TECHNOLOGY TO FACILITATE THE USE OF NEAR-TERM QUANTUM COMPUTING HARDWARE

This topic is focused on specific technologies that are required to advance the state of quantum computing and networking. One focus is to facilitate effective implementation of gate-based quantum computing methods on quantum processors available or expected to be available within the next five years. The other focus is on the development and demonstration of a technique for ultra-low-loss integration of two or more quantum network components (for example, but not limited to, an entangled photon source and photon detector) to achieve a higher-level network function. Grant applications are sought in the following subtopics: a. Software for Calibration, Characterization, and Control of Quantum Processors Effective use of near-term quantum processors requires device-specific optimization of individual operations ranging from state preparation and measurement through gate implementation and compilation. Specialized techniques and tailored pulse sequences can suppress noise, mitigate crosstalk and control errors, and maintain optimally high-fidelity operations in the absence of formal error correction. In many cases, regular calibration and device characterization are necessary to ensure optimal performance. As algorithmic complexity and the size of qubit arrays grow, control software also increases in complexity. It is increasingly important to develop control software that combines knowledge of specific characteristics of a device, quantum algorithms, and high-efficiency optimization techniques. Grant applications are sought to develop and validate software tools for automated processor tune-up, characterization, calibration, and optimization of quantum processors; implementation of techniques for suppressing decoherence and mitigating errors; and automation of benchmarking and compiling protocols. Open source software solutions are strongly encouraged, as is testing the software solutions on fully transparent quantum computing platforms available in research laboratories. Grant applications focused on quantum annealing, analog simulation, or other non-gate-based approaches to quantum computing will be considered out of scope. Questions Contact: Claire Cramer, Claire.Cramer@science.doe.gov b. Ultra-Low-Loss Integration of Heterogeneous Quantum Internet Devices As quantum network devices continue to advance in capability, quantum networks are growing in scale increasing in range, number of users and architectural complexity. Eventually many local and regional quantum networks will merge to form the quantum internet. Operational losses of individual quantum network devices will compound as devices connect and the network grows larger. Today, foundational building blocks of the quantum internet are being developed using diverse technical approaches, many of which have benefits and merit exploration. These devices include, but are not limited to, quantum memories, entangled photon and single photon sources and detectors, quantum multiplexors, switches, frequency converters and transducers. Mechanisms of loss that arise from integration of heterogeneous quantum network devices become increasingly important to understand and mitigate as quantum networks scale. Today, quantum network devices are in early stages of development. Co-design of early-stage quantum network devices with ultra-low-loss, high-efficiency integration techniques will become increasingly essential as quantum networks scale. This topic requests development and demonstration of ultra-low-loss, highefficiency integration techniques that interface two or more quantum network devices with each other to create a hybrid device that provides a larger quantum network function. It is required that at least two or more quantum network devices be integrated. Both insertion loss between devices and data loss within a particular device contribute to the combined losses that the integrated quantum network device must be able to tolerate. This topic area is focused on reduction of insertion loss. In the narrative, please estimate the insertion loss in db that you expect your proposed integration technique to achieve. Also, please discuss the assumptions made to arrive at this estimated value of insertion loss and support the assertion that the expected insertion loss is low enough for the integrated quantum network device to function. Examples of integration include, but are not limited to, ultra-low-loss on-chip integration of two or more quantum network devices, or ultra-low-loss interconnection of two or more quantum network devices using optical fiber where ultra-low-loss fiber-coupling of at least one of the devices has not been previously demonstrated. The applicant is required to specify the quantum network devices that will be the focus of their integration efforts, and clearly describe the larger quantum network function that integration of these devices will achieve. Example component devices to be interfaced could be, but are not limited to, single or entangled photon sources and detectors. The proposed effort should include a systems-level engineering approach that harmonizes relevant operational properties of component devices to enable their ultra-low-loss, highefficiency integration.