Communication and Control for Quantum Circuits

Communication and Control for Quantum Circuits by Yatish Patel Doctor of Philosophy in Computer Science University of California, Berkeley Professor John Kubiatowicz, Chair Quantum computers will potentially be able to solve certain classes of problems more efficiently than possible on a classical computer. Due to the fragility of quantum data, a large scale quantum computer will require a robust system to enable reliable communication within the datapath. We present a scalable architecture for a quantum computer which specifically addresses communication concerns. Our design minimizes communication error by using a specialized interconnection network to perform long-distance movement. We developed a set of tools to construct and study quantum datapath designs based on ion trap quantum technology. Our tools automatically synthesize and insert the interconnection network used for long-distance communication into the target datapath. We present a set of greedy heuristics to optimize the routing and scheduling of communication within this network and show that our approach performs as well as an optimal case determined using integer linear programming. We study a number of different quantum circuits including randomly generated circuits, quantum adder circuits, and ultimately Shor’s factorization algorithm and show that designs using our optimizations significantly improve upon prior work in terms of a probabilistic area delay metric.