Deterministic remote entanglement using a chiral quantum interconnect

Abstract

Quantum interconnects facilitate entanglement distribution between non-local computational nodes in a quantum network. For superconducting processors, microwave photons are a natural means to mediate this distribution. However, many existing architectures limit node connectivity and directionality. In this work, we construct a chiral quantum interconnect between two nominally identical modules in separate microwave packages. Our approach uses quantum interference to emit and absorb microwave photons on demand and in a chosen direction between these modules. We optimize our protocol using model-free reinforcement learning to maximize the 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 approximately 62% fidelity in each direction, limited mainly by propagation loss. This quantum network architecture enables all-to-all connectivity between non-local processors for modular and extensible quantum simulation and computation.