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 limit node connectivity and 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. 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. A chiral quantum network comprising many modules provides a platform for the exploration of novel many-body physics and quantum simulation. This quantum network architecture enables all-to-all connectivity between non-local processors for modular and extensible quantum computation.
@article{arxiv.2408.05164,
title = {Deterministic remote entanglement using a chiral quantum interconnect},
author = {Aziza Almanakly and Beatriz Yankelevich and Max Hays and Bharath Kannan and Reouven Assouly and Alex Greene and Michael Gingras and Bethany M. Niedzielski and Hannah Stickler and Mollie E. Schwartz and Kyle Serniak and Joel I-J. Wang and Terry P. Orlando and Simon Gustavsson and Jeffrey A. Grover and William D. Oliver},
journal= {arXiv preprint arXiv:2408.05164},
year = {2025}
}