A Quantum Computational Compiler and Design Tool for Technology-Specific Targets

Quantum computing, once just a theoretical field, is quickly advancing as physical quantum technology increases in size, capability, and reliability. In order to fully harness the power of a general quantum computer or an application-specific device, compilers and tools must be developed that optimize specifications and map them to a realization on a specific architecture. In this work, a technique and prototype tool for synthesizing algorithms into a quantum computer is described and evaluated. Most recently reported methods produce technologically-independent reversible cascades comprised of a functionally complete set of operators with no regard to actual technologically-dependent cell libraries or constraints due to a device's pre-configured interconnectivity. In contrast, our prototype tool synthesizes algorithms into technologically-dependent specifications that consist of a set of primitives and connectivity constraints present in the computer architecture. The tool performs optimizations based on actual architectural constraints, and a high-quality technology-dependent synthesized result is achieved through the use of optimizing cost functions derived from real hardware and architecture parameters. Additionally, another important aspect of our tool is the incorporation of internal formal equivalence checking that ensures the initially specified algorithm is functionally equivalent to the optimized, technologically-mapped output. Experimental results are provided that target the IBM Q family of quantum computers.