Scalable instrumentation for general purpose quantum computers

As quantum computers grow to increasing numbers of qubits, it becomes advantageous to use specialized or customized hardware to generate the microwave pulses that control the qubits. We present an FPGA-based system for controlling qubits that demonstrates a number of advantages over commercially available test equipment. The system has been optimized to minimize the noise sources to which the qubits are most susceptible, enabling high fidelity quantum gates. The overall architecture is designed to support hybrid quantum-classical algorithms. Optimized processor cores control the microwave signal generation and provide arbitrary control flow, allowing gates to be applied conditioned on a measurement result. Gate parameters, such as rotation angle, can also be dynamically computed, or loaded from classical shared memory, and applied in real-time. We present results from a straightforward usage of this capability: actively resetting a qubit to its ground state.