Scalability analysis for transmon-based quantum computers

Quantum computing has been envisioned to offer unprecedented advantages over conventional supercomputers in certain computational applications such as drug discovery and materials design. Despite of the tremendous developments in recent years, concerns about building a practical quantum computer persist. This Letter examines, from engineering viewpoint, the grand challenges to building such a machine based on the leading technology platform “transmon”. The examination leads to proposal of technological solutions to break the scalability barriers that originate from the physics behind the transmon design, thereby to enable giga-scale integration necessary for the promised applications.