Implementation of a Quantum Switch with Superconducting Circuits: Part 2 - Experiment

A quantum switch (QSwitch) is a four-node quantum router that swaps a single photon between an input and two outputs based on a quantum address. In contrast to previous quantum routers, which require the output qubit to be classically selected, a QSwitch can route to a superposition of outputs. A QSwitch is a necessary component for building a quantum RAM (QRAM), as the gate that it enables forms the basis of the memory access operation upon which QRAM usage relies. In this talk, we present experimental updates on a QSwitch implemented using four fixed-frequency transmons. We will first discuss its circuit geometry and explain how our device is calibrated. We will then characterize and compare the performance of different implementations of the quantum routing protocol.