QubiC 2.0: A Flexible Advanced Full Stack Quantum Bit Control System

Manipulating qubits and measuring quantum processors via quantum bit control systems is traditionally done using expensive, off-the-shelf commercial electronics setups. Previously, we have introduced QubiC, an open-source FPGA-based quantum bit control system developed at Lawrence Berkeley National Laboratory. After a few years of operating on the QubiC 1.0, we realized the urgent requirements on the mid-circuits measurement and feed forward to implement advanced quantum algorithms. This requirement led to engineering a novel QubiC 2.0 on top of the RFSoC technique, incorporating enriched features. The QubiC 2.0. presented in this manuscript is implemented on the Xilinx evaluation board ZCU216. We developed a portable FPGA gateware with a lean soft processor to handle the quantum commands on the fly. Further, we created a distributed architecture with multiple processors, with a one-to-one mapping between processors and qubits, creating a parallel qubit control and measurement. Like a regular CPU, these processors access pulse envelope commands with parameterized amplitude, phase, and frequency to generate pulse information on the FPGA to ensure the speed and reusability of the entire quantum circuit. The Python software layer abstracts the low-level gateware and provides the compiler, assembler, and remote procedure call for host-to-board communication. The compiled software runs on a Python runtime environment, interfacing with the low-level gateware and hardware connected to a Quantum Processing Unit, creating a full-stack quantum bit control system. We demonstrate the architecture and the broad capabilities of QubiC 2.0 with a simplified feed forward experiment on a conditional circuit.