Quantum Optimal Control without Arbitrary Waveform Generators

TL;DR

This paper introduces a scalable quantum control method that uses simple on/off switching of control fields, designed via optimal control algorithms, reducing computational complexity and enhancing robustness for quantum computing applications.

Contribution

It presents a novel quantum control approach that eliminates the need for arbitrary waveform generators, simplifying implementation and improving scalability in quantum processors.

Findings

Control achieved by turning fields on/off in sequence

Reduced computational resources for control design

Demonstrated robustness in superconducting circuits

Abstract

Simple, precise, and robust control is demanded for operating a large quantum information processor. However, existing routes to high-fidelity quantum control rely heavily on arbitrary waveform generators that are difficult to scale up. Here, we show that arbitrary control of a quantum system can be achieved by simply turning on and off the control fields in a proper sequence. The switching instances can be designed by conventional quantum optimal control algorithms, while the required computational resources for matrix exponential can be substantially reduced. We demonstrate the flexibility and robustness of the resulting control protocol, and apply it to superconducting quantum circuits for illustration. We expect this proposal to be readily achievable with current semiconductor and superconductor technologies, which offers a significant step towards scalable quantum computing.