Distributed Processor for FPGA-based Superconducting Qubit Control

Abstract

Quantum circuits utilizing real time feedback techniques (such as active reset and mid-circuit measurement) are a powerful tool for NISQ-era quantum computing. Such techniques are crucial for implementing error correction protocols, and can reduce the resource requirements of certain quantum algorithms. Realizing these capabilities requires flexible, low-latency classical control. We present the development of an open-source FPGA (field-programmable gate array) based processor for pulse-level qubit control. Our processor is designed primarily as an upgrade to QubiC, an open source qubit control platform, but can also be adapted to other systems. The processor is distributed in nature, with one core per arbitrary waveform generator (AWG); simplifying the design and allowing for straightforward scaling. Each processor core implements an instruction set consisting of timed pulse commands as well as simple arithmetic and branching instructions. Our design also includes interfaces for synchronizing the different cores and requesting/receiving (optionally processed) measurement results. Together, these features will allow a user to program arbitrary control flow within a quantum circuit based on previous measurement results. In this poster, we detail our design along with the expected resource utilization on the Xilinx Virtex 7 FPGA, and present pulse-level simulations of our system in the context of a simple feedback experiment.