Implementation of a Quantum Switch with Superconducting Circuits

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 swap gate that it enables forms the basis of the memory access operation upon which QRAM usage relies. In this talk, we present a QSwitch implemented using four transmons, which to our knowledge is the first experimental demonstration of a QSwitch on any qubit platform. We discuss our memory access gate simulations, which predict a high fidelity operation. We then present our experimental realization of the QSwitch, including its circuit geometry and characterizations of its performance.