Quantum Computing with an Open Source Qubit Controller

Abstract

A useful quantum computer requires a full stack of components, where each layer in the stack can actually scale. In this thesis we go through each layer of the quantum computing stack, from the bottom to the top. First, we discuss planar tantalum transmon qubit fabrication. We iterate on the design and fabrication of an entangling gate module with two fixed-frequency transmon qubits and a tunable coupler. We share our perspective on making a robust parametric entangling gate architecture for planar superconducting qubits. Next, we introduce the QICK (Quantum Instrumentation Control Kit), which is a standalone open source controller for both superconducting and atomic qubits as well as various detectors. Highly integrated open source firmware and software has been designed to allow the QICK to scale to hundreds of qubits. We develop the QICK for the superconducting qubit platform and use it to conduct the first single and multi-qubit experiments. Finally, we develop two modular simulation frameworks---one for a multinode quantum computer, and one for heterogeneous qubit architectures.