The implementation of a quantum router capable of performing both quantum signal routing and quantum addressing (a Q2-router) represents a key step toward building quantum networks and quantum random access memories. We realize a Q2-router that uses fixed-frequency transmon qubits to implement a routing protocol based on two native controlled-iSWAP gates. These gates leverage a large ZZ interaction to selectively route information according to a quantum address. We find an estimated average routing fidelity of 95.3%, with errors arising primarily from decoherence or state preparation and measurement. We present a comprehensive calibration and characterization of both the c-iSWAP gates and the overall routing protocol through randomized benchmarking techniques and state tomography.
@article{arxiv.2503.04295,
title = {Implementation of a quantum addressable router using superconducting qubits},
author = {Connie Miao and Sébastien Léger and Ziqian Li and Gideon Lee and Liang Jiang and David I. Schuster},
journal= {arXiv preprint arXiv:2503.04295},
year = {2025}
}