Quantum Control System (QCS)

Introduction: Accelerating Quantum Innovation

The Keysight Quantum Control System comes with powerful and intuitive software that enables easy execution of textbook quantum experiments and the flexibility to quickly design and execute custom pulse sequences, all while automatically ensuring tight timing and synchronization.  

The software is controlled through the QCS API, a Python API that lets users program experiments at the level of their quantum device. To enable this, users create a system configuration file to define the mapping of their quantum system onto physical channels of the QCS. When this has been created, sequences or experiments can be written in terms of objects like qubits, couplers, and readout resonators.

This API leverages the FPGAs on the associated QCS hardware, enabling real-time performance and features without the need for complicated FPGA programming.

Quantum Configuration

Users can define the classical components, the quantum components, and the mapping between them in a configuration YAML file. The classical components consist of Instruments that correspond to Keysight PXIe modules in the QCS. The quantum components are the objects in the quantum processor that these Instruments control, such as Qubits, Readouts, and Couplers. 

Available instruments include:

• M5200A PXIe Digitizer 

• M5201A PXIe Down Converter 

• M5300A PXIe RF AWG

Available quantum components include:

• Tunable Qubit

• Tunable Coupler 

• Readout Resonator 

Additionally, the API is designed to be easily extensible to allow users to create or customize additional components to match the user’s unique system. When a new quantum component and its mapping to classical channels is defined, the software can use that component throughout the stack. 

Features 

The QCS software contains the following features.

• Quantum configuration file allows users to define mapping between quantum components and classical channels

• QCS API enables programmatic creation of experiments and pulse sequences

• Multiple backends allow easy switching setup, execution, and visualization of quantum sequences

• Separation of calibration parameters simplifies tune-up routines

• Tight integration with QCS hardware leverages FPGA acceleration and synchronization through the python API

Required Licenses

To use all features of the QCS SW detailed in this document, the one of the following licenses are required.

Conclusion

The Keysight Quantum Control System (QCS) provides a natural software interface for users to program quantum experiments. Pulse sequences are written in the languages of the qubits, couplers, and resonators rather than AWG and digitizer channels. This enables users to program at the level of their quantum hardware rather than worrying about the details of their classical instrumentation.