Design-space exploration of fault-tolerant building blocks for large-scale quantum computing

In this paper, we present a design methodology for quantifying the role each building component of a logical fault-tolerant building block for quantum computers plays in the performance of the logical block. A logical building block is the set of operations necessary to execute a fault-tolerant circuit structure in quantum programs, such as the network of operations implementing a logical quantum bit. By analyzing the interaction between the algorithmic structure of a building block and the number of lower-level elements where faults are likely to occur, we can quantify the sensitivity of logical building blocks to two things: (1) to changes in the failure rates of the lower level elements comprising a proposed microarchitecture model, which are defined as logic gates, memory mechanisms, and data communication mechanisms; and (2) to transformation of the program structure for each building block through compilation techniques. We further show how this information can be used to develop optimized building blocks by inserting the gathered design constraints in our compilation mechanisms.