Cost-effective Monitoring of Quantum Software Applications

量子计算机需要配备在其上运行的丰富可靠的软件栈，以充分发挥其解决实际问题的潜力。需要回答的一个基本问题是如何经济有效地确保量子软件的正确性和可靠性。监控对于验证软件质量和诊断软件错误至关重要。然而，监控量子软件是独特且具有挑战性的。例如，测量量子变量的状态（即，量子比特（quantum bits，或qubit）会将它们坍缩成经典比特，并破坏它们的量子特性，如叠加。此外，监控量子应用程序需要额外的计算和存储资源（即，量子位和在量子位上操作的量子门）。由于量子计算资源在可预见的未来仍然非常有限，因此确保监控不会引入太多的性能开销（例如，额外的量子位和操作）。该项目旨在通过研究可靠且具有成本效益的监控量子软件应用程序中间状态的方法来应对这些挑战。我们的第一个目标是设计可重复使用的量子监控组件，这些组件可以可靠地推断量子比特的状态，同时保持它们的保真度（即，最小化监控的功能影响）。我们的第二个目标是设计一个框架，以最佳方式将监控组件插入量子应用程序，以最大限度地减少监控对性能的影响。该项目的成果将为提高量子软件应用程序的可观测性提供机会，这反过来将有助于加拿大的量子计算研究人员和量子软件开发人员了解其应用程序的运行时行为，并有效地定位运行时错误。我们的项目将在确保量子软件应用的质量方面发挥重要作用，从而确保加拿大在量子计算方面的优势。

Quantum computers need to be equipped with a rich and reliable software stack running on top of them to reach their full potential in solving practical problems. A fundamental question that needs to be answered is how to cost-effectively ensure that quantum software is correct and reliable. Monitoring is essential to verify the quality of software and diagnose software errors. However, monitoring quantum software is unique and challenging. For example, measuring the states of quantum variables (i.e., quantum bits, or qubits) would collapse them into classical bits and destroy their quantum properties such as superposition. Additionally, monitoring a quantum application requires extra computing and storage resources (i.e., qubits and quantum gates that operate on the qubits). As quantum computing resources are and will continue to be very limited in the foreseeable future, it is critical to ensure that monitoring does not introduce too much performance overhead (e.g., extra qubits and operations). This project aims to address these challenges by investigating methods to reliably and cost-effectively monitor the intermediate states of quantum software applications. Our first goal is to design reusable quantum monitoring components that can reliably infer the states of qubits while preserving their fidelity (i.e., minimizing the functional impact of monitoring). Our second goal is to design a framework to optimally instrument the monitoring components into quantum applications to minimize the performance impact of monitoring. The outcomes of this project will provide opportunities to improve the observability of quantum software applications, which will in turn help quantum computing researchers and quantum software developers in Canada understand the runtime behaviors of their applications and effectively locate runtime errors. Our project will play an important part in assuring the quality of quantum software applications and hence, ensuring Canada's advantage in quantum computing.