubit W state with 62.4 ± 1.6% (leftward photon propagation) and 62.1 ± 1.2% (rightward) fidelity, limited mainly by propagation loss. This quantum network architecture enables all-to-all connectivity between non-local processors for modular and extensible quantum computation. In part 1 of this series of talks, we will discuss current results.

[1] Gheeraert, N. et al. Phys. Rev. A 102, 053720 (2020)

[2] Kannan, B., Almanakly, A., et al. Nat. Phys. 19, 394–400 (2023).

[3] Almanakly, A., Yankelevich, B. et al. arXiv:2408.05164 (2024).